[[tags: egg]]

== multipart-form-data

[[toc:]]

=== Description

Reads & decodes HTTP multipart/form-data requests.

=== Source Code

[[https://bitbucket.org/knodium/multipart-form-data]]

=== Author

[[/users/andyjpb|Andy Bennett]]

=== Requirements

[[intarweb]], [[comparse]], [[records]]

=== API

==== http-multipart-request-data-limit

<parameter> http-multipart-request-data-limit</parameter>

Not implemented yet! :-(

==== read-multipart-form-data

<procedure>(read-multipart-form-data request [max-length])</procedure>

Implements the same interface as Intarweb's [[intarweb#read-urlencoded-request-data|read-urlencoded-request-data]].

==== multipart-form-data-decode

<procedure>(multipart-form-data-decode str-port-or-seq boundary [max-length])</procedure>

Decodes a multipart/form-data encoded body. This procedure requires the
boundary token information from the HTTP headers.

Returns an alist: a list of name, value pairs or name, multipart-file pairs if
the value was created from an HTML Forms File Input.

==== multipart-file?

<procedure>(multipart-file? X)</procedure>

Tests to see if the value (cdrs of the pairs returned from
{{multipart-form-data-decode}}) is the result of an HTML Forms File Input.

==== multipart-file-port

<procedure>(multipart-file-port X)</procedure>

A port from which you can read the contents of the file.

==== mutipart-file-filename

<procedure>(multipart-file-filename X)</procedure>

The filename that the browser supplied for the data read from the port.

==== multipart-file-headers

<procedure>(multipart-file-headers X)</procedure>

A list of HTTP style headers that can tell you about the Content-Type and
encoding of the data read from the port.

Use the header procedures from [[intarweb]] to access the value returned.

=== Examples

==== 1
Here we present a decoder that can decide whether to decode multipart/form-data
or application/x-www-form-urlencoded data based on the request headers:

	(use intarweb multipart-form-data)
	
	(define (read-request-data req)
	  (let* ((content-type (header-values 'content-type (request-headers req)))
		 (_            (assert (= 1 (length content-type))))
		 (content-type (car content-type))
		 (proc         (case content-type
				 ((application/x-www-form-urlencoded)
				  read-urlencoded-request-data)
				 ((multipart/form-data)
				  read-multipart-form-data)
				 (else
				   (abort "Unable to decode these shenannigans!")))))
	    (proc req)))


=== License

  Copyright (C) 2014, Andy Bennett
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
  
  Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
  Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
  Neither the name of the author nor the names of its contributors may be
  used to endorse or promote products derived from this software without
  specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.

=== Version History
* 0.1, (2014/10/12) : Preliminary support for decoding multipart/form-data
encoded POST bodies. Very slow and copies the (possibly large) data around a
fair bit. Also, it doesn't currently limit the amount of data that the user can
send, although we provide a parameter and API for it
(http-multipart-request-data-limit)