GZIPInputStream produces an unknown format (magic number 213c)

Question

While I used GZIPInputStream to compress bytes from the Internet, the program launches the error as follows:

05-08 17:37:02.465: W/System.err(744): java.io.IOException: unknown format (magic number 213c) 05-08 17:37:02.465: W/System.err(744): at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:84) 05-08 17:37:02.465: W/System.err(744): at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:64) 05-08 17:37:02.475: W/System.err(744): at com.Android.Sample.TestActivity.onCreate(TestActivity.java:54) 05-08 17:37:02.475: W/System.err(744): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 05-08 17:37:02.475: W/System.err(744): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 05-08 17:37:02.475: W/System.err(744): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 05-08 17:37:02.475: W/System.err(744): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 05-08 17:37:02.475: W/System.err(744): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 05-08 17:37:02.475: W/System.err(744): at android.os.Handler.dispatchMessage(Handler.java:99) 05-08 17:37:02.475: W/System.err(744): at android.os.Looper.loop(Looper.java:123) 05-08 17:37:02.475: W/System.err(744): at android.app.ActivityThread.main(ActivityThread.java:3683) 05-08 17:37:02.475: W/System.err(744): at java.lang.reflect.Method.invokeNative(Native Method) 05-08 17:37:02.475: W/System.err(744): at java.lang.reflect.Method.invoke(Method.java:507) 05-08 17:37:02.475: W/System.err(744): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 05-08 17:37:02.475: W/System.err(744): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 05-08 17:37:02.486: W/System.err(744): at dalvik.system.NativeStart.main(Native Method) 

And my codes are:

 HttpGet request = new HttpGet("http://www.google.com"); HttpResponse response = new DefaultHttpClient().execute(request); HttpEntity entity = response.getEntity(); InputStream stream = entity.getContent(); InputStream zippedStream = new GZIPInputStream(stream); InputStreamReader reader = new InputStreamReader(zippedStream); BufferedReader buffer = new BufferedReader(reader); 

If I just use

 InputStreamReader reader = new InputStreamReader(stream); 

do not compress the flow, this will be normal.

Answer 1

You must check the Content-Encoding before accepting the input stream. If the response is encoded in GZIP, use GZIPInputStream . This is my solution that I use in my API call .

 InputStream responseStream = null; ... // receive response String encoding = connection.getHeaderField("Content-Encoding"); boolean gzipped = encoding!=null && encoding.toLowerCase().contains("gzip"); try { InputStream inputStream = connection.getInputStream(); if(gzipped) responseStream = new BufferedInputStream(new GZIPInputStream(inputStream)); else responseStream = new BufferedInputStream(inputStream); } catch(FileNotFoundException e) { // error stream InputStream errorStream = connection.getErrorStream(); if(gzipped) responseStream = new BufferedInputStream(new GZIPInputStream(errorStream)); else responseStream = new BufferedInputStream(errorStream); } ... // TODO: close stream 

Answer 2

Are you sure that what you get is concise? If you get an “unknown format,” this is certainly not the case. You should check the response headers and enable gzip accordingly.