Replace username picker with a template (#9275)

There's some prelimiary work here to pull out the construction of a jinja environment to a separate function.

I wanted to load the template at display time rather than load time, so that it's easy to update on the fly. Honestly, I think we should do this with all our templates: the risk of ending up with malformed templates is far outweighed by the improved turnaround time for an admin trying to update them.

3 files changed, 37 insertions, 38 deletions

diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index 94144efc87..35e5594b73 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -18,18 +18,18 @@
 import argparse
 import errno
 import os
-import time
-import urllib.parse
 from collections import OrderedDict
 from hashlib import sha256
 from textwrap import dedent
-from typing import Any, Callable, Iterable, List, MutableMapping, Optional
+from typing import Any, Iterable, List, MutableMapping, Optional
 
 import attr
 import jinja2
 import pkg_resources
 import yaml
 
+from synapse.util.templates import _create_mxc_to_http_filter, _format_ts_filter
+
 
 class ConfigError(Exception):
     """Represents a problem parsing the configuration
@@ -248,6 +248,7 @@ class Config:
             # Search the custom template directory as well
             search_directories.insert(0, custom_template_directory)
 
+        # TODO: switch to synapse.util.templates.build_jinja_env
         loader = jinja2.FileSystemLoader(search_directories)
         env = jinja2.Environment(loader=loader, autoescape=autoescape)
 
@@ -267,38 +268,6 @@ class Config:
         return templates
 
 
-def _format_ts_filter(value: int, format: str):
-    return time.strftime(format, time.localtime(value / 1000))
-
-
-def _create_mxc_to_http_filter(public_baseurl: str) -> Callable:
-    """Create and return a jinja2 filter that converts MXC urls to HTTP
-
-    Args:
-        public_baseurl: The public, accessible base URL of the homeserver
-    """
-
-    def mxc_to_http_filter(value, width, height, resize_method="crop"):
-        if value[0:6] != "mxc://":
-            return ""
-
-        server_and_media_id = value[6:]
-        fragment = None
-        if "#" in server_and_media_id:
-            server_and_media_id, fragment = server_and_media_id.split("#", 1)
-            fragment = "#" + fragment
-
-        params = {"width": width, "height": height, "method": resize_method}
-        return "%s_matrix/media/v1/thumbnail/%s?%s%s" % (
-            public_baseurl,
-            server_and_media_id,
-            urllib.parse.urlencode(params),
-            fragment or "",
-        )
-
-    return mxc_to_http_filter
-
-
 class RootConfig:
     """
     Holder of an application's configuration.
diff --git a/synapse/config/oidc_config.py b/synapse/config/oidc_config.py
index f31511e039..784b416f95 100644
--- a/synapse/config/oidc_config.py
+++ b/synapse/config/oidc_config.py
@@ -152,7 +152,8 @@ class OIDCConfig(Config):
         #
         #             localpart_template: Jinja2 template for the localpart of the MXID.
         #                 If this is not set, the user will be prompted to choose their
-        #                 own username.
+        #                 own username (see 'sso_auth_account_details.html' in the 'sso'
+        #                 section of this file).
         #
         #             display_name_template: Jinja2 template for the display name to set
         #                 on first login. If unset, no displayname will be set.
diff --git a/synapse/config/sso.py b/synapse/config/sso.py
index a470112ed4..e308fc9333 100644
--- a/synapse/config/sso.py
+++ b/synapse/config/sso.py
@@ -27,7 +27,7 @@ class SSOConfig(Config):
         sso_config = config.get("sso") or {}  # type: Dict[str, Any]
 
         # The sso-specific template_dir
-        template_dir = sso_config.get("template_dir")
+        self.sso_template_dir = sso_config.get("template_dir")
 
         # Read templates from disk
         (
@@ -48,7 +48,7 @@ class SSOConfig(Config):
                 "sso_auth_success.html",
                 "sso_auth_bad_user.html",
             ],
-            template_dir,
+            self.sso_template_dir,
         )
 
         # These templates have no placeholders, so render them here
@@ -124,6 +124,35 @@ class SSOConfig(Config):
             #
             #     * idp: the 'idp_id' of the chosen IDP.
             #
+            # * HTML page to prompt new users to enter a userid and confirm other
+            #   details: 'sso_auth_account_details.html'. This is only shown if the
+            #   SSO implementation (with any user_mapping_provider) does not return
+            #   a localpart.
+            #
+            #   When rendering, this template is given the following variables:
+            #
+            #     * server_name: the homeserver's name.
+            #
+            #     * idp: details of the SSO Identity Provider that the user logged in
+            #       with: an object with the following attributes:
+            #
+            #         * idp_id: unique identifier for the IdP
+            #         * idp_name: user-facing name for the IdP
+            #         * idp_icon: if specified in the IdP config, an MXC URI for an icon
+            #              for the IdP
+            #         * idp_brand: if specified in the IdP config, a textual identifier
+            #              for the brand of the IdP
+            #
+            #     * user_attributes: an object containing details about the user that
+            #       we received from the IdP. May have the following attributes:
+            #
+            #         * display_name: the user's display_name
+            #         * emails: a list of email addresses
+            #
+            #   The template should render a form which submits the following fields:
+            #
+            #     * username: the localpart of the user's chosen user id
+            #
             # * HTML page for a confirmation step before redirecting back to the client
             #   with the login token: 'sso_redirect_confirm.html'.
             #