initial commit

src/Link.js

@@ -0,0 +1,151 @@
+/*
+Copyright 2020 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.
+*/
+
+
+import {createEnum} from "./utils/enum.js";
+
+const ROOMALIAS_PATTERN = /^#([^:]*):(.+)$/;
+const ROOMID_PATTERN = /^!([^:]*):(.+)$/;
+const EVENT_WITH_ROOMID_PATTERN = /^[!]([^:]*):(.+)\/\$([^:]+):(.+)$/;
+const EVENT_WITH_ROOMALIAS_PATTERN = /^[#]([^:]*):(.+)\/\$([^:]+):(.+)$/;
+const USERID_PATTERN = /^@([^:]+):(.+)$/;
+const GROUPID_PATTERN = /^\+([^:]+):(.+)$/;
+
+export const IdentifierKind = createEnum(
+	"RoomId",
+	"RoomAlias",
+	"UserId",
+	"GroupId",
+);
+
+function asPrefix(identifierKind) {
+	switch (identifierKind) {
+		case IdentifierKind.RoomId: return "!";
+		case IdentifierKind.RoomAlias: return "#";
+		case IdentifierKind.GroupId: return "+";
+		case IdentifierKind.UserId: return "@";
+		default: throw new Error("invalid id kind " + identifierKind);
+	}
+}
+
+export const LinkKind = createEnum(
+	"Room",
+	"User",
+	"Group",
+	"Event"
+)
+
+function orderedUnique(array) {
+	const copy = [];
+	for (let i = 0; i < array.length; ++i) {
+		if (i === 0 || array.lastIndexOf(array[i], i - 1) === -1) {
+			copy.push(array[i]);
+		}
+	}
+	return copy;
+}
+
+export class Link {
+	static parseFragment(fragment) {
+		let [identifier, queryParams] = fragment.split("?");
+
+		let viaServers = [];
+		if (queryParams) {
+			viaServers = queryParams.split("&")
+				.map(pair => pair.split("="))
+				.filter(([key, value]) => key === "via")
+				.map(([,value]) => value);
+		}
+
+		if (identifier.startsWith("#/")) {
+			identifier = identifier.substr(2);
+		}
+
+		let kind;
+		let matches;
+		// longest first, so they dont get caught by ROOMALIAS_PATTERN and ROOMID_PATTERN
+		matches = EVENT_WITH_ROOMID_PATTERN.exec(identifier);
+		if (matches) {
+			const roomServer = matches[2];
+			const messageServer = matches[4];
+			const roomLocalPart = matches[1];
+			const messageLocalPart = matches[3];
+			return new Link(viaServers, IdentifierKind.RoomId, roomLocalPart, roomServer, messageLocalPart, messageServer);
+		}
+		matches = EVENT_WITH_ROOMALIAS_PATTERN.exec(identifier);
+		if (matches) {
+			const roomServer = matches[2];
+			const messageServer = matches[4];
+			const roomLocalPart = matches[1];
+			const messageLocalPart = matches[3];
+			return new Link(viaServers, IdentifierKind.RoomAlias, roomLocalPart, roomServer, messageLocalPart, messageServer);
+		}
+		matches = USERID_PATTERN.exec(identifier);
+		if (matches) {
+			const server = matches[2];
+			const localPart = matches[1];
+			return new Link(viaServers, IdentifierKind.UserId, localPart, server);
+		}
+		matches = ROOMALIAS_PATTERN.exec(identifier);
+		if (matches) {
+			const server = matches[2];
+			const localPart = matches[1];
+			return new Link(viaServers, IdentifierKind.RoomAlias, localPart, server);
+		}
+		matches = ROOMID_PATTERN.exec(identifier);
+		if (matches) {
+			const server = matches[2];
+			const localPart = matches[1];
+			return new Link(viaServers, IdentifierKind.RoomId, localPart, server);
+		}
+		matches = GROUPID_PATTERN.exec(identifier);
+		if (matches) {
+			const server = matches[2];
+			const localPart = matches[1];
+			return new Link(viaServers, IdentifierKind.GroupId, localPart, server);
+		}
+		return;
+	}
+
+	constructor(viaServers, identifierKind, localPart, server, messageLocalPart = null, messageServer = null) {
+		const servers = [server];
+		if (messageServer) {
+			servers.push(messageServer);
+		}
+		servers.push(...viaServers);
+		this.servers = orderedUnique(servers);
+		this.identifierKind = identifierKind;
+		this.identifier = `${asPrefix(identifierKind)}${localPart}:${server}`;
+		this.eventId = messageLocalPart ? `$${messageLocalPart}:${messageServer}` : null;
+	}
+
+	get kind() {
+		if (this.eventId) {
+			return LinkKind.Event;
+		}
+		switch (this.identifierKind) {
+			case IdentifierKind.RoomId:
+			case IdentifierKind.RoomAlias:
+				return LinkKind.Room;
+			case IdentifierKind.UserId:
+				return LinkKind.User;
+			case IdentifierKind.GroupId:
+				return LinkKind.Group;
+			default:
+				return null;
+		}
+	}
+}