Merge pull request #89 from matrix-org/matrixtwo/linkparser

Create link parser and formatter

jest.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+};

package.json

@@ -63,6 +63,7 @@
         "@testing-library/user-event": "^7.1.2",
         "@types/classnames": "^2.2.10",
         "@types/jest": "^24.0.0",
+        "@types/lodash": "^4.14.159",
         "@types/node": "^12.0.0",
         "@types/react": "^16.9.0",
         "@types/react-dom": "^16.9.0",
@@ -73,6 +74,7 @@
         "node-sass": "^4.14.1",
         "prettier": "^2.0.5",
         "storybook-addon-designs": "^5.4.0",
+        "ts-jest": "^26.1.4",
         "typescript": "~3.7.2"
     }
 }

src/components/CreateLinkTile.stories.tsx

@@ -23,7 +23,8 @@ export default {
     parameters: {
         design: {
             type: "figma",
-            url: "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=59%3A1",
+            url:
+                "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=59%3A1",
         },
     },
 };

src/components/Input.stories.tsx

@@ -25,7 +25,8 @@ export default {
     parameters: {
         design: {
             type: "figma",
-            url: "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=59%3A1",
+            url:
+                "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=59%3A1",
         },
     },
     decorators: [withDesign],

src/components/TextButton.stories.tsx

@@ -23,7 +23,8 @@ export default {
     parameters: {
         design: {
             type: "figma",
-            url: "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=149%3A10756",
+            url:
+                "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=149%3A10756",
         },
     },
 };

src/components/Tile.stories.tsx

@@ -23,7 +23,8 @@ export default {
     parameters: {
         design: {
             type: "figma",
-            url: "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=143%3A5853",
+            url:
+                "https://figma.com/file/WSXjCGc1k6FVI093qhlzOP/04-Recieving-share-link?node-id=143%3A5853",
         },
     },
 };

src/parser/parser.test.ts

@@ -0,0 +1,64 @@
+/* eslint-disable no-fallthrough */
+
+import {
+    parseHash,
+    parsePermalink,
+    parseArgs,
+    verifiers,
+    identifyTypeFromRegex,
+    toURL,
+} from "./parser";
+
+import { LinkKind } from "./types";
+
+const identifierType = (id: string): LinkKind =>
+    identifyTypeFromRegex(id, verifiers, LinkKind.ParseFailed);
+
+it("types identifiers correctly", () => {
+    expect(identifierType("@user:matrix.org")).toEqual(LinkKind.UserId);
+    expect(identifierType("!room:matrix.org")).toEqual(LinkKind.RoomId);
+    expect(identifierType("!somewhere:example.org/$event:example.org")).toEqual(
+        LinkKind.Permalink
+    );
+    expect(identifierType("+group:matrix.org")).toEqual(LinkKind.GroupId);
+    expect(identifierType("#alias:matrix.org")).toEqual(LinkKind.Alias);
+});
+
+it("types garbage as such", () => {
+    expect(identifierType("sdfa;fdlkja")).toEqual(LinkKind.ParseFailed);
+    expect(identifierType("$event$matrix.org")).toEqual(LinkKind.ParseFailed);
+    expect(identifierType("/user:matrix.org")).toEqual(LinkKind.ParseFailed);
+});
+
+it("parses args correctly", () => {
+    expect(
+        parseArgs("via=example.org&via=alt.example.org")
+    ).toHaveProperty("vias", ["example.org", "alt.example.org"]);
+    expect(parseArgs("sharer=blah")).toHaveProperty("sharer", "blah");
+    expect(parseArgs("client=blah.com")).toHaveProperty("client", "blah.com");
+});
+
+it("parses permalinks", () => {
+    expect(parsePermalink("!somewhere:example.org/$event:example.org")).toEqual(
+        {
+            roomKind: LinkKind.RoomId,
+            roomLink: "!somewhere:example.org",
+            eventId: "$event:example.org",
+        }
+    );
+});
+
+it("formats links correctly", () => {
+    const bigLink =
+        "!somewhere:example.org/$event:example.org?via=dfasdf&via=jfjafjaf";
+    const origin = "https://matrix.org";
+    const prefix = origin + "/#/";
+    const parse = parseHash(bigLink);
+
+    switch (parse.kind) {
+        case LinkKind.ParseFailed:
+            fail("Parse failed");
+        default:
+            expect(toURL(origin, parse).toString()).toEqual(prefix + bigLink);
+    }
+});

src/parser/parser.ts

@@ -0,0 +1,163 @@
+import forEach from "lodash/forEach";
+
+import {
+    LinkKind,
+    SafeLink,
+    Link,
+    LinkContent,
+    Arguments,
+    Permalink,
+} from "./types";
+
+/*
+ * Verifiers are regexes which will match valid
+ * identifiers to their type. (This is a lie, they
+ * can return anything)
+ */
+type Verifier<A> = [RegExp, A];
+export const roomVerifiers: Verifier<LinkKind.Alias | LinkKind.RoomId>[] = [
+    [/^#([^/:]+?):(.+)$/, LinkKind.Alias],
+    [/^!([^/:]+?):(.+)$/, LinkKind.RoomId],
+];
+export const verifiers: Verifier<LinkKind>[] = [
+    [/^[!#]([^/:]+?):(.+?)\/\$([^/:]+?):(.+?)$/, LinkKind.Permalink],
+    [/^@([^/:]+?):(.+)$/, LinkKind.UserId],
+    [/^\+([^/:]+?):(.+)$/, LinkKind.GroupId],
+    ...roomVerifiers,
+];
+
+/*
+ * identifyTypeFromRegex applies the verifiers to the identifier and
+ * returns the identifier's type
+ */
+export function identifyTypeFromRegex<T, F>(
+    identifier: string,
+    verifiers: Verifier<T>[],
+    fail: F
+): T | F {
+    if (identifier !== encodeURI(identifier)) {
+        return fail;
+    }
+
+    return verifiers.reduce<T | F>((kind, verifier) => {
+        if (kind !== fail) {
+            return kind;
+        }
+
+        if (identifier.match(verifier[0])) {
+            return verifier[1];
+        }
+
+        return kind;
+    }, fail);
+}
+
+/*
+ * Parses a permalink.
+ * Assumes the permalink is correct.
+ */
+export function parsePermalink(identifier: string): Permalink {
+    const [roomLink, eventId] = identifier.split("/");
+    const roomKind = identifyTypeFromRegex(
+        roomLink,
+        roomVerifiers,
+        // This is hacky but we're assuming identifier is a valid permalink
+        LinkKind.Alias
+    );
+
+    return {
+        roomKind,
+        roomLink,
+        eventId,
+    };
+}
+
+/*
+ * Repalces null with undefined
+ */
+function bottomExchange<T>(nullable: T | null): T | undefined {
+    if (nullable === null) return undefined;
+    return nullable;
+}
+
+/*
+ * parseArgs parses the <extra args> part of matrix.to links
+ */
+export function parseArgs(args: string): Arguments {
+    const params = new URLSearchParams(args);
+
+    return {
+        vias: params.getAll("via"),
+        client: bottomExchange(params.get("client")),
+        sharer: bottomExchange(params.get("sharer")),
+    };
+}
+
+/*
+ * parseLink takes a striped matrix.to hash link (without the '#/' prefix)
+ * and parses into a Link. If the parse failed the result will
+ * be ParseFailed
+ */
+export function parseHash(hash: string): Link {
+    const [identifier, args] = hash.split("?");
+
+    const kind = identifyTypeFromRegex(
+        identifier,
+        verifiers,
+        LinkKind.ParseFailed
+    );
+
+    const parsedLink: LinkContent = {
+        identifier,
+        arguments: parseArgs(args),
+        originalLink: hash,
+    };
+
+    if (kind === LinkKind.Permalink) {
+        const { roomKind, roomLink, eventId } = parsePermalink(identifier);
+
+        return {
+            kind,
+            ...parsedLink,
+            roomKind,
+            roomLink,
+            eventId,
+        };
+    }
+
+    return {
+        kind,
+        ...parsedLink,
+    };
+}
+
+/*
+ * toURI converts a Link to a url. It's recommended
+ * to use the original link instead of toURI if it existed.
+ * This is handy function in case the Link was constructed.
+ */
+export function toURL(origin: string, link: SafeLink): URL {
+    const params = new URLSearchParams();
+    const url = new URL(origin);
+    switch (link.kind) {
+        case LinkKind.GroupId:
+        case LinkKind.UserId:
+        case LinkKind.RoomId:
+        case LinkKind.Alias:
+        case LinkKind.Permalink:
+            forEach(link.arguments, (value, key) => {
+                if (value === undefined) {
+                    // do nothing
+                } else if (key === "vias") {
+                    (value as string[]).forEach((via) =>
+                        params.append("via", via)
+                    );
+                } else {
+                    params.append(key, value.toString());
+                }
+            });
+
+            url.hash = `/${link.identifier}?${params.toString()}`;
+    }
+    return url;
+}

src/parser/types.ts

@@ -0,0 +1,54 @@
+export interface Arguments {
+    vias: string[];
+    // Schemeless http identifier
+    client?: string;
+    // MXID
+    sharer?: string;
+}
+
+export interface LinkContent {
+    identifier: string;
+    arguments: Arguments;
+    originalLink: string;
+}
+
+export enum LinkKind {
+    Alias = "ALIAS",
+    RoomId = "ROOM_ID",
+    UserId = "USER_ID",
+    Permalink = "PERMALINK",
+    GroupId = "GROUP_ID",
+    ParseFailed = "PARSE_FAILED",
+}
+
+export interface Alias extends LinkContent {
+    kind: LinkKind.Alias;
+}
+
+export interface RoomId extends LinkContent {
+    kind: LinkKind.RoomId;
+}
+
+export interface UserId extends LinkContent {
+    kind: LinkKind.UserId;
+}
+
+export interface GroupId extends LinkContent {
+    kind: LinkKind.GroupId;
+}
+
+export interface Permalink extends LinkContent {
+    kind: LinkKind.Permalink;
+    roomKind: LinkKind.RoomId | LinkKind.Alias;
+    roomLink: string;
+    eventId: string;
+}
+
+export interface ParseFailed {
+    kind: LinkKind.ParseFailed;
+    originalLink: string;
+}
+
+export type SafeLink = Alias | RoomId | UserId | Permalink | GroupId;
+
+export type Link = SafeLink | ParseFailed;

tsconfig.json

@@ -16,6 +16,7 @@
         "moduleResolution": "node",
         "resolveJsonModule": true,
         "isolatedModules": true,
+        "strictNullChecks": true,
         "noEmit": true,
         "jsx": "react"
     },