Java: process http.proxyUser and http.proxyPassword

Published by cybso on 2012-04-20

This is a post from my original site, which was hosted by the former blog service of the University of Osnabrück. I have moved it to the new site for archiving. Pages linked in this article may no longer work today, and the blog comments under the article no longer exist. Opinions expressed in this article reflect the point of view of the time of publication and do not necessarily reflect my opinion today.

Some tutorials suggest to use the system properties http.proxyUser and http.proxyPassword to get proxy authentication, but that won't work since - in contrast to http.proxyHost and http.proxyPort - these properties will not be processed by Java's HttpURLConnection.

Other suggest to use a custom default Authenticator. But that's dangerous because this would send your password to anybody who asks.

The following snippet contains some code that uses an Authenticator to process http.proxyUser, but ensures that these information will be sent to the host that is defined by http.proxyHost:

// Java ignores http.proxyUser. Here come's the workaround.
Authenticator.setDefault(new Authenticator() {
    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        if (getRequestorType() == RequestorType.PROXY) {
            String prot = getRequestingProtocol().toLowerCase();
            String host = System.getProperty(prot + ".proxyHost", "");
            String port = System.getProperty(prot + ".proxyPort", "");
            String user = System.getProperty(prot + ".proxyUser", "");
            String password = System.getProperty(prot + ".proxyPassword", "");

            if (getRequestingHost().toLowerCase().equals(host.toLowerCase())) {
                if (Integer.parseInt(port) == getRequestingPort()) {
                    // Seems to be OK.
                    return new PasswordAuthentication(user, password.toCharArray());  
                }
            }
        }
        return null;
    }  
});