java - How to read full response from HttpURLConnection?

Question

I make some proxy server in andorid which modify http headers, it works ok, but I have to forward full response to 'top layer'.
How I can read whole response (all headers, content, everything) from HttpURLConnection?

HttpURLConnection httpURLConnection;
URL url = new URL(ADDRESS);
httpURLConnection = (HttpURLConnection) url.openConnection();
// add headers, write output stream, flush
if (httpURLConnection.getResponseCode() == HttpsURLConnection.HTTP_OK)
{
    Map<String, List<String>> map = httpURLConnection.getHeaderFields();
    System.out.println("Printing Response Header...
");

    for (Map.Entry<String, List<String>> entry : map.entrySet())
    {
        System.out.println("Key : " + entry.getKey() + " ,Value : " + entry.getValue());
    }

    return new DataInputStream(httpURLConnection.getInputStream());
}

In getInputStream I received only content it is possible to have some stream with whole reposne?

Answer 1

There's no way to dump the full HTTP response directly using the HttpURLConnection, but you can use its various method to reconstruct it. For example,

HttpURLConnection httpURLConnection;
URL url = new URL("http://www.google.com");
httpURLConnection = (HttpURLConnection) url.openConnection();
StringBuilder builder = new StringBuilder();
builder.append(httpURLConnection.getResponseCode())
       .append(" ")
       .append(httpURLConnection.getResponseMessage())
       .append("
");

Map<String, List<String>> map = httpURLConnection.getHeaderFields();
for (Map.Entry<String, List<String>> entry : map.entrySet())
{
    if (entry.getKey() == null) 
        continue;
    builder.append( entry.getKey())
           .append(": ");

    List<String> headerValues = entry.getValue();
    Iterator<String> it = headerValues.iterator();
    if (it.hasNext()) {
        builder.append(it.next());

        while (it.hasNext()) {
            builder.append(", ")
                   .append(it.next());
        }
    }

    builder.append("
");
}

System.out.println(builder);

prints

200 OK
X-Frame-Options: SAMEORIGIN
Transfer-Encoding: chunked
Date: Tue, 07 Jan 2014 16:06:45 GMT
P3P: CP="This is not a P3P policy! See http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info."
X-XSS-Protection: 1; mode=block
Expires: -1
Alternate-Protocol: 80:quic
Set-Cookie: NID=67=OIu8_xhcxE-UPCSfIoTINvRyOe4ALVhIqan2NUI6LMdRkSJHTPGvNkYeYE--WqPSEPK4c4ubvmjWGUyFgXsa453KHavX9gUeKdzfInU2Q25yWP3YtMhsIhJpUQbYL4gq; expires=Wed, 09-Jul-2014 16:06:45 GMT; path=/; domain=.google.ca; HttpOnly, PREF=ID=4496ed99b812997d:FF=0:TM=1389110805:LM=1389110805:S=jxodjb3UjGJSZGaF; expires=Thu, 07-Jan-2016 16:06:45 GMT; path=/; domain=.google.ca
Content-Type: text/html; charset=ISO-8859-1
Server: gws
Cache-Control: private, max-age=0

You can then get the InputStream and print its content too.