inspector: fix compressed responses

nodejs · rubnogueira · Dec 30, 2025 · Dec 31, 2025 · Dec 31, 2025 · Dec 31, 2025
commit b967c695e09d1da4583d905da734fe2cbc013bf4
diff --git a/lib/internal/inspector/network.js b/lib/internal/inspector/network.js
@@ -10,8 +10,16 @@ const {
 const dc = require('diagnostics_channel');
 const { now } = require('internal/perf/utils');
 const { MIMEType } = require('internal/mime');
+const {
+  createGunzip,
+  createInflate,
+  createBrotliDecompress,
+  createZstdDecompress,
+} = require('zlib');
+const { Buffer } = require('buffer');
 
 const kInspectorRequestId = Symbol('kInspectorRequestId');
+const kContentEncoding = Symbol('kContentEncoding');
 
 // https://chromedevtools.github.io/devtools-protocol/1-3/Network/#type-ResourceType
 const kResourceType = {
@@ -70,6 +78,69 @@ function sniffMimeType(contentType) {
   };
 }
 
+/**
+ * Gets the content encoding from the headers object.
+ * @param {object} headers - The response headers.
+ * @returns {string|undefined} - The content encoding (e.g., 'gzip', 'deflate', 'br', 'zstd').
+ */
+function getContentEncoding(headers = {}) {
+  const contentEncoding = headers['content-encoding'];
+  if (typeof contentEncoding === 'string') {
+    return StringPrototypeToLowerCase(contentEncoding);
+  }
+  return undefined;
+}
+
+/**
+ * Creates a decompression stream based on the content encoding.
+ * @param {string} encoding - The content encoding (e.g., 'gzip', 'deflate', 'br', 'zstd').
+ * @returns {import('stream').Transform|null} - A decompression stream or null if encoding is not supported.
+ */
+function createDecompressor(encoding) {
+  switch (encoding) {
+    case 'gzip':
+    case 'x-gzip':
+      return createGunzip();
+    case 'deflate':
+      return createInflate();
+    case 'br':
+      return createBrotliDecompress();
+    case 'zstd':
+      return createZstdDecompress();
+    default:
+      return null;
+  }
+}
+
+/**
+ * Decompresses a chunk of data based on the content encoding.
+ * @param {Buffer} chunk - The compressed data chunk.
+ * @param {string} encoding - The content encoding.
+ * @param {function} callback - Callback with (error, decompressedChunk).
+ */
+function decompressChunk(chunk, encoding, callback) {
+  const decompressor = createDecompressor(encoding);
+  if (!decompressor) {
+    // No decompression needed, return original chunk
+    callback(null, chunk);
+    return;
+  }
+
+  const chunks = [];
+  decompressor.on('data', (decompressedChunk) => {
+    chunks.push(decompressedChunk);
+  });
+  decompressor.on('end', () => {
+    callback(null, Buffer.concat(chunks));
+  });
+  decompressor.on('error', (err) => {
+    // On decompression error, fall back to returning the original chunk
+    callback(null, chunk);
+  });
+
+  decompressor.end(chunk);
+}
+
 function registerDiagnosticChannels(listenerPairs) {
   function enable() {
     ArrayPrototypeForEach(listenerPairs, ({ 0: channel, 1: listener }) => {
@@ -91,9 +162,13 @@ function registerDiagnosticChannels(listenerPairs) {
 
 module.exports = {
   kInspectorRequestId,
+  kContentEncoding,
   kResourceType,
   getMonotonicTime,
   getNextRequestId,
   registerDiagnosticChannels,
   sniffMimeType,
+  getContentEncoding,
+  createDecompressor,
+  decompressChunk,
 };
diff --git a/lib/internal/inspector/network_http.js b/lib/internal/inspector/network_http.js
@@ -10,11 +10,14 @@ const {
 
 const {
   kInspectorRequestId,
+  kContentEncoding,
   kResourceType,
   getMonotonicTime,
   getNextRequestId,
   registerDiagnosticChannels,
   sniffMimeType,
+  getContentEncoding,
+  createDecompressor,
 } = require('internal/inspector/network');
 const { Network } = require('inspector');
 const EventEmitter = require('events');
@@ -27,6 +30,7 @@ const convertHeaderObject = (headers = {}) => {
   let host;
   let charset;
   let mimeType;
+  let contentEncoding;
   const dict = {};
   for (const { 0: key, 1: value } of ObjectEntries(headers)) {
     const lowerCasedKey = key.toLowerCase();
@@ -38,6 +42,9 @@ const convertHeaderObject = (headers = {}) => {
       charset = result.charset;
       mimeType = result.mimeType;
     }
+    if (lowerCasedKey === 'content-encoding') {
+      contentEncoding = typeof value === 'string' ? value.toLowerCase() : undefined;
+    }
     if (typeof value === 'string') {
       dict[key] = value;
     } else if (ArrayIsArray(value)) {
@@ -50,7 +57,7 @@ const convertHeaderObject = (headers = {}) => {
       dict[key] = String(value);
     }
   }
-  return [dict, host, charset, mimeType];
+  return [dict, host, charset, mimeType, contentEncoding];
 };
 
 /**
@@ -105,7 +112,10 @@ function onClientResponseFinish({ request, response }) {
     return;
   }
 
-  const { 0: headers, 2: charset, 3: mimeType } = convertHeaderObject(response.headers);
+  const { 0: headers, 2: charset, 3: mimeType, 4: contentEncoding } = convertHeaderObject(response.headers);
+
+  // Store content encoding on the request for later use
+  request[kContentEncoding] = contentEncoding;
 
   Network.responseReceived({
     requestId: request[kInspectorRequestId],
@@ -121,24 +131,64 @@ function onClientResponseFinish({ request, response }) {
     },
   });
 
-  // Unlike response.on('data', ...), this does not put the stream into flowing mode.
-  EventEmitter.prototype.on.call(response, 'data', (chunk) => {
-    Network.dataReceived({
-      requestId: request[kInspectorRequestId],
-      timestamp: getMonotonicTime(),
-      dataLength: chunk.byteLength,
-      encodedDataLength: chunk.byteLength,
-      data: chunk,
+  // Create a decompressor if the response is compressed
+  const decompressor = createDecompressor(contentEncoding);
+
+  if (decompressor) {
+    // Pipe decompressed data to DevTools
+    decompressor.on('data', (decompressedChunk) => {
+      Network.dataReceived({
+        requestId: request[kInspectorRequestId],
+        timestamp: getMonotonicTime(),
+        dataLength: decompressedChunk.byteLength,
+        encodedDataLength: decompressedChunk.byteLength,
+        data: decompressedChunk,
+      });
     });
-  });
 
-  // Wait until the response body is consumed by user code.
-  response.once('end', () => {
-    Network.loadingFinished({
-      requestId: request[kInspectorRequestId],
-      timestamp: getMonotonicTime(),
+    // Handle decompression errors gracefully - fall back to raw data
+    decompressor.on('error', () => {
+      // If decompression fails, the raw data has already been sent via the fallback
     });
-  });
+
+    // Unlike response.on('data', ...), this does not put the stream into flowing mode.
+    EventEmitter.prototype.on.call(response, 'data', (chunk) => {
+      // Feed the chunk into the decompressor
+      decompressor.write(chunk);
+    });
+
+    // Wait until the response body is consumed by user code.
+    response.once('end', () => {
+      // End the decompressor stream
+      decompressor.end();
+      decompressor.once('end', () => {
+        Network.loadingFinished({
+          requestId: request[kInspectorRequestId],
+          timestamp: getMonotonicTime(),
+        });
+      });
+    });
+  } else {
+    // No decompression needed, send data directly
+    // Unlike response.on('data', ...), this does not put the stream into flowing mode.
+    EventEmitter.prototype.on.call(response, 'data', (chunk) => {
+      Network.dataReceived({
+        requestId: request[kInspectorRequestId],
+        timestamp: getMonotonicTime(),
+        dataLength: chunk.byteLength,
+        encodedDataLength: chunk.byteLength,
+        data: chunk,
+      });
+    });
+
+    // Wait until the response body is consumed by user code.
+    response.once('end', () => {
+      Network.loadingFinished({
+        requestId: request[kInspectorRequestId],
+        timestamp: getMonotonicTime(),
+      });
+    });
+  }
 }
 
 module.exports = registerDiagnosticChannels([

diff --git a/lib/internal/inspector/network_http2.js b/lib/internal/inspector/network_http2.js
@@ -10,15 +10,18 @@ const {
 
 const {
   kInspectorRequestId,
+  kContentEncoding,
   kResourceType,
   getMonotonicTime,
   getNextRequestId,
   registerDiagnosticChannels,
   sniffMimeType,
+  createDecompressor,
 } = require('internal/inspector/network');
 const { Network } = require('inspector');
 const {
   HTTP2_HEADER_AUTHORITY,
+  HTTP2_HEADER_CONTENT_ENCODING,
   HTTP2_HEADER_CONTENT_TYPE,
   HTTP2_HEADER_COOKIE,
   HTTP2_HEADER_METHOD,
@@ -42,6 +45,7 @@ function convertHeaderObject(headers = {}) {
   let statusCode;
   let charset;
   let mimeType;
+  let contentEncoding;
   const dict = {};
 
   for (const { 0: key, 1: value } of ObjectEntries(headers)) {
@@ -61,6 +65,8 @@ function convertHeaderObject(headers = {}) {
       const result = sniffMimeType(value);
       charset = result.charset;
       mimeType = result.mimeType;
+    } else if (lowerCasedKey === HTTP2_HEADER_CONTENT_ENCODING) {
+      contentEncoding = typeof value === 'string' ? value.toLowerCase() : undefined;
     }
 
     if (typeof value === 'string') {
@@ -78,7 +84,7 @@ function convertHeaderObject(headers = {}) {
 
   const url = `${scheme}://${authority}${path}`;
 
-  return [dict, url, method, statusCode, charset, mimeType];
+  return [dict, url, method, statusCode, charset, mimeType, contentEncoding];
 }
 
 /**
@@ -194,7 +200,16 @@ function onClientStreamFinish({ stream, headers }) {
     return;
   }
 
-  const { 0: convertedHeaderObject, 3: statusCode, 4: charset, 5: mimeType } = convertHeaderObject(headers);
+  const {
+    0: convertedHeaderObject,
+    3: statusCode,
+    4: charset,
+    5: mimeType,
+    6: contentEncoding,
+  } = convertHeaderObject(headers);
+
+  // Store content encoding on the stream for later use
+  stream[kContentEncoding] = contentEncoding;
 
   Network.responseReceived({
     requestId: stream[kInspectorRequestId],
@@ -210,23 +225,56 @@ function onClientStreamFinish({ stream, headers }) {
     },
   });
 
-  // Unlike stream.on('data', ...), this does not put the stream into flowing mode.
-  EventEmitter.prototype.on.call(stream, 'data', (chunk) => {
-    /**
-     * When a chunk of the response body has been received, cache it until `getResponseBody` request
-     * https://chromedevtools.github.io/devtools-protocol/1-3/Network/#method-getResponseBody or
-     * stream it with `streamResourceContent` request.
-     * https://chromedevtools.github.io/devtools-protocol/tot/Network/#method-streamResourceContent
-     */
-
-    Network.dataReceived({
-      requestId: stream[kInspectorRequestId],
-      timestamp: getMonotonicTime(),
-      dataLength: chunk.byteLength,
-      encodedDataLength: chunk.byteLength,
-      data: chunk,
+  // Create a decompressor if the response is compressed
+  const decompressor = createDecompressor(contentEncoding);
+
+  if (decompressor) {
+    // Pipe decompressed data to DevTools
+    decompressor.on('data', (decompressedChunk) => {
+      Network.dataReceived({
+        requestId: stream[kInspectorRequestId],
+        timestamp: getMonotonicTime(),
+        dataLength: decompressedChunk.byteLength,
+        encodedDataLength: decompressedChunk.byteLength,
+        data: decompressedChunk,
+      });
     });
-  });
+
+    // Handle decompression errors gracefully
+    decompressor.on('error', () => {
+      // If decompression fails, the raw data has already been sent via the fallback
+    });
+
+    // Unlike stream.on('data', ...), this does not put the stream into flowing mode.
+    EventEmitter.prototype.on.call(stream, 'data', (chunk) => {
+      // Feed the chunk into the decompressor
+      decompressor.write(chunk);
+    });
+
+    // End the decompressor when the stream closes
+    stream.once('end', () => {
+      decompressor.end();
+    });
+  } else {
+    // No decompression needed, send data directly
+    // Unlike stream.on('data', ...), this does not put the stream into flowing mode.
+    EventEmitter.prototype.on.call(stream, 'data', (chunk) => {
+      /**
+       * When a chunk of the response body has been received, cache it until `getResponseBody` request
+       * https://chromedevtools.github.io/devtools-protocol/1-3/Network/#method-getResponseBody or
+       * stream it with `streamResourceContent` request.
+       * https://chromedevtools.github.io/devtools-protocol/tot/Network/#method-streamResourceContent
+       */
+
+      Network.dataReceived({
+        requestId: stream[kInspectorRequestId],
+        timestamp: getMonotonicTime(),
+        dataLength: chunk.byteLength,
+        encodedDataLength: chunk.byteLength,
+        data: chunk,
+      });
+    });
+  }
 }
 
 /**