Federation: Implement Query Profile API

Implements the server portion of: `GET
/_matrix/federation/v1/query/profile?user_id=...&field=...`

Closes #278

Signed-off-by: Andrew (anoa) <anoa@openmailbox.org>

src/github.com/matrix-org/dendrite/clientapi/jsonerror/jsonerror.go

@@ -67,6 +67,18 @@ func NotFound(msg string) *MatrixError {
 	return &MatrixError{"M_NOT_FOUND", msg}
 }
 
+// MissingArgument is an error when the client tries to access a resource
+// without providing an argument that is required.
+func MissingArgument(msg string) *MatrixError {
+	return &MatrixError{"M_MISSING_ARGUMENT", msg}
+}
+
+// InvalidArgumentBody is an error when the client tries to provide an
+// invalid body under a valid argument
+func InvalidArgumentBody(msg string) *MatrixError {
+	return &MatrixError{"M_INVALID_ARGUMENT_BODY", msg}
+}
+
 // MissingToken is an error when the client tries to access a resource which
 // requires authentication without supplying credentials.
 func MissingToken(msg string) *MatrixError {

src/github.com/matrix-org/dendrite/federationapi/routing/profile.go

@@ -0,0 +1,93 @@
+// Copyright 2017 New Vector 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.
+
+package routing
+
+import (
+	"net/http"
+
+	"github.com/matrix-org/dendrite/clientapi/auth/storage/accounts"
+	"github.com/matrix-org/dendrite/clientapi/httputil"
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+type profileResponse struct {
+	AvatarURL   string `json:"avatar_url"`
+	DisplayName string `json:"displayname"`
+}
+
+type avatarURL struct {
+	AvatarURL string `json:"avatar_url"`
+}
+
+type displayName struct {
+	DisplayName string `json:"displayname"`
+}
+
+// GetProfile implements /_matrix/federation/v1/query/profile
+func GetProfile(
+	httpReq *http.Request,
+	accountDB *accounts.Database,
+) util.JSONResponse {
+	userID, field := httpReq.FormValue("user_id"), httpReq.FormValue("field")
+
+	// httpReq.FormValue will return an empty string if value is not found
+	if userID == "" {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.MissingArgument("The request body did not contain required argument 'user_id'."),
+		}
+	}
+
+	localpart, _, err := gomatrixserverlib.SplitID('@', userID)
+	if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+
+	profile, err := accountDB.GetProfileByLocalpart(httpReq.Context(), localpart)
+	if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+
+	var res interface{}
+	code := 200
+
+	if field != "" {
+		switch field {
+		case "displayname":
+			res = displayName{
+				profile.DisplayName,
+			}
+		case "avatar_url":
+			res = avatarURL{
+				profile.AvatarURL,
+			}
+		default:
+			code = 400
+			res = jsonerror.InvalidArgumentBody("The request body did not contain allowed values of argument 'field'. Allowed: 'avatar_url', 'displayname'.")
+		}
+	} else {
+		res = profileResponse{
+			profile.AvatarURL,
+			profile.DisplayName,
+		}
+	}
+
+	return util.JSONResponse{
+		Code: code,
+		JSON: res,
+	}
+}

src/github.com/matrix-org/dendrite/federationapi/routing/routing.go

@@ -105,6 +105,15 @@ func Setup(
 		},
 	)).Methods("GET")
 
+	v1fedmux.Handle("/query/profile", common.MakeFedAPI(
+		"federation_query_profile", cfg.Matrix.ServerName, keys,
+		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
+			return GetProfile(
+				httpReq, accountDB,
+			)
+		},
+	)).Methods("GET")
+
 	v1fedmux.Handle("/version", common.MakeExternalAPI(
 		"federation_version",
 		func(httpReq *http.Request) util.JSONResponse {