/samples/WiktionarySimple/src/com/example/android/simplewiktionary/SimpleWikiHelper.java
Java | 214 lines | 99 code | 26 blank | 89 comment | 6 complexity | 142bfc6f42ec1f178342d01024a7e8cb MD5 | raw file
- /*
- * 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.example.android.simplewiktionary;
- 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 org.json.JSONArray;
- import org.json.JSONException;
- import org.json.JSONObject;
- import android.content.Context;
- import android.content.pm.PackageInfo;
- import android.content.pm.PackageManager;
- import android.content.pm.PackageManager.NameNotFoundException;
- import android.net.Uri;
- import android.util.Log;
- import java.io.ByteArrayOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- /**
- * Helper methods to simplify talking with and parsing responses from a
- * lightweight Wiktionary API. Before making any requests, you should call
- * {@link #prepareUserAgent(Context)} to generate a User-Agent string based on
- * your application package name and version.
- */
- public class SimpleWikiHelper {
- private static final String TAG = "SimpleWikiHelper";
- /**
- * Regular expression that splits "Word of the day" entry into word
- * name, word type, and the first description bullet point.
- */
- public static final String WORD_OF_DAY_REGEX =
- "(?s)\\{\\{wotd\\|(.+?)\\|(.+?)\\|([^#\\|]+).*?\\}\\}";
- /**
- * Partial URL to use when requesting the detailed entry for a specific
- * Wiktionary page. Use {@link String#format(String, Object...)} to insert
- * the desired page title after escaping it as needed.
- */
- private static final String WIKTIONARY_PAGE =
- "http://en.wiktionary.org/w/api.php?action=query&prop=revisions&titles=%s&" +
- "rvprop=content&format=json%s";
- /**
- * Partial URL to append to {@link #WIKTIONARY_PAGE} when you want to expand
- * any templates found on the requested page. This is useful when browsing
- * full entries, but may use more network bandwidth.
- */
- private static final String WIKTIONARY_EXPAND_TEMPLATES =
- "&rvexpandtemplates=true";
- /**
- * {@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 #prepareUserAgent(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);
- }
- }
- /**
- * Thrown when there were problems parsing the response to an API call,
- * either because the response was empty, or it was malformed.
- */
- public static class ParseException extends Exception {
- public ParseException(String detailMessage, Throwable throwable) {
- super(detailMessage, throwable);
- }
- }
- /**
- * 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 prepareUserAgent(Context context) {
- try {
- // Read package name and version number from manifest
- PackageManager manager = context.getPackageManager();
- PackageInfo info = manager.getPackageInfo(context.getPackageName(), 0);
- sUserAgent = String.format(context.getString(R.string.template_user_agent),
- info.packageName, info.versionName);
- } catch(NameNotFoundException e) {
- Log.e(TAG, "Couldn't find package information in PackageManager", e);
- }
- }
- /**
- * Read and return the content for a specific Wiktionary page. This makes a
- * lightweight API call, and trims out just the page content returned.
- * Because this call blocks until results are available, it should not be
- * run from a UI thread.
- *
- * @param title The exact title of the Wiktionary page requested.
- * @param expandTemplates If true, expand any wiki templates found.
- * @return Exact content of page.
- * @throws ApiException If any connection or server error occurs.
- * @throws ParseException If there are problems parsing the response.
- */
- public static String getPageContent(String title, boolean expandTemplates)
- throws ApiException, ParseException {
- // Encode page title and expand templates if requested
- String encodedTitle = Uri.encode(title);
- String expandClause = expandTemplates ? WIKTIONARY_EXPAND_TEMPLATES : "";
- // Query the API for content
- String content = getUrlContent(String.format(WIKTIONARY_PAGE,
- encodedTitle, expandClause));
- try {
- // Drill into the JSON response to find the content body
- JSONObject response = new JSONObject(content);
- JSONObject query = response.getJSONObject("query");
- JSONObject pages = query.getJSONObject("pages");
- JSONObject page = pages.getJSONObject((String) pages.keys().next());
- JSONArray revisions = page.getJSONArray("revisions");
- JSONObject revision = revisions.getJSONObject(0);
- return revision.getString("*");
- } catch (JSONException e) {
- throw new ParseException("Problem parsing API response", e);
- }
- }
- /**
- * 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 (sUserAgent == null) {
- throw new ApiException("User-Agent string must be prepared");
- }
- // 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);
- }
- }
- }