Re: sub filter‘s bug?

[Simon Liu]

i find this result  is cause by postpone filter is removed. because i
use --without-http_ssi_module config nginx. and i read nginx config find
this   in  auto/modules:

if [ $HTTP_SSI = YES ]; then
    HTTP_POSTPONE=YES
fi


if [ $HTTP_ADDITION = YES ]; then
    HTTP_POSTPONE=YES
fi

and why  postpone is yes when ssi or addition module is on ?
and then i debug nginx find some code in ngx_http_postpone_filter method :

    if (r->postponed == NULL) {

        if (in || c->buffered) {
            return ngx_http_next_filter(r->main, in);
        }

        return NGX_OK;
    }

therefore if no postpone module, sub filter module may emerge the result in
my previous email  .

On Wed, Sep 15, 2010 at 11:00 AM, Simon Liu <simohayha.bobo at gmail.com>wrote:

> my nginx version is 0.7.67.
>
> I test nginx's sub filter, there have some alert log in error log:
>
> *the http output chain is empty while sending response to client.*
> *
> *
> and  i debug nginx , and then found this is cause by sub filter. so  i read
>  sub filter's source.
>
> in  ngx_http_sub_body_filter:
>
>   *  if (ctx->once && (ctx->buf == NULL || ctx->in == NULL)) {*
> *
> *
> *        if (ctx->busy) {*
> *            if (ngx_http_sub_output(r, ctx) == NGX_ERROR) {*
> *                return NGX_ERROR;*
> *            }*
> *        }*
> *
> *
> *        return ngx_http_next_body_filter(r, in);*
> *    }*
>
> i found when  sub_filter_once is on , after  text have replaced . and the
> second enter ngx_http_sub_body_filter.
> At the moment when in is null,ctx->busy is not null,and so *ngx_http_sub_output
>  may send  *the rest of* buf  completely**,  therefore in  **ngx_http_next_body_filter
> will log alert log : the http output chain is empty while sending response
> to client. *
> *
> *
> *i*n conclusion I *think  there should add a *judgement that in is whether
> or not NULL.
> *
> *
> *this is my patch:*
> *
> *
> *
> --- nginx-0.7.67/src/http/modules/ngx_http_sub_filter_module.c 2009-10-26
> 23:54:29.000000000 +0800
> +++ nginx-0.7.67_new/src/http/modules/ngx_http_sub_filter_module.c 2010-09-15
> 10:14:04.996666685 +0800
> @@ -187,16 +187,16 @@ ngx_http_sub_body_filter(ngx_http_reques
>      }
>
>      if (ctx->once && (ctx->buf == NULL || ctx->in == NULL)) {
>
>          if (ctx->busy) {
> -            if (ngx_http_sub_output(r, ctx) == NGX_ERROR) {
> -                return NGX_ERROR;
> -            }
> +            rc = ngx_http_sub_output(r, ctx);
>          }
>
> -        return ngx_http_next_body_filter(r, in);
>  +        if (rc != NGX_ERROR && in != NULL)
> +            return ngx_http_next_body_filter(r, in);
> +        return rc;
>      }
>
>      /* add the incoming chain to the chain ctx->in */
>
>      if (in) {
> *
> *
> *
> --
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>
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>
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>
> twitter: www.twitter.com/minibobo
>



-- 
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