Logging and error message tweaks

services/web/app/coffee/Features/LinkedFiles/LinkedFilesController.coffee

@@ -24,6 +24,7 @@ module.exports = LinkedFilesController = {
 		linkedFileData.provider = provider
 		Agent.writeIncomingFileToDisk project_id, linkedFileData, user_id, (error, fsPath) ->
 			if error?
+				logger.error {err: error, project_id, name, linkedFileData, parent_folder_id, user_id}, 'error writing linked file to disk'
 				return Agent.handleError(error, req, res, next)
 			EditorController.upsertFile project_id, parent_folder_id, name, fsPath, linkedFileData, "upload", user_id, (error) ->
 				return next(error) if error?

services/web/app/coffee/Features/LinkedFiles/UrlAgent.coffee

@@ -31,15 +31,15 @@ module.exports = UrlAgent = {
 		callback = _.once(callback)
 		url = data.url
 		if !urlValidator.isWebUri(url)
-			return callback(new InvalidUrlError())
-		url = @._wrapWithProxy(url)
+			return callback(new InvalidUrlError("invalid url: #{url}"))
+		url = UrlAgent._wrapWithProxy(url)
 		readStream = request.get(url)
 		readStream.on "error", callback
 		readStream.on "response", (response) ->
 			if 200 <= response.statusCode < 300
 				FileWriter.writeStreamToDisk project_id, readStream, callback
 			else
-				error = new UrlFetchFailedError()
+				error = new UrlFetchFailedError("url fetch failed: #{url}")
 				error.statusCode = response.statusCode
 				callback(error)