# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1309187038 -14400
# Node ID e56caa64771c6fcffa661943b8b3e4f2a291d485
# Parent 31aaaef96cb108e118afe407346cb4f04a444437
Memcached: memcached_gzip_flag directive.

This directive allows to test desired flag as returned by memcached and
sets Content-Encoding to gzip if one found.

This is reimplementation of patch by Tomash Brechko as available on
http://openhack.ru/. It should be a bit more correct though (at least
I think so). In particular, it doesn't try to detect if we are able to
gunzip data, but instead just sets correct Content-Encoding.

Originally by: Tomash Brechko

diff --git a/src/http/modules/ngx_http_memcached_module.c b/src/http/modules/ngx_http_memcached_module.c
--- a/src/http/modules/ngx_http_memcached_module.c
+++ b/src/http/modules/ngx_http_memcached_module.c
@@ -12,6 +12,7 @@
typedef struct {
ngx_http_upstream_conf_t upstream;
ngx_int_t index;
+ ngx_uint_t gzip_flag;
} ngx_http_memcached_loc_conf_t;


@@ -100,6 +101,13 @@ static ngx_command_t ngx_http_memcached
offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream),
&ngx_http_memcached_next_upstream_masks },

+ { ngx_string("memcached_gzip_flag"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+ ngx_conf_set_num_slot,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_memcached_loc_conf_t, gzip_flag),
+ NULL },
+
ngx_null_command
};

@@ -280,10 +288,13 @@ ngx_http_memcached_reinit_request(ngx_ht
static ngx_int_t
ngx_http_memcached_process_header(ngx_http_request_t *r)
{
- u_char *p, *len;
- ngx_str_t line;
- ngx_http_upstream_t *u;
- ngx_http_memcached_ctx_t *ctx;
+ u_char *p, *start;
+ ngx_str_t line;
+ ngx_uint_t flags;
+ ngx_table_elt_t *h;
+ ngx_http_upstream_t *u;
+ ngx_http_memcached_ctx_t *ctx;
+ ngx_http_memcached_loc_conf_t *mlcf;

u = r->upstream;

@@ -308,6 +319,7 @@ found:
p = u->buffer.pos;

ctx = ngx_http_get_module_ctx(r, ngx_http_memcached_module);
+ mlcf = ngx_http_get_module_loc_conf(r, ngx_http_memcached_module);

if (ngx_strncmp(p, "VALUE ", sizeof("VALUE ") - 1) == 0) {

@@ -328,23 +340,56 @@ found:
goto no_valid;
}

- /* skip flags */
+ /* flags */
+
+ start = p;

while (*p) {
if (*p++ == ' ') {
- goto length;
+ if (mlcf->gzip_flag) {
+ goto flags;
+ } else {
+ goto length;
+ }
}
}

goto no_valid;

+ flags:
+
+ flags = ngx_atoi(start, p - start - 1);
+
+ if (flags == (ngx_uint_t) NGX_ERROR) {
+ ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+ "memcached sent invalid flags in response \"%V\" "
+ "for key \"%V\"",
+ &line, &ctx->key);
+ return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+ }
+
+ if (flags & mlcf->gzip_flag) {
+ h = ngx_list_push(&r->headers_out.headers);
+ if (h == NULL) {
+ return NGX_ERROR;
+ }
+
+ h->hash = 1;
+ h->key.len = sizeof("Content-Encoding") - 1;
+ h->key.data = (u_char *) "Content-Encoding";
+ h->value.len = sizeof("gzip") - 1;
+ h->value.data = (u_char *) "gzip";
+
+ r->headers_out.content_encoding = h;
+ }
+
length:

- len = p;
+ start = p;

while (*p && *p++ != CR) { /* void */ }

- r->headers_out.content_length_n = ngx_atoof(len, p - len - 1);
+ r->headers_out.content_length_n = ngx_atoof(start, p - start - 1);
if (r->headers_out.content_length_n == -1) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"memcached sent invalid length in response \"%V\" "
@@ -533,6 +578,7 @@ ngx_http_memcached_create_loc_conf(ngx_c
conf->upstream.pass_request_body = 0;

conf->index = NGX_CONF_UNSET;
+ conf->gzip_flag = NGX_CONF_UNSET_UINT;

return conf;
}
@@ -576,6 +622,8 @@ ngx_http_memcached_merge_loc_conf(ngx_co
conf->index = prev->index;
}

+ ngx_conf_merge_uint_value(conf->gzip_flag, prev->gzip_flag, 0);
+
return NGX_CONF_OK;
}


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