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+/*
+ * 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);
+ }
+ }
+}