feat: add getInstallationUrl method (#542)

README.md

@@ -16,6 +16,7 @@
   - [`app.getInstallationOctokit`](#appgetinstallationoctokit)
   - [`app.eachInstallation`](#appeachinstallation)
   - [`app.eachRepository`](#appeachrepository)
+  - [`app.getInstallationUrl`](#appgetinstallationurl)
   - [`app.webhooks`](#appwebhooks)
   - [`app.oauth`](#appoauth)
 - [Middlewares](#middlewares)
@@ -299,6 +300,22 @@ for await (const { octokit, repository } of app.eachRepository.iterator({ instal
 await app.eachRepository({ installationId }, ({ octokit, repository }) => /* ... */)
 ```
 
+### `app.getInstallationUrl`
+
+```js
+const installationUrl = await app.getInstallationUrl();
+return res.redirect(installationUrl);
+```
+
+Optionally pass the ID of a GitHub organization or user to request installation on that specific target.
+
+If the user will be sent to a redirect URL after installation (such as if you request user authorization during installation), you can also supply a `state` string that will be included in the query of the post-install redirect.
+
+```js
+const installationUrl = await app.getInstallationUrl({ state, target_id });
+return res.redirect(installationUrl);
+```
+
 ### `app.webhooks`
 
 An [`@octokit/webhooks` instance](https://github.com/octokit/webhooks.js/#readme)

src/get-installation-url.ts

@@ -0,0 +1,39 @@
+import type { App } from "./index.js";
+import type { GetInstallationUrlOptions } from "./types.js";
+
+export function getInstallationUrlFactory(app: App) {
+  let installationUrlBasePromise: Promise<string> | undefined;
+
+  return async function getInstallationUrl(
+    options: GetInstallationUrlOptions = {},
+  ) {
+    if (!installationUrlBasePromise) {
+      installationUrlBasePromise = getInstallationUrlBase(app);
+    }
+
+    const installationUrlBase = await installationUrlBasePromise;
+    const installationUrl = new URL(installationUrlBase);
+
+    if (options.target_id !== undefined) {
+      installationUrl.pathname += "/permissions";
+      installationUrl.searchParams.append(
+        "target_id",
+        options.target_id.toFixed(),
+      );
+    }
+
+    if (options.state !== undefined) {
+      installationUrl.searchParams.append("state", options.state);
+    }
+
+    return installationUrl.href;
+  };
+}
+
+async function getInstallationUrlBase(app: App) {
+  const { data: appInfo } = await app.octokit.request("GET /app");
+  if (!appInfo) {
+    throw new Error("[@octokit/app] unable to fetch metadata for app");
+  }
+  return `${appInfo.html_url}/installations/new`;
+}

src/index.ts

@@ -9,6 +9,7 @@ import type {
   EachInstallationInterface,
   EachRepositoryInterface,
   GetInstallationOctokitInterface,
+  GetInstallationUrlInterface,
 } from "./types.js";
 
 // Export types required for the App class
@@ -18,13 +19,15 @@ export type {
   EachInstallationInterface,
   EachRepositoryInterface,
   GetInstallationOctokitInterface,
+  GetInstallationUrlInterface,
 } from "./types.js";
 
 import { VERSION } from "./version.js";
 import { webhooks } from "./webhooks.js";
 import { eachInstallationFactory } from "./each-installation.js";
 import { eachRepositoryFactory } from "./each-repository.js";
 import { getInstallationOctokit } from "./get-installation-octokit.js";
+import { getInstallationUrlFactory } from "./get-installation-url.js";
 
 type Constructor<T> = new (...args: any[]) => T;
 
@@ -70,6 +73,7 @@ export class App<TOptions extends Options = Options> {
   >;
   eachInstallation: EachInstallationInterface<OctokitType<TOptions>>;
   eachRepository: EachRepositoryInterface<OctokitType<TOptions>>;
+  getInstallationUrl: GetInstallationUrlInterface;
   log: {
     debug: (message: string, additionalInfo?: object) => void;
     info: (message: string, additionalInfo?: object) => void;
@@ -150,6 +154,7 @@ export class App<TOptions extends Options = Options> {
     this.eachRepository = eachRepositoryFactory(
       this,
     ) as EachRepositoryInterface<OctokitType<TOptions>>;
+    this.getInstallationUrl = getInstallationUrlFactory(this);
   }
 }
 

src/types.ts

@@ -67,3 +67,12 @@ export interface EachRepositoryInterface<O> {
 export interface GetInstallationOctokitInterface<O> {
   (installationId: number): Promise<O>;
 }
+
+export interface GetInstallationUrlOptions {
+  state?: string;
+  target_id?: number;
+}
+
+export interface GetInstallationUrlInterface {
+  (options?: GetInstallationUrlOptions): Promise<string>;
+}

test/get-installation-url.test.ts

@@ -0,0 +1,166 @@
+import { Octokit } from "@octokit/core";
+import fetchMock from "fetch-mock";
+import MockDate from "mockdate";
+
+const APP_ID = 1;
+const PRIVATE_KEY = `-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEA1c7+9z5Pad7OejecsQ0bu3aozN3tihPmljnnudb9G3HECdnH
+lWu2/a1gB9JW5TBQ+AVpum9Okx7KfqkfBKL9mcHgSL0yWMdjMfNOqNtrQqKlN4kE
+p6RD++7sGbzbfZ9arwrlD/HSDAWGdGGJTSOBM6pHehyLmSC3DJoR/CTu0vTGTWXQ
+rO64Z8tyXQPtVPb/YXrcUhbBp8i72b9Xky0fD6PkEebOy0Ip58XVAn2UPNlNOSPS
+ye+Qjtius0Md4Nie4+X8kwVI2Qjk3dSm0sw/720KJkdVDmrayeljtKBx6AtNQsSX
+gzQbeMmiqFFkwrG1+zx6E7H7jqIQ9B6bvWKXGwIDAQABAoIBAD8kBBPL6PPhAqUB
+K1r1/gycfDkUCQRP4DbZHt+458JlFHm8QL6VstKzkrp8mYDRhffY0WJnYJL98tr4
+4tohsDbqFGwmw2mIaHjl24LuWXyyP4xpAGDpl9IcusjXBxLQLp2m4AKXbWpzb0OL
+Ulrfc1ZooPck2uz7xlMIZOtLlOPjLz2DuejVe24JcwwHzrQWKOfA11R/9e50DVse
+hnSH/w46Q763y4I0E3BIoUMsolEKzh2ydAAyzkgabGQBUuamZotNfvJoDXeCi1LD
+8yNCWyTlYpJZJDDXooBU5EAsCvhN1sSRoaXWrlMSDB7r/E+aQyKua4KONqvmoJuC
+21vSKeECgYEA7yW6wBkVoNhgXnk8XSZv3W+Q0xtdVpidJeNGBWnczlZrummt4xw3
+xs6zV+rGUDy59yDkKwBKjMMa42Mni7T9Fx8+EKUuhVK3PVQyajoyQqFwT1GORJNz
+c/eYQ6VYOCSC8OyZmsBM2p+0D4FF2/abwSPMmy0NgyFLCUFVc3OECpkCgYEA5OAm
+I3wt5s+clg18qS7BKR2DuOFWrzNVcHYXhjx8vOSWV033Oy3yvdUBAhu9A1LUqpwy
+Ma+unIgxmvmUMQEdyHQMcgBsVs10dR/g2xGjMLcwj6kn+xr3JVIZnbRT50YuPhf+
+ns1ScdhP6upo9I0/sRsIuN96Gb65JJx94gQ4k9MCgYBO5V6gA2aMQvZAFLUicgzT
+u/vGea+oYv7tQfaW0J8E/6PYwwaX93Y7Q3QNXCoCzJX5fsNnoFf36mIThGHGiHY6
+y5bZPPWFDI3hUMa1Hu/35XS85kYOP6sGJjf4kTLyirEcNKJUWH7CXY+00cwvTkOC
+S4Iz64Aas8AilIhRZ1m3eQKBgQCUW1s9azQRxgeZGFrzC3R340LL530aCeta/6FW
+CQVOJ9nv84DLYohTVqvVowdNDTb+9Epw/JDxtDJ7Y0YU0cVtdxPOHcocJgdUGHrX
+ZcJjRIt8w8g/s4X6MhKasBYm9s3owALzCuJjGzUKcDHiO2DKu1xXAb0SzRcTzUCn
+7daCswKBgQDOYPZ2JGmhibqKjjLFm0qzpcQ6RPvPK1/7g0NInmjPMebP0K6eSPx0
+9/49J6WTD++EajN7FhktUSYxukdWaCocAQJTDNYP0K88G4rtC2IYy5JFn9SWz5oh
+x//0u+zd/R/QRUzLOw4N72/Hu+UG6MNt5iDZFCtapRaKt6OvSBwy8w==
+-----END RSA PRIVATE KEY-----`;
+const CLIENT_ID = "0123";
+const CLIENT_SECRET = "0123secret";
+const WEBHOOK_SECRET = "secret";
+
+import { App } from "../src/index.ts";
+
+describe("app.getInstallationUrl", () => {
+  let app: InstanceType<typeof App>;
+  let mock: typeof fetchMock;
+
+  beforeEach(() => {
+    MockDate.set(0);
+    mock = fetchMock.sandbox();
+
+    app = new App({
+      appId: APP_ID,
+      privateKey: PRIVATE_KEY,
+      oauth: {
+        clientId: CLIENT_ID,
+        clientSecret: CLIENT_SECRET,
+      },
+      webhooks: {
+        secret: WEBHOOK_SECRET,
+      },
+      Octokit: Octokit.defaults({
+        request: {
+          fetch: mock,
+        },
+      }),
+    });
+  });
+
+  test("throws when response is null", async () => {
+    mock.getOnce("path:/app", {
+      body: "null",
+      headers: { "Content-Type": "application/json" },
+    });
+
+    await expect(app.getInstallationUrl()).rejects.toThrow(
+      "[@octokit/app] unable to fetch metadata for app",
+    );
+
+    expect(mock.done()).toBe(true);
+  });
+
+  test("returns correct url", async () => {
+    mock.getOnce("path:/app", {
+      html_url: "https://github.com/apps/octokit",
+    });
+
+    const url = await app.getInstallationUrl();
+
+    expect(url).toEqual("https://github.com/apps/octokit/installations/new");
+    expect(mock.done()).toBe(true);
+  });
+
+  test("caches url", async () => {
+    mock.getOnce("path:/app", {
+      html_url: "https://github.com/apps/octokit",
+    });
+
+    const urls = await Promise.all([
+      app.getInstallationUrl(),
+      app.getInstallationUrl(),
+      app.getInstallationUrl(),
+    ]);
+
+    expect(urls).toEqual(
+      new Array(3).fill("https://github.com/apps/octokit/installations/new"),
+    );
+    expect(mock.done()).toBe(true);
+  });
+
+  test("does not cache state", async () => {
+    mock.getOnce("path:/app", {
+      html_url: "https://github.com/apps/octokit",
+    });
+    const state = "abc123";
+
+    const urlWithoutState = await app.getInstallationUrl();
+    const urlWithState = await app.getInstallationUrl({ state });
+
+    expect(urlWithoutState).toEqual(
+      "https://github.com/apps/octokit/installations/new",
+    );
+    expect(urlWithState).toEqual(
+      `https://github.com/apps/octokit/installations/new?state=${state}`,
+    );
+    expect(mock.done()).toBe(true);
+  });
+
+  test("adds the url-encoded state string to the url", async () => {
+    mock.getOnce("path:/app", {
+      html_url: "https://github.com/apps/octokit",
+    });
+    const state = "abc123%/{";
+
+    const url = await app.getInstallationUrl({ state });
+
+    expect(url).toEqual(
+      `https://github.com/apps/octokit/installations/new?state=${encodeURIComponent(state)}`,
+    );
+    expect(mock.done()).toBe(true);
+  });
+
+  test("appends /permissions to the url when target_id present", async () => {
+    mock.getOnce("path:/app", {
+      html_url: "https://github.com/apps/octokit",
+    });
+    const target_id = 456;
+
+    const url = await app.getInstallationUrl({ target_id });
+
+    expect(url).toEqual(
+      `https://github.com/apps/octokit/installations/new/permissions?target_id=${target_id}`,
+    );
+    expect(mock.done()).toBe(true);
+  });
+
+  test("adds both state and target_id to the url", async () => {
+    mock.getOnce("path:/app", {
+      html_url: "https://github.com/apps/octokit",
+    });
+    const state = "abc123";
+    const target_id = 456;
+
+    const url = await app.getInstallationUrl({ state, target_id });
+
+    expect(url).toEqual(
+      `https://github.com/apps/octokit/installations/new/permissions?target_id=${target_id}&state=${state}`,
+    );
+    expect(mock.done()).toBe(true);
+  });
+});