While working with the JQuery-Upload control, I encountered the following error:
unexpected token <
The real kicker was the fact that my target file was still being created.
The cause of the problem (as I eventually discovered) was my REST contract; my endpoint as configured as follows:
[WebInvoke(Method = "POST",
ResponseFormat = WebMessageFormat.Xml,
BodyStyle = WebMessageBodyStyle.WrappedResponse,
UriTemplate = "/file/upload")]
StatusData Upload(Stream fileData);
but my endpoint was returning a JSON response.
This resulted in a mismatch, as the expected response format was XML.
Changing the contract to Json resolved the problem.