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Diffstat (limited to 'samples/WiktionarySimple/src/com/example/android/simplewiktionary/SimpleWikiHelper.java')
| -rw-r--r-- | samples/WiktionarySimple/src/com/example/android/simplewiktionary/SimpleWikiHelper.java | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/samples/WiktionarySimple/src/com/example/android/simplewiktionary/SimpleWikiHelper.java b/samples/WiktionarySimple/src/com/example/android/simplewiktionary/SimpleWikiHelper.java new file mode 100644 index 000000000..bb39d7bd7 --- /dev/null +++ b/samples/WiktionarySimple/src/com/example/android/simplewiktionary/SimpleWikiHelper.java @@ -0,0 +1,214 @@ +/* + * 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); + } + } +} |
