HttpApiWithBasicAuth.java

/**
 * Copyright 2009 Joe LaPenna
 */

package com.joelapenna.foursquare.http;

import com.joelapenna.foursquare.error.FoursquareCredentialsException;
import com.joelapenna.foursquare.error.FoursquareException;
import com.joelapenna.foursquare.error.FoursquareParseException;
import com.joelapenna.foursquare.parsers.Parser;
import com.joelapenna.foursquare.types.FoursquareType;

import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.AuthState;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.client.protocol.ClientContext;
import org.apache.http.impl.auth.BasicScheme;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.ExecutionContext;
import org.apache.http.protocol.HttpContext;

import java.io.IOException;

/**
 * @author Joe LaPenna (joe@joelapenna.com)
 */
public class HttpApiWithBasicAuth extends AbstractHttpApi {

    private HttpRequestInterceptor preemptiveAuth = new HttpRequestInterceptor() {

        @Override
        public void process(final HttpRequest request, final HttpContext context)
                throws HttpException, IOException {

            AuthState authState = (AuthState)context.getAttribute(ClientContext.TARGET_AUTH_STATE);
            CredentialsProvider credsProvider = (CredentialsProvider)context
                    .getAttribute(ClientContext.CREDS_PROVIDER);
            HttpHost targetHost = (HttpHost)context.getAttribute(ExecutionContext.HTTP_TARGET_HOST);

            // If not auth scheme has been initialized yet
            if (authState.getAuthScheme() == null) {
                AuthScope authScope = new AuthScope(targetHost.getHostName(), targetHost.getPort());
                // Obtain credentials matching the target host
                org.apache.http.auth.Credentials creds = credsProvider.getCredentials(authScope);
                // If found, generate BasicScheme preemptively
                if (creds != null) {
                    authState.setAuthScheme(new BasicScheme());
                    authState.setCredentials(creds);
                }
            }
        }

    };

    public HttpApiWithBasicAuth(DefaultHttpClient httpClient, String clientVersion) {
        super(httpClient, clientVersion);
        httpClient.addRequestInterceptor(preemptiveAuth, 0);
    }

    public FoursquareType doHttpRequest(HttpRequestBase httpRequest,
            Parser<? extends FoursquareType> parser) throws FoursquareCredentialsException,
            FoursquareParseException, FoursquareException, IOException {
        return executeHttpRequest(httpRequest, parser);
    }
}