On Tue, 23 Aug 2016 02:09:24 -0700 (PDT), Normal Loone
<andreas.m.wi...@gmx.de> wrote:
>Yeah, my main problem is how do I pack the file into a JSON Object
>and then send it?
Just FYI: JSON is a printable coding, so any non-printable characters
in a binary file must be escaped - making the transfer larger.
The read-json and write-json functions take care of escaping, but if
you are sending large files, the overhead may be significant.
>With (require net/http-client) I could already establish a connection
>with (http-conn-sendrecv! hc uri), but All I can send is the empty
>header of the http request.
>
>How do I add the HTML code or the file in the json object within it?
If I understand correctly, you're trying to send the file to a server
via HTTP from a Racket client.
If the file is JSON encoded, you can send it as a simple HTTP
parameter: e.g.,
(require net/http-client
net/uri-codec)
(let [
(params
(alist->form-urlencoded
(list (cons 'file (write-bytes your-file-data ))
)))
(headers
(list "Content-Type: application/x-www-form-urlencoded")
)
]
(let-values
[
((resp-code resp-hdrs port)
(http-sendrecv host
url
#:method #"POST"
#:data params
#:headers headers
))
]
(printf "~s~n~s~n~s~n"
resp-code
resp-hdrs
(port->bytes port))
))
Sending binary file data or extremely long files (that can't be loaded
fully into memory) requires an HTTP multipart form.
Multipart forms are complex to encode: they have opening headers,
boundary markers enclosing and sometimes interspersed with the data,
and closing footers after the data. I don't have a ready example.
For more information see http://www.rfc-base.org/rfc-1867.html
Hope this helps,
George
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