Add /_dendrite/admin/purgeRoom/{roomID} (#2662)

This adds a new admin endpoint `/_dendrite/admin/purgeRoom/{roomID}`. It
completely erases all database entries for a given room ID.

The roomserver will start by clearing all data for that room and then
will generate an output event to notify downstream components (i.e. the
sync API and federation API) to do the same.

It does not currently clear media and it is currently not implemented
for SQLite since it relies on SQL array operations right now.

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
Co-authored-by: Till Faelligen <2353100+S7evinK@users.noreply.github.com>

clientapi/routing/admin.go

@@ -1,6 +1,7 @@
 package routing
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -98,6 +99,37 @@ func AdminEvacuateUser(req *http.Request, cfg *config.ClientAPI, device *userapi
 	}
 }
 
+func AdminPurgeRoom(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, rsAPI roomserverAPI.ClientRoomserverAPI) util.JSONResponse {
+	vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
+	if err != nil {
+		return util.ErrorResponse(err)
+	}
+	roomID, ok := vars["roomID"]
+	if !ok {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.MissingArgument("Expecting room ID."),
+		}
+	}
+	res := &roomserverAPI.PerformAdminPurgeRoomResponse{}
+	if err := rsAPI.PerformAdminPurgeRoom(
+		context.Background(),
+		&roomserverAPI.PerformAdminPurgeRoomRequest{
+			RoomID: roomID,
+		},
+		res,
+	); err != nil {
+		return util.ErrorResponse(err)
+	}
+	if err := res.Error; err != nil {
+		return err.JSONResponse()
+	}
+	return util.JSONResponse{
+		Code: 200,
+		JSON: res,
+	}
+}
+
 func AdminResetPassword(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, userAPI userapi.ClientUserAPI) util.JSONResponse {
 	if req.Body == nil {
 		return util.JSONResponse{

clientapi/routing/routing.go

@@ -165,6 +165,12 @@ func Setup(
 		}),
 	).Methods(http.MethodGet, http.MethodOptions)
 
+	dendriteAdminRouter.Handle("/admin/purgeRoom/{roomID}",
+		httputil.MakeAdminAPI("admin_purge_room", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			return AdminPurgeRoom(req, cfg, device, rsAPI)
+		}),
+	).Methods(http.MethodPost, http.MethodOptions)
+
 	dendriteAdminRouter.Handle("/admin/resetPassword/{userID}",
 		httputil.MakeAdminAPI("admin_reset_password", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
 			return AdminResetPassword(req, cfg, device, userAPI)