added mod actions: ability to send PM via subreddit & ability to sticky a post (#227)

* added ability to send PM via subreddit (mod action)
added ability to sticky a post (mod action)

Author: artofdarkness123

RedditSharp/Reddit.cs

@@ -295,17 +295,43 @@ public Post GetPost(Uri uri)
             return new Post().Init(this, GetToken(uri), WebAgent);
         }
 
-        public void ComposePrivateMessage(string subject, string body, string to, string captchaId = "", string captchaAnswer = "")
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="subject"></param>
+        /// <param name="body"></param>
+        /// <param name="to"></param>
+        /// <param name="fromSubReddit">The subreddit to send the message as (optional).</param>
+        /// <param name="captchaId"></param>
+        /// <param name="captchaAnswer"></param>
+        /// <remarks>If <paramref name="fromSubReddit"/> is passed in then the message is sent from the subreddit. the sender must be a mod of the specified subreddit.</remarks>
+        /// <exception cref="AuthenticationException">Thrown when a subreddit is passed in and the user is not a mod of that sub.</exception>
+        public void ComposePrivateMessage(string subject, string body, string to, string fromSubReddit = "", string captchaId = "", string captchaAnswer = "")
         {
             if (User == null)
                 throw new Exception("User can not be null.");
+
+            if (!String.IsNullOrWhiteSpace(fromSubReddit))
+            {
+                var subReddit = this.GetSubreddit(fromSubReddit);
+                var modNameList = subReddit.Moderators.Select(b => b.Name).ToList();
+
+                if (!modNameList.Contains(User.Name))
+                    throw new AuthenticationException(
+                        String.Format(
+                            @"User {0} is not a moderator of subreddit {1}.",
+                            User.Name,
+                            subReddit.Name));
+            }
+
             var request = WebAgent.CreatePost(ComposeMessageUrl);
             WebAgent.WritePostBody(request.GetRequestStream(), new
             {
                 api_type = "json",
                 subject,
                 text = body,
                 to,
+                from_sr = fromSubReddit,
                 uh = User.Modhash,
                 iden = captchaId,
                 captcha = captchaAnswer
@@ -415,6 +441,7 @@ public Listing<T> SearchByTimestamp<T>(DateTime from, DateTime to, string query
             return new Listing<T>(this, string.Format(SearchUrl, searchQuery, sort, time), WebAgent);
         }
 
+
         #region SubredditSearching
 
         /// <summary>

RedditSharp/Things/Post.cs

@@ -23,6 +23,7 @@ public class Post : VotableThing
         private const string MarkNSFWUrl = "/api/marknsfw";
         private const string UnmarkNSFWUrl = "/api/unmarknsfw";
         private const string ContestModeUrl = "/api/set_contest_mode";
+        private const string StickyModeUrl = "/api/set_subreddit_sticky";
 
         [JsonIgnore]
         private Reddit Reddit { get; set; }
@@ -181,10 +182,20 @@ private string SimpleAction(string endpoint)
             return data;
         }
 
-        private string SimpleActionToggle(string endpoint, bool value)
+        private string SimpleActionToggle(string endpoint, bool value, bool requiresModAction = false)
         {
             if (Reddit.User == null)
                 throw new AuthenticationException("No user logged in.");
+
+            var modNameList = this.Subreddit.Moderators.Select(b => b.Name).ToList();
+
+            if (requiresModAction && !modNameList.Contains(Reddit.User.Name))
+                throw new AuthenticationException(
+                    String.Format(
+                        @"User {0} is not a moderator of subreddit {1}.", 
+                        Reddit.User.Name,
+                        this.Subreddit.Name));
+
             var request = WebAgent.CreatePost(endpoint);
             var stream = request.GetRequestStream();
             WebAgent.WritePostBody(stream, new
@@ -259,6 +270,11 @@ public void ContestMode(bool state)
             var data = SimpleActionToggle(ContestModeUrl, state);
         }
 
+        public void StickyMode(bool state)
+        {
+            var data = SimpleActionToggle(StickyModeUrl, state, true);
+        }
+
         #region Obsolete Getter Methods
 
         [Obsolete("Use Comments property instead")]