Add canonical support

clientapi/jsonerror/jsonerror.go

@@ -58,6 +58,11 @@ func BadJSON(msg string) *MatrixError {
 	return &MatrixError{"M_BAD_JSON", msg}
 }
 
+// BadAlias is an error when the client supplies a bad alias.
+func BadAlias(msg string) *MatrixError {
+	return &MatrixError{"M_BAD_ALIAS", msg}
+}
+
 // NotJSON is an error when the client supplies something that is not JSON
 // to a JSON endpoint.
 func NotJSON(msg string) *MatrixError {

clientapi/routing/sendevent.go

@@ -16,6 +16,8 @@ package routing
 
 import (
 	"context"
+	"encoding/json"
+	"fmt"
 	"net/http"
 	"sync"
 	"time"
@@ -120,6 +122,40 @@ func SendEvent(
 	}
 	timeToGenerateEvent := time.Since(startedGeneratingEvent)
 
+	// validate that the aliases exists
+	if eventType == gomatrixserverlib.MRoomCanonicalAlias {
+		aliasReq := api.AliasEvent{}
+		if err = json.Unmarshal(e.Content(), &aliasReq); err != nil {
+			return util.ErrorResponse(fmt.Errorf("unable to parse alias event: %w", err))
+		}
+		if !aliasReq.Valid() {
+			return util.JSONResponse{
+				Code: http.StatusBadRequest,
+				JSON: jsonerror.InvalidParam("Request contains invalid aliases."),
+			}
+		}
+		aliasRes := &api.GetAliasesForRoomIDResponse{}
+		if err = rsAPI.GetAliasesForRoomID(req.Context(), &api.GetAliasesForRoomIDRequest{RoomID: roomID}, aliasRes); err != nil {
+			return jsonerror.InternalServerError()
+		}
+		var found int
+		requestAliases := append(aliasReq.AltAliases, aliasReq.Alias)
+		for _, alias := range aliasRes.Aliases {
+			for _, altAlias := range requestAliases {
+				if altAlias == alias {
+					found++
+				}
+			}
+		}
+		// check that we found at least the same amount of existing aliases as are in the request
+		if aliasReq.Alias != "" && found < len(requestAliases) {
+			return util.JSONResponse{
+				Code: http.StatusBadRequest,
+				JSON: jsonerror.BadAlias("No matching alias found."),
+			}
+		}
+	}
+
 	var txnAndSessionID *api.TransactionID
 	if txnID != nil {
 		txnAndSessionID = &api.TransactionID{

roomserver/api/alias.go

@@ -14,6 +14,8 @@
 
 package api
 
+import "regexp"
+
 // SetRoomAliasRequest is a request to SetRoomAlias
 type SetRoomAliasRequest struct {
 	// ID of the user setting the alias
@@ -84,3 +86,27 @@ type RemoveRoomAliasResponse struct {
 	// Did we remove it?
 	Removed bool `json:"removed"`
 }
+
+type AliasEvent struct {
+	Alias      string   `json:"alias"`
+	AltAliases []string `json:"alt_aliases"`
+}
+
+var validateAliasRegex = regexp.MustCompile("^#.*:.+$")
+
+func (a AliasEvent) Valid() bool {
+	// alias is set to be removed
+	if a.Alias == "" {
+		return true
+	}
+	if !validateAliasRegex.MatchString(a.Alias) {
+		return false
+	}
+	for _, alias := range a.AltAliases {
+		if !validateAliasRegex.MatchString(alias) {
+			return false
+		}
+	}
+	return true
+}
+

roomserver/internal/alias.go

@@ -16,12 +16,15 @@ package internal
 
 import (
 	"context"
+	"database/sql"
 	"fmt"
-
+	"time"
-	"github.com/matrix-org/dendrite/roomserver/api"
-	"github.com/matrix-org/gomatrixserverlib"
 
 	asAPI "github.com/matrix-org/dendrite/appservice/api"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
 )
 
 // RoomserverInternalAPIDatabase has the storage APIs needed to implement the alias API.
@@ -183,6 +186,65 @@ func (r *RoomserverInternalAPI) RemoveRoomAlias(
 		}
 	}
 
+	ev, err := r.DB.GetStateEvent(ctx, roomID, gomatrixserverlib.MRoomCanonicalAlias, "")
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+
+	stateAlias := gjson.GetBytes(ev.Content(), "alias").Str
+	// the alias to remove is currently set as the canonical alias, remove it
+	if stateAlias == request.Alias {
+		res, err := sjson.DeleteBytes(ev.Content(), "alias")
+		if err != nil {
+			return err
+		}
+
+		stateRes := &api.QueryLatestEventsAndStateResponse{}
+
+		if err = r.QueryLatestEventsAndState(ctx, &api.QueryLatestEventsAndStateRequest{RoomID: roomID}, stateRes); err != nil {
+			return err
+		}
+
+		stateEventIDs := make([]string, len(stateRes.StateEvents))
+		for i, ev := range stateRes.StateEvents {
+			stateEventIDs[i] = ev.EventID()
+		}
+
+		sender := request.UserID
+		if request.UserID != ev.Sender() {
+			sender = ev.Sender()
+		}
+		builder := &gomatrixserverlib.EventBuilder{
+			Sender:     sender,
+			RoomID:     ev.RoomID(),
+			Type:       ev.Type(),
+			StateKey:   ev.StateKey(),
+			PrevEvents: []string{ev.EventID()},
+			AuthEvents: stateEventIDs,
+			Content:    res,
+		}
+
+		newEvent, err := builder.Build(time.Now(), r.ServerName, r.Cfg.Matrix.KeyID, r.Cfg.Matrix.PrivateKey, ev.RoomVersion)
+		if err != nil {
+			return err
+		}
+
+		inputEvent := api.InputRoomEvent{
+			Kind:          api.KindNew,
+			Event:         newEvent.Headered(ev.RoomVersion),
+			Origin:        r.ServerName,
+			StateEventIDs: stateEventIDs,
+			HasState:      true,
+			SendAsServer:  string(r.ServerName),
+		}
+
+		respInput := &api.InputRoomEventsResponse{}
+		r.InputRoomEvents(ctx, &api.InputRoomEventsRequest{InputRoomEvents: []api.InputRoomEvent{inputEvent}}, respInput)
+		if respInput.NotAllowed || respInput.ErrMsg != "" {
+			return fmt.Errorf(respInput.ErrMsg)
+		}
+	}
+
 	// Remove the alias from the database
 	if err := r.DB.RemoveRoomAlias(ctx, request.Alias); err != nil {
 		return err

sytest-whitelist

@@ -604,4 +604,7 @@ Remote banned user is kicked and may not rejoin until unbanned
 registration remembers parameters
 registration accepts non-ascii passwords
 registration with inhibit_login inhibits login
-
+Canonical alias can be set
+Canonical alias can include alt_aliases
+Can delete canonical alias
+Multiple calls to /sync should not cause 500 errors