[racket] HTTP-POST byte string gets truncated

From: Mikko Tiihonen (mikko.tiihonen at tmtiihonen.fi)
Date: Mon Oct 8 08:04:39 EDT 2012

Thanks, Greg and Danny!

Problem solved - now the POST parameters are also correct! Seems that the different representation of headers in net/head caused the POST parameters following the header being parsed incorrectly.

Cheers,
-Mikko


On 8.10.2012, at 14:52, Greg Hendershott wrote:

>> validate-header validates the header as one string, but post-pure-port requires that the header is contained in a list of strings ("optional list of strings can be used to send header lines to the server"). Is there some kind of a mismatch between net/url and net/head?
> 
> Yes, unfortunately they represent headers differently. net/head
> represents headers as a single "string" or #"bytes string" consisting
> of \r\n separated elements. This is closest to the headers in real
> life.  However net/url uses a list of elements (and they're "string"
> elements only; not #"byte string").
> 
> Since you're using post-pure-port from net/url, I think you want:
> 
> (define header
>  (list "Host: localhost:8080"
>        "Connection: keep-alive"
>        "User-Agent: Mozilla/5.0 (testClient.rkt 0.1)"
>        "Accept-Encoding: gzip"
>        "Accept:
> text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
>        "Accept-Language: en-us"
>        "Accept-Charset: ISO-8859-1,UTF-8;q=0.7,*;q=0.7"
>        "Cache-control: no-cache"))
> (post-pure-port my-url my-data header)
> 
> 
> On Mon, Oct 8, 2012 at 3:07 AM, Mikko Tiihonen
> <mikko.tiihonen at tmtiihonen.fi> wrote:
>> Hi, Danny,
>> 
>> the header is here:
>> 
>> (define header (list (insert-field #"Host" #"localhost:8080"
>>                                 (insert-field #"Connection" #"keep-alive"
>>                                               (insert-field #"User-Agent" #"Mozilla/5.0 (testClient.rkt 0.1)"
>>                                                             (insert-field #"Accept-Encoding" #"gzip"
>>                                                                           (insert-field #"Accept" #"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
>>                                                                                         (insert-field #"Accept-Language" #"en-us"
>>                                                                                                       (insert-field #"Accept-Charset" #"ISO-8859-1,UTF-8;q=0.7,*;q=0.7"
>>                                                                                                                     (insert-field #"Cache-control" #"no-cache" empty-header))))))))))
>> 
>> For some reason the request struct on the server side seems to get the POST data four bytes off... I also noticed that empty-header does not evaluate to "\r\n\r\n" as specified in net/head documentation:
>>> empty-header
>> "\r\n"
>> 
>> validate-header validates the header as one string, but post-pure-port requires that the header is contained in a list of strings ("optional list of strings can be used to send header lines to the server"). Is there some kind of a mismatch between net/url and net/head?
>> 
>> Cheers,
>> 
>> -Mikko
>> 
>> 
>> On 8.10.2012, at 2:49, Danny Yoo wrote:
>> 
>>> On Sat, Oct 6, 2012 at 4:50 AM, Mikko Tiihonen
>>> <mikko.tiihonen at tmtiihonen.fi> wrote:
>>>> Hi, again!
>>>> 
>>>> I'm continuing to build a small HTTP-client. The problem is now that the POST parameter/value byte strings sent by put-pure-port and post-pure-port seem to get truncated somewhere. The request-post-data/raw shows that the byte string gets prepended with "\r\n\r\n" and truncated by four bytes. E.g.
>>>> 
>>>> (post-pure-port uri #"param1=hello&param2=world" header)
>>>> 
>>>> is received as
>>>> 
>>>> #"\r\n\r\nparam1=hello&param2=w"
>>> 
>>> 
>>> Odd.  What's the content of 'header' here?  It's the only free
>>> variable I see whose value I don't quite understand yet.
>> 
>> 
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