PHP: rfc:curl-file-upload

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====== Request for Comments: Fix CURL file uploads ======
  * Version: 1.0
  * Date: 2013-01-06
  * Author: Stas Malyshev <stas@php.net>
  * Status: Implemented in PHP 5.5
  * First Published at: http://wiki.php.net/rfc/curl-file-upload
  * See also: https://bugs.php.net/bug.php?id=46439
  * Implementation: https://github.com/php/php-src/pull/255

This RFC discusses improvement for CURL file uploading option.
===== Introduction =====

Currently, cURL file uploading is done as:

<code php>
curl_setopt($curl_handle, CURLOPT_POST, 1);
$args['file'] = '@/path/to/file';
curl_setopt($curl_handle, CURLOPT_POSTFIELDS, $args);
</code>

This API is both inconvenient and insecure, it is impossible to send data starting with '@' to the POST, and any user data that is being re-sent via cURL need to be sanitized so that the data value does not start with @. In general, in-bound signalling usually vulnerable to all sorts of injections and better not done in this way.

===== CurlFile proposal =====

Instead of using the above method, the following should be used to upload files with CURLOPT_POSTFIELDS:

<code php>
curl_setopt($curl_handle, CURLOPT_POST, 1);
$args['file'] = new CurlFile('filename.png', 'image/png');
curl_setopt($curl_handle, CURLOPT_POSTFIELDS, $args);
</code>

The curl API will be modified to look for objects of type CurlFile and treat them as entries with @ were previously treated. 

The file given to CurlFile will not be opened/read until curl_setopt() call. 
===== CURLFile API =====

<code php>
class CURLFile
{
    /**
     * Create CurlFile object
     * @param string $name File name
     * @param string $mimetype Mime type, optional
     * @param string $postfilename Post filename, defaults to actual filename
     */
    public function __construct($name, $mimetype = '', $postfilename = '')
    {}

    /**
     * Set mime type
     * @param string $mimetype
     * @return CurlFile
     */
    public function setMimeType($mimetype)
    {}

    /**
     * Set mime type
     * @param string $mimetype
     * @return string
     */
    public function getMimeType($mimetype)
    {}

    /**
     * Get file name from which the data will be read
     * @return string
     */
    public function getFilename()
    {}

    /**
     * Get file name which will be sent in the post
     * @param string $name File name
     * @return string
     */
    public function setPostFilename($name)
    {}

    /**
     * Set file name which will be sent in the post
     * @return string
     * @return CurlFile
     */
    public function getPostFilename()
    {}
}
</code>

Also, the functional API to creating CURLFile is provided by request:

<code php>
    /**
     * Create CURLFile object
     * @param string $name File name
     * @param string $mimetype Mime type, optional
     * @param string $postfilename Post filename, defaults to actual filename
     */
    function curl_file_create($name, $mimetype = '', $postfilename = '')
    {}
</code>

This will create a new ```CURLFile``` object just as ```new CURLFile()``` would.
===== Backward compatibility =====

A new option is introduced: ''CURLOPT_SAFE_UPLOAD''. By default, in order to assure orderly transition to the use of the new API, the proposal is in 5.5 to leave the @ option working,  but make it produce E_DEPRECATED error referring the user to the use of the new API. In order to disable it, ''CURLOPT_SAFE_UPLOAD'' can be used:

<code php>
curl_setopt($curl_handle, CURLOPT_SAFE_UPLOAD, true);
</code>

In 5.6, @ option will be switched off by default, but can still be enabled by explicit curl_setopt setting, such as: 

<code php>
curl_setopt($curl_handle, CURLOPT_SAFE_UPLOAD, false);
</code>

In future versions, this capability may be removed completely.
===== Optional =====
  * If upstream cURL API permits, we could add in the future uploading files from string buffers, stream names, stream resources and such, which is now impossible with existing @-based API. The CurlFile API above will then be extended with required functions to support these, such as "setUploadData()", "setUploadStream()" etc. 

   * It is possible to include validation of the file resource given in the constructor, so that appropriate error message can be produced if this file can not be read. 
   
===== References =====
    * CURL form API: http://curl.haxx.se/libcurl/c/curl_formadd.html
    * curl_setopt: http://php.net/manual/en/function.curl-setopt.php
    * Pull request: https://github.com/php/php-src/pull/255

===== Vote =====

Voting ended on Monday, January 28th 2013. In order to pass, the requirement is 50%+1 vote, since PHP core language is not changed. The result is: **ACCEPTED**.

<doodle 
title="Accept the CURLFile API as preferred solution for file uploads in CURL?" auth="stas" voteType="single" closed="True">
   * Yes
   * No
</doodle>

===== Changelog =====
  * 2013-01-05 First draft
  * 2013-01-06 Added pull req
  * 2013-01-07 Added CURLOPT_SAFE_UPLOAD description
  * 2013-01-12 Added curl_file_create()
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