fix: Check gzip log via magic numbers (#1891)

* We are directly checking the bytes content of the log.
    If, for any reason, the content is not compressed, or is compressed
    but with wrong file extension, we are still going to properly
    decompress the file content.

Closes #1887

Author: alanpeixinho

dashboard/src/api/logViewer.ts

@@ -16,33 +16,29 @@ const STALE_DURATION_MS = minutesToMilliseconds(60);
 type FetchAndDecompressLogsResponse = {
   content: string;
 };
+
+const isGzipBytes = (data: Uint8Array): boolean =>
+  // eslint-disable-next-line no-magic-numbers
+  data.length >= 2 && data[0] === 0x1f && data[1] === 0x8b;
+
 async function fetchAndDecompressLog(
   url: string,
 ): Promise<FetchAndDecompressLogsResponse> {
   const proxyUrl = `/api/proxy/?url=${encodeURIComponent(url)}`;
-  const urlPathname = new URL(url).pathname;
-  const isGzipped = urlPathname.endsWith('.gz');
 
   try {
-    if (isGzipped) {
-      const response = await RequestData.get<ArrayBuffer>(proxyUrl, {
-        responseType: 'arraybuffer',
-      });
-
-      const uint8ArrayResponse = new Uint8Array(response);
-      const decompressedData = pako.inflate(uint8ArrayResponse);
-      const textDecoder = new TextDecoder('utf-8');
-      const decompressedText = textDecoder.decode(decompressedData);
-
-      return { content: decompressedText };
-    } else {
-      // For non-gzipped files, request as text
-      const response = await RequestData.get<string>(proxyUrl, {
-        responseType: 'text',
-      });
-
-      return { content: response };
+    const response = await RequestData.get<ArrayBuffer>(proxyUrl, {
+      responseType: 'arraybuffer',
+    });
+
+    let byteResponse = new Uint8Array(response);
+    const textDecoder = new TextDecoder('utf-8');
+
+    while (isGzipBytes(byteResponse)) {
+      byteResponse = pako.inflate(byteResponse);
     }
+
+    return { content: textDecoder.decode(byteResponse) };
   } catch (error) {
     console.error(error);