Java tutorial
/** * Copyright 2010-present Facebook. * * 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.facebook; import android.net.Uri; import android.os.Bundle; import bolts.AppLink; import bolts.AppLinkResolver; import bolts.Continuation; import bolts.Task; import com.facebook.model.GraphObject; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.util.*; /** * Provides an implementation for the {@link AppLinkResolver AppLinkResolver} interface that uses the Facebook App Link * index to solve App Links, given a Url. It also provides an additional helper method that can resolve multiple App * Links in a single call. */ public class FacebookAppLinkResolver implements AppLinkResolver { private static final String APP_LINK_KEY = "app_links"; private static final String APP_LINK_ANDROID_TARGET_KEY = "android"; private static final String APP_LINK_WEB_TARGET_KEY = "web"; private static final String APP_LINK_TARGET_PACKAGE_KEY = "package"; private static final String APP_LINK_TARGET_CLASS_KEY = "class"; private static final String APP_LINK_TARGET_APP_NAME_KEY = "app_name"; private static final String APP_LINK_TARGET_URL_KEY = "url"; private static final String APP_LINK_TARGET_SHOULD_FALLBACK_KEY = "should_fallback"; private final HashMap<Uri, AppLink> cachedAppLinks = new HashMap<Uri, AppLink>(); /** * Asynchronously resolves App Link data for the passed in Uri * * @param uri Uri to be resolved into an App Link * @return A Task that, when successful, will return an AppLink for the passed in Uri. This may be null if no App * Link data was found for this Uri. * In the case of general server errors, the task will be completed with the corresponding error. */ public Task<AppLink> getAppLinkFromUrlInBackground(final Uri uri) { ArrayList<Uri> uris = new ArrayList<Uri>(); uris.add(uri); Task<Map<Uri, AppLink>> resolveTask = getAppLinkFromUrlsInBackground(uris); return resolveTask.onSuccess(new Continuation<Map<Uri, AppLink>, AppLink>() { @Override public AppLink then(Task<Map<Uri, AppLink>> resolveUrisTask) throws Exception { return resolveUrisTask.getResult().get(uri); } }); } /** * Asynchronously resolves App Link data for multiple Urls * * @param uris A list of Uri objects to resolve into App Links * @return A Task that, when successful, will return a Map of Uri->AppLink for each Uri that was successfully * resolved into an App Link. Uris that could not be resolved into App Links will not be present in the Map. * In the case of general server errors, the task will be completed with the corresponding error. */ public Task<Map<Uri, AppLink>> getAppLinkFromUrlsInBackground(List<Uri> uris) { final Map<Uri, AppLink> appLinkResults = new HashMap<Uri, AppLink>(); final HashSet<Uri> urisToRequest = new HashSet<Uri>(); StringBuilder graphRequestFields = new StringBuilder(); for (Uri uri : uris) { AppLink appLink = null; synchronized (cachedAppLinks) { appLink = cachedAppLinks.get(uri); } if (appLink != null) { appLinkResults.put(uri, appLink); } else { if (!urisToRequest.isEmpty()) { graphRequestFields.append(','); } graphRequestFields.append(uri.toString()); urisToRequest.add(uri); } } if (urisToRequest.isEmpty()) { return Task.forResult(appLinkResults); } final Task<Map<Uri, AppLink>>.TaskCompletionSource taskCompletionSource = Task.create(); Bundle appLinkRequestParameters = new Bundle(); appLinkRequestParameters.putString("ids", graphRequestFields.toString()); appLinkRequestParameters.putString("fields", String.format("%s.fields(%s,%s)", APP_LINK_KEY, APP_LINK_ANDROID_TARGET_KEY, APP_LINK_WEB_TARGET_KEY)); Request appLinkRequest = new Request(null, /* Session */ "", /* Graph path */ appLinkRequestParameters, /* Query parameters */ null, /* HttpMethod */ new Request.Callback() { /* Callback */ @Override public void onCompleted(Response response) { FacebookRequestError error = response.getError(); if (error != null) { taskCompletionSource.setError(error.getException()); return; } GraphObject responseObject = response.getGraphObject(); JSONObject responseJson = responseObject != null ? responseObject.getInnerJSONObject() : null; if (responseJson == null) { taskCompletionSource.setResult(appLinkResults); return; } for (Uri uri : urisToRequest) { String uriString = uri.toString(); if (!responseJson.has(uriString)) { continue; } JSONObject urlData = null; try { urlData = responseJson.getJSONObject(uri.toString()); JSONObject appLinkData = urlData.getJSONObject(APP_LINK_KEY); JSONArray rawTargets = appLinkData.getJSONArray(APP_LINK_ANDROID_TARGET_KEY); int targetsCount = rawTargets.length(); List<AppLink.Target> targets = new ArrayList<AppLink.Target>(targetsCount); for (int i = 0; i < targetsCount; i++) { AppLink.Target target = getAndroidTargetFromJson(rawTargets.getJSONObject(i)); if (target != null) { targets.add(target); } } Uri webFallbackUrl = getWebFallbackUriFromJson(uri, appLinkData); AppLink appLink = new AppLink(uri, targets, webFallbackUrl); appLinkResults.put(uri, appLink); synchronized (cachedAppLinks) { cachedAppLinks.put(uri, appLink); } } catch (JSONException e) { // The data for this uri was missing or badly formed. continue; } } taskCompletionSource.setResult(appLinkResults); } }); appLinkRequest.executeAsync(); return taskCompletionSource.getTask(); } private static AppLink.Target getAndroidTargetFromJson(JSONObject targetJson) { String packageName = tryGetStringFromJson(targetJson, APP_LINK_TARGET_PACKAGE_KEY, null); if (packageName == null) { // Package name is mandatory for each Android target return null; } String className = tryGetStringFromJson(targetJson, APP_LINK_TARGET_CLASS_KEY, null); String appName = tryGetStringFromJson(targetJson, APP_LINK_TARGET_APP_NAME_KEY, null); String targetUrlString = tryGetStringFromJson(targetJson, APP_LINK_TARGET_URL_KEY, null); Uri targetUri = null; if (targetUrlString != null) { targetUri = Uri.parse(targetUrlString); } return new AppLink.Target(packageName, className, targetUri, appName); } private static Uri getWebFallbackUriFromJson(Uri sourceUrl, JSONObject urlData) { // Try and get a web target. This is best effort. Any failures results in null being returned. try { JSONObject webTarget = urlData.getJSONObject(APP_LINK_WEB_TARGET_KEY); boolean shouldFallback = tryGetBooleanFromJson(webTarget, APP_LINK_TARGET_SHOULD_FALLBACK_KEY, true); if (!shouldFallback) { // Don't use a fallback url return null; } String webTargetUrlString = tryGetStringFromJson(webTarget, APP_LINK_TARGET_URL_KEY, null); Uri webUri = null; if (webTargetUrlString != null) { webUri = Uri.parse(webTargetUrlString); } // If we weren't able to parse a url from the web target, use the source url return webUri != null ? webUri : sourceUrl; } catch (JSONException e) { // If we were missing a web target, just use the source as the web url return sourceUrl; } } private static String tryGetStringFromJson(JSONObject json, String propertyName, String defaultValue) { try { return json.getString(propertyName); } catch (JSONException e) { return defaultValue; } } private static boolean tryGetBooleanFromJson(JSONObject json, String propertyName, boolean defaultValue) { try { return json.getBoolean(propertyName); } catch (JSONException e) { return defaultValue; } } }