adding reaction emoji feature

It is now possible for the bot to automatically add a reaction
emoji to any message on any channel it has access.

Change-Id: I223b07a7a6b7d3d8ec84297a031d806cb3bbe7b3

build.gradle

@@ -23,7 +23,7 @@ apply plugin: 'maven-publish'
 
 group = 'com.ullink.slack'
 archivesBaseName = 'simpleslackapi'
-version = '0.4.2-SNAPSHOT'
+version = '0.4.3'
 
 
 task javadocJar(type: Jar) {

src/main/java/com/ullink/slack/simpleslackapi/SlackSession.java

@@ -51,6 +51,8 @@ public interface SlackSession
 
     SlackMessageHandle sendMessageOverWebSocket(SlackChannel channel, String message, SlackAttachment attachment);
 
+    SlackMessageHandle addReactionToMessage(SlackChannel channel, String messageTimeStamp, String emojiCode);
+
     SlackPersona.SlackPresence getPresence(SlackPersona persona);
 
     void addchannelArchivedListener(SlackChannelArchivedListener listener);

src/main/java/com/ullink/slack/simpleslackapi/impl/SlackWebSocketSessionImpl.java

@@ -391,6 +391,34 @@ public SlackMessageHandle updateMessage(String timeStamp, SlackChannel channel,
         return handle;
     }
 
+    @Override
+    public SlackMessageHandle addReactionToMessage(SlackChannel channel, String messageTimeStamp, String emojiCode)
+    {
+        SlackMessageHandleImpl handle = new SlackMessageHandleImpl(getNextMessageId());
+        HttpClient client = getHttpClient();
+        HttpPost request = new HttpPost("https://slack.com/api/reactions.add");
+        List<NameValuePair> nameValuePairList = new ArrayList<>();
+        nameValuePairList.add(new BasicNameValuePair("token", authToken));
+        nameValuePairList.add(new BasicNameValuePair("channel", channel.getId()));
+        nameValuePairList.add(new BasicNameValuePair("timestamp", messageTimeStamp));
+        nameValuePairList.add(new BasicNameValuePair("name", emojiCode));
+        try
+        {
+            request.setEntity(new UrlEncodedFormEntity(nameValuePairList, "UTF-8"));
+            HttpResponse response = client.execute(request);
+            String jsonResponse = CharStreams.toString(new InputStreamReader(response.getEntity().getContent()));
+            LOGGER.debug("PostMessage return: " + jsonResponse);
+            SlackReplyImpl reply = SlackJSONReplyParser.decode(parseObject(jsonResponse));
+            handle.setSlackReply(reply);
+        }
+        catch (Exception e)
+        {
+            // TODO : improve exception handling
+            e.printStackTrace();
+        }
+        return handle;
+    }
+
     private HttpClient getHttpClient()
     {
         HttpClient client = null;

src/test/java/com/ullink/slack/simpleslackapi/impl/TestAbstractSlackSessionImpl.java

@@ -1,7 +1,6 @@
 package com.ullink.slack.simpleslackapi.impl;
 
 import static org.assertj.core.api.Assertions.assertThat;
-
 import com.ullink.slack.simpleslackapi.SlackPersona;
 import org.junit.Test;
 import com.ullink.slack.simpleslackapi.SlackAttachment;
@@ -64,6 +63,12 @@ public SlackMessageHandle updateMessage(String timeStamp, SlackChannel channel,
         {
             return null;
         }
+
+        @Override
+        public SlackMessageHandle addReactionToMessage(SlackChannel channel, String messageTimeStamp, String emojiCode)
+        {
+            return null;
+        }
     }
 
     @Test

src/test/java/com/ullink/slack/simpleslackapi/impl/TestSlackJSONMessageParser.java

@@ -85,6 +85,12 @@ public SlackMessageHandle updateMessage(String timeStamp, SlackChannel channel,
                 return null;
             }
 
+            @Override
+            public SlackMessageHandle addReactionToMessage(SlackChannel channel, String messageTimeStamp, String emojiCode)
+            {
+                return null;
+            }
+
         };
         try
         {