Develop Reference

CometD: Use SSL/TLS

How do I enable secure connections with CometD?
I have an app that is working when I use an "http" protocol for the BayeuxServer. If I switch to "https", I get failed handshakes.
What is the correct way to use a secure connection in CometD?
This is via the Java Client.
Here is the error:
{failure={exception=java.lang.NullPointerException, message={ext={ack=true}, supportedConnectionTypes=[long-polling], channel=/meta/handshake, id=4, version=1.0}, connectionType=long-polling}, channel=/meta/handshake, id=4, subscription=null, successful=false}
I do not see any exceptions on the server (ie, the null pointer is not in our code), and if I use HTTP, it works fine.
I've pieced together the following for the Java client side:
SslContextFactory sslContextFactory = new SslContextFactory();
sslContextFactory.setTrustAll(true); // only interacting with our backend, so accept self-signed certs
WebSocketClient webSocketClient = new WebSocketClient(sslContextFactory);
webSocketClient.start();
ClientTransport wsTransport = new JettyWebSocketTransport(null, null, webSocketClient);
HttpClient httpClient = new HttpClient(sslContextFactory);
httpClient.start();
ClientTransport httpTransport = new LongPollingTransport(null, httpClient);
I believe that will do it.
I still need to figure out how to configure the server side cometd to accept the secure connections. I am using the Spring setup.
The answer to the server side is: Its a pain in the ass.
Here is how you can get it working with the jetty maven plugin:
http://juplo.de/configure-https-for-jetty-maven-plugin-9-0-x/#comment-53352

Validating client credentials on a server using Java SimpleFramework

I am developing a SSL/TLS enabled server using the Java SimpleFramework. I am wondering how to validate client authentications on the server.
On the server side, I am extending org.simpleframework.http.core.ContainerServer and overriding the process() method as follows:
#Override
public void process(Socket socket) throws IOException {
// Ensures client authentication is required
socket.getEngine().setNeedClientAuth(true);
super.process(socket);
}
This is to make sure that clients authenticate. Note that if I remove the call to setNeedClientAuth(), my program works perfectly.
On the client side, the following code is used:
HttpClient client = new HttpClient();
Credentials defaultcreds = new UsernamePasswordCredentials("username", "password");
client.getState().setCredentials(AuthScope.ANY, defaultcreds);
GetMethod get = new GetMethod("https://url.to.server");
get.setDoAuthentication(true);
client.executeMethod(get);
When enabling authentication requirement, I get the following exception:
javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake
I am guessing this relates to the fact that the passed credentials is never validated.
To summarize my question, how should I proceed to validate clients on the server?

JAVA - Using httpclient to post a file to google apps via http proxy (squid) gets stuck when calling execute

Context
I have a desktop JAVA application I use to upload files (blobs) to a google app blobstore.
Everything works fine with a direct connection to the Internet but it doesn't when connecting through an HTTP proxy (Squid) with authentication.
I am using httpClient 4.2.3 and I don't get any error or response. It just gets stuck when calling httpClient.execute(post).
Code
I added these lines to handle the proxy authentication and it works well when using URL to get a page:
System.setProperty("http.proxyUser", username);
System.setProperty("http.proxyPassword", password);
I tried those as well:
Authenticator.setDefault(
new Authenticator() {
#Override
public PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(
username, password.toCharArray());
}
}
);
And from now on this is the same code that works when not using a proxy.
First of all I download a page where I get the url to use to post a file to the blobstore:
URL url = new URL("http://www.example.com/get-upload-url.jsp");
String urlWhereToPost=IOUtils.toString(url.openStream());
DefaultHttpClient client = new DefaultHttpClient ();
Here we prepare the multipart post:
HttpPost post
= new HttpPost( urlWhereToPost.trim() );
MultipartEntity entity
= new MultipartEntity( HttpMultipartMode.BROWSER_COMPATIBLE);
entity.addPart( "key"
, new FileBody(new File(jpgFilePath)
, "image/jpeg" )
);
post.setEntity((HttpEntity)entity);
And it is when calling execute that nothing happens (and it never get's to the next instruction):
HttpResponse execute = client.execute( post );
Tests
I have been trying several things but nothing worked:
In the beginning I thought the problem was using POST because GET works fine using URL()
but I tried using HttpClient to execute a GET and it gets stuck as well.
I used Wireshark to check the packets send to the proxy and I saw that when using URL() Wireshark recognizes the calls to the proxy as requests to execute a GET from the proxy. But when using httpClient it looks like the request is not well built because Wireshark shows a packet but doesn't recognize the inner request.
Then I tried building the POST using HttpURLConnection and it gets through the proxy and I get the answer from the server but it looks like I am not building it well because appengine doesn't find the file I send (but this would be another question...).
Conclusion
Anyone with the same problem? Any idea?

Your proxy settings are for the Java system classes. Apache HttpClient is supposed to be configured in a different way.
This link may help: Proxy authentication

Can't authenticate with DefaultHttpClient

I want to add authentication header to my request. I'm using DefaultHttpClient from Apache httpclient 4.0.
I found that's done this way:
URI uri = new URI("http://www.bla.bla/folder/");
String host = uri.getHost();
int port = uri.getPort();
httpClient.getCredentialsProvider().setCredentials(
new AuthScope(host, port, AuthScope.ANY_SCHEME),
new UsernamePasswordCredentials("myuser", "mypassword")
);
This is executed and even with the debugger I see some credentials variable of the httpClient are set at the moment of doing the request. But I inspect web traffic with Charles and there's no authentication header.
Content of vars:
host: www.bla.bla
port: -1
Btw. I enabled Charles as a proxy to see the headers of the request, with:
HttpHost proxy = new HttpHost("127.0.0.1", 8888, "http");
httpParameters.setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);
I think that should not be altering my headers, would make no sense for webproxy... anyways if I disable the proxy stuff it also doesn't work (although I can't see the content of the header but I suppose it's the same reason).
Also tried using a request interceptor like described in Softhinker.com's post here: How can I send HTTP Basic Authentication headers in Android?
And I get exactly the same request, without authentification header.
What am I doing wrong?
Thanks in advance.

I got it working setting the header "manually" in the request.
request.setHeader(new BasicHeader("Authorization", authstring));

How to use an HTTP proxy in java

I am writing a code that connects to websites and checks some code, like a crawler. But I need to connect trough a proxy and change the IP address (so it doesn't show the client's IP in the server logs).
How can this be done through java?

You can use the java system properties to set up a proxy or pass it as command line options.
You can find some details and samples here.
Ex: Before opening the connection
System.setProperty("http.proxyHost", "myProxyServer.com");
System.setProperty("http.proxyPort", "80");
Or you can use the default network proxies configured in the sytem
System.setProperty("java.net.useSystemProxies", "true");
Since Java 1.5 you can create a instance of proxy and pass it to the openConnection() method.
Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("123.0.0.1", 8080));
URL url = new URL("http://www.yahoo.com");
HttpURLConnection uc = (HttpURLConnection)url.openConnection(proxy);
uc.connect();
Or as lisak suggested, you can use some 3rd party libraries which supports your need better.

Or you can also use HttpClient which would suit your needs better. Check out the documentation, it's brief and very informative.
DefaultHttpClient httpclient = new DefaultHttpClient();
HttpHost proxy = new HttpHost("someproxy", 8080);
httpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);

Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("123.0.0.1", 8080));
URL url = new URL("http://www.yahoo.com");
HttpURLConnection uc = (HttpURLConnection)url.openConnection(proxy);
uc.connect();
This worked for me. I was able to use the proxy for the specific connection or transfer. Earlier we were using System.setProperty which used to set it at system level and all the requests internal/external started using the same proxy.
Also Proxy.Type.HTTP works for both http and https