Develop Reference

PORT Change in error case: HttpURLConnection

I am consuming API using HttpURLConnection in my android application and its running fine but if I get response code except then 200 ok (like 404, 500) my port is changing when I hit next request after error response code:
my code for android request is below and wireshark log as well:
try {
url = new URL(path_url + apiMsg); //in the real code, there is an ip and a port
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setConnectTimeout(5000);
conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
conn.setRequestMethod("POST");
conn.setRequestProperty("Accept","*/*");
}
Please refer wireshark log:
https://files.fm/u/w7umrwwk
So how to avoid PORT change in error scenario as well like in success 200 case, so that we continue to run on the same PORT.

read about sun.net.http.errorstream.enableBuffering in HttpURLConnection source code.
By default when response code is >= 400 then the connection is closed.
It is a clean though not so efficient way of handling error streams.
Instead of setting obscure system properties to handle this, it would be better to move to a proper http client like apache.

HttpUrlConnection Post with header info but no body

I am developing an Android app that uses an API I developed.
I am doing this connection using HttpUrlConnection and so far the login works fine. The problem arises with the logout. It´s not doing anything. When I do the logout request with Postman then it works fine, but with HttpUrlConnection it does not.
The logout works like this:
Do a POST request to http://ipaddress:12345/api/LogOut
and in the header include the token of the logged user. Then the server should go to the database and delete the token for that user:
This is how I´m trying to do the request:
URL url = new URL(getString(R.string.url) + "LogOut");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestProperty("Content-Type", "application/json");
con.setRequestProperty("Token", TokenSingleton.getToken());
con.setReadTimeout(10000);
con.setConnectTimeout(15000);
con.setRequestMethod("POST");
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
con.connect();
con.getOutputStream().flush();
con.getOutputStream().close();
con.disconnect();

Nothing happens until you do some input. At least call getResponseCode() to see whether you got a 200 or not. Preferably you should consume the input stream, if 200 <= response code <= 299, otherwise the error stream.
NB setDoOutput(true) sets the request method to POST. You don't need to do that yourself. And setDoInput(true) is the default. And close() implies flush().

HTTP 403 while executing a PUT request

I am creating a django rest api, and I'm trying to send JSON data via PUT request from an Android device, using HttpUrlConnection.
URL url = new URL(myurl);
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(10000 /* milliseconds */);
conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestMethod("PUT");
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
conn.setRequestProperty("Accept", "application/json");
Log.v("Apiput", MainActivity.cookieManager.getCookieStore().getCookies().get(0).toString());
conn.connect();
if(conn.getResponseCode() != 200) {
return "" + conn.getResponseCode();
}
OutputStreamWriter osw = new OutputStreamWriter(conn.getOutputStream());
osw.write(put);
osw.flush();
osw.close();`
I know I have to send a csrf token, but I think that I'm sending it already.
By examining the META in my request I can see the csrf token both in headers and cookies:
'HTTP_COOKIE': 'csrftoken=3jLNzfLIu1P5dBH4WWwggHMH7oDQC7Rx;'
And in my android device i have a CookieManager that says that the csrf cookie has the same value.
V/Apiput﹕ csrftoken=3jLNzfLIu1P5dBH4WWwggHMH7oDQC7Rx
I am getting a 403 (Forbidden) Http error besides the user is authenticated (I can make GET Requests)
[26/Sep/2015 00:16:04]"PUT /api/works/34/ HTTP/1.1" 403 58
With curl I am able to send the request without any problem, with the same user credentials.
I wonder if anyone can tell me what am I doing wrong.
Thanks.

You don't have to set the cookie if you're doing a JSON call to Django REST framework.
It would definitively help if you can provide the permissions associated to the view.

IHS (Apache) 400 Error when adding UUID header to HttpUrlConnection

I need to add a header ("correlationIdHeader") to a GET Request using Java's HttpUrlConnection. However the server (IBM Http Server - built on Apache) answers with a 400 Error and the following info:
Request header field is missing ':' separator
My code:
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setRequestProperty("correlationIdHeader", UUID.randomUUID().toString());
conn.setRequestMethod(HttpMethod.GET.name());
conn.setRequestProperty("Accept", contentType);
int responseCode= conn.getResponseCode();
Any idea what could be happening here?
EDIT: it has to do with UUID.randomUUID().toString(). I don't know why but it doesn't like UUID's format. Why?

HttpUrlConnection getOutputStream() throwing java.net.SocketException: Unexpected end of file from server

I am trying to invoke a REST webservice using java code.
I am able to execute it thru Rest Client Postman.
My code:
URL url = new URL(appURL);
httpCon = (HttpURLConnection) url.openConnection();
httpCon.setRequestMethod("POST");
httpCon.setDoInput(true);
httpCon.setUseCaches(false);
httpCon.setAllowUserInteraction(false);
httpCon.setDoOutput(true);
httpCon.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
httpCon.setRequestProperty("Host", "www.astecanalytics.com");
httpCon.setRequestProperty("Expect", "100-continue");
OutputStream outstream = httpCon.getOutputStream();
I am getting below error:
java.net.SocketException: Unexpected end of file from server
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:772)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:633)
at sun.net.www.protocol.http.HttpURLConnection.doTunneling(HttpURLConnection.java:1789)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:183)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1091)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:250)
at com.ktt.business.keywords.webservice.ExecuteWebServiceKeyword.postHTTPRequestAndGetRespone(ExecuteWebServiceKeyword.java:618)
Can someone help?

Since the response from server is ok, then no issues on the server side.
Compare the request body send through Rest Client with the one send from code.
Then try to map.
Check this tutorial link:http://www.mkyong.com/java/how-to-send-http-request-getpost-in-java/
This helped me when I tried to do the same thing as you are currently trying