Import::fmterr URLExecute wont import JSON

Question

I'm trying to perform a multiple element GET request from an alfresco database of elements. The way we have it set up is if a GET request is made with a body, it will return the elements listed in the body. I have the following code, and everything works as it should up until the URLFetch:

Begin["`Private`"];

getElements[server_,branch_,site_,elementIDs_]:=( 
    (*elementIDs is a list of strings*)
  url=StringJoin[server,"/alfresco/service/workspaces/",branch,"/elements"]
 ; assoc=<|"elements"->Association/@Thread["id"->elementIDs]|>
 ; jsonElements = ExportString[assoc,"RawJSON"]
 ; Return @ URLFetch[
       url
     , "Method"->"GET"
     , "Body"->jsonElements
     , "Headers"->{
           "Content-Type"->"application/json;charset=UTF-8"
         , "Content-Length"->"0"
         , "Accept"->"application/json;charset=UTF-8"
       }
    ];
)

End[];

I would like to use URLExecute, but it returns the following error:

Import::fmterr: Cannot import data as JSON format.

When using URLFetch, it is returning "Could not complete DB transaction, see Alfresco logs for details." I dont know if it's a problem with my code, Mathematica, or the api.

Answer 1

EDIT 04/25/2017: I got a response to the bug report. Apparently Mathematica developers have resolved the issue on a future release.

---

Alright, I ran the code using curl and even checked my tcp logs when executing it in Mathematica. It seems that Mathematica is taking the headers and making them lower-case when sending to the url. Normally this wouldn't matter, but some APIs (like ours) are case sensitive.

So "Content-Type" is being sent as "content-type" (cant remember if I used a hyphen). This is producing the error.

I've catalogued the problem in a bug report sent to Wolfram Support. I'm leaving the post up until they resolve the issue just in case either anyone knows a workaround or someone has a similar problem and cant figure out the cause.