Add HtmlAppLinkResolver

Bolts/src/bolts/HtmlAppLinkResolver.java

@@ -0,0 +1,110 @@
+/*
+ *  Copyright (c) 2014, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+package bolts;
+
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
+import android.text.Editable;
+import android.text.Html;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.xml.sax.Attributes;
+import org.xml.sax.SAXException;
+import org.xml.sax.XMLReader;
+import org.xml.sax.helpers.DefaultHandler;
+
+/**
+ * A simple implementation for an App Link resolver that parses the HTML containing App Link metadata
+ * using {@link android.text.Html#fromHtml}.
+ */
+public class HtmlAppLinkResolver implements AppLinkResolver {
+  /**
+   * Creates an {@code HtmlAppLinkResolver}.
+   */
+  public HtmlAppLinkResolver() {
+  }
+
+  private static final String META_TAG = "meta";
+  private static final String META_TAG_PREFIX = "al:";
+  private static final String META_ATTR_PROPERTY = "property";
+  private static final String META_ATTR_CONTENT = "content";
+
+  @Override
+  public Task<AppLink> getAppLinkFromUrlInBackground(final Uri url) {
+    return ResolverUtils.fetchUrl(url)
+        .onSuccess(new Continuation<ResolverUtils.StringEntity, JSONArray>() {
+          @Override
+          public JSONArray then(Task<ResolverUtils.StringEntity> task) throws Exception {
+            return parseMetaTags(task.getResult().getContent());
+          }
+        }).onSuccess(new Continuation<JSONArray, AppLink>() {
+      @Override
+      public AppLink then(Task<JSONArray> task) throws Exception {
+        return ResolverUtils.parseAppLinkFromAlData(task.getResult(), url);
+      }
+    });
+  }
+
+  private static JSONArray parseMetaTags(String html) throws Exception {
+    final MetaTagHandler metaTagHandler = new MetaTagHandler();
+    Html.fromHtml(html, metaTagHandler, metaTagHandler);
+
+    return metaTagHandler.getJsonArray();
+  }
+
+  private static class MetaTagHandler extends DefaultHandler implements Html.TagHandler, Html.ImageGetter {
+
+    private JSONArray jsonArray = new JSONArray();
+
+    @Override
+    public void handleTag(boolean opening, String tag, Editable output, XMLReader xmlReader) {
+      xmlReader.setContentHandler(this);
+    }
+
+    @Override
+    public Drawable getDrawable(String source) {
+      return null;
+    }
+
+    @Override
+    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
+      if (META_TAG.equalsIgnoreCase(localName)) {
+        addMetaElement(attributes);
+      }
+    }
+
+    public JSONArray getJsonArray() {
+      return jsonArray;
+    }
+
+    private void addMetaElement(Attributes attributes) throws SAXException {
+      String property = attributes.getValue(META_ATTR_PROPERTY);
+
+      if (property != null && property.startsWith(META_TAG_PREFIX)) {
+        String content = attributes.getValue(META_ATTR_CONTENT);
+
+        JSONObject metaObject = new JSONObject();
+        try {
+          metaObject.put(META_ATTR_PROPERTY, property);
+          if (content != null) {
+            metaObject.put(META_ATTR_CONTENT, content);
+          }
+        } catch (JSONException e) {
+          throw new SAXException(e);
+        }
+
+        jsonArray.put(metaObject);
+      }
+    }
+
+  }
+}

Bolts/src/bolts/MeasurementEvent.java

@@ -7,7 +7,6 @@
  *  of patent rights can be found in the PATENTS file in the same directory.
  *
  */
-
 package bolts;
 
 import android.content.ComponentName;