Java tutorial
/* * Copyright (C) 2010 Usl of >FA< * Licensed under the Apache License, Version 2.0 (the "License"); * * This is derivative work of code originally distributed under the following license: * * Copyright (C) 2009 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 com.fallenangelsguild.eltime; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import android.content.Context; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.content.pm.PackageManager.NameNotFoundException; import android.util.Log; /** * Helper methods to simplify talking with a web EL-time service. * Before making any requests, you should call * {@link #initialize(Context)} to generate a User-Agent string based on * your application package name and version. */ public class WebHelper { private static Context c = null; private static final String TAG = "WebHelper"; /** * {@link StatusLine} HTTP status code when no server error has occurred. */ private static final int HTTP_STATUS_OK = 200; /** * Shared buffer used by {@link #getUrlContent(String)} when reading results * from an API request. */ private static byte[] sBuffer = new byte[512]; /** * User-agent string to use when making requests. Should be filled using * {@link #initialize(Context)} before making any other calls. */ private static String sUserAgent = null; /** * Thrown when there were problems contacting the remote API server, either * because of a network error, or the server returned a bad status code. */ public static class ApiException extends Exception { public ApiException(String detailMessage, Throwable throwable) { super(detailMessage, throwable); } public ApiException(String detailMessage) { super(detailMessage); } } /** * Prepare the internal User-Agent string for use. This requires a * {@link Context} to pull the package name and version number for this * application. */ public static void initialize(Context context) { c = context; try { // Read package name and version number from manifest PackageManager manager = c.getPackageManager(); PackageInfo info = manager.getPackageInfo(c.getPackageName(), 0); sUserAgent = String.format(c.getString(R.string.template_user_agent), info.packageName, info.versionName); } catch (NameNotFoundException e) { Log.e(TAG, "Couldn't find package information in PackageManager", e); } } public static String getPageContent(String page, boolean flag) throws ApiException { if (c == null) { throw new ApiException("Must initialize() first"); } // Typical output: // UTC: 1287125021 // Game time: 3:23 // Today is the 2nd Mortun, in the month of Vespia, in the year 0024, Age of the Eternals. // Today is a special day: // Day of Magic // Today you gain twice the magic experience. // or // UTC: 1287149227 // Game time: 4:2 // Today is the 2nd Zarun, in the month of Vespia, in the year 0024, Age of the Eternals. // Just an ordinary day String content = getUrlContent(page); return content; // "UTC: 1287125021\n"+ // "Game time: 3:23\n"+ // "Today is the 2nd Mortun, in the month of Vespia, in the year 0024, Age of the Eternals.\n"+ // "Today is a special day:\n"+ // "Day of Magic\n"+ // "Today you gain twice the magic experience."; } /** * Pull the raw text content of the given URL. This call blocks until the * operation has completed, and is synchronized because it uses a shared * buffer {@link #sBuffer}. * * @param url The exact URL to request. * @return The raw content returned by the server. * @throws ApiException If any connection or server error occurs. */ protected static synchronized String getUrlContent(String url) throws ApiException { if (c == null) { throw new ApiException("Must initialize() first"); } // Create client and set our specific user-agent string HttpClient client = new DefaultHttpClient(); HttpGet request = new HttpGet(url); request.setHeader("User-Agent", sUserAgent); try { HttpResponse response = client.execute(request); // Check if server response is valid StatusLine status = response.getStatusLine(); if (status.getStatusCode() != HTTP_STATUS_OK) { throw new ApiException("Invalid response from server: " + status.toString()); } // Pull content stream from response HttpEntity entity = response.getEntity(); InputStream inputStream = entity.getContent(); ByteArrayOutputStream content = new ByteArrayOutputStream(); // Read response into a buffered stream int readBytes = 0; while ((readBytes = inputStream.read(sBuffer)) != -1) { content.write(sBuffer, 0, readBytes); } // Return result from buffered stream return new String(content.toByteArray()); } catch (IOException e) { throw new ApiException("Problem communicating with API", e); } } }