[PATCH 11 of 20] Upstream: simplified Content-Encoding handling

[Sergey Kandaurov]

On Thu, Apr 21, 2022 at 01:18:51AM +0300, Maxim Dounin wrote:
> # HG changeset patch
> # User Maxim Dounin <mdounin at mdounin.ru>
> # Date 1650492330 -10800
> #      Thu Apr 21 01:05:30 2022 +0300
> # Node ID 6441069e16a0c4755c662bc07bdcb0960c9ac04a
> # Parent  ee1a8a4aa2c262d25a4aa871cda4f6c4515fc85c
> Upstream: simplified Content-Encoding handling.
> 
> Since introduction of offset handling in ngx_http_upstream_copy_header_line()
> in revision 573:58475592100c, the ngx_http_upstream_copy_content_encoding()
> function is no longer needed, as its behaviour is exactly equivalent to
> ngx_http_upstream_copy_header_line() with appropriate offset.  As such,
> the ngx_http_upstream_copy_content_encoding() function was removed.
> 
> Further, the u->headers_in.content_encoding field is not used anywhere,
> so it was removed as well.

jftr, it's used (seemingly incorrect) in ngx_http_redis for gzip decompression
https://github.com/onnimonni/redis-nginx-module/commit/cbe2630fd070
It might be better to improve gunzip filter itself as marked in TODO.

> 
> Further, Content-Encoding handling no longer depends on NGX_HTTP_GZIP,
> as it can be used even without any gzip handling compiled in (for example,
> in the charset filter).
> 
> diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
> --- a/src/http/ngx_http_upstream.c
> +++ b/src/http/ngx_http_upstream.c
> @@ -147,11 +147,6 @@ static ngx_int_t ngx_http_upstream_rewri
>  static ngx_int_t ngx_http_upstream_copy_allow_ranges(ngx_http_request_t *r,
>      ngx_table_elt_t *h, ngx_uint_t offset);
>  
> -#if (NGX_HTTP_GZIP)
> -static ngx_int_t ngx_http_upstream_copy_content_encoding(ngx_http_request_t *r,
> -    ngx_table_elt_t *h, ngx_uint_t offset);
> -#endif
> -
>  static ngx_int_t ngx_http_upstream_add_variables(ngx_conf_t *cf);
>  static ngx_int_t ngx_http_upstream_addr_variable(ngx_http_request_t *r,
>      ngx_http_variable_value_t *v, uintptr_t data);
> @@ -316,12 +311,10 @@ static ngx_http_upstream_header_t  ngx_h
>                   ngx_http_upstream_process_transfer_encoding, 0,
>                   ngx_http_upstream_ignore_header_line, 0, 0 },
>  
> -#if (NGX_HTTP_GZIP)
>      { ngx_string("Content-Encoding"),
> -                 ngx_http_upstream_process_header_line,
> -                 offsetof(ngx_http_upstream_headers_in_t, content_encoding),
> -                 ngx_http_upstream_copy_content_encoding, 0, 0 },
> -#endif
> +                 ngx_http_upstream_ignore_header_line, 0,
> +                 ngx_http_upstream_copy_header_line,
> +                 offsetof(ngx_http_headers_out_t, content_encoding), 0 },
>  
>      { ngx_null_string, NULL, 0, NULL, 0, 0 }
>  };
> @@ -5349,29 +5342,6 @@ ngx_http_upstream_copy_allow_ranges(ngx_
>  }
>  
>  
> -#if (NGX_HTTP_GZIP)
> -
> -static ngx_int_t
> -ngx_http_upstream_copy_content_encoding(ngx_http_request_t *r,
> -    ngx_table_elt_t *h, ngx_uint_t offset)
> -{
> -    ngx_table_elt_t  *ho;
> -
> -    ho = ngx_list_push(&r->headers_out.headers);
> -    if (ho == NULL) {
> -        return NGX_ERROR;
> -    }
> -
> -    *ho = *h;
> -
> -    r->headers_out.content_encoding = ho;
> -
> -    return NGX_OK;
> -}
> -
> -#endif
> -
> -
>  static ngx_int_t
>  ngx_http_upstream_add_variables(ngx_conf_t *cf)
>  {
> diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
> --- a/src/http/ngx_http_upstream.h
> +++ b/src/http/ngx_http_upstream.h
> @@ -285,10 +285,6 @@ typedef struct {
>      ngx_table_elt_t                 *transfer_encoding;
>      ngx_table_elt_t                 *vary;
>  
> -#if (NGX_HTTP_GZIP)
> -    ngx_table_elt_t                 *content_encoding;
> -#endif
> -
>      ngx_table_elt_t                 *cache_control;
>      ngx_table_elt_t                 *set_cookie;
>  
>