feat(forges): support the GitLab public instance

gitlab.com is the public instance of GitLab.

Ref #1

Author: Linkid

DOCUMENTATION.md

@@ -109,11 +109,13 @@ fine-grained) — no scope is required for public repositories; grant repository
 read access for private ones. For Bitbucket Cloud, create a
 [repository, project or workspace access token][bb-token] (or an API token)
 with pull-request read access. For Codeberg, create an [access token][cb-token]
-in your account settings with repository read scope.
+in your account settings with repository read scope. For GitLab, create a
+[personal or project access token][gl-token] with the `read_api` scope.
 
 [gh-token]: https://github.com/settings/tokens
 [bb-token]: https://support.atlassian.com/bitbucket-cloud/docs/access-tokens/
 [cb-token]: https://docs.codeberg.org/advanced/access-token/
+[gl-token]: https://docs.gitlab.com/ee/user/profile/personal_access_tokens.html
 
 ## Forges
 
@@ -152,7 +154,8 @@ So, to add a new forge:
 Supported forges:
 - **GitHub**: https://docs.github.com/en/rest/pulls
 - **Bitbucket** (Cloud): https://developer.atlassian.com/cloud/bitbucket/rest/api-group-pullrequests/
-- **Codeberg** (Forgejo, Gitea-compatible API): https://forgejo.org/docs/latest/user/api-usage/.
+- **Codeberg** (Forgejo, Gitea-compatible API): https://forgejo.org/docs/latest/user/api-usage/
+- **GitLab**: https://docs.gitlab.com/ee/api/merge_requests.html.
 
 ## Internationalization
 

README.md

@@ -24,3 +24,4 @@ API rate limit and list pull requests from private repositories.
 - GitHub
 - Bitbucket
 - Codeberg
+- GitLab

forges.js

@@ -182,8 +182,73 @@ export const codeberg = {
     },
 }
 
+// API docs: https://docs.gitlab.com/ee/api/merge_requests.html
+// GitLab calls PRs "merge requests" and identifies a project by its full,
+// URL-encoded path (namespaces can be nested: group/subgroup/project), so the
+// adapter carries a single `projectPath` in `info` rather than a projectKey /
+// repoSlug pair. The `/-/` separator in web URLs delimits the project path from
+// the route type (blob, merge_requests, …).
+export const gitlab = {
+    label: "GitLab",
+    hostnames: ["gitlab.com"],
+    base_url: "https://gitlab.com/api/v4",
+
+    parseUrl(url) {
+        // file view: /{group}/.../{project}/-/blob/{ref}/{filepath}
+        const m = url.pathname.match(
+            "^/(?<projectPath>.+?)/-/blob/[^/]+/(?<filepath>.+)$")
+        if (!m) return null
+        return { ...m.groups, origin: url.origin }
+    },
+
+    // the project is addressed by its URL-encoded full path
+    projectId(info) {
+        return encodeURIComponent(info.projectPath)
+    },
+
+    listPRsUrl(info) {
+        // /merge_requests defaults to every state, so filter to the open ones
+        return `${this.base_url}/projects/${this.projectId(info)}/merge_requests?state=opened`
+    },
+
+    // the list endpoint returns a JSON array of merge requests
+    pullRequests(data) {
+        return data
+    },
+
+    filesUrl(info, pr) {
+        return `${this.base_url}/projects/${this.projectId(info)}/merge_requests/${this.prNumber(pr)}/diffs`
+    },
+
+    // a diff entry keeps new_path == old_path for deletions, so new_path is safe
+    filenames(files) {
+        return files.map(file => file.new_path)
+    },
+
+    // iid is the project-internal number shown in URLs (id is global)
+    prNumber(pr) {
+        return pr.iid
+    },
+
+    prWebUrl(info, prNumber) {
+        return `${info.origin}/${info.projectPath}/-/merge_requests/${prNumber}`
+    },
+
+    // GitLab exposes rate-limit info only through response headers, not a
+    // pollable endpoint.
+    rateLimit: null,
+
+    // GitLab accepts a personal or project access token via the PRIVATE-TOKEN
+    // header. Authenticating grants access to private repositories.
+    tokenStorageKey: "gitlabToken",
+
+    authHeader(token) {
+        return { "PRIVATE-TOKEN": token }
+    },
+}
+
 // registry of forges matched by a static hostname
-const staticForges = [github, bitbucket, codeberg]
+const staticForges = [github, bitbucket, codeberg, gitlab]
 
 // pick a forge adapter for a page hostname (null if none matches).
 export function forgeForHostname(hostname) {

manifest.json

@@ -54,6 +54,7 @@
   "host_permissions": [
     "*://api.github.com/*",
     "*://api.bitbucket.org/*",
-    "*://codeberg.org/*"
+    "*://codeberg.org/*",
+    "*://gitlab.com/*"
   ]
 }

tests/forges.test.js

@@ -1,7 +1,7 @@
 import { test } from "node:test"
 import assert from "node:assert/strict"
 
-import { github, bitbucket, codeberg, forgeForHostname } from "../forges.js"
+import { github, bitbucket, codeberg, gitlab, forgeForHostname } from "../forges.js"
 
 //
 // forgeForHostname
@@ -18,13 +18,16 @@ test("forgeForHostname matches codeberg.org", () => {
     assert.equal(forgeForHostname("codeberg.org"), codeberg)
 })
 
+test("forgeForHostname matches gitlab.com", () => {
+    assert.equal(forgeForHostname("gitlab.com"), gitlab)
+})
+
 test("forgeForHostname matches a subdomain containing the hostname", () => {
     // hostnames are matched as substrings of the page hostname
     assert.equal(forgeForHostname("www.github.com"), github)
 })
 
 test("forgeForHostname returns null for an unknown forge", () => {
-    assert.equal(forgeForHostname("gitlab.com"), null)
     assert.equal(forgeForHostname("example.com"), null)
 })
 
@@ -260,3 +263,71 @@ test("codeberg.authHeader builds a token Authorization header", () => {
         Authorization: "token cb_secret",
     })
 })
+
+//
+// gitlab adapter (merge requests, nested namespaces, URL-encoded project path)
+//
+test("gitlab.parseUrl extracts the project path and filepath from a blob URL", () => {
+    const url = new URL("https://gitlab.com/gitlab-org/gitlab/-/blob/master/README.md")
+    assert.deepEqual(gitlab.parseUrl(url), {
+        projectPath: "gitlab-org/gitlab",
+        filepath: "README.md",
+        origin: "https://gitlab.com",
+    })
+})
+
+test("gitlab.parseUrl keeps nested group namespaces in the project path", () => {
+    const url = new URL("https://gitlab.com/group/subgroup/widget/-/blob/main/dir/app.js")
+    const info = gitlab.parseUrl(url)
+    assert.equal(info.projectPath, "group/subgroup/widget")
+    assert.equal(info.filepath, "dir/app.js")
+})
+
+test("gitlab.parseUrl returns null for a non-file URL", () => {
+    assert.equal(gitlab.parseUrl(new URL("https://gitlab.com/acme/widget")), null)
+})
+
+test("gitlab.listPRsUrl builds the merge_requests endpoint with the encoded path", () => {
+    const info = { projectPath: "group/subgroup/widget" }
+    assert.equal(
+        gitlab.listPRsUrl(info),
+        "https://gitlab.com/api/v4/projects/group%2Fsubgroup%2Fwidget/merge_requests?state=opened")
+})
+
+test("gitlab.filesUrl builds the diffs endpoint for a merge request", () => {
+    const info = { projectPath: "acme/widget" }
+    assert.equal(
+        gitlab.filesUrl(info, { iid: 42 }),
+        "https://gitlab.com/api/v4/projects/acme%2Fwidget/merge_requests/42/diffs")
+})
+
+test("gitlab.prWebUrl builds the web URL of a merge request", () => {
+    const info = { projectPath: "acme/widget", origin: "https://gitlab.com" }
+    assert.equal(
+        gitlab.prWebUrl(info, 42),
+        "https://gitlab.com/acme/widget/-/merge_requests/42")
+})
+
+test("gitlab.prNumber reads the iid off a merge request object", () => {
+    assert.equal(gitlab.prNumber({ id: 999, iid: 7, title: "ignored" }), 7)
+})
+
+test("gitlab.pullRequests returns the list response as-is", () => {
+    const mrs = [{ iid: 1 }, { iid: 2 }]
+    assert.equal(gitlab.pullRequests(mrs), mrs)
+})
+
+test("gitlab.filenames maps diff entries to their new_path", () => {
+    const files = [{ new_path: "a.js", old_path: "a.js" }, { new_path: "dir/b.js", old_path: "dir/b.js" }]
+    assert.deepEqual(gitlab.filenames(files), ["a.js", "dir/b.js"])
+})
+
+test("gitlab exposes no rate-limit endpoint", () => {
+    assert.equal(gitlab.rateLimit, null)
+})
+
+test("gitlab.authHeader builds a PRIVATE-TOKEN header", () => {
+    assert.deepEqual(gitlab.authHeader("gl_secret"), {
+        "PRIVATE-TOKEN": "gl_secret",
+    })
+})