vscode: add error handling to downloadFile()

Author: Veetaha

editors/code/src/installation/download_file.ts

@@ -13,16 +13,23 @@ export async function downloadFile(
     destFilePath: fs.PathLike,
     onProgress: (readBytes: number, totalBytes: number) => void
 ): Promise<void> {
-    const response = await fetch(url);
+    const res = await fetch(url);
 
-    const totalBytes = Number(response.headers.get('content-length'));
+    if (!res.ok) {
+        console.log("Error", res.status, "while downloading file from", url);
+        console.dir({ body: await res.text(), headers: res.headers }, { depth: 3 });
+
+        throw new Error(`Got response ${res.status} when trying to download a file`);
+    }
+
+    const totalBytes = Number(res.headers.get('content-length'));
     assert(!Number.isNaN(totalBytes), "Sanity check of content-length protocol");
 
     let readBytes = 0;
 
     console.log("Downloading file of", totalBytes, "bytes size from", url, "to", destFilePath);
 
-    return new Promise<void>((resolve, reject) => response.body
+    return new Promise<void>((resolve, reject) => res.body
         .on("data", (chunk: Buffer) => {
             readBytes += chunk.length;
             onProgress(readBytes, totalBytes);