ngx_http_read_client_request_body() and ACCESS_PHASE handler

[Yuriy Taraday]

Hi.

The return code NGX_AGAIN means that you should wait for more data
before you proceed. This behavior is quite clear when you understand
that you have to wait for next TCP packet for some data. You should
expect you handler to be called at least one more time when more data
will be received.

On Thu, Apr 22, 2010 at 6:19 PM, Srebrenko Šehić <ssehic at gmail.com> wrote:
> Hi list,
>
> I am trying to get a module working that can read a POST payload from
> the client, have a look at it, and pass it on (unchanged) to the
> upstream.
>
> Below is the a sample code I wrote for testing purposes. The code
> works as desired for very small POST payloads and with Firefox only.
> It doesn't work (even for small payloads) in any other major browser I
> tried. The reason for that is that FF sends the POST payload in the
> same TCP packet as the HTTP headers - while other browser apparently
> send at least 2 packets.
>
> Return code from call to ngx_http_read_client_request_body() is
> NGX_AGAIN for non-FF browsers.
>
> What am I doing wrong here?
>
> /usr/local/sbin/nginx -V
> nginx version: nginx/0.8.35
> TLS SNI support enabled
> configure arguments: --prefix=/etc/nginx
> --conf-path=/etc/nginx/nginx.conf --sbin-path=/usr/local/sbin/nginx
> --pid-path=/var/run/nginx.pid --lock-path=/var/nginx/tmp/nginx.lock
> --http-client-body-temp-path=/var/nginx/tmp/client_body_temp
> --http-proxy-temp-path=/var/nginx/tmp/proxy_temp
> --http-fastcgi-temp-path=/var/nginx/tmp/fastcgi_temp
> --http-log-path=/var/log/nginx/access.log
> --error-log-path=/var/log/nginx/error.log --user=_nginx --group=_nginx
> --with-http_ssl_module --with-http_stub_status_module --with-debug
> --with-ipv6 --with-http_perl_module --with-http_sub_module
> --add-module=/home/ssehic/dummy
>
> #include <ngx_config.h>
> #include <ngx_core.h>
> #include <ngx_http.h>
>
> static ngx_int_t ngx_http_dummy_init(ngx_conf_t *cf);
>
> static ngx_http_module_t  ngx_http_dummy_module_ctx = {
>    NULL,                                  /* preconfiguration */
>    ngx_http_dummy_init,           /* postconfiguration */
>    NULL,                                  /* create main configuration */
>    NULL,                                  /* init main configuration */
>    NULL,                                  /* create server configuration */
>    NULL,                                  /* merge server configuration */
>    NULL,                                  /* create location configuration */
>    NULL                                   /* merge location configuration */
> };
>
>
> ngx_module_t  ngx_http_dummy_module = {
>    NGX_MODULE_V1,
>    &ngx_http_dummy_module_ctx,            /* module context */
>    NULL,                                  /* module directives */
>    NGX_HTTP_MODULE,                       /* module type */
>    NULL,                                  /* init master */
>    NULL,                                  /* init module */
>    NULL,                                  /* init process */
>    NULL,                                  /* init thread */
>    NULL,                                  /* exit thread */
>    NULL,                                  /* exit process */
>    NULL,                                  /* exit master */
>    NGX_MODULE_V1_PADDING
> };
>
> static ngx_int_t ngx_http_dummy_access_handler(ngx_http_request_t *r);
>
> void
> ngx_http_dummy_payload_handler(ngx_http_request_t *r)
> {
>    ngx_http_finalize_request(r, NGX_DONE);
> }
>
> static ngx_int_t
> ngx_http_dummy_access_handler(ngx_http_request_t *r)
> {
>    if (r->method != NGX_HTTP_POST) {
>        return NGX_OK;
>    }
>
>    return ngx_http_read_client_request_body(r, ngx_http_dummy_payload_handler);
> }
>
> static ngx_int_t
> ngx_http_dummy_init(ngx_conf_t *cf)
> {
>    ngx_http_handler_pt        *h;
>    ngx_http_core_main_conf_t  *cmcf;
>
>    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
>
>    h = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
>    if (h == NULL) {
>        return NGX_ERROR;
>    }
>
>    *h = ngx_http_dummy_access_handler;
>
>    return NGX_OK;
> }
>
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