If calls to UserAgentServiceConnector fail then throw an exception. This lets the caller decide whether to discard the error or not.

This is Oren Hurvitz's 0001 patch from http://opensimulator.org/mantis/view.php?id=6956 but I ended up doing some tweaking to resolve patch application issues.

OpenSim/Region/CoreModules/Avatar/InstantMessage/HGMessageTransferModule.cs

@@ -282,7 +282,17 @@ namespace OpenSim.Region.CoreModules.Avatar.InstantMessage
                         string uasURL = circuit.ServiceURLs["HomeURI"].ToString();
                         m_log.DebugFormat("[HG MESSAGE TRANSFER]: getting UUI of user {0} from {1}", toAgent, uasURL);
                         UserAgentServiceConnector uasConn = new UserAgentServiceConnector(uasURL);
-                        return uasConn.GetUUI(fromAgent, toAgent);
+
+                        string agentUUI = string.Empty;
+                        try
+                        {
+                            agentUUI = uasConn.GetUUI(fromAgent, toAgent);
+                        }
+                        catch (Exception e) {
+                            m_log.Warn("[HG MESSAGE TRANSFER]: GetUUI call failed ", e);
+                        }
+
+                        return agentUUI;
                     }
                 }
             }

OpenSim/Region/CoreModules/Avatar/UserProfiles/UserProfileModule.cs

@@ -1164,7 +1164,16 @@ namespace OpenSim.Region.OptionalModules.Avatar.UserProfiles
 
                 UserAgentServiceConnector uConn = new UserAgentServiceConnector(home_url);
 
-                Dictionary<string, object> account = uConn.GetUserInfo(userID);
+                Dictionary<string, object> account;
+                try
+                {
+                    account = uConn.GetUserInfo(userID);
+                }
+                catch (Exception e)
+                {
+                    m_log.Warn("[PROFILES]: GetUserInfo call failed ", e);
+                    account = new Dictionary<string, object>();
+                }
 
                 if (account.Count > 0)
                 {

OpenSim/Region/CoreModules/Framework/EntityTransfer/HGEntityTransferModule.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright (c) Contributors, http://opensimulator.org/
  * See CONTRIBUTORS.TXT for a full list of copyright holders.
  *
@@ -462,7 +462,17 @@ namespace OpenSim.Region.CoreModules.Framework.EntityTransfer
 
             IUserAgentService userAgentService = new UserAgentServiceConnector(aCircuit.ServiceURLs["HomeURI"].ToString());
             Vector3 position = Vector3.UnitY, lookAt = Vector3.UnitY;
-            GridRegion finalDestination = userAgentService.GetHomeRegion(aCircuit.AgentID, out position, out lookAt);
+
+            GridRegion finalDestination = null;
+            try
+            {
+                finalDestination = userAgentService.GetHomeRegion(aCircuit.AgentID, out position, out lookAt);
+            }
+            catch (Exception e)
+            {
+                m_log.Warn("[HG ENTITY TRANSFER MODULE]: GetHomeRegion call failed ", e);
+            }
+            
             if (finalDestination == null)
             {
                 client.SendTeleportFailed("Your home region could not be found");

OpenSim/Region/CoreModules/Framework/UserManagement/HGUserManagementModule.cs

@@ -130,7 +130,17 @@ namespace OpenSim.Region.CoreModules.Framework.UserManagement
                         }
 
                         UserAgentServiceConnector uasConn = new UserAgentServiceConnector(uriStr);
-                        UUID userID = uasConn.GetUUID(names[0], names[1]);
+                        
+                        UUID userID = UUID.Zero;
+                        try
+                        {
+                            userID = uasConn.GetUUID(names[0], names[1]);
+                        }
+                        catch (Exception e)
+                        {
+                            m_log.Warn("[USER MANAGEMENT MODULE]: GetUUID call failed ", e);
+                        }
+                        
                         if (!userID.Equals(UUID.Zero))
                         {
                             UserData ud = new UserData();

OpenSim/Region/CoreModules/Framework/UserManagement/UserManagementModule.cs

@@ -473,7 +473,16 @@ namespace OpenSim.Region.CoreModules.Framework.UserManagement
                     //    serverType, userdata.HomeURL, userID);
 
                     UserAgentServiceConnector uConn = new UserAgentServiceConnector(userdata.HomeURL);
-                    userdata.ServerURLs = uConn.GetServerURLs(userID);
+                    try
+                    {
+                        userdata.ServerURLs = uConn.GetServerURLs(userID);
+                    }
+                    catch (Exception e)
+                    {
+                        m_log.Warn("[USER MANAGEMENT MODULE]: GetServerURLs call failed ", e);
+                        userdata.ServerURLs = new Dictionary<string, object>();
+                    }
+                    
                     if (userdata.ServerURLs != null && userdata.ServerURLs.ContainsKey(serverType) && userdata.ServerURLs[serverType] != null)
                         return userdata.ServerURLs[serverType].ToString();
                 }

OpenSim/Services/Connectors/Hypergrid/UserAgentServiceConnector.cs

@@ -78,7 +78,8 @@ namespace OpenSim.Services.Connectors.Hypergrid
                     m_log.DebugFormat("[USER AGENT CONNECTOR]: Malformed Uri {0}: {1}", m_ServerURL, e.Message);
                 }
             }
-            m_log.DebugFormat("[USER AGENT CONNECTOR]: new connector to {0} ({1})", url, m_ServerURL);
+
+            //m_log.DebugFormat("[USER AGENT CONNECTOR]: new connector to {0} ({1})", url, m_ServerURL);
         }
 
         public UserAgentServiceConnector(IConfigSource config)
@@ -190,6 +191,40 @@ namespace OpenSim.Services.Connectors.Hypergrid
             // no-op
         }
 
+        private Hashtable CallServer(string methodName, Hashtable hash)
+        {
+            IList paramList = new ArrayList();
+            paramList.Add(hash);
+
+            XmlRpcRequest request = new XmlRpcRequest(methodName, paramList);
+
+            // Send and get reply
+            XmlRpcResponse response = null;
+            try
+            {
+                response = request.Send(m_ServerURL, 10000);
+            }
+            catch (Exception e)
+            {
+                m_log.WarnFormat("[USER AGENT CONNECTOR]: {0} call to {1} failed: {2}", methodName, m_ServerURL, e.Message);
+                throw;
+            }
+
+            if (response.IsFault)
+            {
+                throw new Exception(string.Format("[USER AGENT CONNECTOR]: {0} call to {1} returned an error: {2}", methodName, m_ServerURL, response.FaultString));
+            }
+
+            hash = (Hashtable)response.Value;
+
+            if (hash == null)
+            {
+                throw new Exception(string.Format("[USER AGENT CONNECTOR]: {0} call to {1} returned null", methodName, m_ServerURL));
+            }
+
+            return hash;
+        }
+
         public GridRegion GetHomeRegion(UUID userID, out Vector3 position, out Vector3 lookAt)
         {
             position = Vector3.UnitY; lookAt = Vector3.UnitY;
@@ -197,89 +232,58 @@ namespace OpenSim.Services.Connectors.Hypergrid
             Hashtable hash = new Hashtable();
             hash["userID"] = userID.ToString();
 
-            IList paramList = new ArrayList();
+            hash = CallServer("get_home_region", hash);
-            paramList.Add(hash);
 
-            XmlRpcRequest request = new XmlRpcRequest("get_home_region", paramList);
+            bool success;
-            XmlRpcResponse response = null;
+            if (!Boolean.TryParse((string)hash["result"], out success) || !success)
-            try
-            {
-                response = request.Send(m_ServerURL, 10000);
-            }
-            catch (Exception)
-            {
                 return null;
-            }
 
-            if (response.IsFault)
+            GridRegion region = new GridRegion();
+
+            UUID.TryParse((string)hash["uuid"], out region.RegionID);
+            //m_log.Debug(">> HERE, uuid: " + region.RegionID);
+            int n = 0;
+            if (hash["x"] != null)
             {
-                return null;
+                Int32.TryParse((string)hash["x"], out n);
+                region.RegionLocX = n;
+                //m_log.Debug(">> HERE, x: " + region.RegionLocX);
             }
-
+            if (hash["y"] != null)
-            hash = (Hashtable)response.Value;
-            //foreach (Object o in hash)
-            //    m_log.Debug(">> " + ((DictionaryEntry)o).Key + ":" + ((DictionaryEntry)o).Value);
-            try
             {
-                bool success = false;
+                Int32.TryParse((string)hash["y"], out n);
-                Boolean.TryParse((string)hash["result"], out success);
+                region.RegionLocY = n;
-                if (success)
+                //m_log.Debug(">> HERE, y: " + region.RegionLocY);
-                {
-                    GridRegion region = new GridRegion();
-
-                    UUID.TryParse((string)hash["uuid"], out region.RegionID);
-                    //m_log.Debug(">> HERE, uuid: " + region.RegionID);
-                    int n = 0;
-                    if (hash["x"] != null)
-                    {
-                        Int32.TryParse((string)hash["x"], out n);
-                        region.RegionLocX = n;
-                        //m_log.Debug(">> HERE, x: " + region.RegionLocX);
-                    }
-                    if (hash["y"] != null)
-                    {
-                        Int32.TryParse((string)hash["y"], out n);
-                        region.RegionLocY = n;
-                        //m_log.Debug(">> HERE, y: " + region.RegionLocY);
-                    }
-                    if (hash["region_name"] != null)
-                    {
-                        region.RegionName = (string)hash["region_name"];
-                        //m_log.Debug(">> HERE, name: " + region.RegionName);
-                    }
-                    if (hash["hostname"] != null)
-                        region.ExternalHostName = (string)hash["hostname"];
-                    if (hash["http_port"] != null)
-                    {
-                        uint p = 0;
-                        UInt32.TryParse((string)hash["http_port"], out p);
-                        region.HttpPort = p;
-                    }
-                    if (hash.ContainsKey("server_uri") && hash["server_uri"] != null)
-                        region.ServerURI = (string)hash["server_uri"];
-
-                    if (hash["internal_port"] != null)
-                    {
-                        int p = 0;
-                        Int32.TryParse((string)hash["internal_port"], out p);
-                        region.InternalEndPoint = new IPEndPoint(IPAddress.Parse("0.0.0.0"), p);
-                    }
-                    if (hash["position"] != null)
-                        Vector3.TryParse((string)hash["position"], out position);
-                    if (hash["lookAt"] != null)
-                        Vector3.TryParse((string)hash["lookAt"], out lookAt);
-
-                    // Successful return
-                    return region;
-                }
-
             }
-            catch (Exception)
+            if (hash["region_name"] != null)
             {
-                return null;
+                region.RegionName = (string)hash["region_name"];
+                //m_log.Debug(">> HERE, name: " + region.RegionName);
             }
+            if (hash["hostname"] != null)
+                region.ExternalHostName = (string)hash["hostname"];
+            if (hash["http_port"] != null)
+            {
+                uint p = 0;
+                UInt32.TryParse((string)hash["http_port"], out p);
+                region.HttpPort = p;
+            }
+            if (hash.ContainsKey("server_uri") && hash["server_uri"] != null)
+                region.ServerURI = (string)hash["server_uri"];
 
-            return null;
+            if (hash["internal_port"] != null)
+            {
+                int p = 0;
+                Int32.TryParse((string)hash["internal_port"], out p);
+                region.InternalEndPoint = new IPEndPoint(IPAddress.Parse("0.0.0.0"), p);
+            }
+            if (hash["position"] != null)
+                Vector3.TryParse((string)hash["position"], out position);
+            if (hash["lookAt"] != null)
+                Vector3.TryParse((string)hash["lookAt"], out lookAt);
+
+            // Successful return
+            return region;
         }
 
         public bool IsAgentComingHome(UUID sessionID, string thisGridExternalName)
@@ -488,50 +492,16 @@ namespace OpenSim.Services.Connectors.Hypergrid
             Hashtable hash = new Hashtable();
             hash["userID"] = userID.ToString();
 
-            IList paramList = new ArrayList();
+            hash = CallServer("get_user_info", hash);
-            paramList.Add(hash);
-
-            XmlRpcRequest request = new XmlRpcRequest("get_user_info", paramList);
 
             Dictionary<string, object> info = new Dictionary<string, object>();
-            XmlRpcResponse response = null;
-            try
-            {
-                response = request.Send(m_ServerURL, 10000);
-            }
-            catch
-            {
-                m_log.DebugFormat("[USER AGENT CONNECTOR]: Unable to contact remote server {0} for GetUserInfo", m_ServerURL);
-                return info;
-            }
 
-            if (response.IsFault)
+            foreach (object key in hash.Keys)
             {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: remote call to {0} for GetServerURLs returned an error: {1}", m_ServerURL, response.FaultString);
+                if (hash[key] != null)
-                return info;
-            }
-
-            hash = (Hashtable)response.Value;
-            try
-            {
-                if (hash == null)
                 {
-                    m_log.ErrorFormat("[USER AGENT CONNECTOR]: GetUserInfo Got null response from {0}! THIS IS BAAAAD", m_ServerURL);
+                    info.Add(key.ToString(), hash[key]);
-                    return info;
                 }
-
-                // Here is the actual response
-                foreach (object key in hash.Keys)
-                {
-                    if (hash[key] != null)
-                    {
-                        info.Add(key.ToString(), hash[key]);
-                    }
-                }
-            }
-            catch
-            {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: Got exception on GetOnlineFriends response.");
             }
 
             return info;
@@ -542,60 +512,16 @@ namespace OpenSim.Services.Connectors.Hypergrid
             Hashtable hash = new Hashtable();
             hash["userID"] = userID.ToString();
 
-            IList paramList = new ArrayList();
+            hash = CallServer("get_server_urls", hash);
-            paramList.Add(hash);
+           
-
+            Dictionary<string, object> serverURLs = new Dictionary<string, object>();
-            XmlRpcRequest request = new XmlRpcRequest("get_server_urls", paramList);
+            foreach (object key in hash.Keys)
-//            string reason = string.Empty;
-
-            // Send and get reply
-            Dictionary<string, object> serverURLs = new Dictionary<string,object>();
-            XmlRpcResponse response = null;
-            try
             {
-                response = request.Send(m_ServerURL, 10000);
+                if (key is string && ((string)key).StartsWith("SRV_") && hash[key] != null)
-            }
-            catch
-            {
-                m_log.DebugFormat("[USER AGENT CONNECTOR]: Unable to contact remote server {0} for GetServerURLs for user {1}", m_ServerURL, userID);
-//                reason = "Exception: " + e.Message;
-                return serverURLs;
-            }
-
-            if (response.IsFault)
-            {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: remote call to {0} for GetServerURLs returned an error: {1}", m_ServerURL, response.FaultString);
-//                reason = "XMLRPC Fault";
-                return serverURLs;
-            }
-
-            hash = (Hashtable)response.Value;
-            //foreach (Object o in hash)
-            //    m_log.Debug(">> " + ((DictionaryEntry)o).Key + ":" + ((DictionaryEntry)o).Value);
-            try
-            {
-                if (hash == null)
                 {
-                    m_log.ErrorFormat("[USER AGENT CONNECTOR]: GetServerURLs Got null response from {0}! THIS IS BAAAAD", m_ServerURL);
+                    string serverType = key.ToString().Substring(4); // remove "SRV_"
-//                    reason = "Internal error 1";
+                    serverURLs.Add(serverType, hash[key].ToString());
-                    return serverURLs;
                 }
-
-                // Here is the actual response
-                foreach (object key in hash.Keys)
-                {
-                    if (key is string && ((string)key).StartsWith("SRV_") && hash[key] != null)
-                    {
-                        string serverType = key.ToString().Substring(4); // remove "SRV_"
-                        serverURLs.Add(serverType, hash[key].ToString());
-                    }
-                }
-
-            }
-            catch
-            {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: Got exception on GetOnlineFriends response.");
-//                reason = "Exception: " + e.Message;
             }
 
             return serverURLs;
@@ -606,55 +532,13 @@ namespace OpenSim.Services.Connectors.Hypergrid
             Hashtable hash = new Hashtable();
             hash["userID"] = userID.ToString();
 
-            IList paramList = new ArrayList();
+            hash = CallServer("locate_user", hash);           
-            paramList.Add(hash);
 
-            XmlRpcRequest request = new XmlRpcRequest("locate_user", paramList);
-//            string reason = string.Empty;
-
-            // Send and get reply
             string url = string.Empty;
-            XmlRpcResponse response = null;
-            try
-            {
-                response = request.Send(m_ServerURL, 10000);
-            }
-            catch
-            {
-                m_log.DebugFormat("[USER AGENT CONNECTOR]: Unable to contact remote server {0} for LocateUser", m_ServerURL);
-//                reason = "Exception: " + e.Message;
-                return url;
-            }
 
-            if (response.IsFault)
+            // Here's the actual response
-            {
+            if (hash.ContainsKey("URL"))
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: remote call to {0} for LocateUser returned an error: {1}", m_ServerURL, response.FaultString);
+                url = hash["URL"].ToString();
-//                reason = "XMLRPC Fault";
-                return url;
-            }
-
-            hash = (Hashtable)response.Value;
-            //foreach (Object o in hash)
-            //    m_log.Debug(">> " + ((DictionaryEntry)o).Key + ":" + ((DictionaryEntry)o).Value);
-            try
-            {
-                if (hash == null)
-                {
-                    m_log.ErrorFormat("[USER AGENT CONNECTOR]: LocateUser Got null response from {0}! THIS IS BAAAAD", m_ServerURL);
-//                    reason = "Internal error 1";
-                    return url;
-                }
-
-                // Here's the actual response
-                if (hash.ContainsKey("URL"))
-                    url = hash["URL"].ToString();
-
-            }
-            catch
-            {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: Got exception on LocateUser response.");
-//                reason = "Exception: " + e.Message;
-            }
 
             return url;
         }
@@ -665,55 +549,13 @@ namespace OpenSim.Services.Connectors.Hypergrid
             hash["userID"] = userID.ToString();
             hash["targetUserID"] = targetUserID.ToString();
 
-            IList paramList = new ArrayList();
+            hash = CallServer("get_uui", hash);
-            paramList.Add(hash);
 
-            XmlRpcRequest request = new XmlRpcRequest("get_uui", paramList);
-//            string reason = string.Empty;
-
-            // Send and get reply
             string uui = string.Empty;
-            XmlRpcResponse response = null;
-            try
-            {
-                response = request.Send(m_ServerURL, 10000);
-            }
-            catch
-            {
-                m_log.DebugFormat("[USER AGENT CONNECTOR]: Unable to contact remote server {0} for GetUUI", m_ServerURL);
-//                reason = "Exception: " + e.Message;
-                return uui;
-            }
 
-            if (response.IsFault)
+            // Here's the actual response
-            {
+            if (hash.ContainsKey("UUI"))
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: remote call to {0} for GetUUI returned an error: {1}", m_ServerURL, response.FaultString);
+                uui = hash["UUI"].ToString();
-//                reason = "XMLRPC Fault";
-                return uui;
-            }
-
-            hash = (Hashtable)response.Value;
-            //foreach (Object o in hash)
-            //    m_log.Debug(">> " + ((DictionaryEntry)o).Key + ":" + ((DictionaryEntry)o).Value);
-            try
-            {
-                if (hash == null)
-                {
-                    m_log.ErrorFormat("[USER AGENT CONNECTOR]: GetUUI Got null response from {0}! THIS IS BAAAAD", m_ServerURL);
-//                    reason = "Internal error 1";
-                    return uui;
-                }
-
-                // Here's the actual response
-                if (hash.ContainsKey("UUI"))
-                    uui = hash["UUI"].ToString();
-
-            }
-            catch
-            {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: Got exception on GetUUI response.");
-//                reason = "Exception: " + e.Message;
-            }
 
             return uui;
         }
@@ -724,54 +566,17 @@ namespace OpenSim.Services.Connectors.Hypergrid
             hash["first"] = first;
             hash["last"] = last;
 
-            IList paramList = new ArrayList();
+            hash = CallServer("get_uuid", hash);
-            paramList.Add(hash);
 
-            XmlRpcRequest request = new XmlRpcRequest("get_uuid", paramList);
+            if (!hash.ContainsKey("UUID"))
-            //            string reason = string.Empty;
-
-            // Send and get reply
-            UUID uuid = UUID.Zero;
-            XmlRpcResponse response = null;
-            try
             {
-                response = request.Send(m_ServerURL, 10000);
+                throw new Exception(string.Format("[USER AGENT CONNECTOR]: get_uuid call to {0} didn't return a UUID", m_ServerURL));
-            }
-            catch
-            {
-                m_log.DebugFormat("[USER AGENT CONNECTOR]: Unable to contact remote server {0} for GetUUID", m_ServerURL);
-                //                reason = "Exception: " + e.Message;
-                return uuid;
             }
 
-            if (response.IsFault)
+            UUID uuid;
+            if (!UUID.TryParse(hash["UUID"].ToString(), out uuid))
             {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: remote call to {0} for GetUUID returned an error: {1}", m_ServerURL, response.FaultString);
+                throw new Exception(string.Format("[USER AGENT CONNECTOR]: get_uuid call to {0} returned an invalid UUID: {1}", m_ServerURL, hash["UUID"].ToString()));
-                //                reason = "XMLRPC Fault";
-                return uuid;
-            }
-
-            hash = (Hashtable)response.Value;
-            //foreach (Object o in hash)
-            //    m_log.Debug(">> " + ((DictionaryEntry)o).Key + ":" + ((DictionaryEntry)o).Value);
-            try
-            {
-                if (hash == null)
-                {
-                    m_log.ErrorFormat("[USER AGENT CONNECTOR]: GetUUDI Got null response from {0}! THIS IS BAAAAD", m_ServerURL);
-                    //                    reason = "Internal error 1";
-                    return uuid;
-                }
-
-                // Here's the actual response
-                if (hash.ContainsKey("UUID"))
-                    UUID.TryParse(hash["UUID"].ToString(), out uuid);
-
-            }
-            catch
-            {
-                m_log.ErrorFormat("[USER AGENT CONNECTOR]: Got exception on UUID response.");
-                //                reason = "Exception: " + e.Message;
             }
 
             return uuid;

OpenSim/Services/HypergridService/HGInstantMessageService.cs

@@ -215,7 +215,15 @@ namespace OpenSim.Services.HypergridService
                 {
                     // Let's check with the UAS if the user is elsewhere
                     m_log.DebugFormat("[HG IM SERVICE]: User is not present. Checking location with User Agent service");
-                    url = m_UserAgentService.LocateUser(toAgentID);
+                    try
+                    {
+                        url = m_UserAgentService.LocateUser(toAgentID);
+                    }
+                    catch (Exception e)
+                    {
+                        m_log.Warn("[HG IM SERVICE]: LocateUser call failed ", e);
+                        url = string.Empty;
+                    }
                 }
 
                 // check if we've tried this before..

OpenSim/Services/Interfaces/IHypergridServices.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright (c) Contributors, http://opensimulator.org/
  * See CONTRIBUTORS.TXT for a full list of copyright holders.
  *
@@ -47,15 +47,47 @@ namespace OpenSim.Services.Interfaces
     {
         bool LoginAgentToGrid(AgentCircuitData agent, GridRegion gatekeeper, GridRegion finalDestination, bool fromLogin, out string reason);
         void LogoutAgent(UUID userID, UUID sessionID);
-        GridRegion GetHomeRegion(UUID userID, out Vector3 position, out Vector3 lookAt);
-        Dictionary<string, object> GetServerURLs(UUID userID);
-        Dictionary<string,object> GetUserInfo(UUID userID);
 
+        /// <summary>
+        /// Returns the home region of a remote user.
+        /// </summary>
+        /// <returns>On success: the user's home region. If the user doesn't exist: null.</returns>
+        /// <remarks>Throws an exception if an error occurs (e.g., can't contact the server).</remarks>
+        GridRegion GetHomeRegion(UUID userID, out Vector3 position, out Vector3 lookAt);
+
+        /// <summary>
+        /// Returns the Server URLs of a remote user.
+        /// </summary>
+        /// <returns>On success: the user's Server URLs. If the user doesn't exist: an empty dictionary.</returns>
+        /// <remarks>Throws an exception if an error occurs (e.g., can't contact the server).</remarks>
+        Dictionary<string, object> GetServerURLs(UUID userID);
+
+        /// <summary>
+        /// Returns the UserInfo of a remote user.
+        /// </summary>
+        /// <returns>On success: the user's UserInfo. If the user doesn't exist: an empty dictionary.</returns>
+        /// <remarks>Throws an exception if an error occurs (e.g., can't contact the server).</remarks>
+        Dictionary<string, object> GetUserInfo(UUID userID);
+
+        /// <summary>
+        /// Returns the current location of a remote user.
+        /// </summary>
+        /// <returns>On success: the user's Server URLs. If the user doesn't exist: "".</returns>
+        /// <remarks>Throws an exception if an error occurs (e.g., can't contact the server).</remarks>
         string LocateUser(UUID userID);
-        // Tries to get the universal user identifier for the targetUserId
+        
-        // on behalf of the userID
+        /// <summary>
+        /// Returns the Universal User Identifier for 'targetUserID' on behalf of 'userID'.
+        /// </summary>
+        /// <returns>On success: the user's UUI. If the user doesn't exist: "".</returns>
+        /// <remarks>Throws an exception if an error occurs (e.g., can't contact the server).</remarks>
         string GetUUI(UUID userID, UUID targetUserID);
 
+        /// <summary>
+        /// Returns the remote user that has the given name.
+        /// </summary>
+        /// <returns>On success: the user's UUID. If the user doesn't exist: UUID.Zero.</returns>
+        /// <remarks>Throws an exception if an error occurs (e.g., can't contact the server).</remarks>
         UUID GetUUID(String first, String last);
 
         // Returns the local friends online