Java HttpURLConnection VS Android HttpURLConnection
android, httpurlconnection, java
Solution
Android `HttpURLConnection` is doing some magic transparently for you like caching and gzip-handling.
So if you don't set `Accept-Encoding: identity`, HUC sets `Accept-Encoding: gzip,deflate`. And since nginx is an intelligent nice thing, it might deliver your response `gzip` encoded. You didn't tell HUC to give the response as gzipped back to you, but it decompresses that response for you and drops the header since this was misleading.
You can see this as a powerful feature to save bandwidth and radio power consumption without Android programmers having to deal with `gzip` or `deflate` encoding.
If you just stream the response to your JSON-parser, you will get the uncompressed data in the correct size, though without knowing size in advance.
You could verify what I said by running `wireshark` or `tcpdump` server-side, or if you have a rooted Android device, there are ways to do this client-side as well.
Problem
I have this simple code that run on a Windows VM: ``` URL url = new URL("http:xxx.xxx.xxx.xxx/api/cities.json"); HttpURLConnection connexion = (HttpURLConnection) url.openConnection(); connexion.setRequestMethod("GET"); System.out.println("response " + connexion.getResponseCode()); connexion.connect(); InputStream is = connexion.getInputStream(); for (String header : connexion.getHeaderFields().keySet()) { System.out.println(header + ":" + connexion.getHeaderField(header)); } ``` Giving these headers ``` response 200 null:HTTP/1.1 200 OK X-Frame-Options:SAMEORIGIN Access-Control-Allow-Origin:* Vary:Accept-Encoding Date:Sun, 23 Mar 2014 03:00:06 GMT Content-Length:1894 Connection:keep-alive Content-Type:application/json Server:nginx ``` And the exact same code on Android giving theses headers ``` 03-22 23:10:35.405: I/System.out(23707): null:HTTP/1.1 200 OK 03-22 23:10:35.405: I/System.out(23707): Access-Control-Allow-Origin:* 03-22 23:10:35.405: I/System.out(23707): Connection:keep-alive 03-22 23:10:35.405: I/System.out(23707): Content-Type:application/json 03-22 23:10:35.405: I/System.out(23707): Date:Sun, 23 Mar 2014 03:10:35 GMT 03-22 23:10:35.405: I/System.out(23707): Server:nginx 03-22 23:10:35.405: I/System.out(23707): Vary:Accept-Encoding 03-22 23:10:35.405: I/System.out(23707): X-Android-Received-Millis:1395544235409 03-22 23:10:35.405: I/System.out(23707): X-Android-Response-Source:NETWORK 200 03-22 23:10:35.405: I/System.out(23707): X-Android-Selected-Transport:http/1.1 03-22 23:10:35.405: I/System.out(23707): X-Android-Sent-Millis:1395544235363 03-22 23:10:35.405: I/System.out(23707): X-Frame-Options:SAMEORIGIN ``` I just cant find the content-length header anymore. Im I missing something ?