Unify HTTP query parameter type hints (#12415)

* Pull out query param types to `synapse.http.types`
* Use QueryParams everywhere
* Simplify `encode_query_args`
* Add annotation which would have caught #12410

3 files changed, 37 insertions, 35 deletions

diff --git a/synapse/http/client.py b/synapse/http/client.py
index c01d2326cf..8310fb466a 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -22,7 +22,6 @@ from typing import (
     BinaryIO,
     Callable,
     Dict,
-    Iterable,
     List,
     Mapping,
     Optional,
@@ -72,6 +71,7 @@ from twisted.web.iweb import (
 from synapse.api.errors import Codes, HttpResponseException, SynapseError
 from synapse.http import QuieterFileBodyProducer, RequestTimedOutError, redact_uri
 from synapse.http.proxyagent import ProxyAgent
+from synapse.http.types import QueryParams
 from synapse.logging.context import make_deferred_yieldable
 from synapse.logging.opentracing import set_tag, start_active_span, tags
 from synapse.types import ISynapseReactor
@@ -97,10 +97,6 @@ RawHeaders = Union[Mapping[str, "RawHeaderValue"], Mapping[bytes, "RawHeaderValu
 # the entries can either be Lists or bytes.
 RawHeaderValue = Sequence[Union[str, bytes]]
 
-# the type of the query params, to be passed into `urlencode`
-QueryParamValue = Union[str, bytes, Iterable[Union[str, bytes]]]
-QueryParams = Union[Mapping[str, QueryParamValue], Mapping[bytes, QueryParamValue]]
-
 
 def check_against_blacklist(
     ip_address: IPAddress, ip_whitelist: Optional[IPSet], ip_blacklist: IPSet
@@ -911,7 +907,7 @@ def read_body_with_max_size(
     return d
 
 
-def encode_query_args(args: Optional[Mapping[str, Union[str, List[str]]]]) -> bytes:
+def encode_query_args(args: Optional[QueryParams]) -> bytes:
     """
     Encodes a map of query arguments to bytes which can be appended to a URL.
 
@@ -924,13 +920,7 @@ def encode_query_args(args: Optional[Mapping[str, Union[str, List[str]]]]) -> by
     if args is None:
         return b""
 
-    encoded_args = {}
-    for k, vs in args.items():
-        if isinstance(vs, str):
-            vs = [vs]
-        encoded_args[k] = [v.encode("utf8") for v in vs]
-
-    query_str = urllib.parse.urlencode(encoded_args, True)
+    query_str = urllib.parse.urlencode(args, True)
 
     return query_str.encode("utf8")
 
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 6b98d865f5..5097b3ca57 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -67,6 +67,7 @@ from synapse.http.client import (
     read_body_with_max_size,
 )
 from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
+from synapse.http.types import QueryParams
 from synapse.logging import opentracing
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.logging.opentracing import set_tag, start_active_span, tags
@@ -98,10 +99,6 @@ MAXINT = sys.maxsize
 
 _next_id = 1
 
-
-QueryArgs = Dict[str, Union[str, List[str]]]
-
-
 T = TypeVar("T")
 
 
@@ -144,7 +141,7 @@ class MatrixFederationRequest:
     """A callback to generate the JSON.
     """
 
-    query: Optional[dict] = None
+    query: Optional[QueryParams] = None
     """Query arguments.
     """
 
@@ -165,10 +162,7 @@ class MatrixFederationRequest:
 
         destination_bytes = self.destination.encode("ascii")
         path_bytes = self.path.encode("ascii")
-        if self.query:
-            query_bytes = encode_query_args(self.query)
-        else:
-            query_bytes = b""
+        query_bytes = encode_query_args(self.query)
 
         # The object is frozen so we can pre-compute this.
         uri = urllib.parse.urlunparse(
@@ -485,10 +479,7 @@ class MatrixFederationHttpClient:
         method_bytes = request.method.encode("ascii")
         destination_bytes = request.destination.encode("ascii")
         path_bytes = request.path.encode("ascii")
-        if request.query:
-            query_bytes = encode_query_args(request.query)
-        else:
-            query_bytes = b""
+        query_bytes = encode_query_args(request.query)
 
         scope = start_active_span(
             "outgoing-federation-request",
@@ -746,7 +737,7 @@ class MatrixFederationHttpClient:
         self,
         destination: str,
         path: str,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
         data: Optional[JsonDict] = None,
         json_data_callback: Optional[Callable[[], JsonDict]] = None,
         long_retries: bool = False,
@@ -764,7 +755,7 @@ class MatrixFederationHttpClient:
         self,
         destination: str,
         path: str,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
         data: Optional[JsonDict] = None,
         json_data_callback: Optional[Callable[[], JsonDict]] = None,
         long_retries: bool = False,
@@ -781,7 +772,7 @@ class MatrixFederationHttpClient:
         self,
         destination: str,
         path: str,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
         data: Optional[JsonDict] = None,
         json_data_callback: Optional[Callable[[], JsonDict]] = None,
         long_retries: bool = False,
@@ -891,7 +882,7 @@ class MatrixFederationHttpClient:
         long_retries: bool = False,
         timeout: Optional[int] = None,
         ignore_backoff: bool = False,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
     ) -> Union[JsonDict, list]:
         """Sends the specified json data using POST
 
@@ -961,7 +952,7 @@ class MatrixFederationHttpClient:
         self,
         destination: str,
         path: str,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
         retry_on_dns_fail: bool = True,
         timeout: Optional[int] = None,
         ignore_backoff: bool = False,
@@ -976,7 +967,7 @@ class MatrixFederationHttpClient:
         self,
         destination: str,
         path: str,
-        args: Optional[QueryArgs] = ...,
+        args: Optional[QueryParams] = ...,
         retry_on_dns_fail: bool = ...,
         timeout: Optional[int] = ...,
         ignore_backoff: bool = ...,
@@ -990,7 +981,7 @@ class MatrixFederationHttpClient:
         self,
         destination: str,
         path: str,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
         retry_on_dns_fail: bool = True,
         timeout: Optional[int] = None,
         ignore_backoff: bool = False,
@@ -1085,7 +1076,7 @@ class MatrixFederationHttpClient:
         long_retries: bool = False,
         timeout: Optional[int] = None,
         ignore_backoff: bool = False,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
     ) -> Union[JsonDict, list]:
         """Send a DELETE request to the remote expecting some json response
 
@@ -1150,7 +1141,7 @@ class MatrixFederationHttpClient:
         destination: str,
         path: str,
         output_stream,
-        args: Optional[QueryArgs] = None,
+        args: Optional[QueryParams] = None,
         retry_on_dns_fail: bool = True,
         max_size: Optional[int] = None,
         ignore_backoff: bool = False,
diff --git a/synapse/http/types.py b/synapse/http/types.py
new file mode 100644
index 0000000000..11fe232d77
--- /dev/null
+++ b/synapse/http/types.py
@@ -0,0 +1,21 @@
+#  Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+#  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 typing import Iterable, Mapping, Union
+
+# the type of the query params, to be passed into `urlencode` with `doseq=True`.
+QueryParamValue = Union[str, bytes, Iterable[Union[str, bytes]]]
+QueryParams = Union[Mapping[str, QueryParamValue], Mapping[bytes, QueryParamValue]]
+
+__all__ = ["QueryParams"]