#17160: Displaying clearer error messages in Live Writer

Work Item: 17160

--HG--
branch : 1.x

src/Orchard.Web/Core/XmlRpc/Controllers/HomeController.cs

@@ -35,8 +35,21 @@ namespace Orchard.Core.XmlRpc.Controllers {
 
         private XRpcMethodResponse Dispatch(XRpcMethodCall request) {
             var context = new XmlRpcContext { ControllerContext = ControllerContext, HttpContext = HttpContext, Request = request };
-            foreach (var handler in _xmlRpcHandlers)
+            try {
-                handler.Process(context);
+                foreach (var handler in _xmlRpcHandlers) {
+                    handler.Process(context);
+                }
+            }
+            catch (OrchardCoreException e) {
+                // if a core exception is raised, report the error message, otherwise signal a 500
+                context.Response =  context.Response ?? new XRpcMethodResponse();
+
+                context.Response.Fault = new XRpcFault {
+                    Code = 0, 
+                    Message = e.LocalizedMessage.ToString()
+                };   
+            }
+
             return context.Response;
         }
     }

src/Orchard.Web/Core/XmlRpc/Models/XRpcData.cs

@@ -39,4 +39,9 @@ namespace Orchard.Core.XmlRpc.Models {
 
         public override Type Type { get { return typeof(T); } }
     }
+
+    public class XRpcFault {
+        public string Message { get; set; }
+        public int Code { get; set; }
+    }
 }

src/Orchard.Web/Core/XmlRpc/Models/XRpcMethodResponse.cs

@@ -5,6 +5,7 @@ namespace Orchard.Core.XmlRpc.Models {
         public XRpcMethodResponse() { Params = new List<XRpcData>(); }
 
         public IList<XRpcData> Params { get; set; }
+        public XRpcFault Fault { get; set; }
 
         public XRpcMethodResponse Add<T>(T value) {
             Params.Add(XRpcData.For(value));

src/Orchard.Web/Core/XmlRpc/Services/XmlRpcWriter.cs

@@ -41,10 +41,24 @@ namespace Orchard.Core.XmlRpc.Services {
         public XElement MapMethodResponse(XRpcMethodResponse rpcMethodResponse) {
             Argument.ThrowIfNull(rpcMethodResponse, "rpcMethodResponse");
 
-            return new XElement(
+            // return a valid fault as per http://xmlrpc.scripting.com/spec.html
-                "methodResponse",
+            if(rpcMethodResponse.Fault != null) {
-                new XElement(
+                return new XElement("methodResponse",
-                    "params",
+                    new XElement("fault",
+                        new XElement("value",
+                            new XElement("struct",
+                                new XElement("member",
+                                    new XElement("name", "faultCode"),
+                                    new XElement("value",
+                                        new XElement("int", rpcMethodResponse.Fault.Code))),
+                                new XElement("member",
+                                    new XElement("name", "faultString"),
+                                    new XElement("value",
+                                        new XElement("string", rpcMethodResponse.Fault.Message)))))));
+            }
+
+            return new XElement("methodResponse",
+                new XElement("params",
                     rpcMethodResponse.Params.Select(
                         p => new XElement("param", MapValue(p)))));
         }

src/Orchard.Web/Modules/Orchard.Blogs/Services/XmlRpcHandler.cs

@@ -257,8 +257,9 @@ namespace Orchard.Blogs.Services {
 
             IUser user = ValidateUser(userName, password);
             var blogPost = _blogPostService.Get(postId, VersionOptions.DraftRequired);
-            if (blogPost == null)
+            if (blogPost == null) {
-                throw new ArgumentException();
+                throw new OrchardCoreException(T("The specified Blog Post doesn't exist anymore. Please create a new Blog Post."));
+            }
 
             _authorizationService.CheckAccess(publish ? Permissions.PublishBlogPost : Permissions.EditBlogPost, user, blogPost);