fix: revert skip validation

src/file.ts

@@ -1365,7 +1365,7 @@ class File extends ServiceObject<File> {
 
     const throughStream = streamEvents(new PassThrough());
 
-    let isServedCompressed = true;
+    let isCompressed = true;
     let crc32c = true;
     let md5 = false;
 
@@ -1470,7 +1470,7 @@ class File extends ServiceObject<File> {
         rawResponseStream.on('error', onComplete);
 
         const headers = rawResponseStream.toJSON().headers;
-        isServedCompressed = headers['content-encoding'] === 'gzip';
+        isCompressed = headers['content-encoding'] === 'gzip';
         const throughStreams: Writable[] = [];
 
         if (shouldRunValidation) {
@@ -1496,7 +1496,7 @@ class File extends ServiceObject<File> {
           throughStreams.push(validateStream);
         }
 
-        if (isServedCompressed && options.decompress) {
+        if (isCompressed && options.decompress) {
           throughStreams.push(zlib.createGunzip());
         }
 
@@ -1536,23 +1536,17 @@ class File extends ServiceObject<File> {
           return;
         }
 
-        // TODO(https://github.com/googleapis/nodejs-storage/issues/709):
-        // Remove once the backend issue is fixed.
-        // If object is stored compressed (having
-        // metadata.contentEncoding === 'gzip') and was served decompressed,
-        // then skip checksum validation because the remote checksum is computed
-        // against the compressed version of the object.
-        if (!isServedCompressed) {
+        // Did the server decompress object before serving it back to us?
+        const serverDecompressed =
+          headers['x-goog-stored-content-encoding'] === 'gzip' && !isCompressed;
+
+        if (serverDecompressed) {
           try {
             await this.getMetadata({userProject: options.userProject});
           } catch (e) {
             throughStream.destroy(e as Error);
             return;
           }
-          if (this.metadata.contentEncoding === 'gzip') {
-            throughStream.end();
-            return;
-          }
         }
 
         // If we're doing validation, assume the worst-- a data integrity

system-test/storage.ts

@@ -2516,33 +2516,6 @@ describe('storage', () => {
       await file.delete();
     });
 
-    it('should skip validation if file is served decompressed', async () => {
-      const filename = 'logo-gzipped.png';
-      await bucket.upload(FILES.logo.path, {destination: filename, gzip: true});
-
-      tmp.setGracefulCleanup();
-      const {name: tmpFilePath} = tmp.fileSync();
-
-      const file = bucket.file(filename);
-
-      await new Promise((resolve, reject) => {
-        file
-          .createReadStream()
-          .on('error', reject)
-          .on('response', raw => {
-            assert.strictEqual(
-              raw.toJSON().headers['content-encoding'],
-              undefined
-            );
-          })
-          .pipe(fs.createWriteStream(tmpFilePath))
-          .on('error', reject)
-          .on('finish', resolve);
-      });
-
-      await file.delete();
-    });
-
     describe('simple write', () => {
       it('should save arbitrary data', done => {
         const file = bucket.file('TestFile');

test/file.ts

@@ -1395,19 +1395,6 @@ describe('File', () => {
         };
       }
 
-      describe('server decompression', () => {
-        it('should skip validation if file was stored compressed', done => {
-          file.metadata.crc32c = '.invalid.';
-          file.metadata.contentEncoding = 'gzip';
-
-          file
-            .createReadStream({validation: 'crc32c'})
-            .on('error', done)
-            .on('end', done)
-            .resume();
-        });
-      });
-
       it('should emit errors from the validation stream', done => {
         const expectedError = new Error('test error');