The addition before sub

[Witold Filipczyk]

W dniu 06.06.2013 o 19:56 Maxim Dounin <mdounin at mdounin.ru> pisze:

> Hello!
>
> On Thu, Jun 06, 2013 at 05:43:14PM +0200,  Witold Filipczyk wrote:
>
>> W dniu 06.06.2013 o 15:57 Maxim Dounin <mdounin at mdounin.ru> pisze:
>>
>> >Hello!
>> >
>> >On Thu, Jun 06, 2013 at 03:41:53PM +0200,  Witold Filipczyk wrote:
>> >
>> >>Hello,
>> >>I want to inject something before </body> and before </head>, but
>> >>even if there is no </body>.
>> >>So used add_after_body /after_body;
>> >>/after_body returns the text </body>, so there is at least one
>> >></body> in the page.
>> >>I wanted sub_filter to replace </body> to SOMETHING</body>, but the
>> >>sub_filter is run before the addition_filter.
>> >>Changing the order in modules doesn't help, because the sub_filter
>> >>doesn't replace the text from subrequests.
>> >
>> >Works fine here:
>> >
>> >    location / {
>> >        add_after_body /after.html;
>> >        sub_filter 'foo' 'bar';
>> >    }
>> >
>> >$ cat main.html
>> >this is main.html: foo
>> >$ cat after.html
>> >this is in after.html: foo
>> >$ fetch -qo - 'http://localhost:8080/main.html'
>> >this is main.html: bar
>> >this is in after.html: bar
>> >
>> >The explanation is simple: addition filter uses _subrequests_ to
>> >add text, and these subrequests are in turn processed by the whole
>> >filter chain, including the sub filter.  Hence order of sub and
>> >addition filters doesn't matter.
>> >
>> >Most likely it doesn't work for you because /after_body have some
>> >default mime type not matched by sub_filter_types, see
>> >http://nginx.org/r/sub_filter_types.
>>
>> OK. It works, but:
>>
>> server {
>>    listen 8000;
>>    sub_filter 'foo' 'bar';
>>    sub_filter_once on;
>>
>>    location / {
>>       root /;
>>       add_after_body /after.html;
>>    }
>>
>>    location = /after.html {
>>       root /;
>>    }
>> }
>>
>> /after.html contains "lalala foo"
>> /body.html contains "foo"
>>
>> http://localhost:8000/body.html:
>> bar lalala bar
>>
>> I expected:
>> bar lalala foo
>
> Any reasons for the expectation?

I wanted to replace given substring once.
add_after_body and sub_filter occurs at the "server" level.
There is too many locations.
Thanks for the reply.

I did a workaround:
In ngx_http_sub_body_filter:

ngx_http_sub_ctx_t *ctx_main = ngx_http_get_module_ctx(r->main,  
ngx_http_sub_filter_module);

if (ctx_main && ctx_main->once) {
	ctx->once = ctx_main->once;
}