Feat/installation info endpoint (#7744)

* feat: add installation.info endpoint using DockerHub API

* feat: UI use an server-side API to show version info

* fix: review fixes

* test: installation.info endpoint

* feat: filtering pre-releases in installation.info endpoint

* fix: change fetch to ApiClient usage for getting version info

* Undo translation change

---------

Co-authored-by: Tom Moor <tom.moor@gmail.com>

server/utils/getInstallationInfo.ts

@@ -0,0 +1,62 @@
+import { version } from "../../package.json";
+import fetch from "./fetch";
+
+const dockerhubLink =
+  "https://hub.docker.com/v2/repositories/outlinewiki/outline";
+
+function isFullReleaseVersion(versionName: string): boolean {
+  const releaseRegex = /^(version-)?\d+\.\d+\.\d+$/; // Matches "N.N.N" or "version-N.N.N" for dockerhub releases before v0.56.0"
+  return releaseRegex.test(versionName);
+}
+
+export async function getVersionInfo(currentVersion: string): Promise<{
+  latestVersion: string;
+  versionsBehind: number;
+}> {
+  let allVersions: string[] = [];
+  let latestVersion: string | null = null;
+  let nextUrl: string | null =
+    dockerhubLink + "/tags?name=&ordering=last_updated&page_size=100";
+
+  // Continue fetching pages until the required versions are found or no more pages
+  while (nextUrl) {
+    const response = await fetch(nextUrl);
+    const data = await response.json();
+
+    // Map and filter the versions to keep only full releases
+    const pageVersions = data.results
+      .map((result: any) => result.name)
+      .filter(isFullReleaseVersion);
+
+    allVersions = allVersions.concat(pageVersions);
+
+    // Set the latest version if not already set
+    if (!latestVersion && pageVersions.length > 0) {
+      latestVersion = pageVersions[0];
+    }
+
+    // Check if the current version is found
+    const currentIndex = allVersions.findIndex(
+      (version: string) => version === currentVersion
+    );
+
+    if (currentIndex !== -1) {
+      const versionsBehind = currentIndex; // The number of versions behind
+      return {
+        latestVersion: latestVersion || currentVersion, // Fallback to current if no latest found
+        versionsBehind,
+      };
+    }
+
+    nextUrl = data.next || null;
+  }
+
+  return {
+    latestVersion: latestVersion || currentVersion,
+    versionsBehind: -1, // Return -1 if current version is not found
+  };
+}
+
+export function getVersion(): string {
+  return version;
+}