Re: POST, content-type: application/json and json_decode

On 24/09/12 16:48, jpauli wrote:

On Mon, Sep 24, 2012 at 4:21 PM, Ivan Enderlin @ Hoa <ivan.enderlin@hoa-project.net> wrote:

On 21/09/12 16:16, jpauli wrote:

On Fri, Sep 21, 2012 at 1:05 PM, Ivan Enderlin @ Hoa <ivan.enderlin@hoa-project.net> wrote:

Hello, If PHP receives a HTTP request with the method POST and with the header Content-Type: application/x-www-form-encoded, then, it automatically parses the request body to populate an array in $_POST. If the Content-Type is different (e.g. text/plain or application/json), the request body is reachable by reading php://input. Well, it is ok. But is there any plans to consider application/json by parsing the request body and populate the result in $_POST (with the help of json_decode() maybe)? If so, I would like to propose a patch but I don't find in the source code where request body is caugth and parsed (for POST). Any ideas? Maybe a RFC would also be welcome to complete my suggestion? Thanks.

Hi ! Reading and parsing post data function is defined as a SAPI struct function pointer. You should look at sapi_module_struct definition (http://lxr.php.net/xref/PHP_5_4/main/SAPI.h#251). When a request comes in, sapi_activate() is called. It then calls sapi_read_post_data() http://lxr.php.net/xref/PHP_5_4/main/SAPI.c#459 that itself invokes handlers. Default handlers are defined here : http://lxr.php.net/xref/PHP_5_4/main/php_content_types.c#29 and for POST, by default, sapi_read_standard_form_data() is called (defined here http://lxr.php.net/xref/PHP_5_4/main/SAPI.c#253) This function is in fact just a bridge, it tells PHP to call sapi.read_post() which is a function pointer defined by each SAPI. Finally, later on, sapi.default_post_reader() is called (again, a function pointer defined by each SAPI)

I have some questions. Julien told me in private that he didn't know, hope other could reply. By reading the code, I understand that each SAPI is responsible of parsing the body of a POST request if it is application/x-www-form-urlencoded. Am I right? In SAPI.c, I read that it delegates this task to sapi_module.read_post by giving SG(request_info).post_data (please, see main/SAPI.c#266). It implies that if we would like to add the support of application/json, then we have to do it for each SAPI? Not very nice :-/. When I will locate the code to edit, I'm planning to use php_json_decode_ex & co. (please, see ext/json/json.c#633), but the hash collision risk is always present. In every case, json_decode() must be protected again hash collision (please, see https://bugs.php.net/60655).

The hash collision is a behavior our HashTable implementation carries anyway. Removing it can only be done safely by changing the hash algorithm, which is not such an easy task in case of PHP. I suggest you start your POC writting the json handler without worrying about hash collisions :) It was my goal, yup.

-- Ivan Enderlin Developer of Hoa http://hoa.42/ or http://hoa-project.net/ PhD. student at DISC/Femto-ST (Vesontio) and INRIA (Cassis) http://disc.univ-fcomte.fr/ and http://www.inria.fr/ Member of HTML and WebApps Working Group of W3C http://w3.org/