Android example source code file (RequestHandle.java)

This example Android source code file (RequestHandle.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

a1, a2, android, authorization_header, get, inputstream, internet, io, kd, map, max_redirect_count, md5messagedigest, net, network, post, qop, requesthandle, string, util, webaddress

The RequestHandle.java Android example source code

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.net.http;

import android.net.ParseException;
import android.net.WebAddress;
import android.security.Md5MessageDigest;
import junit.framework.Assert;
import android.webkit.CookieManager;

import org.apache.commons.codec.binary.Base64;

import java.io.InputStream;
import java.lang.Math;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * RequestHandle: handles a request session that may include multiple
 * redirects, HTTP authentication requests, etc.
 * 
 * {@hide}
 */
public class RequestHandle {

    private String        mUrl;
    private WebAddress    mUri;
    private String        mMethod;
    private Map<String, String> mHeaders;
    private RequestQueue  mRequestQueue;
    private Request       mRequest;
    private InputStream   mBodyProvider;
    private int           mBodyLength;
    private int           mRedirectCount = 0;
    // Used only with synchronous requests.
    private Connection    mConnection;

    private final static String AUTHORIZATION_HEADER = "Authorization";
    private final static String PROXY_AUTHORIZATION_HEADER = "Proxy-Authorization";

    public final static int MAX_REDIRECT_COUNT = 16;

    /**
     * Creates a new request session.
     */
    public RequestHandle(RequestQueue requestQueue, String url, WebAddress uri,
            String method, Map<String, String> headers,
            InputStream bodyProvider, int bodyLength, Request request) {

        if (headers == null) {
            headers = new HashMap<String, String>();
        }
        mHeaders = headers;
        mBodyProvider = bodyProvider;
        mBodyLength = bodyLength;
        mMethod = method == null? "GET" : method;

        mUrl = url;
        mUri = uri;

        mRequestQueue = requestQueue;

        mRequest = request;
    }

    /**
     * Creates a new request session with a given Connection. This connection
     * is used during a synchronous load to handle this request.
     */
    public RequestHandle(RequestQueue requestQueue, String url, WebAddress uri,
            String method, Map<String, String> headers,
            InputStream bodyProvider, int bodyLength, Request request,
            Connection conn) {
        this(requestQueue, url, uri, method, headers, bodyProvider, bodyLength,
                request);
        mConnection = conn;
    }

    /**
     * Cancels this request
     */
    public void cancel() {
        if (mRequest != null) {
            mRequest.cancel();
        }
    }

    /**
     * Pauses the loading of this request. For example, called from the WebCore thread
     * when the plugin can take no more data.
     */
    public void pauseRequest(boolean pause) {
        if (mRequest != null) {
            mRequest.setLoadingPaused(pause);
        }
    }

    /**
     * Handles SSL error(s) on the way down from the user (the user
     * has already provided their feedback).
     */
    public void handleSslErrorResponse(boolean proceed) {
        if (mRequest != null) {
            mRequest.handleSslErrorResponse(proceed);
        }
    }

    /**
     * @return true if we've hit the max redirect count
     */
    public boolean isRedirectMax() {
        return mRedirectCount >= MAX_REDIRECT_COUNT;
    }

    public int getRedirectCount() {
        return mRedirectCount;
    }

    public void setRedirectCount(int count) {
        mRedirectCount = count;
    }

    /**
     * Create and queue a redirect request.
     *
     * @param redirectTo URL to redirect to
     * @param statusCode HTTP status code returned from original request
     * @param cacheHeaders Cache header for redirect URL
     * @return true if setup succeeds, false otherwise (redirect loop
     * count exceeded, body provider unable to rewind on 307 redirect)
     */
    public boolean setupRedirect(String redirectTo, int statusCode,
            Map<String, String> cacheHeaders) {
        if (HttpLog.LOGV) {
            HttpLog.v("RequestHandle.setupRedirect(): redirectCount " +
                  mRedirectCount);
        }

        // be careful and remove authentication headers, if any
        mHeaders.remove(AUTHORIZATION_HEADER);
        mHeaders.remove(PROXY_AUTHORIZATION_HEADER);

        if (++mRedirectCount == MAX_REDIRECT_COUNT) {
            // Way too many redirects -- fail out
            if (HttpLog.LOGV) HttpLog.v(
                    "RequestHandle.setupRedirect(): too many redirects " +
                    mRequest);
            mRequest.error(EventHandler.ERROR_REDIRECT_LOOP,
                           com.android.internal.R.string.httpErrorRedirectLoop);
            return false;
        }

        if (mUrl.startsWith("https:") && redirectTo.startsWith("http:")) {
            // implement http://www.w3.org/Protocols/rfc2616/rfc2616-sec15.html#sec15.1.3
            if (HttpLog.LOGV) {
                HttpLog.v("blowing away the referer on an https -> http redirect");
            }
            mHeaders.remove("Referer");
        }

        mUrl = redirectTo;
        try {
            mUri = new WebAddress(mUrl);
        } catch (ParseException e) {
            e.printStackTrace();
        }

        // update the "Cookie" header based on the redirected url
        mHeaders.remove("Cookie");
        String cookie = CookieManager.getInstance().getCookie(mUri);
        if (cookie != null && cookie.length() > 0) {
            mHeaders.put("Cookie", cookie);
        }

        if ((statusCode == 302 || statusCode == 303) && mMethod.equals("POST")) {
            if (HttpLog.LOGV) {
                HttpLog.v("replacing POST with GET on redirect to " + redirectTo);
            }
            mMethod = "GET";
        }
        /* Only repost content on a 307.  If 307, reset the body
           provider so we can replay the body */
        if (statusCode == 307) {
            try {
                if (mBodyProvider != null) mBodyProvider.reset();
            } catch (java.io.IOException ex) {
                if (HttpLog.LOGV) {
                    HttpLog.v("setupRedirect() failed to reset body provider");
                }
                return false;
            }

        } else {
            mHeaders.remove("Content-Type");
            mBodyProvider = null;
        }

        // Update the cache headers for this URL
        mHeaders.putAll(cacheHeaders);

        createAndQueueNewRequest();
        return true;
    }

    /**
     * Create and queue an HTTP authentication-response (basic) request.
     */
    public void setupBasicAuthResponse(boolean isProxy, String username, String password) {
        String response = computeBasicAuthResponse(username, password);
        if (HttpLog.LOGV) {
            HttpLog.v("setupBasicAuthResponse(): response: " + response);
        }
        mHeaders.put(authorizationHeader(isProxy), "Basic " + response);
        setupAuthResponse();
    }

    /**
     * Create and queue an HTTP authentication-response (digest) request.
     */
    public void setupDigestAuthResponse(boolean isProxy,
                                        String username,
                                        String password,
                                        String realm,
                                        String nonce,
                                        String QOP,
                                        String algorithm,
                                        String opaque) {

        String response = computeDigestAuthResponse(
                username, password, realm, nonce, QOP, algorithm, opaque);
        if (HttpLog.LOGV) {
            HttpLog.v("setupDigestAuthResponse(): response: " + response);
        }
        mHeaders.put(authorizationHeader(isProxy), "Digest " + response);
        setupAuthResponse();
    }

    private void setupAuthResponse() {
        try {
            if (mBodyProvider != null) mBodyProvider.reset();
        } catch (java.io.IOException ex) {
            if (HttpLog.LOGV) {
                HttpLog.v("setupAuthResponse() failed to reset body provider");
            }
        }
        createAndQueueNewRequest();
    }

    /**
     * @return HTTP request method (GET, PUT, etc).
     */
    public String getMethod() {
        return mMethod;
    }

    /**
     * @return Basic-scheme authentication response: BASE64(username:password).
     */
    public static String computeBasicAuthResponse(String username, String password) {
        Assert.assertNotNull(username);
        Assert.assertNotNull(password);

        // encode username:password to base64
        return new String(Base64.encodeBase64((username + ':' + password).getBytes()));
    }

    public void waitUntilComplete() {
        mRequest.waitUntilComplete();
    }

    public void processRequest() {
        if (mConnection != null) {
            mConnection.processRequests(mRequest);
        }
    }

    /**
     * @return Digest-scheme authentication response.
     */
    private String computeDigestAuthResponse(String username,
                                             String password,
                                             String realm,
                                             String nonce,
                                             String QOP,
                                             String algorithm,
                                             String opaque) {

        Assert.assertNotNull(username);
        Assert.assertNotNull(password);
        Assert.assertNotNull(realm);

        String A1 = username + ":" + realm + ":" + password;
        String A2 = mMethod  + ":" + mUrl;

        // because we do not preemptively send authorization headers, nc is always 1
        String nc = "000001";
        String cnonce = computeCnonce();
        String digest = computeDigest(A1, A2, nonce, QOP, nc, cnonce);

        String response = "";
        response += "username=" + doubleQuote(username) + ", ";
        response += "realm="    + doubleQuote(realm)    + ", ";
        response += "nonce="    + doubleQuote(nonce)    + ", ";
        response += "uri="      + doubleQuote(mUrl)     + ", ";
        response += "response=" + doubleQuote(digest) ;

        if (opaque     != null) {
            response += ", opaque=" + doubleQuote(opaque);
        }

         if (algorithm != null) {
            response += ", algorithm=" +  algorithm;
        }

        if (QOP        != null) {
            response += ", qop=" + QOP + ", nc=" + nc + ", cnonce=" + doubleQuote(cnonce);
        }

        return response;
    }

    /**
     * @return The right authorization header (dependeing on whether it is a proxy or not).
     */
    public static String authorizationHeader(boolean isProxy) {
        if (!isProxy) {
            return AUTHORIZATION_HEADER;
        } else {
            return PROXY_AUTHORIZATION_HEADER;
        }
    }

    /**
     * @return Double-quoted MD5 digest.
     */
    private String computeDigest(
        String A1, String A2, String nonce, String QOP, String nc, String cnonce) {
        if (HttpLog.LOGV) {
            HttpLog.v("computeDigest(): QOP: " + QOP);
        }

        if (QOP == null) {
            return KD(H(A1), nonce + ":" + H(A2));
        } else {
            if (QOP.equalsIgnoreCase("auth")) {
                return KD(H(A1), nonce + ":" + nc + ":" + cnonce + ":" + QOP + ":" + H(A2));
            }
        }

        return null;
    }

    /**
     * @return MD5 hash of concat(secret, ":", data).
     */
    private String KD(String secret, String data) {
        return H(secret + ":" + data);
    }

    /**
     * @return MD5 hash of param.
     */
    private String H(String param) {
        if (param != null) {
            Md5MessageDigest md5 = new Md5MessageDigest();

            byte[] d = md5.digest(param.getBytes());
            if (d != null) {
                return bufferToHex(d);
            }
        }

        return null;
    }

    /**
     * @return HEX buffer representation.
     */
    private String bufferToHex(byte[] buffer) {
        final char hexChars[] =
            { '0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f' };

        if (buffer != null) {
            int length = buffer.length;
            if (length > 0) {
                StringBuilder hex = new StringBuilder(2 * length);

                for (int i = 0; i < length; ++i) {
                    byte l = (byte) (buffer[i] & 0x0F);
                    byte h = (byte)((buffer[i] & 0xF0) >> 4);

                    hex.append(hexChars[h]);
                    hex.append(hexChars[l]);
                }

                return hex.toString();
            } else {
                return "";
            }
        }

        return null;
    }

    /**
     * Computes a random cnonce value based on the current time.
     */
    private String computeCnonce() {
        Random rand = new Random();
        int nextInt = rand.nextInt();
        nextInt = (nextInt == Integer.MIN_VALUE) ?
                Integer.MAX_VALUE : Math.abs(nextInt);
        return Integer.toString(nextInt, 16);
    }

    /**
     * "Double-quotes" the argument.
     */
    private String doubleQuote(String param) {
        if (param != null) {
            return "\"" + param + "\"";
        }

        return null;
    }

    /**
     * Creates and queues new request.
     */
    private void createAndQueueNewRequest() {
        // mConnection is non-null if and only if the requests are synchronous.
        if (mConnection != null) {
            RequestHandle newHandle = mRequestQueue.queueSynchronousRequest(
                    mUrl, mUri, mMethod, mHeaders, mRequest.mEventHandler,
                    mBodyProvider, mBodyLength);
            mRequest = newHandle.mRequest;
            mConnection = newHandle.mConnection;
            newHandle.processRequest();
            return;
        }
        mRequest = mRequestQueue.queueRequest(
                mUrl, mUri, mMethod, mHeaders, mRequest.mEventHandler,
                mBodyProvider,
                mBodyLength).mRequest;
    }
}