org.github.oauth2.AccessTokenClient.java Source code

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Here is the source code for org.github.oauth2.AccessTokenClient.java

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/******************************************************************************
 *  Copyright (c) 2011 GitHub Inc.
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  which accompanies this distribution, and is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  Contributors:
 *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
 *****************************************************************************/
package org.github.oauth2;

import java.io.IOException;
import java.net.ProxySelector;
import java.net.URI;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.ProxySelectorRoutePlanner;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

/**
 * 
 */
public class AccessTokenClient {

    private final OAuth2Client client;

    /**
     * Create access token client
     * 
     * @param client
     */
    public AccessTokenClient(OAuth2Client client) {
        this.client = client;
    }

    /**
     * Execute request and return response
     * 
     * @param target
     * @param request
     * @return response
     * @throws IOException
     */
    protected HttpResponse execute(HttpHost target, HttpRequest request) throws IOException {
        DefaultHttpClient client = new DefaultHttpClient();
        client.setRoutePlanner(new ProxySelectorRoutePlanner(client.getConnectionManager().getSchemeRegistry(),
                ProxySelector.getDefault()));
        return client.execute(target, request);
    }

    /**
     * Get token from resposne entity
     * 
     * @param entity
     * @return token or null if not present in given entity
     * @throws IOException
     */
    protected String getToken(HttpEntity entity) throws IOException {
        String content = EntityUtils.toString(entity, HTTP.ASCII);
        if (content == null || content.length() == 0)
            return null;
        List<NameValuePair> responseData = new ArrayList<NameValuePair>();
        URLEncodedUtils.parse(responseData, new Scanner(content), null);
        for (NameValuePair param : responseData)
            if (IOAuth2Constants.PARAM_ACCESS_TOKEN.equals(param.getName())) {
                String token = param.getValue();
                if (token != null && token.length() > 0)
                    return token;
            }
        return null;
    }

    /**
     * Get params for access token request
     * 
     * @param code
     * @return list of params
     */
    protected List<NameValuePair> getParams(String code) {
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair(IOAuth2Constants.PARAM_CLIENT_ID, client.getId()));
        params.add(new BasicNameValuePair(IOAuth2Constants.PARAM_CLIENT_SECRET, client.getSecret()));
        params.add(new BasicNameValuePair(IOAuth2Constants.PARAM_CODE, code));
        return params;
    }

    /**
     * Get access token using given code
     * 
     * @param code
     * @return fetched token
     * @throws IOException
     */
    public String fetch(final String code) throws IOException {
        URI uri = URI.create(client.getAccessTokenUrl());
        HttpHost target = URIUtils.extractHost(uri);
        List<NameValuePair> params = getParams(code);
        HttpPost request = new HttpPost(uri.getRawPath());
        if (params != null && !params.isEmpty())
            request.setEntity(new UrlEncodedFormEntity(params));
        HttpResponse response = execute(target, request);
        String token = getToken(response.getEntity());
        if (token == null)
            throw new IOException("Access token not present in response"); //$NON-NLS-1$
        return token;
    }
}