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authorErik Johnston <erik@matrix.org>2016-08-05 11:15:48 +0100
committerErik Johnston <erik@matrix.org>2016-08-05 11:15:48 +0100
commit499dc1b349988e23ab26f829b2005f617134e6c0 (patch)
tree866dec5ab910b42fd22b5826721c0ec7f8ad7cff
parentBump version and changelog (diff)
parentMerge pull request #986 from matrix-org/erikj/state (diff)
downloadsynapse-499dc1b349988e23ab26f829b2005f617134e6c0.tar.xz
Merge branch 'develop' of github.com:matrix-org/synapse into release-v0.17.0
-rw-r--r--MANIFEST.in2
-rwxr-xr-xjenkins-dendron-postgres.sh92
-rwxr-xr-xjenkins-postgres.sh59
-rwxr-xr-xjenkins-sqlite.sh54
-rwxr-xr-xjenkins/clone.sh44
-rwxr-xr-xjenkins/prepare_synapse.sh19
-rw-r--r--scripts-dev/federation_client.py1
-rwxr-xr-xscripts/synapse_port_db175
-rw-r--r--synapse/federation/federation_client.py113
-rw-r--r--synapse/federation/federation_server.py43
-rw-r--r--synapse/federation/transport/client.py22
-rw-r--r--synapse/federation/transport/server.py16
-rw-r--r--synapse/handlers/device.py2
-rw-r--r--synapse/handlers/e2e_keys.py139
-rw-r--r--synapse/rest/client/v2_alpha/keys.py50
-rw-r--r--synapse/rest/media/v1/preview_url_resource.py86
-rw-r--r--synapse/server.py45
-rw-r--r--synapse/server.pyi4
-rw-r--r--synapse/storage/end_to_end_keys.py60
-rw-r--r--synapse/storage/events.py116
-rw-r--r--synapse/storage/schema/delta/33/devices_for_e2e_keys.sql2
-rw-r--r--synapse/storage/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql20
-rw-r--r--tests/handlers/test_e2e_keys.py46
-rw-r--r--tests/storage/test_end_to_end_keys.py90
-rw-r--r--tests/test_preview.py139
25 files changed, 1070 insertions, 369 deletions
diff --git a/MANIFEST.in b/MANIFEST.in
index 216df265b5..981698143f 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -24,5 +24,7 @@ recursive-include synapse/static *.js
 
 exclude jenkins.sh
 exclude jenkins*.sh
+exclude jenkins*
+recursive-exclude jenkins *.sh
 
 prune demo/etc
diff --git a/jenkins-dendron-postgres.sh b/jenkins-dendron-postgres.sh
index f715cd559a..68912a8967 100755
--- a/jenkins-dendron-postgres.sh
+++ b/jenkins-dendron-postgres.sh
@@ -4,85 +4,19 @@ set -eux
 
 : ${WORKSPACE:="$(pwd)"}
 
+export WORKSPACE
 export PYTHONDONTWRITEBYTECODE=yep
 export SYNAPSE_CACHE_FACTOR=1
 
-# Output test results as junit xml
-export TRIAL_FLAGS="--reporter=subunit"
-export TOXSUFFIX="| subunit-1to2 | subunit2junitxml --no-passthrough --output-to=results.xml"
-# Write coverage reports to a separate file for each process
-export COVERAGE_OPTS="-p"
-export DUMP_COVERAGE_COMMAND="coverage help"
-
-# Output flake8 violations to violations.flake8.log
-# Don't exit with non-0 status code on Jenkins,
-# so that the build steps continue and a later step can decided whether to
-# UNSTABLE or FAILURE this build.
-export PEP8SUFFIX="--output-file=violations.flake8.log || echo flake8 finished with status code \$?"
-
-rm .coverage* || echo "No coverage files to remove"
-
-tox --notest -e py27
-
-TOX_BIN=$WORKSPACE/.tox/py27/bin
-python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
-$TOX_BIN/pip install psycopg2
-$TOX_BIN/pip install lxml
-
-: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
-
-if [[ ! -e .dendron-base ]]; then
-    git clone https://github.com/matrix-org/dendron.git .dendron-base --mirror
-else
-    (cd .dendron-base; git fetch -p)
-fi
-
-rm -rf dendron
-git clone .dendron-base dendron --shared
-cd dendron
-
-: ${GOPATH:=${WORKSPACE}/.gopath}
-if [[ "${GOPATH}" != *:* ]]; then
-  mkdir -p "${GOPATH}"
-  export PATH="${GOPATH}/bin:${PATH}"
-fi
-export GOPATH
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
-
-go get github.com/constabulary/gb/...
-gb generate
-gb build
-
-cd ..
-
-
-if [[ ! -e .sytest-base ]]; then
-  git clone https://github.com/matrix-org/sytest.git .sytest-base --mirror
-else
-  (cd .sytest-base; git fetch -p)
-fi
-
-rm -rf sytest
-git clone .sytest-base sytest --shared
-cd sytest
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
-
-: ${PORT_BASE:=20000}
-: ${PORT_COUNT=100}
-
-./jenkins/prep_sytest_for_postgres.sh
-
-mkdir -p var
-
-echo >&2 "Running sytest with PostgreSQL";
-./jenkins/install_and_run.sh --python $TOX_BIN/python \
-                             --synapse-directory $WORKSPACE \
-                             --dendron $WORKSPACE/dendron/bin/dendron \
-                             --pusher \
-                             --synchrotron \
-                             --federation-reader \
-                             --port-range ${PORT_BASE}:$((PORT_BASE+PORT_COUNT-1))
-
-cd ..
+./jenkins/prepare_synapse.sh
+./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
+./jenkins/clone.sh dendron https://github.com/matrix-org/dendron.git
+./dendron/jenkins/build_dendron.sh
+./sytest/jenkins/prep_sytest_for_postgres.sh
+
+./sytest/jenkins/install_and_run.sh \
+    --synapse-directory $WORKSPACE \
+    --dendron $WORKSPACE/dendron/bin/dendron \
+    --pusher \
+    --synchrotron \
+    --federation-reader \
diff --git a/jenkins-postgres.sh b/jenkins-postgres.sh
index 7a43df0d58..f2ca8ccdff 100755
--- a/jenkins-postgres.sh
+++ b/jenkins-postgres.sh
@@ -4,61 +4,14 @@ set -eux
 
 : ${WORKSPACE:="$(pwd)"}
 
+export WORKSPACE
 export PYTHONDONTWRITEBYTECODE=yep
 export SYNAPSE_CACHE_FACTOR=1
 
-# Output test results as junit xml
-export TRIAL_FLAGS="--reporter=subunit"
-export TOXSUFFIX="| subunit-1to2 | subunit2junitxml --no-passthrough --output-to=results.xml"
-# Write coverage reports to a separate file for each process
-export COVERAGE_OPTS="-p"
-export DUMP_COVERAGE_COMMAND="coverage help"
+./jenkins/prepare_synapse.sh
+./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
 
-# Output flake8 violations to violations.flake8.log
-# Don't exit with non-0 status code on Jenkins,
-# so that the build steps continue and a later step can decided whether to
-# UNSTABLE or FAILURE this build.
-export PEP8SUFFIX="--output-file=violations.flake8.log || echo flake8 finished with status code \$?"
+./sytest/jenkins/prep_sytest_for_postgres.sh
 
-rm .coverage* || echo "No coverage files to remove"
-
-tox --notest -e py27
-
-TOX_BIN=$WORKSPACE/.tox/py27/bin
-python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
-$TOX_BIN/pip install psycopg2
-$TOX_BIN/pip install lxml
-
-: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
-
-if [[ ! -e .sytest-base ]]; then
-  git clone https://github.com/matrix-org/sytest.git .sytest-base --mirror
-else
-  (cd .sytest-base; git fetch -p)
-fi
-
-rm -rf sytest
-git clone .sytest-base sytest --shared
-cd sytest
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
-
-: ${PORT_BASE:=20000}
-: ${PORT_COUNT=100}
-
-./jenkins/prep_sytest_for_postgres.sh
-
-echo >&2 "Running sytest with PostgreSQL";
-./jenkins/install_and_run.sh --coverage \
-                             --python $TOX_BIN/python \
-                             --synapse-directory $WORKSPACE \
-                             --port-range ${PORT_BASE}:$((PORT_BASE+PORT_COUNT-1)) \
-
-cd ..
-cp sytest/.coverage.* .
-
-# Combine the coverage reports
-echo "Combining:" .coverage.*
-$TOX_BIN/python -m coverage combine
-# Output coverage to coverage.xml
-$TOX_BIN/coverage xml -o coverage.xml
+./sytest/jenkins/install_and_run.sh \
+    --synapse-directory $WORKSPACE \
diff --git a/jenkins-sqlite.sh b/jenkins-sqlite.sh
index 27e61af6ee..84613d979c 100755
--- a/jenkins-sqlite.sh
+++ b/jenkins-sqlite.sh
@@ -4,56 +4,12 @@ set -eux
 
 : ${WORKSPACE:="$(pwd)"}
 
+export WORKSPACE
 export PYTHONDONTWRITEBYTECODE=yep
 export SYNAPSE_CACHE_FACTOR=1
 
-# Output test results as junit xml
-export TRIAL_FLAGS="--reporter=subunit"
-export TOXSUFFIX="| subunit-1to2 | subunit2junitxml --no-passthrough --output-to=results.xml"
-# Write coverage reports to a separate file for each process
-export COVERAGE_OPTS="-p"
-export DUMP_COVERAGE_COMMAND="coverage help"
+./jenkins/prepare_synapse.sh
+./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
 
-# Output flake8 violations to violations.flake8.log
-# Don't exit with non-0 status code on Jenkins,
-# so that the build steps continue and a later step can decided whether to
-# UNSTABLE or FAILURE this build.
-export PEP8SUFFIX="--output-file=violations.flake8.log || echo flake8 finished with status code \$?"
-
-rm .coverage* || echo "No coverage files to remove"
-
-tox --notest -e py27
-TOX_BIN=$WORKSPACE/.tox/py27/bin
-python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
-$TOX_BIN/pip install lxml
-
-: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
-
-if [[ ! -e .sytest-base ]]; then
-  git clone https://github.com/matrix-org/sytest.git .sytest-base --mirror
-else
-  (cd .sytest-base; git fetch -p)
-fi
-
-rm -rf sytest
-git clone .sytest-base sytest --shared
-cd sytest
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
-
-: ${PORT_BASE:=20000}
-: ${PORT_COUNT=100}
-
-./jenkins/install_and_run.sh --coverage \
-                             --python $TOX_BIN/python \
-                             --synapse-directory $WORKSPACE \
-                             --port-range ${PORT_BASE}:$((PORT_BASE+PORT_COUNT-1)) \
-
-cd ..
-cp sytest/.coverage.* .
-
-# Combine the coverage reports
-echo "Combining:" .coverage.*
-$TOX_BIN/python -m coverage combine
-# Output coverage to coverage.xml
-$TOX_BIN/coverage xml -o coverage.xml
+./sytest/jenkins/install_and_run.sh \
+    --synapse-directory $WORKSPACE \
diff --git a/jenkins/clone.sh b/jenkins/clone.sh
new file mode 100755
index 0000000000..ab30ac7782
--- /dev/null
+++ b/jenkins/clone.sh
@@ -0,0 +1,44 @@
+#! /bin/bash
+
+# This clones a project from github into a named subdirectory
+# If the project has a branch with the same name as this branch
+# then it will checkout that branch after cloning.
+# Otherwise it will checkout "origin/develop."
+# The first argument is the name of the directory to checkout
+# the branch into.
+# The second argument is the URL of the remote repository to checkout.
+# Usually something like https://github.com/matrix-org/sytest.git
+
+set -eux
+
+NAME=$1
+PROJECT=$2
+BASE=".$NAME-base"
+
+# Update our mirror.
+if [ ! -d ".$NAME-base" ]; then
+  # Create a local mirror of the source repository.
+  # This saves us from having to download the entire repository
+  # when this script is next run.
+  git clone "$PROJECT" "$BASE" --mirror
+else
+  # Fetch any updates from the source repository.
+  (cd "$BASE"; git fetch -p)
+fi
+
+# Remove the existing repository so that we have a clean copy
+rm -rf "$NAME"
+# Cloning with --shared means that we will share portions of the
+# .git directory with our local mirror.
+git clone "$BASE" "$NAME" --shared
+
+# Jenkins may have supplied us with the name of the branch in the
+# environment. Otherwise we will have to guess based on the current
+# commit.
+: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
+cd "$NAME"
+# check out the relevant branch
+git checkout "${GIT_BRANCH}" || (
+    echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop"
+    git checkout "origin/develop"
+)
diff --git a/jenkins/prepare_synapse.sh b/jenkins/prepare_synapse.sh
new file mode 100755
index 0000000000..237223c81b
--- /dev/null
+++ b/jenkins/prepare_synapse.sh
@@ -0,0 +1,19 @@
+#! /bin/bash
+
+cd "`dirname $0`/.."
+
+TOX_DIR=$WORKSPACE/.tox
+
+mkdir -p $TOX_DIR
+
+if ! [ $TOX_DIR -ef .tox ]; then
+    ln -s "$TOX_DIR" .tox
+fi
+
+# set up the virtualenv
+tox -e py27 --notest -v
+
+TOX_BIN=$TOX_DIR/py27/bin
+python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
+$TOX_BIN/pip install lxml
+$TOX_BIN/pip install psycopg2
diff --git a/scripts-dev/federation_client.py b/scripts-dev/federation_client.py
index caa3cee4e7..59c3dce3d7 100644
--- a/scripts-dev/federation_client.py
+++ b/scripts-dev/federation_client.py
@@ -128,6 +128,7 @@ def get_json(origin_name, origin_key, destination, path):
         headers={"Authorization": authorization_headers[0]},
         verify=False,
     )
+    sys.stderr.write("Status Code: %d\n" % (result.status_code,))
     return result.json()
 
 
diff --git a/scripts/synapse_port_db b/scripts/synapse_port_db
index efd04da2d6..66c61b0198 100755
--- a/scripts/synapse_port_db
+++ b/scripts/synapse_port_db
@@ -34,7 +34,7 @@ logger = logging.getLogger("synapse_port_db")
 
 
 BOOLEAN_COLUMNS = {
-    "events": ["processed", "outlier"],
+    "events": ["processed", "outlier", "contains_url"],
     "rooms": ["is_public"],
     "event_edges": ["is_state"],
     "presence_list": ["accepted"],
@@ -92,8 +92,12 @@ class Store(object):
 
     _simple_select_onecol_txn = SQLBaseStore.__dict__["_simple_select_onecol_txn"]
     _simple_select_onecol = SQLBaseStore.__dict__["_simple_select_onecol"]
+    _simple_select_one = SQLBaseStore.__dict__["_simple_select_one"]
+    _simple_select_one_txn = SQLBaseStore.__dict__["_simple_select_one_txn"]
     _simple_select_one_onecol = SQLBaseStore.__dict__["_simple_select_one_onecol"]
-    _simple_select_one_onecol_txn = SQLBaseStore.__dict__["_simple_select_one_onecol_txn"]
+    _simple_select_one_onecol_txn = SQLBaseStore.__dict__[
+        "_simple_select_one_onecol_txn"
+    ]
 
     _simple_update_one = SQLBaseStore.__dict__["_simple_update_one"]
     _simple_update_one_txn = SQLBaseStore.__dict__["_simple_update_one_txn"]
@@ -158,31 +162,40 @@ class Porter(object):
     def setup_table(self, table):
         if table in APPEND_ONLY_TABLES:
             # It's safe to just carry on inserting.
-            next_chunk = yield self.postgres_store._simple_select_one_onecol(
+            row = yield self.postgres_store._simple_select_one(
                 table="port_from_sqlite3",
                 keyvalues={"table_name": table},
-                retcol="rowid",
+                retcols=("forward_rowid", "backward_rowid"),
                 allow_none=True,
             )
 
             total_to_port = None
-            if next_chunk is None:
+            if row is None:
                 if table == "sent_transactions":
-                    next_chunk, already_ported, total_to_port = (
+                    forward_chunk, already_ported, total_to_port = (
                         yield self._setup_sent_transactions()
                     )
+                    backward_chunk = 0
                 else:
                     yield self.postgres_store._simple_insert(
                         table="port_from_sqlite3",
-                        values={"table_name": table, "rowid": 1}
+                        values={
+                            "table_name": table,
+                            "forward_rowid": 1,
+                            "backward_rowid": 0,
+                        }
                     )
 
-                    next_chunk = 1
+                    forward_chunk = 1
+                    backward_chunk = 0
                     already_ported = 0
+            else:
+                forward_chunk = row["forward_rowid"]
+                backward_chunk = row["backward_rowid"]
 
             if total_to_port is None:
                 already_ported, total_to_port = yield self._get_total_count_to_port(
-                    table, next_chunk
+                    table, forward_chunk, backward_chunk
                 )
         else:
             def delete_all(txn):
@@ -196,46 +209,85 @@ class Porter(object):
 
             yield self.postgres_store._simple_insert(
                 table="port_from_sqlite3",
-                values={"table_name": table, "rowid": 0}
+                values={
+                    "table_name": table,
+                    "forward_rowid": 1,
+                    "backward_rowid": 0,
+                }
             )
 
-            next_chunk = 1
+            forward_chunk = 1
+            backward_chunk = 0
 
             already_ported, total_to_port = yield self._get_total_count_to_port(
-                table, next_chunk
+                table, forward_chunk, backward_chunk
             )
 
-        defer.returnValue((table, already_ported, total_to_port, next_chunk))
+        defer.returnValue(
+            (table, already_ported, total_to_port, forward_chunk, backward_chunk)
+        )
 
     @defer.inlineCallbacks
-    def handle_table(self, table, postgres_size, table_size, next_chunk):
+    def handle_table(self, table, postgres_size, table_size, forward_chunk,
+                     backward_chunk):
         if not table_size:
             return
 
         self.progress.add_table(table, postgres_size, table_size)
 
         if table == "event_search":
-            yield self.handle_search_table(postgres_size, table_size, next_chunk)
+            yield self.handle_search_table(
+                postgres_size, table_size, forward_chunk, backward_chunk
+            )
             return
 
-        select = (
+        forward_select = (
             "SELECT rowid, * FROM %s WHERE rowid >= ? ORDER BY rowid LIMIT ?"
             % (table,)
         )
 
+        backward_select = (
+            "SELECT rowid, * FROM %s WHERE rowid <= ? ORDER BY rowid LIMIT ?"
+            % (table,)
+        )
+
+        do_forward = [True]
+        do_backward = [True]
+
         while True:
             def r(txn):
-                txn.execute(select, (next_chunk, self.batch_size,))
-                rows = txn.fetchall()
-                headers = [column[0] for column in txn.description]
+                forward_rows = []
+                backward_rows = []
+                if do_forward[0]:
+                    txn.execute(forward_select, (forward_chunk, self.batch_size,))
+                    forward_rows = txn.fetchall()
+                    if not forward_rows:
+                        do_forward[0] = False
+
+                if do_backward[0]:
+                    txn.execute(backward_select, (backward_chunk, self.batch_size,))
+                    backward_rows = txn.fetchall()
+                    if not backward_rows:
+                        do_backward[0] = False
+
+                if forward_rows or backward_rows:
+                    headers = [column[0] for column in txn.description]
+                else:
+                    headers = None
 
-                return headers, rows
+                return headers, forward_rows, backward_rows
 
-            headers, rows = yield self.sqlite_store.runInteraction("select", r)
+            headers, frows, brows = yield self.sqlite_store.runInteraction(
+                "select", r
+            )
 
-            if rows:
-                next_chunk = rows[-1][0] + 1
+            if frows or brows:
+                if frows:
+                    forward_chunk = max(row[0] for row in frows) + 1
+                if brows:
+                    backward_chunk = min(row[0] for row in brows) - 1
 
+                rows = frows + brows
                 self._convert_rows(table, headers, rows)
 
                 def insert(txn):
@@ -247,7 +299,10 @@ class Porter(object):
                         txn,
                         table="port_from_sqlite3",
                         keyvalues={"table_name": table},
-                        updatevalues={"rowid": next_chunk},
+                        updatevalues={
+                            "forward_rowid": forward_chunk,
+                            "backward_rowid": backward_chunk,
+                        },
                     )
 
                 yield self.postgres_store.execute(insert)
@@ -259,7 +314,8 @@ class Porter(object):
                 return
 
     @defer.inlineCallbacks
-    def handle_search_table(self, postgres_size, table_size, next_chunk):
+    def handle_search_table(self, postgres_size, table_size, forward_chunk,
+                            backward_chunk):
         select = (
             "SELECT es.rowid, es.*, e.origin_server_ts, e.stream_ordering"
             " FROM event_search as es"
@@ -270,7 +326,7 @@ class Porter(object):
 
         while True:
             def r(txn):
-                txn.execute(select, (next_chunk, self.batch_size,))
+                txn.execute(select, (forward_chunk, self.batch_size,))
                 rows = txn.fetchall()
                 headers = [column[0] for column in txn.description]
 
@@ -279,7 +335,7 @@ class Porter(object):
             headers, rows = yield self.sqlite_store.runInteraction("select", r)
 
             if rows:
-                next_chunk = rows[-1][0] + 1
+                forward_chunk = rows[-1][0] + 1
 
                 # We have to treat event_search differently since it has a
                 # different structure in the two different databases.
@@ -312,7 +368,10 @@ class Porter(object):
                         txn,
                         table="port_from_sqlite3",
                         keyvalues={"table_name": "event_search"},
-                        updatevalues={"rowid": next_chunk},
+                        updatevalues={
+                            "forward_rowid": forward_chunk,
+                            "backward_rowid": backward_chunk,
+                        },
                     )
 
                 yield self.postgres_store.execute(insert)
@@ -324,7 +383,6 @@ class Porter(object):
             else:
                 return
 
-
     def setup_db(self, db_config, database_engine):
         db_conn = database_engine.module.connect(
             **{
@@ -395,10 +453,32 @@ class Porter(object):
                 txn.execute(
                     "CREATE TABLE port_from_sqlite3 ("
                     " table_name varchar(100) NOT NULL UNIQUE,"
-                    " rowid bigint NOT NULL"
+                    " forward_rowid bigint NOT NULL,"
+                    " backward_rowid bigint NOT NULL"
                     ")"
                 )
 
+            # The old port script created a table with just a "rowid" column.
+            # We want people to be able to rerun this script from an old port
+            # so that they can pick up any missing events that were not
+            # ported across.
+            def alter_table(txn):
+                txn.execute(
+                    "ALTER TABLE IF EXISTS port_from_sqlite3"
+                    " RENAME rowid TO forward_rowid"
+                )
+                txn.execute(
+                    "ALTER TABLE IF EXISTS port_from_sqlite3"
+                    " ADD backward_rowid bigint NOT NULL DEFAULT 0"
+                )
+
+            try:
+                yield self.postgres_store.runInteraction(
+                    "alter_table", alter_table
+                )
+            except Exception as e:
+                logger.info("Failed to create port table: %s", e)
+
             try:
                 yield self.postgres_store.runInteraction(
                     "create_port_table", create_port_table
@@ -458,7 +538,7 @@ class Porter(object):
     @defer.inlineCallbacks
     def _setup_sent_transactions(self):
         # Only save things from the last day
-        yesterday = int(time.time()*1000) - 86400000
+        yesterday = int(time.time() * 1000) - 86400000
 
         # And save the max transaction id from each destination
         select = (
@@ -514,7 +594,11 @@ class Porter(object):
 
         yield self.postgres_store._simple_insert(
             table="port_from_sqlite3",
-            values={"table_name": "sent_transactions", "rowid": next_chunk}
+            values={
+                "table_name": "sent_transactions",
+                "forward_rowid": next_chunk,
+                "backward_rowid": 0,
+            }
         )
 
         def get_sent_table_size(txn):
@@ -535,13 +619,18 @@ class Porter(object):
         defer.returnValue((next_chunk, inserted_rows, total_count))
 
     @defer.inlineCallbacks
-    def _get_remaining_count_to_port(self, table, next_chunk):
-        rows = yield self.sqlite_store.execute_sql(
+    def _get_remaining_count_to_port(self, table, forward_chunk, backward_chunk):
+        frows = yield self.sqlite_store.execute_sql(
             "SELECT count(*) FROM %s WHERE rowid >= ?" % (table,),
-            next_chunk,
+            forward_chunk,
         )
 
-        defer.returnValue(rows[0][0])
+        brows = yield self.sqlite_store.execute_sql(
+            "SELECT count(*) FROM %s WHERE rowid <= ?" % (table,),
+            backward_chunk,
+        )
+
+        defer.returnValue(frows[0][0] + brows[0][0])
 
     @defer.inlineCallbacks
     def _get_already_ported_count(self, table):
@@ -552,10 +641,10 @@ class Porter(object):
         defer.returnValue(rows[0][0])
 
     @defer.inlineCallbacks
-    def _get_total_count_to_port(self, table, next_chunk):
+    def _get_total_count_to_port(self, table, forward_chunk, backward_chunk):
         remaining, done = yield defer.gatherResults(
             [
-                self._get_remaining_count_to_port(table, next_chunk),
+                self._get_remaining_count_to_port(table, forward_chunk, backward_chunk),
                 self._get_already_ported_count(table),
             ],
             consumeErrors=True,
@@ -686,7 +775,7 @@ class CursesProgress(Progress):
             color = curses.color_pair(2) if perc == 100 else curses.color_pair(1)
 
             self.stdscr.addstr(
-                i+2, left_margin + max_len - len(table),
+                i + 2, left_margin + max_len - len(table),
                 table,
                 curses.A_BOLD | color,
             )
@@ -694,18 +783,18 @@ class CursesProgress(Progress):
             size = 20
 
             progress = "[%s%s]" % (
-                "#" * int(perc*size/100),
-                " " * (size - int(perc*size/100)),
+                "#" * int(perc * size / 100),
+                " " * (size - int(perc * size / 100)),
             )
 
             self.stdscr.addstr(
-                i+2, left_margin + max_len + middle_space,
+                i + 2, left_margin + max_len + middle_space,
                 "%s %3d%% (%d/%d)" % (progress, perc, data["num_done"], data["total"]),
             )
 
         if self.finished:
             self.stdscr.addstr(
-                rows-1, 0,
+                rows - 1, 0,
                 "Press any key to exit...",
             )
 
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index b06387051c..65778fd4ee 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -314,6 +314,40 @@ class FederationClient(FederationBase):
             Deferred: Results in a list of PDUs.
         """
 
+        try:
+            # First we try and ask for just the IDs, as thats far quicker if
+            # we have most of the state and auth_chain already.
+            # However, this may 404 if the other side has an old synapse.
+            result = yield self.transport_layer.get_room_state_ids(
+                destination, room_id, event_id=event_id,
+            )
+
+            state_event_ids = result["pdu_ids"]
+            auth_event_ids = result.get("auth_chain_ids", [])
+
+            fetched_events, failed_to_fetch = yield self.get_events(
+                [destination], room_id, set(state_event_ids + auth_event_ids)
+            )
+
+            if failed_to_fetch:
+                logger.warn("Failed to get %r", failed_to_fetch)
+
+            event_map = {
+                ev.event_id: ev for ev in fetched_events
+            }
+
+            pdus = [event_map[e_id] for e_id in state_event_ids]
+            auth_chain = [event_map[e_id] for e_id in auth_event_ids]
+
+            auth_chain.sort(key=lambda e: e.depth)
+
+            defer.returnValue((pdus, auth_chain))
+        except HttpResponseException as e:
+            if e.code == 400 or e.code == 404:
+                logger.info("Failed to use get_room_state_ids API, falling back")
+            else:
+                raise e
+
         result = yield self.transport_layer.get_room_state(
             destination, room_id, event_id=event_id,
         )
@@ -327,12 +361,26 @@ class FederationClient(FederationBase):
             for p in result.get("auth_chain", [])
         ]
 
+        seen_events = yield self.store.get_events([
+            ev.event_id for ev in itertools.chain(pdus, auth_chain)
+        ])
+
         signed_pdus = yield self._check_sigs_and_hash_and_fetch(
-            destination, pdus, outlier=True
+            destination,
+            [p for p in pdus if p.event_id not in seen_events],
+            outlier=True
+        )
+        signed_pdus.extend(
+            seen_events[p.event_id] for p in pdus if p.event_id in seen_events
         )
 
         signed_auth = yield self._check_sigs_and_hash_and_fetch(
-            destination, auth_chain, outlier=True
+            destination,
+            [p for p in auth_chain if p.event_id not in seen_events],
+            outlier=True
+        )
+        signed_auth.extend(
+            seen_events[p.event_id] for p in auth_chain if p.event_id in seen_events
         )
 
         signed_auth.sort(key=lambda e: e.depth)
@@ -340,6 +388,67 @@ class FederationClient(FederationBase):
         defer.returnValue((signed_pdus, signed_auth))
 
     @defer.inlineCallbacks
+    def get_events(self, destinations, room_id, event_ids, return_local=True):
+        """Fetch events from some remote destinations, checking if we already
+        have them.
+
+        Args:
+            destinations (list)
+            room_id (str)
+            event_ids (list)
+            return_local (bool): Whether to include events we already have in
+                the DB in the returned list of events
+
+        Returns:
+            Deferred: A deferred resolving to a 2-tuple where the first is a list of
+            events and the second is a list of event ids that we failed to fetch.
+        """
+        if return_local:
+            seen_events = yield self.store.get_events(event_ids)
+            signed_events = seen_events.values()
+        else:
+            seen_events = yield self.store.have_events(event_ids)
+            signed_events = []
+
+        failed_to_fetch = set()
+
+        missing_events = set(event_ids)
+        for k in seen_events:
+            missing_events.discard(k)
+
+        if not missing_events:
+            defer.returnValue((signed_events, failed_to_fetch))
+
+        def random_server_list():
+            srvs = list(destinations)
+            random.shuffle(srvs)
+            return srvs
+
+        batch_size = 20
+        missing_events = list(missing_events)
+        for i in xrange(0, len(missing_events), batch_size):
+            batch = set(missing_events[i:i + batch_size])
+
+            deferreds = [
+                self.get_pdu(
+                    destinations=random_server_list(),
+                    event_id=e_id,
+                )
+                for e_id in batch
+            ]
+
+            res = yield defer.DeferredList(deferreds, consumeErrors=True)
+            for success, result in res:
+                if success:
+                    signed_events.append(result)
+                    batch.discard(result.event_id)
+
+            # We removed all events we successfully fetched from `batch`
+            failed_to_fetch.update(batch)
+
+        defer.returnValue((signed_events, failed_to_fetch))
+
+    @defer.inlineCallbacks
     @log_function
     def get_event_auth(self, destination, room_id, event_id):
         res = yield self.transport_layer.get_event_auth(
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 612d274bdb..aba19639c7 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -215,6 +215,27 @@ class FederationServer(FederationBase):
         defer.returnValue((200, resp))
 
     @defer.inlineCallbacks
+    def on_state_ids_request(self, origin, room_id, event_id):
+        if not event_id:
+            raise NotImplementedError("Specify an event")
+
+        in_room = yield self.auth.check_host_in_room(room_id, origin)
+        if not in_room:
+            raise AuthError(403, "Host not in room.")
+
+        pdus = yield self.handler.get_state_for_pdu(
+            room_id, event_id,
+        )
+        auth_chain = yield self.store.get_auth_chain(
+            [pdu.event_id for pdu in pdus]
+        )
+
+        defer.returnValue((200, {
+            "pdu_ids": [pdu.event_id for pdu in pdus],
+            "auth_chain_ids": [pdu.event_id for pdu in auth_chain],
+        }))
+
+    @defer.inlineCallbacks
     def _on_context_state_request_compute(self, room_id, event_id):
         pdus = yield self.handler.get_state_for_pdu(
             room_id, event_id,
@@ -372,27 +393,9 @@ class FederationServer(FederationBase):
             (200, send_content)
         )
 
-    @defer.inlineCallbacks
     @log_function
     def on_query_client_keys(self, origin, content):
-        query = []
-        for user_id, device_ids in content.get("device_keys", {}).items():
-            if not device_ids:
-                query.append((user_id, None))
-            else:
-                for device_id in device_ids:
-                    query.append((user_id, device_id))
-
-        results = yield self.store.get_e2e_device_keys(query)
-
-        json_result = {}
-        for user_id, device_keys in results.items():
-            for device_id, json_bytes in device_keys.items():
-                json_result.setdefault(user_id, {})[device_id] = json.loads(
-                    json_bytes
-                )
-
-        defer.returnValue({"device_keys": json_result})
+        return self.on_query_request("client_keys", content)
 
     @defer.inlineCallbacks
     @log_function
@@ -602,7 +605,7 @@ class FederationServer(FederationBase):
                     origin, pdu.room_id, pdu.event_id,
                 )
             except:
-                logger.warn("Failed to get state for event: %s", pdu.event_id)
+                logger.exception("Failed to get state for event: %s", pdu.event_id)
 
         yield self.handler.on_receive_pdu(
             origin,
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index ebb698e278..3d088e43cb 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -55,6 +55,28 @@ class TransportLayerClient(object):
         )
 
     @log_function
+    def get_room_state_ids(self, destination, room_id, event_id):
+        """ Requests all state for a given room from the given server at the
+        given event. Returns the state's event_id's
+
+        Args:
+            destination (str): The host name of the remote home server we want
+                to get the state from.
+            context (str): The name of the context we want the state of
+            event_id (str): The event we want the context at.
+
+        Returns:
+            Deferred: Results in a dict received from the remote homeserver.
+        """
+        logger.debug("get_room_state_ids dest=%s, room=%s",
+                     destination, room_id)
+
+        path = PREFIX + "/state_ids/%s/" % room_id
+        return self.client.get_json(
+            destination, path=path, args={"event_id": event_id},
+        )
+
+    @log_function
     def get_event(self, destination, event_id, timeout=None):
         """ Requests the pdu with give id and origin from the given server.
 
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 26fa88ae84..0bc6e0801d 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -271,6 +271,17 @@ class FederationStateServlet(BaseFederationServlet):
         )
 
 
+class FederationStateIdsServlet(BaseFederationServlet):
+    PATH = "/state_ids/(?P<room_id>[^/]*)/"
+
+    def on_GET(self, origin, content, query, room_id):
+        return self.handler.on_state_ids_request(
+            origin,
+            room_id,
+            query.get("event_id", [None])[0],
+        )
+
+
 class FederationBackfillServlet(BaseFederationServlet):
     PATH = "/backfill/(?P<context>[^/]*)/"
 
@@ -367,10 +378,8 @@ class FederationThirdPartyInviteExchangeServlet(BaseFederationServlet):
 class FederationClientKeysQueryServlet(BaseFederationServlet):
     PATH = "/user/keys/query"
 
-    @defer.inlineCallbacks
     def on_POST(self, origin, content, query):
-        response = yield self.handler.on_query_client_keys(origin, content)
-        defer.returnValue((200, response))
+        return self.handler.on_query_client_keys(origin, content)
 
 
 class FederationClientKeysClaimServlet(BaseFederationServlet):
@@ -538,6 +547,7 @@ SERVLET_CLASSES = (
     FederationPullServlet,
     FederationEventServlet,
     FederationStateServlet,
+    FederationStateIdsServlet,
     FederationBackfillServlet,
     FederationQueryServlet,
     FederationMakeJoinServlet,
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index f4bf159bb5..8d630c6b1a 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -29,7 +29,7 @@ class DeviceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def check_device_registered(self, user_id, device_id,
-                                initial_device_display_name):
+                                initial_device_display_name=None):
         """
         If the given device has not been registered, register it with the
         supplied display name.
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
new file mode 100644
index 0000000000..2c7bfd91ed
--- /dev/null
+++ b/synapse/handlers/e2e_keys.py
@@ -0,0 +1,139 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import collections
+import json
+import logging
+
+from twisted.internet import defer
+
+from synapse.api import errors
+import synapse.types
+
+logger = logging.getLogger(__name__)
+
+
+class E2eKeysHandler(object):
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.federation = hs.get_replication_layer()
+        self.is_mine_id = hs.is_mine_id
+        self.server_name = hs.hostname
+
+        # doesn't really work as part of the generic query API, because the
+        # query request requires an object POST, but we abuse the
+        # "query handler" interface.
+        self.federation.register_query_handler(
+            "client_keys", self.on_federation_query_client_keys
+        )
+
+    @defer.inlineCallbacks
+    def query_devices(self, query_body):
+        """ Handle a device key query from a client
+
+        {
+            "device_keys": {
+                "<user_id>": ["<device_id>"]
+            }
+        }
+        ->
+        {
+            "device_keys": {
+                "<user_id>": {
+                    "<device_id>": {
+                        ...
+                    }
+                }
+            }
+        }
+        """
+        device_keys_query = query_body.get("device_keys", {})
+
+        # separate users by domain.
+        # make a map from domain to user_id to device_ids
+        queries_by_domain = collections.defaultdict(dict)
+        for user_id, device_ids in device_keys_query.items():
+            user = synapse.types.UserID.from_string(user_id)
+            queries_by_domain[user.domain][user_id] = device_ids
+
+        # do the queries
+        # TODO: do these in parallel
+        results = {}
+        for destination, destination_query in queries_by_domain.items():
+            if destination == self.server_name:
+                res = yield self.query_local_devices(destination_query)
+            else:
+                res = yield self.federation.query_client_keys(
+                    destination, {"device_keys": destination_query}
+                )
+                res = res["device_keys"]
+            for user_id, keys in res.items():
+                if user_id in destination_query:
+                    results[user_id] = keys
+
+        defer.returnValue((200, {"device_keys": results}))
+
+    @defer.inlineCallbacks
+    def query_local_devices(self, query):
+        """Get E2E device keys for local users
+
+        Args:
+            query (dict[string, list[string]|None): map from user_id to a list
+                 of devices to query (None for all devices)
+
+        Returns:
+            defer.Deferred: (resolves to dict[string, dict[string, dict]]):
+                 map from user_id -> device_id -> device details
+        """
+        local_query = []
+
+        result_dict = {}
+        for user_id, device_ids in query.items():
+            if not self.is_mine_id(user_id):
+                logger.warning("Request for keys for non-local user %s",
+                               user_id)
+                raise errors.SynapseError(400, "Not a user here")
+
+            if not device_ids:
+                local_query.append((user_id, None))
+            else:
+                for device_id in device_ids:
+                    local_query.append((user_id, device_id))
+
+            # make sure that each queried user appears in the result dict
+            result_dict[user_id] = {}
+
+        results = yield self.store.get_e2e_device_keys(local_query)
+
+        # Build the result structure, un-jsonify the results, and add the
+        # "unsigned" section
+        for user_id, device_keys in results.items():
+            for device_id, device_info in device_keys.items():
+                r = json.loads(device_info["key_json"])
+                r["unsigned"] = {}
+                display_name = device_info["device_display_name"]
+                if display_name is not None:
+                    r["unsigned"]["device_display_name"] = display_name
+                result_dict[user_id][device_id] = r
+
+        defer.returnValue(result_dict)
+
+    @defer.inlineCallbacks
+    def on_federation_query_client_keys(self, query_body):
+        """ Handle a device key query from a federated server
+        """
+        device_keys_query = query_body.get("device_keys", {})
+        res = yield self.query_local_devices(device_keys_query)
+        defer.returnValue({"device_keys": res})
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index dc1d4d8fc6..c5ff16adf3 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -130,9 +130,7 @@ class KeyUploadServlet(RestServlet):
         # old access_token without an associated device_id. Either way, we
         # need to double-check the device is registered to avoid ending up with
         # keys without a corresponding device.
-        self.device_handler.check_device_registered(
-            user_id, device_id, "unknown device"
-        )
+        self.device_handler.check_device_registered(user_id, device_id)
 
         result = yield self.store.count_e2e_one_time_keys(user_id, device_id)
         defer.returnValue((200, {"one_time_key_counts": result}))
@@ -186,17 +184,19 @@ class KeyQueryServlet(RestServlet):
     )
 
     def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer):
+        """
         super(KeyQueryServlet, self).__init__()
-        self.store = hs.get_datastore()
         self.auth = hs.get_auth()
-        self.federation = hs.get_replication_layer()
-        self.is_mine = hs.is_mine
+        self.e2e_keys_handler = hs.get_e2e_keys_handler()
 
     @defer.inlineCallbacks
     def on_POST(self, request, user_id, device_id):
         yield self.auth.get_user_by_req(request)
         body = parse_json_object_from_request(request)
-        result = yield self.handle_request(body)
+        result = yield self.e2e_keys_handler.query_devices(body)
         defer.returnValue(result)
 
     @defer.inlineCallbacks
@@ -205,45 +205,11 @@ class KeyQueryServlet(RestServlet):
         auth_user_id = requester.user.to_string()
         user_id = user_id if user_id else auth_user_id
         device_ids = [device_id] if device_id else []
-        result = yield self.handle_request(
+        result = yield self.e2e_keys_handler.query_devices(
             {"device_keys": {user_id: device_ids}}
         )
         defer.returnValue(result)
 
-    @defer.inlineCallbacks
-    def handle_request(self, body):
-        local_query = []
-        remote_queries = {}
-        for user_id, device_ids in body.get("device_keys", {}).items():
-            user = UserID.from_string(user_id)
-            if self.is_mine(user):
-                if not device_ids:
-                    local_query.append((user_id, None))
-                else:
-                    for device_id in device_ids:
-                        local_query.append((user_id, device_id))
-            else:
-                remote_queries.setdefault(user.domain, {})[user_id] = list(
-                    device_ids
-                )
-        results = yield self.store.get_e2e_device_keys(local_query)
-
-        json_result = {}
-        for user_id, device_keys in results.items():
-            for device_id, json_bytes in device_keys.items():
-                json_result.setdefault(user_id, {})[device_id] = json.loads(
-                    json_bytes
-                )
-
-        for destination, device_keys in remote_queries.items():
-            remote_result = yield self.federation.query_client_keys(
-                destination, {"device_keys": device_keys}
-            )
-            for user_id, keys in remote_result["device_keys"].items():
-                if user_id in device_keys:
-                    json_result[user_id] = keys
-        defer.returnValue((200, {"device_keys": json_result}))
-
 
 class OneTimeKeyServlet(RestServlet):
     """
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 74c64f1371..4060593f7f 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -29,6 +29,8 @@ from synapse.http.server import (
 from synapse.util.async import ObservableDeferred
 from synapse.util.stringutils import is_ascii
 
+from copy import deepcopy
+
 import os
 import re
 import fnmatch
@@ -329,20 +331,23 @@ class PreviewUrlResource(Resource):
                 # ...or if they are within a <script/> or <style/> tag.
                 # This is a very very very coarse approximation to a plain text
                 # render of the page.
-                text_nodes = tree.xpath("//text()[not(ancestor::header | ancestor::nav | "
-                                        "ancestor::aside | ancestor::footer | "
-                                        "ancestor::script | ancestor::style)]" +
-                                        "[ancestor::body]")
-                text = ''
-                for text_node in text_nodes:
-                    if len(text) < 500:
-                        text += text_node + ' '
-                    else:
-                        break
-                text = re.sub(r'[\t ]+', ' ', text)
-                text = re.sub(r'[\t \r\n]*[\r\n]+', '\n', text)
-                text = text.strip()[:500]
-                og['og:description'] = text if text else None
+
+                # We don't just use XPATH here as that is slow on some machines.
+
+                # We clone `tree` as we modify it.
+                cloned_tree = deepcopy(tree.find("body"))
+
+                TAGS_TO_REMOVE = ("header", "nav", "aside", "footer", "script", "style",)
+                for el in cloned_tree.iter(TAGS_TO_REMOVE):
+                    el.getparent().remove(el)
+
+                # Split all the text nodes into paragraphs (by splitting on new
+                # lines)
+                text_nodes = (
+                    re.sub(r'\s+', '\n', el.text).strip()
+                    for el in cloned_tree.iter() if el.text
+                )
+                og['og:description'] = summarize_paragraphs(text_nodes)
 
         # TODO: delete the url downloads to stop diskfilling,
         # as we only ever cared about its OG
@@ -450,3 +455,56 @@ class PreviewUrlResource(Resource):
             content_type.startswith("application/xhtml")
         ):
             return True
+
+
+def summarize_paragraphs(text_nodes, min_size=200, max_size=500):
+    # Try to get a summary of between 200 and 500 words, respecting
+    # first paragraph and then word boundaries.
+    # TODO: Respect sentences?
+
+    description = ''
+
+    # Keep adding paragraphs until we get to the MIN_SIZE.
+    for text_node in text_nodes:
+        if len(description) < min_size:
+            text_node = re.sub(r'[\t \r\n]+', ' ', text_node)
+            description += text_node + '\n\n'
+        else:
+            break
+
+    description = description.strip()
+    description = re.sub(r'[\t ]+', ' ', description)
+    description = re.sub(r'[\t \r\n]*[\r\n]+', '\n\n', description)
+
+    # If the concatenation of paragraphs to get above MIN_SIZE
+    # took us over MAX_SIZE, then we need to truncate mid paragraph
+    if len(description) > max_size:
+        new_desc = ""
+
+        # This splits the paragraph into words, but keeping the
+        # (preceeding) whitespace intact so we can easily concat
+        # words back together.
+        for match in re.finditer("\s*\S+", description):
+            word = match.group()
+
+            # Keep adding words while the total length is less than
+            # MAX_SIZE.
+            if len(word) + len(new_desc) < max_size:
+                new_desc += word
+            else:
+                # At this point the next word *will* take us over
+                # MAX_SIZE, but we also want to ensure that its not
+                # a huge word. If it is add it anyway and we'll
+                # truncate later.
+                if len(new_desc) < min_size:
+                    new_desc += word
+                break
+
+        # Double check that we're not over the limit
+        if len(new_desc) > max_size:
+            new_desc = new_desc[:max_size]
+
+        # We always add an ellipsis because at the very least
+        # we chopped mid paragraph.
+        description = new_desc.strip() + "…"
+    return description if description else None
diff --git a/synapse/server.py b/synapse/server.py
index e8b166990d..6bb4988309 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -19,39 +19,38 @@
 # partial one for unit test mocking.
 
 # Imports required for the default HomeServer() implementation
-from twisted.web.client import BrowserLikePolicyForHTTPS
+import logging
+
 from twisted.enterprise import adbapi
+from twisted.web.client import BrowserLikePolicyForHTTPS
 
-from synapse.appservice.scheduler import ApplicationServiceScheduler
+from synapse.api.auth import Auth
+from synapse.api.filtering import Filtering
+from synapse.api.ratelimiting import Ratelimiter
 from synapse.appservice.api import ApplicationServiceApi
+from synapse.appservice.scheduler import ApplicationServiceScheduler
+from synapse.crypto.keyring import Keyring
+from synapse.events.builder import EventBuilderFactory
 from synapse.federation import initialize_http_replication
-from synapse.handlers.device import DeviceHandler
-from synapse.http.client import SimpleHttpClient, InsecureInterceptableContextFactory
-from synapse.notifier import Notifier
-from synapse.api.auth import Auth
 from synapse.handlers import Handlers
+from synapse.handlers.appservice import ApplicationServicesHandler
+from synapse.handlers.auth import AuthHandler
+from synapse.handlers.device import DeviceHandler
+from synapse.handlers.e2e_keys import E2eKeysHandler
 from synapse.handlers.presence import PresenceHandler
+from synapse.handlers.room import RoomListHandler
 from synapse.handlers.sync import SyncHandler
 from synapse.handlers.typing import TypingHandler
-from synapse.handlers.room import RoomListHandler
-from synapse.handlers.auth import AuthHandler
-from synapse.handlers.appservice import ApplicationServicesHandler
+from synapse.http.client import SimpleHttpClient, InsecureInterceptableContextFactory
+from synapse.http.matrixfederationclient import MatrixFederationHttpClient
+from synapse.notifier import Notifier
+from synapse.push.pusherpool import PusherPool
+from synapse.rest.media.v1.media_repository import MediaRepository
 from synapse.state import StateHandler
 from synapse.storage import DataStore
+from synapse.streams.events import EventSources
 from synapse.util import Clock
 from synapse.util.distributor import Distributor
-from synapse.streams.events import EventSources
-from synapse.api.ratelimiting import Ratelimiter
-from synapse.crypto.keyring import Keyring
-from synapse.push.pusherpool import PusherPool
-from synapse.events.builder import EventBuilderFactory
-from synapse.api.filtering import Filtering
-from synapse.rest.media.v1.media_repository import MediaRepository
-
-from synapse.http.matrixfederationclient import MatrixFederationHttpClient
-
-import logging
-
 
 logger = logging.getLogger(__name__)
 
@@ -94,6 +93,7 @@ class HomeServer(object):
         'room_list_handler',
         'auth_handler',
         'device_handler',
+        'e2e_keys_handler',
         'application_service_api',
         'application_service_scheduler',
         'application_service_handler',
@@ -202,6 +202,9 @@ class HomeServer(object):
     def build_device_handler(self):
         return DeviceHandler(self)
 
+    def build_e2e_keys_handler(self):
+        return E2eKeysHandler(self)
+
     def build_application_service_api(self):
         return ApplicationServiceApi(self)
 
diff --git a/synapse/server.pyi b/synapse/server.pyi
index 902f725c06..c0aa868c4f 100644
--- a/synapse/server.pyi
+++ b/synapse/server.pyi
@@ -1,6 +1,7 @@
 import synapse.handlers
 import synapse.handlers.auth
 import synapse.handlers.device
+import synapse.handlers.e2e_keys
 import synapse.storage
 import synapse.state
 
@@ -14,6 +15,9 @@ class HomeServer(object):
     def get_device_handler(self) -> synapse.handlers.device.DeviceHandler:
         pass
 
+    def get_e2e_keys_handler(self) -> synapse.handlers.e2e_keys.E2eKeysHandler:
+        pass
+
     def get_handlers(self) -> synapse.handlers.Handlers:
         pass
 
diff --git a/synapse/storage/end_to_end_keys.py b/synapse/storage/end_to_end_keys.py
index 62b7790e91..385d607056 100644
--- a/synapse/storage/end_to_end_keys.py
+++ b/synapse/storage/end_to_end_keys.py
@@ -12,6 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import collections
 
 import twisted.internet.defer
 
@@ -38,24 +39,49 @@ class EndToEndKeyStore(SQLBaseStore):
             query_list(list): List of pairs of user_ids and device_ids.
         Returns:
             Dict mapping from user-id to dict mapping from device_id to
-            key json byte strings.
+            dict containing "key_json", "device_display_name".
         """
-        def _get_e2e_device_keys(txn):
-            result = {}
-            for user_id, device_id in query_list:
-                user_result = result.setdefault(user_id, {})
-                keyvalues = {"user_id": user_id}
-                if device_id:
-                    keyvalues["device_id"] = device_id
-                rows = self._simple_select_list_txn(
-                    txn, table="e2e_device_keys_json",
-                    keyvalues=keyvalues,
-                    retcols=["device_id", "key_json"]
-                )
-                for row in rows:
-                    user_result[row["device_id"]] = row["key_json"]
-            return result
-        return self.runInteraction("get_e2e_device_keys", _get_e2e_device_keys)
+        if not query_list:
+            return {}
+
+        return self.runInteraction(
+            "get_e2e_device_keys", self._get_e2e_device_keys_txn, query_list
+        )
+
+    def _get_e2e_device_keys_txn(self, txn, query_list):
+        query_clauses = []
+        query_params = []
+
+        for (user_id, device_id) in query_list:
+            query_clause = "k.user_id = ?"
+            query_params.append(user_id)
+
+            if device_id:
+                query_clause += " AND k.device_id = ?"
+                query_params.append(device_id)
+
+            query_clauses.append(query_clause)
+
+        sql = (
+            "SELECT k.user_id, k.device_id, "
+            "    d.display_name AS device_display_name, "
+            "    k.key_json"
+            " FROM e2e_device_keys_json k"
+            "    LEFT JOIN devices d ON d.user_id = k.user_id"
+            "      AND d.device_id = k.device_id"
+            " WHERE %s"
+        ) % (
+            " OR ".join("(" + q + ")" for q in query_clauses)
+        )
+
+        txn.execute(sql, query_params)
+        rows = self.cursor_to_dict(txn)
+
+        result = collections.defaultdict(dict)
+        for row in rows:
+            result[row["user_id"]][row["device_id"]] = row
+
+        return result
 
     def add_e2e_one_time_keys(self, user_id, device_id, time_now, key_list):
         def _add_e2e_one_time_keys(txn):
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index c63ca36df6..e4dbaa3547 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -26,7 +26,8 @@ from synapse.api.constants import EventTypes
 from synapse.api.errors import SynapseError
 
 from canonicaljson import encode_canonical_json
-from collections import deque, namedtuple
+from collections import deque, namedtuple, OrderedDict
+from functools import wraps
 
 import synapse
 import synapse.metrics
@@ -150,6 +151,26 @@ class _EventPeristenceQueue(object):
 _EventCacheEntry = namedtuple("_EventCacheEntry", ("event", "redacted_event"))
 
 
+def _retry_on_integrity_error(func):
+    """Wraps a database function so that it gets retried on IntegrityError,
+    with `delete_existing=True` passed in.
+
+    Args:
+        func: function that returns a Deferred and accepts a `delete_existing` arg
+    """
+    @wraps(func)
+    @defer.inlineCallbacks
+    def f(self, *args, **kwargs):
+        try:
+            res = yield func(self, *args, **kwargs)
+        except self.database_engine.module.IntegrityError:
+            logger.exception("IntegrityError, retrying.")
+            res = yield func(self, *args, delete_existing=True, **kwargs)
+        defer.returnValue(res)
+
+    return f
+
+
 class EventsStore(SQLBaseStore):
     EVENT_ORIGIN_SERVER_TS_NAME = "event_origin_server_ts"
     EVENT_FIELDS_SENDER_URL_UPDATE_NAME = "event_fields_sender_url"
@@ -229,8 +250,10 @@ class EventsStore(SQLBaseStore):
 
         self._event_persist_queue.handle_queue(room_id, persisting_queue)
 
+    @_retry_on_integrity_error
     @defer.inlineCallbacks
-    def _persist_events(self, events_and_contexts, backfilled=False):
+    def _persist_events(self, events_and_contexts, backfilled=False,
+                        delete_existing=False):
         if not events_and_contexts:
             return
 
@@ -273,12 +296,15 @@ class EventsStore(SQLBaseStore):
                         self._persist_events_txn,
                         events_and_contexts=chunk,
                         backfilled=backfilled,
+                        delete_existing=delete_existing,
                     )
                     persist_event_counter.inc_by(len(chunk))
 
+    @_retry_on_integrity_error
     @defer.inlineCallbacks
     @log_function
-    def _persist_event(self, event, context, current_state=None, backfilled=False):
+    def _persist_event(self, event, context, current_state=None, backfilled=False,
+                       delete_existing=False):
         try:
             with self._stream_id_gen.get_next() as stream_ordering:
                 with self._state_groups_id_gen.get_next() as state_group_id:
@@ -291,6 +317,7 @@ class EventsStore(SQLBaseStore):
                         context=context,
                         current_state=current_state,
                         backfilled=backfilled,
+                        delete_existing=delete_existing,
                     )
                     persist_event_counter.inc()
         except _RollbackButIsFineException:
@@ -353,7 +380,8 @@ class EventsStore(SQLBaseStore):
         defer.returnValue({e.event_id: e for e in events})
 
     @log_function
-    def _persist_event_txn(self, txn, event, context, current_state, backfilled=False):
+    def _persist_event_txn(self, txn, event, context, current_state, backfilled=False,
+                           delete_existing=False):
         # We purposefully do this first since if we include a `current_state`
         # key, we *want* to update the `current_state_events` table
         if current_state:
@@ -393,16 +421,38 @@ class EventsStore(SQLBaseStore):
             txn,
             [(event, context)],
             backfilled=backfilled,
+            delete_existing=delete_existing,
         )
 
     @log_function
-    def _persist_events_txn(self, txn, events_and_contexts, backfilled):
+    def _persist_events_txn(self, txn, events_and_contexts, backfilled,
+                            delete_existing=False):
         """Insert some number of room events into the necessary database tables.
 
         Rejected events are only inserted into the events table, the events_json table,
         and the rejections table. Things reading from those table will need to check
         whether the event was rejected.
+
+        If delete_existing is True then existing events will be purged from the
+        database before insertion. This is useful when retrying due to IntegrityError.
         """
+        # Ensure that we don't have the same event twice.
+        # Pick the earliest non-outlier if there is one, else the earliest one.
+        new_events_and_contexts = OrderedDict()
+        for event, context in events_and_contexts:
+            prev_event_context = new_events_and_contexts.get(event.event_id)
+            if prev_event_context:
+                if not event.internal_metadata.is_outlier():
+                    if prev_event_context[0].internal_metadata.is_outlier():
+                        # To ensure correct ordering we pop, as OrderedDict is
+                        # ordered by first insertion.
+                        new_events_and_contexts.pop(event.event_id, None)
+                        new_events_and_contexts[event.event_id] = (event, context)
+            else:
+                new_events_and_contexts[event.event_id] = (event, context)
+
+        events_and_contexts = new_events_and_contexts.values()
+
         depth_updates = {}
         for event, context in events_and_contexts:
             # Remove the any existing cache entries for the event_ids
@@ -433,8 +483,6 @@ class EventsStore(SQLBaseStore):
             for event_id, outlier in txn.fetchall()
         }
 
-        # Remove the events that we've seen before.
-        event_map = {}
         to_remove = set()
         for event, context in events_and_contexts:
             if context.rejected:
@@ -445,23 +493,6 @@ class EventsStore(SQLBaseStore):
                     to_remove.add(event)
                 continue
 
-            # Handle the case of the list including the same event multiple
-            # times. The tricky thing here is when they differ by whether
-            # they are an outlier.
-            if event.event_id in event_map:
-                other = event_map[event.event_id]
-
-                if not other.internal_metadata.is_outlier():
-                    to_remove.add(event)
-                    continue
-                elif not event.internal_metadata.is_outlier():
-                    to_remove.add(event)
-                    continue
-                else:
-                    to_remove.add(other)
-
-            event_map[event.event_id] = event
-
             if event.event_id not in have_persisted:
                 continue
 
@@ -539,6 +570,43 @@ class EventsStore(SQLBaseStore):
                 ]
             }
 
+        if delete_existing:
+            # For paranoia reasons, we go and delete all the existing entries
+            # for these events so we can reinsert them.
+            # This gets around any problems with some tables already having
+            # entries.
+
+            logger.info("Deleting existing")
+
+            for table in (
+                "events",
+                "event_auth",
+                "event_json",
+                "event_content_hashes",
+                "event_destinations",
+                "event_edge_hashes",
+                "event_edges",
+                "event_forward_extremities",
+                "event_push_actions",
+                "event_reference_hashes",
+                "event_search",
+                "event_signatures",
+                "event_to_state_groups",
+                "guest_access",
+                "history_visibility",
+                "local_invites",
+                "room_names",
+                "state_events",
+                "rejections",
+                "redactions",
+                "room_memberships",
+                "state_events"
+            ):
+                txn.executemany(
+                    "DELETE FROM %s WHERE event_id = ?" % (table,),
+                    [(ev.event_id,) for ev, _ in events_and_contexts]
+                )
+
         self._simple_insert_many_txn(
             txn,
             table="event_json",
diff --git a/synapse/storage/schema/delta/33/devices_for_e2e_keys.sql b/synapse/storage/schema/delta/33/devices_for_e2e_keys.sql
index 140f2b63e0..aa4a3b9f2f 100644
--- a/synapse/storage/schema/delta/33/devices_for_e2e_keys.sql
+++ b/synapse/storage/schema/delta/33/devices_for_e2e_keys.sql
@@ -16,4 +16,4 @@
 -- make sure that we have a device record for each set of E2E keys, so that the
 -- user can delete them if they like.
 INSERT INTO devices
-    SELECT user_id, device_id, 'unknown device' FROM e2e_device_keys_json;
+    SELECT user_id, device_id, NULL FROM e2e_device_keys_json;
diff --git a/synapse/storage/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql b/synapse/storage/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql
new file mode 100644
index 0000000000..6671573398
--- /dev/null
+++ b/synapse/storage/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql
@@ -0,0 +1,20 @@
+/* Copyright 2016 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- a previous version of the "devices_for_e2e_keys" delta set all the device
+-- names to "unknown device". This wasn't terribly helpful
+UPDATE devices
+    SET display_name = NULL
+    WHERE display_name = 'unknown device';
diff --git a/tests/handlers/test_e2e_keys.py b/tests/handlers/test_e2e_keys.py
new file mode 100644
index 0000000000..878a54dc34
--- /dev/null
+++ b/tests/handlers/test_e2e_keys.py
@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import mock
+from twisted.internet import defer
+
+import synapse.api.errors
+import synapse.handlers.e2e_keys
+
+import synapse.storage
+from tests import unittest, utils
+
+
+class E2eKeysHandlerTestCase(unittest.TestCase):
+    def __init__(self, *args, **kwargs):
+        super(E2eKeysHandlerTestCase, self).__init__(*args, **kwargs)
+        self.hs = None       # type: synapse.server.HomeServer
+        self.handler = None  # type: synapse.handlers.e2e_keys.E2eKeysHandler
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        self.hs = yield utils.setup_test_homeserver(
+            handlers=None,
+            replication_layer=mock.Mock(),
+        )
+        self.handler = synapse.handlers.e2e_keys.E2eKeysHandler(self.hs)
+
+    @defer.inlineCallbacks
+    def test_query_local_devices_no_devices(self):
+        """If the user has no devices, we expect an empty list.
+        """
+        local_user = "@boris:" + self.hs.hostname
+        res = yield self.handler.query_local_devices({local_user: None})
+        self.assertDictEqual(res, {local_user: {}})
diff --git a/tests/storage/test_end_to_end_keys.py b/tests/storage/test_end_to_end_keys.py
new file mode 100644
index 0000000000..453bc61438
--- /dev/null
+++ b/tests/storage/test_end_to_end_keys.py
@@ -0,0 +1,90 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from twisted.internet import defer
+
+import tests.unittest
+import tests.utils
+
+
+class EndToEndKeyStoreTestCase(tests.unittest.TestCase):
+    def __init__(self, *args, **kwargs):
+        super(EndToEndKeyStoreTestCase, self).__init__(*args, **kwargs)
+        self.store = None  # type: synapse.storage.DataStore
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        hs = yield tests.utils.setup_test_homeserver()
+
+        self.store = hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def test_key_without_device_name(self):
+        now = 1470174257070
+        json = '{ "key": "value" }'
+
+        yield self.store.set_e2e_device_keys(
+            "user", "device", now, json)
+
+        res = yield self.store.get_e2e_device_keys((("user", "device"),))
+        self.assertIn("user", res)
+        self.assertIn("device", res["user"])
+        dev = res["user"]["device"]
+        self.assertDictContainsSubset({
+            "key_json": json,
+            "device_display_name": None,
+        }, dev)
+
+    @defer.inlineCallbacks
+    def test_get_key_with_device_name(self):
+        now = 1470174257070
+        json = '{ "key": "value" }'
+
+        yield self.store.set_e2e_device_keys(
+            "user", "device", now, json)
+        yield self.store.store_device(
+            "user", "device", "display_name"
+        )
+
+        res = yield self.store.get_e2e_device_keys((("user", "device"),))
+        self.assertIn("user", res)
+        self.assertIn("device", res["user"])
+        dev = res["user"]["device"]
+        self.assertDictContainsSubset({
+            "key_json": json,
+            "device_display_name": "display_name",
+        }, dev)
+
+    @defer.inlineCallbacks
+    def test_multiple_devices(self):
+        now = 1470174257070
+
+        yield self.store.set_e2e_device_keys(
+            "user1", "device1", now, 'json11')
+        yield self.store.set_e2e_device_keys(
+            "user1", "device2", now, 'json12')
+        yield self.store.set_e2e_device_keys(
+            "user2", "device1", now, 'json21')
+        yield self.store.set_e2e_device_keys(
+            "user2", "device2", now, 'json22')
+
+        res = yield self.store.get_e2e_device_keys((("user1", "device1"),
+                                                    ("user2", "device2")))
+        self.assertIn("user1", res)
+        self.assertIn("device1", res["user1"])
+        self.assertNotIn("device2", res["user1"])
+        self.assertIn("user2", res)
+        self.assertNotIn("device1", res["user2"])
+        self.assertIn("device2", res["user2"])
diff --git a/tests/test_preview.py b/tests/test_preview.py
new file mode 100644
index 0000000000..2a801173a0
--- /dev/null
+++ b/tests/test_preview.py
@@ -0,0 +1,139 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014-2016 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from . import unittest
+
+from synapse.rest.media.v1.preview_url_resource import summarize_paragraphs
+
+
+class PreviewTestCase(unittest.TestCase):
+
+    def test_long_summarize(self):
+        example_paras = [
+            """Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:
+            Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in
+            Troms county, Norway. The administrative centre of the municipality is
+            the city of Tromsø. Outside of Norway, Tromso and Tromsö are
+            alternative spellings of the city.Tromsø is considered the northernmost
+            city in the world with a population above 50,000. The most populous town
+            north of it is Alta, Norway, with a population of 14,272 (2013).""",
+
+            """Tromsø lies in Northern Norway. The municipality has a population of
+            (2015) 72,066, but with an annual influx of students it has over 75,000
+            most of the year. It is the largest urban area in Northern Norway and the
+            third largest north of the Arctic Circle (following Murmansk and Norilsk).
+            Most of Tromsø, including the city centre, is located on the island of
+            Tromsøya, 350 kilometres (217 mi) north of the Arctic Circle. In 2012,
+            Tromsøya had a population of 36,088. Substantial parts of the urban area
+            are also situated on the mainland to the east, and on parts of Kvaløya—a
+            large island to the west. Tromsøya is connected to the mainland by the Tromsø
+            Bridge and the Tromsøysund Tunnel, and to the island of Kvaløya by the
+            Sandnessund Bridge. Tromsø Airport connects the city to many destinations
+            in Europe. The city is warmer than most other places located on the same
+            latitude, due to the warming effect of the Gulf Stream.""",
+
+            """The city centre of Tromsø contains the highest number of old wooden
+            houses in Northern Norway, the oldest house dating from 1789. The Arctic
+            Cathedral, a modern church from 1965, is probably the most famous landmark
+            in Tromsø. The city is a cultural centre for its region, with several
+            festivals taking place in the summer. Some of Norway's best-known
+             musicians, Torbjørn Brundtland and Svein Berge of the electronica duo
+             Röyksopp and Lene Marlin grew up and started their careers in Tromsø.
+             Noted electronic musician Geir Jenssen also hails from Tromsø.""",
+        ]
+
+        desc = summarize_paragraphs(example_paras, min_size=200, max_size=500)
+
+        self.assertEquals(
+            desc,
+            "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
+            " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
+            " Troms county, Norway. The administrative centre of the municipality is"
+            " the city of Tromsø. Outside of Norway, Tromso and Tromsö are"
+            " alternative spellings of the city.Tromsø is considered the northernmost"
+            " city in the world with a population above 50,000. The most populous town"
+            " north of it is Alta, Norway, with a population of 14,272 (2013)."
+        )
+
+        desc = summarize_paragraphs(example_paras[1:], min_size=200, max_size=500)
+
+        self.assertEquals(
+            desc,
+            "Tromsø lies in Northern Norway. The municipality has a population of"
+            " (2015) 72,066, but with an annual influx of students it has over 75,000"
+            " most of the year. It is the largest urban area in Northern Norway and the"
+            " third largest north of the Arctic Circle (following Murmansk and Norilsk)."
+            " Most of Tromsø, including the city centre, is located on the island of"
+            " Tromsøya, 350 kilometres (217 mi) north of the Arctic Circle. In 2012,"
+            " Tromsøya had a population of 36,088. Substantial parts of the…"
+        )
+
+    def test_short_summarize(self):
+        example_paras = [
+            "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
+            " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
+            " Troms county, Norway.",
+
+            "Tromsø lies in Northern Norway. The municipality has a population of"
+            " (2015) 72,066, but with an annual influx of students it has over 75,000"
+            " most of the year.",
+
+            "The city centre of Tromsø contains the highest number of old wooden"
+            " houses in Northern Norway, the oldest house dating from 1789. The Arctic"
+            " Cathedral, a modern church from 1965, is probably the most famous landmark"
+            " in Tromsø.",
+        ]
+
+        desc = summarize_paragraphs(example_paras, min_size=200, max_size=500)
+
+        self.assertEquals(
+            desc,
+            "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
+            " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
+            " Troms county, Norway.\n"
+            "\n"
+            "Tromsø lies in Northern Norway. The municipality has a population of"
+            " (2015) 72,066, but with an annual influx of students it has over 75,000"
+            " most of the year."
+        )
+
+    def test_small_then_large_summarize(self):
+        example_paras = [
+            "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
+            " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
+            " Troms county, Norway.",
+
+            "Tromsø lies in Northern Norway. The municipality has a population of"
+            " (2015) 72,066, but with an annual influx of students it has over 75,000"
+            " most of the year."
+            " The city centre of Tromsø contains the highest number of old wooden"
+            " houses in Northern Norway, the oldest house dating from 1789. The Arctic"
+            " Cathedral, a modern church from 1965, is probably the most famous landmark"
+            " in Tromsø.",
+        ]
+
+        desc = summarize_paragraphs(example_paras, min_size=200, max_size=500)
+        self.assertEquals(
+            desc,
+            "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
+            " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
+            " Troms county, Norway.\n"
+            "\n"
+            "Tromsø lies in Northern Norway. The municipality has a population of"
+            " (2015) 72,066, but with an annual influx of students it has over 75,000"
+            " most of the year. The city centre of Tromsø contains the highest number"
+            " of old wooden houses in Northern Norway, the oldest house dating from"
+            " 1789. The Arctic Cathedral, a modern church…"
+        )