Make APK download more resilient to GH issues & rate limit

Author: pimterry

src/interceptors/android/fetch-apk.ts

@@ -7,11 +7,25 @@ import * as fs from '../../util/fs';
 import { HtkConfig } from '../../config';
 import { logError } from '../../error-tracking';
 
-async function getLatestRelease(): Promise<{ version: string, url: string } | undefined> {
+const APK_REPO_RELEASE = 'httptoolkit/httptoolkit-android/releases/latest';
+
+async function getLatestRelease(): Promise<
+    | { version: string, url: string }
+    | 'unknown-latest'
+    | undefined
+> {
     try {
-        const response = await fetch(
-            "https://api.github.com/repos/httptoolkit/httptoolkit-android/releases/latest"
-        );
+        const response = await fetch(`https://api.github.com/repos/${APK_REPO_RELEASE}`);
+
+        if (response.status === 403 && response.headers.get('x-ratelimit-remaining') === '0') {
+            // Likely connectable but we can't check the version (API rate limit). Used only if
+            // we don't have any other APK available.
+            console.log("Can't check latest APK version due to GitHub rate limit");
+            return 'unknown-latest';
+        } else if (!response.ok) {
+            throw new Error(`Checking latest Android app release failed with ${response.status}`);
+        }
+
         const release = await response.json();
         const apkAsset = release.assets.filter((a: any) => a.name === "httptoolkit.apk")[0];
         const releaseName = release.name || release.tag_name;
@@ -119,8 +133,18 @@ export async function streamLatestApk(config: HtkConfig): Promise<stream.Readabl
         if (!latestApkRelease) {
             throw new Error("Couldn't find an Android APK locally or remotely");
         } else {
+            // No APK locally, but we can get one remotely:
+
             console.log('Streaming remote APK directly');
-            const apkStream = (await fetch(latestApkRelease.url)).body;
+            const apkUrl = latestApkRelease === 'unknown-latest'
+                ? `https://github.com/${APK_REPO_RELEASE}/download/httptoolkit.apk`
+                : latestApkRelease.url;
+
+            const apkResponse = await fetch(apkUrl);
+            if (!apkResponse.ok) {
+                throw new Error(`APK download failed with ${apkResponse.status}`);
+            }
+            const apkStream = apkResponse.body;
 
             // We buffer output into two passthrough streams, so both file & install
             // stream usage can be set up async independently. Buffers are 10MB, to
@@ -130,12 +154,21 @@ export async function streamLatestApk(config: HtkConfig): Promise<stream.Readabl
             const apkOutputStream = new stream.PassThrough({ highWaterMark: 10485760 });
             apkStream.pipe(apkOutputStream);
 
-            updateLocalApk(latestApkRelease.version, apkFileStream, config).catch(logError);
+            if (latestApkRelease !== 'unknown-latest') {
+                updateLocalApk(latestApkRelease.version, apkFileStream, config).catch(logError);
+            }
+
             return apkOutputStream;
         }
     }
 
-    if (!latestApkRelease || semver.gte(localApk.version, latestApkRelease.version, true)) {
+    // So, we now have a local APK. Do we want to pull the remote one anyway?
+
+    if (
+        !latestApkRelease || // Can't get releases at all
+        latestApkRelease === 'unknown-latest' || // Can get, but don't know the version
+        semver.gte(localApk.version, latestApkRelease.version, true) // Already up to date
+    ) {
         console.log('Streaming local APK');
         // If we have an APK locally and it's up to date, or we can't tell, just use it
         return fs.createReadStream(localApk.path);