Migrate from Commons HttpClient to HttpComponents Client

Question

I would like to migrate from Commons HttpClient (3.x) to HttpComponents Client (4.x) but having difficulty how to handle redirects. The code works properly under Commons HttpClient but breaks when migrated to HttpComponents Client. Some of the links get undesirable redirects but when I set "http.protocol.handle-redirects" to 'false' a large number links stop working altogether.

Commons HttpClient 3.x:

private static HttpClient httpClient = null;
private static MultiThreadedHttpConnectionManager connectionManager = null;
private static final long MAX_CONNECTION_IDLE_TIME = 60000; // milliseconds

static {
    //HttpURLConnection.setFollowRedirects(true);
    CookieManager manager = new CookieManager();
    manager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
    CookieHandler.setDefault(manager);

connectionManager = new MultiThreadedHttpConnectionManager();
connectionManager.getParams().setDefaultMaxConnectionsPerHost(1000); // will need to set from properties file
connectionManager.getParams().setMaxTotalConnections(1000);
httpClient = new HttpClient(connectionManager);
}




/*
* Retrieve HTML
*/  
public String fetchURL(String url) throws IOException{

    if ( StringUtils.isEmpty(url) )
        return null;

    GetMethod getMethod = new GetMethod(url);
    HttpClient httpClient = new HttpClient();
    //configureMethod(getMethod);
    //ObjectInputStream oin = null;
    InputStream in = null;
    int code = -1;
    String html = "";
    String lastModified = null;
    try {
      code = httpClient.executeMethod(getMethod);

      in = getMethod.getResponseBodyAsStream();
        //oin = new ObjectInputStream(in);
        //html = getMethod.getResponseBodyAsString();
        html = CharStreams.toString(new InputStreamReader(in));

    }


    catch (Exception except) {
    }
    finally {

      try {
        //oin.close();
        in.close();
      }
      catch (Exception except) {}

      getMethod.releaseConnection();
      connectionManager.closeIdleConnections(MAX_CONNECTION_IDLE_TIME);
    }

    if (code <= 400){
        return html.replaceAll("\\s+", " ");
    } else {
        throw new Exception("URL: " + url + " returned response code " + code);
    }

}

HttpComponents Client 4.x :

private static HttpClient httpClient = null;
private static HttpParams params = null;
//private static MultiThreadedHttpConnectionManager connectionManager = null;
private static ThreadSafeClientConnManager connectionManager = null;
private static final int MAX_CONNECTION_IDLE_TIME = 60000; // milliseconds


static {
    //HttpURLConnection.setFollowRedirects(true);
    CookieManager manager = new CookieManager();
    manager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
    CookieHandler.setDefault(manager);


connectionManager = new ThreadSafeClientConnManager();
connectionManager.setDefaultMaxPerRoute(1000); // will need to set from properties file
connectionManager.setMaxTotal(1000);
httpClient = new DefaultHttpClient(connectionManager);



    // HTTP parameters stores header etc.
    params = new BasicHttpParams();
    params.setParameter("http.protocol.handle-redirects",false);

}




/*
* Retrieve HTML
*/  
public String fetchURL(String url) throws IOException{

    if ( StringUtils.isEmpty(url) )
        return null;

    InputStream in = null;
    //int code = -1;
    String html = "";

 // Prepare a request object
 HttpGet httpget = new HttpGet(url);
httpget.setParams(params);

 // Execute the request
 HttpResponse response = httpClient.execute(httpget);

 // The response status
 //System.out.println(response.getStatusLine());
int code = response.getStatusLine().getStatusCode();

 // Get hold of the response entity
 HttpEntity entity = response.getEntity();

 // If the response does not enclose an entity, there is no need
 // to worry about connection release
 if (entity != null) {

        try {
            //code = httpClient.executeMethod(getMethod);

            //in = getMethod.getResponseBodyAsStream();
            in = entity.getContent();
            html = CharStreams.toString(new InputStreamReader(in));

        }


        catch (Exception except) {
            throw new Exception("URL: " + url + " returned response code " + code);
        }
        finally {

            try {
                //oin.close();
                in.close();
            }
            catch (Exception except) {}

            //getMethod.releaseConnection();
            connectionManager.closeIdleConnections(MAX_CONNECTION_IDLE_TIME, TimeUnit.MILLISECONDS);
            connectionManager.closeExpiredConnections();
        }

    }

    if (code <= 400){
        return html;
    } else {
        throw new Exception("URL: " + url + " returned response code " + code);
    }


}

I won't want redirects but under HttpClient 4.x if I enable redirects then I get some that are undesirable, e.g. http://www.walmart.com/ => http://mobile.walmart.com/. Under HttpClient 3.x no such redirects happens.

What do I need to do to migrate HttpClient 3.x to HttpClient 4.x without breaking the code?

Answer 1

It is not the issue with HttpClient 4.x, might be the way target server handle the request, since the user agent is httpclient, it may be handled as mobile (target server may consider other than available browsers like, i.e, chrome, mozilla etc as mobile.)

Please use below code to set it manually

 httpclient.getParams().setParameter(
            org.apache.http.params.HttpProtocolParams.USER_AGENT,
            "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.2) Gecko/20100316 Firefox/3.6.2"
        );