Post json to asp jscript

[Andrew Poulos]

I'm trying to us an elearning tracking piece of js called tincan that
posts JSON to an endpoint. The content type is set to application/json
and the request body (as IE's F12 developer console shows) is json. The
response headers give

response : HTTP/1.1 200 OK
content-length : 0
content-type : application/json; charset=utf-8

Though Chrome's developer console gives a content length of 16568.

When (on the server with classic ASP and JScript) I try

var dat = Request.Form;
or
var dat = Request.Form + "";
or
var dat = eval("(" + Request.Form + ")");

I just get 'undefined'.

My question is, if the payload is not empty why does request give undefined?

Andrew Poulos

[Martin Honnen]

As far as I remember, with classic ASP the Request.Form collection is
provided for reading out the values posted by a HTML form. If you
directly post JSON then I think you need to read out the request body
with http://msdn.microsoft.com/en-us/library/ms525710%28v=vs.90%29.aspx,
only the object you get from that is a SafeArray that does not fit in
well with the JScript data types. So you need something along the lines of

var responseArray = new
VBArray(Request.BinaryRead(Request.TotalBytes)).toArray();

See
http://msdn.microsoft.com/en-us/library/ie/y39d47w8%28v=vs.94%29.aspx
for the methods.


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[Andrew Poulos]

I wishfully thought I could just use your code without without having to
do any work. Alas, I get "error '800a1395' VBArray expected".

Thanks for the advice. Now I have a direction to work to.

Andrew Poulos

[Andrew Poulos]

Unfortunately I can't get it to work - even trying to rewrite the page
using vbscript proved problematic - so instead I've modified tincan.js
so that when it posts it does so as a "form". Its still sending json but
not as application/json.

Andrew Poulos

[Andrew Poulos]

To anyone that might be interested, here's one "solution":

<%@ language="javascript" %>

<script runat="server" language="vbscript">
Dim vntPostedData, lngCount, bString

lngCount = Request.TotalBytes
vntPostedData = Request.BinaryRead(lngCount)
bString = binaryToString(vntPostedData)

Function binaryToString(Binary)
'SimpleBinaryToString converts binary data
' (VT_UI1 | VT_ARRAY Or MultiByte string)
' to a string (BSTR) using MultiByte VBS functions
Dim I, S
For I = 1 To LenB(Binary)
S = S & Chr(AscB(MidB(Binary, I, 1)))
Next
BinaryToString = S
End Function
</script>

<script runat="server" type="text/javascript" language="javascript">
Response.Write(bString);
</script>

Apparently in a Classic ASP page the non-default language script gets
run before the default language script.

Andrew Poulos

[Evertjan.]

Andrew Poulos <ap_...@hotmail.com> wrote on 10 aug 2014 in
comp.lang.javascript:

> Apparently in a Classic ASP page the non-default language script gets
> run before the default language script.

Therefore there is confusing to set your
Response.Write(bString);
in its own section.

And:

1 it is customary to set the non-default language sections at the bottom,
and only define functions there to be called in the main script.

2 VBS 'Dim'-ing without 'Option Explicit' set is only window dressing.

3 for large binaries read this for faster response:
<http://www.motobit.com/tips/detpg_binarytostring/>

Try, [not tested]:

=====================
<%@ language="javascript" %>

Response.Write(bString);

<script runat="server" language="vbscript">

Function bString()

lngCount = Request.TotalBytes
vntPostedData = Request.BinaryRead(lngCount)
bString = binaryToString(vntPostedData)

End Function

Function binaryToString(Binary)
S = ""

For I = 1 To LenB(Binary)
S = S & Chr(AscB(MidB(Binary, I, 1)))
Next
BinaryToString = S
End Function

</script>

=====================


--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Andrew Poulos]

On 10/08/2014 5:52 PM, Evertjan. wrote:
> Andrew Poulos <ap_...@hotmail.com> wrote on 10 aug 2014 in
> comp.lang.javascript:
>
>> Apparently in a Classic ASP page the non-default language script gets
>> run before the default language script.
>
> Therefore there is confusing to set your
> Response.Write(bString);
> in its own section.

I needed to be sure that the vbs value was available to js.

Thanks.

Andrew Poulos