From: Kirill A. Korinskiy <catap@catap.ru>

`ngx_http_empty_gif_module' is a simplpe module for send 1x1
transparent gif. Since the gif can contain any number of garbages data
after the header, I added a directive `empty_gif_size' that sets the
size of "size" for gif 1x1 transparent gif.
---
src/http/modules/ngx_http_empty_gif_module.c | 162 ++++++++++++++++++++++----
1 files changed, 137 insertions(+), 25 deletions(-)

diff --git a/src/http/modules/ngx_http_empty_gif_module.c b/src/http/modules/ngx_http_empty_gif_module.c
index 20e4413c086bc9cce0c54b591edc3b5324cf591b..2abbc19ceb9991be85ebd2236d106c4800ae6508 100644
--- a/src/http/modules/ngx_http_empty_gif_module.c
+++ b/src/http/modules/ngx_http_empty_gif_module.c
@@ -8,9 +8,22 @@
#include <ngx_http.h>


+typedef struct {
+ ngx_str_t fake;
+} ngx_http_empty_gif_loc_conf_t;
+
+
static char *ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);

+static void *ngx_http_empty_gif_create_local_conf(ngx_conf_t *cf);
+static char *ngx_http_empty_gif_merge_local_conf(ngx_conf_t *cf,
+ void *parent, void *child);
+
+static char *ngx_http_empty_gif_size(ngx_conf_t *cf,
+ ngx_command_t *cmd, void *conf);
+
+
static ngx_command_t ngx_http_empty_gif_commands[] = {

{ ngx_string("empty_gif"),
@@ -20,6 +33,13 @@ static ngx_command_t ngx_http_empty_gif_commands[] = {
0,
NULL },

+ { ngx_string("empty_gif_size"),
+ NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+ ngx_http_empty_gif_size,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_empty_gif_loc_conf_t, fake),
+ NULL },
+
ngx_null_command
};

@@ -75,32 +95,32 @@ static u_char ngx_empty_gif[] = {


static ngx_http_module_t ngx_http_empty_gif_module_ctx = {
- NULL, /* preconfiguration */
- NULL, /* postconfiguration */
+ NULL, /* preconfiguration */
+ NULL, /* postconfiguration */

- NULL, /* create main configuration */
- NULL, /* init main configuration */
+ NULL, /* create main configuration */
+ NULL, /* init main configuration */

- NULL, /* create server configuration */
- NULL, /* merge server configuration */
+ NULL, /* create server configuration */
+ NULL, /* merge server configuration */

- NULL, /* create location configuration */
- NULL /* merge location configuration */
+ ngx_http_empty_gif_create_local_conf, /* create location configuration */
+ ngx_http_empty_gif_merge_local_conf /* merge location configuration */
};


ngx_module_t ngx_http_empty_gif_module = {
NGX_MODULE_V1,
- &ngx_http_empty_gif_module_ctx, /* module context */
- ngx_http_empty_gif_commands, /* 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_http_empty_gif_module_ctx, /* module context */
+ ngx_http_empty_gif_commands, /* 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
};

@@ -108,9 +128,12 @@ ngx_module_t ngx_http_empty_gif_module = {
static ngx_int_t
ngx_http_empty_gif_handler(ngx_http_request_t *r)
{
- ngx_int_t rc;
- ngx_buf_t *b;
- ngx_chain_t out;
+ ngx_int_t rc;
+ ngx_buf_t *b;
+ ngx_chain_t out[2];
+ ngx_http_empty_gif_loc_conf_t *conf;
+
+ conf = ngx_http_get_module_loc_conf(r, ngx_http_empty_gif_module);

if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) {
return NGX_HTTP_NOT_ALLOWED;
@@ -129,6 +152,9 @@ ngx_http_empty_gif_handler(ngx_http_request_t *r)
if (r->method == NGX_HTTP_HEAD) {
r->headers_out.status = NGX_HTTP_OK;
r->headers_out.content_length_n = sizeof(ngx_empty_gif);
+ if (conf->fake.len) {
+ r->headers_out.content_length_n += conf->fake.len;
+ }
r->headers_out.last_modified_time = 23349600;

r->headers_out.etag_size = 40;
@@ -144,18 +170,36 @@ ngx_http_empty_gif_handler(ngx_http_request_t *r)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}

- out.buf = b;
- out.next = NULL;
+ out[0].buf = b;
+ out[0].next = NULL;

b->pos = ngx_empty_gif;
b->last = ngx_empty_gif + sizeof(ngx_empty_gif);
b->memory = 1;
- b->last_buf = 1;

r->headers_out.status = NGX_HTTP_OK;
r->headers_out.content_length_n = sizeof(ngx_empty_gif);
r->headers_out.last_modified_time = 23349600;

+ if (conf->fake.len) {
+ out[0].next = &out[1];
+ r->headers_out.content_length_n += conf->fake.len;
+
+ b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
+ if (b == NULL) {
+ return NGX_HTTP_INTERNAL_SERVER_ERROR;
+ }
+
+ out[1].next = NULL;
+ out[1].buf = b;
+
+ b->pos = conf->fake.data;
+ b->last = conf->fake.data + conf->fake.len;
+ b->memory = 1;
+ }
+
+ b->last_buf = 1;
+
r->headers_out.etag_size = 40;
r->headers_out.etag_time = 5;
r->headers_out.etag_uniq = 6535;
@@ -166,7 +210,7 @@ ngx_http_empty_gif_handler(ngx_http_request_t *r)
return rc;
}

- return ngx_http_output_filter(r, &out);
+ return ngx_http_output_filter(r, &out[0]);
}


@@ -180,3 +224,71 @@ ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)

return NGX_CONF_OK;
}
+
+
+static void *
+ngx_http_empty_gif_create_local_conf(ngx_conf_t *cf)
+{
+ ngx_http_empty_gif_loc_conf_t *conf;
+
+ conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_empty_gif_loc_conf_t));
+ if (conf == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ return conf;
+}
+
+static char *
+ngx_http_empty_gif_merge_local_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+ ngx_http_empty_gif_loc_conf_t *prev = parent;
+ ngx_http_empty_gif_loc_conf_t *conf = child;
+
+ if (prev->fake.len) {
+ conf->fake = prev->fake;
+ }
+
+ return NGX_CONF_OK;
+}
+
+static char *
+ngx_http_empty_gif_size(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+ char *p = conf;
+
+ ngx_str_t *field, *value;
+ ngx_conf_post_t *post;
+
+ field = (ngx_str_t *) (p + cmd->offset);
+
+ if (field->data) {
+ return "is duplicate";
+ }
+
+ value = cf->args->elts;
+
+ field->len = ngx_parse_size(&value[1]);
+
+ if (field->len == (size_t) NGX_ERROR) {
+ return "invalid value";
+ }
+
+ if (field->len < sizeof(ngx_empty_gif)) {
+ return "is shortly";
+ }
+
+ field->len -= sizeof(ngx_empty_gif);
+
+ field->data = ngx_pcalloc(cf->pool, field->len);
+ if (field->data == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ if (cmd->post) {
+ post = cmd->post;
+ return post->post_handler(cf, post, field);
+ }
+
+ return NGX_CONF_OK;
+}
--
1.6.2