diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index 0ca08038f4..ab12951da8 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -23,6 +23,7 @@
import enum
import logging
+import urllib.parse as urlparse
from http import HTTPStatus
from typing import (
TYPE_CHECKING,
@@ -450,6 +451,87 @@ def parse_string(
)
+def parse_json(
+ request: Request,
+ name: str,
+ default: Optional[dict] = None,
+ required: bool = False,
+ encoding: str = "ascii",
+) -> Optional[JsonDict]:
+ """
+ Parse a JSON parameter from the request query string.
+
+ Args:
+ request: the twisted HTTP request.
+ name: the name of the query parameter.
+ default: value to use if the parameter is absent,
+ defaults to None.
+ required: whether to raise a 400 SynapseError if the
+ parameter is absent, defaults to False.
+ encoding: The encoding to decode the string content with.
+
+ Returns:
+ A JSON value, or `default` if the named query parameter was not found
+ and `required` was False.
+
+ Raises:
+ SynapseError if the parameter is absent and required, or if the
+ parameter is present and not a JSON object.
+ """
+ args: Mapping[bytes, Sequence[bytes]] = request.args # type: ignore
+ return parse_json_from_args(
+ args,
+ name,
+ default,
+ required=required,
+ encoding=encoding,
+ )
+
+
+def parse_json_from_args(
+ args: Mapping[bytes, Sequence[bytes]],
+ name: str,
+ default: Optional[dict] = None,
+ required: bool = False,
+ encoding: str = "ascii",
+) -> Optional[JsonDict]:
+ """
+ Parse a JSON parameter from the request query string.
+
+ Args:
+ args: a mapping of request args as bytes to a list of bytes (e.g. request.args).
+ name: the name of the query parameter.
+ default: value to use if the parameter is absent,
+ defaults to None.
+ required: whether to raise a 400 SynapseError if the
+ parameter is absent, defaults to False.
+ encoding: the encoding to decode the string content with.
+
+ A JSON value, or `default` if the named query parameter was not found
+ and `required` was False.
+
+ Raises:
+ SynapseError if the parameter is absent and required, or if the
+ parameter is present and not a JSON object.
+ """
+ name_bytes = name.encode("ascii")
+
+ if name_bytes not in args:
+ if not required:
+ return default
+
+ message = f"Missing required integer query parameter {name}"
+ raise SynapseError(HTTPStatus.BAD_REQUEST, message, errcode=Codes.MISSING_PARAM)
+
+ json_str = parse_string_from_args(args, name, required=True, encoding=encoding)
+
+ try:
+ return json_decoder.decode(urlparse.unquote(json_str))
+ except Exception:
+ message = f"Query parameter {name} must be a valid JSON object"
+ raise SynapseError(HTTPStatus.BAD_REQUEST, message, errcode=Codes.NOT_JSON)
+
+
EnumT = TypeVar("EnumT", bound=enum.Enum)
|
