static ngx_int_t ngx_http_breach_header_filter(ngx_http_request_t *r)
{
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,"BREACH HEADER FILTER Start!.");
ngx_http_breach_conf_t *conf;
conf = ngx_http_get_module_loc_conf (r, ngx_http_breach_filter_module);
if ((r->headers_out.status != NGX_HTTP_OK &&
r->headers_out.status != NGX_HTTP_FORBIDDEN &&
r->headers_out.status != NGX_HTTP_NOT_FOUND) ||
r->header_only ||
r->headers_out.content_type.len == 0 ||
(r->headers_out.content_encoding &&
r->headers_out.content_encoding->value.len) ||
conf->enable == 0)
{
return ngx_http_next_header_filter(r);
}
if (ngx_strncasecmp(r->headers_out.content_type.data, (u_char *)"text/html", sizeof("text/html") - 1) != 0)
{
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,"BREACH HEADER FILTER: this is not text/html content!.");
return ngx_http_next_header_filter(r);
}
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,"BREACH HEADER FILTER: end!.");
return ngx_http_next_header_filter(r);
}
ngx_int_t
ngx_http_echo_send_header_if_needed(ngx_http_request_t *r,
ngx_http_echo_ctx_t *ctx)
{
ngx_int_t rc;
ngx_http_echo_loc_conf_t *elcf;
if (!r->header_sent && !ctx->header_sent) {
elcf = ngx_http_get_module_loc_conf(r, ngx_http_echo_module);
r->headers_out.status = (ngx_uint_t) elcf->status;
if (ngx_http_set_content_type(r) != NGX_OK) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
rc = ngx_http_send_header(r);
ctx->header_sent = 1;
return rc;
}
return NGX_OK;
}
static ngx_int_t ngx_http_dynamic_etags_header_filter(ngx_http_request_t *r) {
ngx_http_dynamic_etags_module_ctx_t *ctx;
ctx = ngx_http_get_module_ctx(r, ngx_http_dynamic_etags_module);
if (ctx) {
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_dynamic_etags_module_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_dynamic_etags_module);
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
r->main_filter_need_in_memory = 1;
r->filter_need_in_memory = 1;
return NGX_OK;
}
static ngx_int_t
ngx_http_addition_header_filter(ngx_http_request_t *r)
{
ngx_http_addition_ctx_t *ctx;
ngx_http_addition_conf_t *conf;
if (r->headers_out.status != NGX_HTTP_OK || r != r->main) {
return ngx_http_next_header_filter(r);
}
conf = ngx_http_get_module_loc_conf(r, ngx_http_addition_filter_module);
if (conf->before_body.len == 0 && conf->after_body.len == 0) {
return ngx_http_next_header_filter(r);
}
if (ngx_http_test_content_type(r, &conf->types) == NULL) {
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_addition_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_addition_filter_module);
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_foo_header_filter(ngx_http_request_t *r)
{
ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0, "Header filter add header");
ngx_table_elt_t *h;
/*
* The filter handler adds "X-Foo: foo" header
* to every HTTP 200 response
*/
if (r->headers_out.status != NGX_HTTP_OK) {
return ngx_http_next_header_filter(r);
}
h = ngx_list_push(&r->headers_out.headers);
if (h == NULL) {
return NGX_ERROR;
}
h->hash = 1;
ngx_str_set(&h->key, "X-Foo");
ngx_str_set(&h->value, "foo");
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_http_weak_etag(r);
return ngx_http_next_header_filter(r);
}
ngx_int_t
ngx_http_lua_send_header_if_needed(ngx_http_request_t *r,
ngx_http_lua_ctx_t *ctx)
{
if ( ! ctx->headers_sent ) {
if (r->headers_out.status == 0) {
r->headers_out.status = NGX_HTTP_OK;
}
if (! ctx->headers_set && ngx_http_set_content_type(r) != NGX_OK) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
if (! ctx->headers_set) {
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
}
if (r->http_version >= NGX_HTTP_VERSION_11) {
/* Send response headers for HTTP version <= 1.0 elsewhere */
ctx->headers_sent = 1;
return ngx_http_send_header(r);
}
}
return NGX_OK;
}
static ngx_int_t
ngx_http_gunzip_header_filter(ngx_http_request_t *r)
{
ngx_http_gunzip_ctx_t *ctx;
ngx_http_gunzip_conf_t *conf;
conf = ngx_http_get_module_loc_conf(r, ngx_http_gunzip_filter_module);
/* TODO support multiple content-codings */
/* TODO ignore content encoding? */
if (conf->enable == NGX_HTTP_GUNZIP_OFF
|| r->headers_out.content_encoding == NULL
|| r->headers_out.content_encoding->value.len != 4
|| ngx_strncasecmp(r->headers_out.content_encoding->value.data,
(u_char *) "gzip", 4) != 0)
{
return ngx_http_next_header_filter(r);
}
r->gzip_vary = 1;
if (conf->enable == NGX_HTTP_GUNZIP_ON) {
if (!r->gzip_tested) {
if (ngx_http_gzip_ok(r) == NGX_OK) {
return ngx_http_next_header_filter(r);
}
} else if (r->gzip_ok) {
return ngx_http_next_header_filter(r);
}
} else if (conf->enable == NGX_HTTP_GUNZIP_ALWAYS
&& ngx_http_test_content_type(r, &conf->types) == NULL)
{
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_gunzip_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_gunzip_filter_module);
ctx->request = r;
r->filter_need_in_memory = 1;
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_http_weak_etag(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_not_modified_header_filter(ngx_http_request_t *r)
{
if (r->headers_out.status != NGX_HTTP_OK
|| r != r->main
|| r->disable_not_modified)
{
return ngx_http_next_header_filter(r);
}
if (r->headers_in.if_unmodified_since
&& !ngx_http_test_if_unmodified(r))
{
return ngx_http_filter_finalize_request(r, NULL,
NGX_HTTP_PRECONDITION_FAILED);
}
if (r->headers_in.if_match
&& !ngx_http_test_if_match(r, r->headers_in.if_match, 0))
{
return ngx_http_filter_finalize_request(r, NULL,
NGX_HTTP_PRECONDITION_FAILED);
}
if (r->headers_in.if_modified_since || r->headers_in.if_none_match) {
if (r->headers_in.if_modified_since
&& ngx_http_test_if_modified(r))
{
return ngx_http_next_header_filter(r);
}
if (r->headers_in.if_none_match
&& !ngx_http_test_if_match(r, r->headers_in.if_none_match, 1))
{
return ngx_http_next_header_filter(r);
}
/* not modified */
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (r->headers_out.content_encoding) {
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
}
return ngx_http_next_header_filter(r);
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_trim_header_filter(ngx_http_request_t *r)
{
ngx_int_t rc;
ngx_str_t flag;
ngx_http_trim_ctx_t *ctx;
ngx_http_trim_loc_conf_t *conf;
conf = ngx_http_get_module_loc_conf(r, ngx_http_trim_filter_module);
if (!conf->trim_enable
|| r->headers_out.status != NGX_HTTP_OK
|| (r->method & NGX_HTTP_HEAD)
|| r->headers_out.content_length_n == 0
|| (r->headers_out.content_encoding
&& r->headers_out.content_encoding->value.len)
|| ngx_http_test_content_type(r, &conf->types) == NULL)
{
return ngx_http_next_header_filter(r);
}
rc = ngx_http_arg(r, (u_char *) NGX_HTTP_TRIM_FLAG,
sizeof(NGX_HTTP_TRIM_FLAG) - 1, &flag);
if(rc == NGX_OK
&& flag.len == sizeof("off") - 1
&& ngx_strncmp(flag.data, "off", sizeof("off") - 1) == 0)
{
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_trim_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
ctx->prev = ' ';
ctx->first_line = 1;
ngx_http_set_ctx(r, ctx, ngx_http_trim_filter_module);
r->main_filter_need_in_memory = 1;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_not_modified_header_filter(ngx_http_request_t *r)
{
time_t ims;
ngx_http_core_loc_conf_t *clcf;
if (r->headers_out.status != NGX_HTTP_OK
|| r != r->main
|| r->headers_in.if_modified_since == NULL
|| r->headers_out.last_modified_time == -1)
{
return ngx_http_next_header_filter(r);
}
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
if (clcf->if_modified_since == NGX_HTTP_IMS_OFF) {
return ngx_http_next_header_filter(r);
}
ims = ngx_http_parse_time(r->headers_in.if_modified_since->value.data,
r->headers_in.if_modified_since->value.len);
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http ims:%d lm:%d", ims, r->headers_out.last_modified_time);
if (ims != r->headers_out.last_modified_time) {
if (clcf->if_modified_since == NGX_HTTP_IMS_EXACT
|| ims < r->headers_out.last_modified_time)
{
return ngx_http_next_header_filter(r);
}
}
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (r->headers_out.content_encoding) {
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_srcache_send_not_modified(ngx_http_request_t *r)
{
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (r->headers_out.content_encoding) {
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
}
return ngx_http_srcache_next_header_filter(r);
}
static ngx_int_t
ngx_http_echo_header_filter(ngx_http_request_t *r)
{
ngx_http_echo_loc_conf_t *conf;
ngx_http_echo_ctx_t *ctx;
dd("We're in the header filter...");
ctx = ngx_http_get_module_ctx(r, ngx_http_echo_module);
/* XXX we should add option to insert contents for responses
* of non-200 status code here... */
/*
if (r->headers_out.status != NGX_HTTP_OK) {
if (ctx != NULL) {
ctx->skip_filter = 1;
}
return ngx_http_echo_next_header_filter(r);
}
*/
conf = ngx_http_get_module_loc_conf(r, ngx_http_echo_module);
if (conf->before_body_cmds == NULL && conf->after_body_cmds == NULL) {
if (ctx != NULL) {
ctx->skip_filter = 1;
}
return ngx_http_echo_next_header_filter(r);
}
if (ctx == NULL) {
ctx = ngx_http_echo_create_ctx(r);
if (ctx == NULL) {
return NGX_ERROR;
}
ctx->headers_sent = 1;
ngx_http_set_ctx(r, ctx, ngx_http_echo_module);
}
/* enable streaming here (use chunked encoding) */
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_echo_next_header_filter(r);
}
static ngx_int_t
ngx_http_echo_header_filter(ngx_http_request_t *r)
{
ngx_http_echo_loc_conf_t *conf;
ngx_http_echo_ctx_t *ctx;
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"echo header filter, uri \"%V?%V\"", &r->uri, &r->args);
ctx = ngx_http_get_module_ctx(r, ngx_http_echo_module);
/* XXX we should add option to insert contents for responses
* of non-200 status code here... */
/*
if (r->headers_out.status != NGX_HTTP_OK) {
if (ctx != NULL) {
ctx->skip_filter = 1;
}
return ngx_http_echo_next_header_filter(r);
}
*/
conf = ngx_http_get_module_loc_conf(r, ngx_http_echo_module);
if (conf->before_body_cmds == NULL && conf->after_body_cmds == NULL) {
if (ctx != NULL) {
ctx->skip_filter = 1;
}
return ngx_http_echo_next_header_filter(r);
}
if (ctx == NULL) {
ctx = ngx_http_echo_create_ctx(r);
if (ctx == NULL) {
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_echo_module);
}
/* enable streaming here (use chunked encoding) */
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_echo_next_header_filter(r);
}
ngx_int_t
ngx_http_echo_send_header_if_needed(ngx_http_request_t* r)
{
if (!r->header_sent) {
r->headers_out.status = 200;
if (ngx_http_set_content_type(r) != NGX_OK) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_send_header(r);
}
return NGX_OK;
}
ngx_int_t
ngx_http_secure_token_init_body_filter(ngx_http_request_t *r, ngx_str_t* token)
{
ngx_http_secure_token_loc_conf_t *conf;
ngx_http_secure_token_ctx_t* ctx;
body_processor_t* processor;
conf = ngx_http_get_module_loc_conf(r, ngx_http_secure_token_filter_module);
// Note: content_type_lowcase is already initialized since we called ngx_http_test_content_type
processor = ngx_hash_find(&conf->processors_hash, r->headers_out.content_type_hash, r->headers_out.content_type_lowcase, r->headers_out.content_type_len);
if (processor == NULL)
{
return NGX_DONE;
}
// add the token to all the URLs in the response
ctx = ngx_pcalloc(r->pool, sizeof(*ctx));
if (ctx == NULL)
{
return NGX_ERROR;
}
ctx->token = *token;
ctx->process = processor->process;
ctx->processor_context_offset = processor->processor_context_offset;
ctx->processor_params = processor->processor_params;
ngx_http_set_ctx(r, ctx, ngx_http_secure_token_filter_module);
ctx->last_out = &ctx->out;
r->filter_need_in_memory = 1;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_http_clear_etag(r);
return NGX_OK;
}
static ngx_int_t ngx_http_no_newlines_header_filter (ngx_http_request_t *r)
{
ngx_http_no_newlines_ctx_t *ctx; /* to maintain state */
ngx_http_no_newlines_conf_t *conf; /* to check whether module is enabled or not */
conf = ngx_http_get_module_loc_conf (r, ngx_http_no_newlines_module);
/* step 1: decide whether to operate */
if ((r->headers_out.status != NGX_HTTP_OK &&
r->headers_out.status != NGX_HTTP_FORBIDDEN &&
r->headers_out.status != NGX_HTTP_NOT_FOUND) ||
r->header_only ||
r->headers_out.content_type.len == 0 ||
(r->headers_out.content_encoding &&
r->headers_out.content_encoding->value.len) ||
conf->enable == 0) {
return ngx_http_next_header_filter(r);
}
if (ngx_strncasecmp(r->headers_out.content_type.data, (u_char *)"text/html", sizeof("text/html") - 1) != 0) {
return ngx_http_next_header_filter(r);
}
/* step 2: operate on the header */
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_no_newlines_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_no_newlines_module);
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
r->main_filter_need_in_memory = 1;
/* step 3: call the next filter */
return ngx_http_next_header_filter(r);
}
ngx_int_t
ngx_http_echo_send_header_if_needed(ngx_http_request_t* r,
ngx_http_echo_ctx_t *ctx) {
/* ngx_int_t rc; */
if ( ! ctx->headers_sent ) {
r->headers_out.status = NGX_HTTP_OK;
if (ngx_http_set_content_type(r) != NGX_OK) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (r->http_version >= NGX_HTTP_VERSION_11) {
ctx->headers_sent = 1;
return ngx_http_send_header(r);
}
}
return NGX_OK;
}
static ngx_int_t ngx_http_static_etags_header_filter(ngx_http_request_t *r) {
char new_string[100];
char buffer[30];
int status;
ngx_log_t *log;
u_char *p;
size_t root;
ngx_str_t path;
ngx_http_static_etags_loc_conf_t *loc_conf;
struct stat stat_result;
log = r->connection->log;
loc_conf = ngx_http_get_module_loc_conf( r, ngx_http_static_etags_module );
if ( 1 == loc_conf->FileETag ) {
p = ngx_http_map_uri_to_path( r, &path, &root, 0 );
status = stat( (char *) path.data, &stat_result );
if ( NULL == p ) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
if ( 0 == status) {
ngx_memzero(&new_string, 100);
strcat(new_string, "\"");
if (loc_conf->etag_options->MD5) {
int ret;
char md5sum[33];
ret = ngx_http_static_etags_md5((unsigned int) stat_result.st_size, (char *) path.data, (char *) &md5sum, (ngx_log_t *) log);
if (ret) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "MD5ERROR Return: %s", md5sum);
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
strcat(new_string, (char *) md5sum);
}
if (loc_conf->etag_options->Size) {
sprintf(buffer, "%x", (unsigned int) stat_result.st_size);
strcat(new_string, (char *) buffer);
}
if (loc_conf->etag_options->MTime) {
sprintf(buffer, "%x", (unsigned int ) stat_result.st_mtime);
strcat(new_string, (char *) buffer);
}
if (loc_conf->etag_options->INode) {
sprintf(buffer, "%x", (unsigned int ) stat_result.st_ino);
strcat(new_string, (char *) buffer);
}
strcat(new_string, "\"");
r->headers_out.etag = ngx_list_push(&r->headers_out.headers);
if (r->headers_out.etag == NULL) {
return NGX_ERROR;
}
ngx_table_elt_t *header;
int nelts = r->headers_in.headers.part.nelts;
header = r->headers_in.headers.part.elts;
int i;
for (i = 0; i < nelts; i++) {
if (ngx_strncmp(header[i].key.data, "If-None-Match", strlen ("If-None-Match")) == 0) {
if(ngx_strncmp(header[i].value.data, new_string, strlen (new_string)) == 0) {
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_next_header_filter(r);
}
}
}
r->headers_out.etag->hash = 1;
r->headers_out.etag->key.len = sizeof("Etag") - 1;
r->headers_out.etag->key.data = (u_char *) "Etag";
r->headers_out.etag->value.len = strlen( new_string );
r->headers_out.etag->value.data = (u_char *) new_string;
}
else {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "Could not stat(): %s", path.data);
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
}
return ngx_http_next_header_filter(r);
}
/*
{If-None-Match和ETag , If-Modified-Since和Last-Modified
If-Modified-Since（浏览器） = Last-Modified（服务器）
作用：浏览器端第一次访问获得服务器的Last-Modified，第2次访问把浏览器端缓存页面的最后修改时间发送到服务器去，服务器会把这
个时间与服务器上实际文件的最后修改时间进行对比。如果时间一致，那么返回304，客户端就直接使用本地缓存文件。如果时间不一致，就
会返回200和新的文件内容。客户端接到之后，会丢弃旧文件，把新文件缓存起来，并显示在浏览器中.
If-None-Match（浏览器） = ETag（服务器）
作用: If-None-Match和ETag一起工作，工作原理是在HTTP Response中添加ETag信息。 当用户再次请求该资源时，将在HTTP Request 中加入If-None-Match
信息(ETag的值)。如果服务器验证资源的ETag没有改变（该资源没有更新），将返回一个304状态告诉客户端使用本地缓存文件。否则将返回200状态和新的资源和Etag.
}
{
ETags和If-None-Match是一种常用的判断资源是否改变的方法。类似于Last-Modified和HTTP-If-Modified-Since。但是有所不同的是Last-Modified和HTTP-If-Modified-Since只判断资源的最后修改时间，而ETags和If-None-Match可以是资源任何的任何属性。
ETags和If-None-Match的工作原理是在HTTPResponse中添加ETags信息。当客户端再次请求该资源时，将在HTTPRequest中加入If-None-Match信息（ETags的值）。如果服务器验证资源的ETags没有改变（该资源没有改变），将返回一个304状态；否则，服务器将返回200状态，并返回该资源和新的ETags。
}
{
http响应Last-Modified和ETag
基础知识
1) 什么是”Last-Modified”?
在浏览器第一次请求某一个URL时，服务器端的返回状态会是200，内容是你请求的资源，同时有一个Last-Modified的属性标记此文件在服务期端
最后被修改的时间，格式类似这样：Last-Modified: Fri, 12 May 2006 18:53:33 GMT
客户端第二次请求此URL时，根据 HTTP 协议的规定，浏览器会向服务器传送 If-Modified-Since 报头，询问该时间之后文件是否有被修改过：
If-Modified-Since: Fri, 12 May 2006 18:53:33 GMT
如果服务器端的资源没有变化，则自动返回 HTTP 304 （Not Changed.）状态码，内容为空，这样就节省了传输数据量。当服务器端代码发生改
变或者重启服务器时，则重新发出资源，返回和第一次请求时类似。从而保证不向客户端重复发出资源，也保证当服务器有变化时，客户端能够得到最新的资源。
2) 什么是”Etag”?
HTTP 协议规格说明定义ETag为“被请求变量的实体值” （参见 ―― 章节 14.19）。 另一种说法是，ETag是一个可以与Web资源关联的记号（token）。典型的Web资源可以一个Web页，但也可能是JSON或XML文档。服务器单独负责判断记号是什么及其含义，并在HTTP响应头中将其传送到客户端，以下是服务器端返回的格式：
ETag: "50b1c1d4f775c61:df3"
客户端的查询更新格式是这样的：
If-None-Match: W/"50b1c1d4f775c61:df3"
如果ETag没改变，则返回状态304然后不返回，这也和Last-Modified一样。本人测试Etag主要在断点下载时比较有用。
Last-Modified和Etags如何帮助提高性能?
聪明的开发者会把Last-Modified 和ETags请求的http报头一起使用，这样可利用客户端（例如浏览器）的缓存。因为服务器首先产生
Last-Modified/Etag标记，服务器可在稍后使用它来判断页面是否已经被修改。本质上，客户端通过将该记号传回服务器要求服务器验证其（客户端）缓存。过程如下:
1.客户端请求一个页面（A）。
2.服务器返回页面A，并在给A加上一个Last-Modified/ETag。
3.客户端展现该页面，并将页面连同Last-Modified/ETag一起缓存。
4.客户再次请求页面A，并将上次请求时服务器返回的Last-Modified/ETag一起传递给服务器。
5.服务器检查该Last-Modified或ETag，并判断出该页面自上次客户端请求之后还未被修改，直接返回响应304和一个空的响应体。
}
*/
static ngx_int_t
ngx_http_not_modified_header_filter(ngx_http_request_t *r)
{
if (r->headers_out.status != NGX_HTTP_OK //只有返回类型为OK的才进行304 not modified判断
|| r != r->main
|| r->disable_not_modified)
{
return ngx_http_next_header_filter(r);
}
/*
If-Unmodified-Since: 从字面上看, 意思是: 如果从某个时间点算起, 文件没有被修改.....
1. 如果没有被修改: 则开始`继续'传送文件: 服务器返回: 200 OK
2. 如果文件被修改: 则不传输, 服务器返回: 412 Precondition failed (预处理错误)
用途:断点续传(一般会指定Range参数). 要想断点续传, 那么文件就一定不能被修改, 否则就不是同一个文件了
*/
if (r->headers_in.if_unmodified_since
&& !ngx_http_test_if_unmodified(r))
/*
如果从某个时间点算起, 文件被修改了，客户端请求行中带有if_unmodified_since，表示如果文件如果从某个时间段起没有被修改，
则继续200 OK传送给客户端包体。但是现在文件却被修改了，因此返回错误
*/
{
return ngx_http_filter_finalize_request(r, NULL,
NGX_HTTP_PRECONDITION_FAILED);
}
if (r->headers_in.if_match
&& !ngx_http_test_if_match(r, r->headers_in.if_match, 0))
{
return ngx_http_filter_finalize_request(r, NULL,
NGX_HTTP_PRECONDITION_FAILED);
}
if (r->headers_in.if_modified_since || r->headers_in.if_none_match) {
if (r->headers_in.if_modified_since
&& ngx_http_test_if_modified(r)) //文件有发生了修改
{
return ngx_http_next_header_filter(r);
}
if (r->headers_in.if_none_match
&& !ngx_http_test_if_match(r, r->headers_in.if_none_match, 1)) //etag不匹配，说明文件也发生了修改
{
return ngx_http_next_header_filter(r);
}
/* not modified */
//回送304表示文件没有修改
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (r->headers_out.content_encoding) {
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
}
return ngx_http_next_header_filter(r);
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_gunzip_header_filter(ngx_http_request_t *r)
{
ngx_http_gunzip_ctx_t *ctx;
ngx_http_gunzip_conf_t *conf;
conf = ngx_http_get_module_loc_conf(r, ngx_http_gunzip_filter_module);
/* TODO support multiple content-codings */
/* TODO always gunzip - due to configuration or module request */
/* TODO ignore content encoding? */
if (!conf->enable
|| r->headers_out.content_encoding == NULL
|| r->headers_out.content_encoding->value.len != 4
|| ngx_strncasecmp(r->headers_out.content_encoding->value.data,
(u_char *) "gzip", 4) != 0)
{
return ngx_http_next_header_filter(r);
}
#if (nginx_version >= 8025 || (nginx_version >= 7065 && nginx_version < 8000))
r->gzip_vary = 1;
if (!r->gzip_tested) {
if (ngx_http_gzip_ok(r) == NGX_OK) {
return ngx_http_next_header_filter(r);
}
} else if (!r->gzip_ok) {
return ngx_http_next_header_filter(r);
}
#else
if (ngx_http_gzip_ok(r) == NGX_OK) {
return ngx_http_next_header_filter(r);
}
#endif
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_gunzip_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_gunzip_filter_module);
ctx->request = r;
r->filter_need_in_memory = 1;
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_xss_header_filter(ngx_http_request_t *r)
{
ngx_http_xss_ctx_t *ctx;
ngx_http_xss_conf_t *conf;
ngx_str_t callback;
u_char *p, *src, *dst;
if (r->headers_out.status != NGX_HTTP_OK || r != r->main) {
dd("skipped: status not 200 or in subrequest");
return ngx_http_next_header_filter(r);
}
conf = ngx_http_get_module_loc_conf(r, ngx_http_xss_filter_module);
if ( ! conf->get_enabled || r->method != NGX_HTTP_GET) {
dd("skipped: get_enabled disabled or the current method is not GET");
return ngx_http_next_header_filter(r);
}
if (conf->callback_arg.len == 0) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"xss: xss_get is enabled but no xss_callback_arg specified");
return ngx_http_next_header_filter(r);
}
if (ngx_http_test_content_type(r, &conf->input_types) == NULL) {
dd("skipped: content type test not passed");
return ngx_http_next_header_filter(r);
}
if (ngx_http_arg(r, conf->callback_arg.data, conf->callback_arg.len,
&callback) != NGX_OK)
{
dd("skipped: no callback arg found in the current request: %.*s",
conf->callback_arg.len, conf->callback_arg.data);
return ngx_http_next_header_filter(r);
}
p = ngx_palloc(r->pool, callback.len);
if (p == NULL) {
return NGX_ERROR;
}
src = callback.data; dst = p;
ngx_unescape_uri(&dst, &src, callback.len,
NGX_UNESCAPE_URI_COMPONENT);
if (src != callback.data + callback.len) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"xss: unescape uri: input data not consumed completely");
return NGX_ERROR;
}
callback.data = p;
callback.len = dst - p;
if (ngx_http_xss_test_callback((char *) callback.data, callback.len)
!= NGX_OK)
{
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"xss: bad callback argument: \"%V\"", &callback);
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_xss_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
/*
* set by ngx_pcalloc():
*
* ctx->callback = { 0, NULL };
* conf->before_body_sent = 0;
*/
ctx->callback = callback;
ngx_http_set_ctx(r, ctx, ngx_http_xss_filter_module);
r->headers_out.content_type = conf->output_type;
r->headers_out.content_type_len = conf->output_type.len;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_brotli_header_filter(ngx_http_request_t *r)
{
ngx_table_elt_t *h, *ae;
ngx_http_brotli_ctx_t *ctx;
ngx_http_brotli_conf_t *conf;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http brotli header filter");
conf = ngx_http_get_module_loc_conf(r, ngx_http_brotli_filter_module);
if (!conf->enable
|| (r->headers_out.status != NGX_HTTP_OK
&& r->headers_out.status != NGX_HTTP_FORBIDDEN
&& r->headers_out.status != NGX_HTTP_NOT_FOUND)
|| (r->headers_out.content_encoding
&& r->headers_out.content_encoding->value.len)
|| (r->headers_out.content_length_n != -1
&& r->headers_out.content_length_n < conf->min_length)
|| ngx_http_test_content_type(r, &conf->types) == NULL
|| r->header_only)
{
return ngx_http_next_header_filter(r);
}
/* Check that brotli is supported. We do not check possible q value
* if brotli is supported it takes precendence over gzip if size >
* brotli_min_length */
ae = r->headers_in.accept_encoding;
if(!ae) {
return ngx_http_next_header_filter(r);
}
/* Since there is no reason for the br string to be present
* unless brotli is accepted either as "br" or "brotli" we
* just check for "br" */
if (!ngx_strstrn(ae->value.data, "br", 1)) {
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_brotli_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
if (ngx_strstrn(ae->value.data, "brotli", 5)) {
ctx->br = 0;
} else {
ctx->br = 1;
}
#if (NGX_HTTP_GZIP)
r->gzip_vary = 1;
/* Make sure gzip does not execute */
r->gzip_tested = 1;
r->gzip_ok = 0;
#endif
ngx_http_set_ctx(r, ctx, ngx_http_brotli_filter_module);
ctx->request = r;
h = ngx_list_push(&r->headers_out.headers);
if (h == NULL) {
return NGX_ERROR;
}
h->hash = 1;
ngx_str_set(&h->key, "Content-Encoding");
if (ctx->br) {
ngx_str_set(&h->value, "br");
} else {
ngx_str_set(&h->value, "brotli");
}
r->headers_out.content_encoding = h;
r->main_filter_need_in_memory = 1;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_http_weak_etag(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_send_refresh(ngx_http_request_t *r)
{
u_char *p, *location;
size_t len, size;
uintptr_t escape;
ngx_int_t rc;
ngx_buf_t *b;
ngx_chain_t out;
len = r->headers_out.location->value.len;
location = r->headers_out.location->value.data;
escape = 2 * ngx_escape_uri(NULL, location, len, NGX_ESCAPE_REFRESH);
size = sizeof(ngx_http_msie_refresh_head) - 1
+ escape + len
+ sizeof(ngx_http_msie_refresh_tail) - 1;
r->err_status = NGX_HTTP_OK;
r->headers_out.content_type_len = sizeof("text/html") - 1;
ngx_str_set(&r->headers_out.content_type, "text/html");
r->headers_out.content_type_lowcase = NULL;
r->headers_out.location->hash = 0;
r->headers_out.location = NULL;
r->headers_out.content_length_n = size;
if (r->headers_out.content_length) {
r->headers_out.content_length->hash = 0;
r->headers_out.content_length = NULL;
}
ngx_http_clear_accept_ranges(r);
ngx_http_clear_last_modified(r);
ngx_http_clear_etag(r);
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || r->header_only) {
return rc;
}
b = ngx_create_temp_buf(r->pool, size);
if (b == NULL) {
return NGX_ERROR;
}
p = ngx_cpymem(b->pos, ngx_http_msie_refresh_head,
sizeof(ngx_http_msie_refresh_head) - 1);
if (escape == 0) {
p = ngx_cpymem(p, location, len);
} else {
p = (u_char *) ngx_escape_uri(p, location, len, NGX_ESCAPE_REFRESH);
}
b->last = ngx_cpymem(p, ngx_http_msie_refresh_tail,
sizeof(ngx_http_msie_refresh_tail) - 1);
b->last_buf = 1;
b->last_in_chain = 1;
out.buf = b;
out.next = NULL;
return ngx_http_output_filter(r, &out);
}
static ngx_int_t
ngx_http_gzip_header_filter(ngx_http_request_t *r)
{
ngx_table_elt_t *h;
ngx_http_gzip_ctx_t *ctx;
ngx_http_gzip_conf_t *conf;
conf = ngx_http_get_module_loc_conf(r, ngx_http_gzip_filter_module);
if (!conf->enable
|| (r->headers_out.status != NGX_HTTP_OK
&& r->headers_out.status != NGX_HTTP_FORBIDDEN
&& r->headers_out.status != NGX_HTTP_NOT_FOUND)
|| (r->headers_out.content_encoding
&& r->headers_out.content_encoding->value.len)
|| (r->headers_out.content_length_n != -1
&& r->headers_out.content_length_n < conf->min_length)
|| ngx_http_test_content_type(r, &conf->types) == NULL
|| r->header_only)
{
return ngx_http_next_header_filter(r);
}
r->gzip_vary = 1;
#if (NGX_HTTP_DEGRADATION)
{
ngx_http_core_loc_conf_t *clcf;
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
if (clcf->gzip_disable_degradation && ngx_http_degraded(r))
{
return ngx_http_next_header_filter(r);
}
}
#endif
if (!r->gzip_tested)
{
if (ngx_http_gzip_ok(r) != NGX_OK)
{
return ngx_http_next_header_filter(r);
}
}
else if (!r->gzip_ok)
{
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_gzip_ctx_t));
if (ctx == NULL)
{
return NGX_ERROR;
}
ngx_http_set_ctx(r, ctx, ngx_http_gzip_filter_module);
ctx->request = r;
ctx->buffering = (conf->postpone_gzipping != 0);
ngx_http_gzip_filter_memory(r, ctx);
h = ngx_list_push(&r->headers_out.headers);
if (h == NULL)
{
return NGX_ERROR;
}
h->hash = 1;
ngx_str_set(&h->key, "Content-Encoding");
ngx_str_set(&h->value, "gzip");
r->headers_out.content_encoding = h;
r->main_filter_need_in_memory = 1;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_http_weak_etag(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_brotli_header_filter(ngx_http_request_t *r)
{
ngx_table_elt_t *h;
ngx_http_brotli_ctx_t *ctx;
ngx_http_brotli_conf_t *conf;
conf = ngx_http_get_module_loc_conf(r, ngx_http_brotli_filter_module);
if (!conf->enable
|| (r->headers_out.status != NGX_HTTP_OK
&& r->headers_out.status != NGX_HTTP_FORBIDDEN
&& r->headers_out.status != NGX_HTTP_NOT_FOUND)
|| (r->headers_out.content_length_n != -1
&& r->headers_out.content_length_n < conf->min_length)
|| ngx_http_test_content_type(r, &conf->types) == NULL
|| r->header_only)
{
return ngx_http_next_header_filter(r);
}
if (r->headers_out.content_encoding
&& r->headers_out.content_encoding->value.len)
{
return ngx_http_next_header_filter(r);
}
/* Check that brotli is supported. We do not check possible q value
* if brotli is supported it takes precendence over gzip if size >
* brotli_min_length */
if (accept_br(r->headers_in.accept_encoding) != NGX_OK) {
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_brotli_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
#if (NGX_HTTP_GZIP)
r->gzip_vary = 1;
/* Make sure gzip does not execute */
r->gzip_tested = 1;
r->gzip_ok = 0;
#endif
ngx_http_set_ctx(r, ctx, ngx_http_brotli_filter_module);
ctx->request = r;
h = ngx_list_push(&r->headers_out.headers);
if (h == NULL) {
return NGX_ERROR;
}
h->hash = 1;
ngx_str_set(&h->key, "Content-Encoding");
ngx_str_set(&h->value, "br");
r->headers_out.content_encoding = h;
r->main_filter_need_in_memory = 1;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
ngx_http_weak_etag(r);
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_xss_header_filter(ngx_http_request_t *r)
{
ngx_http_xss_ctx_t *ctx;
ngx_http_xss_loc_conf_t *xlcf;
ngx_str_t callback;
u_char *p, *src, *dst;
if (r != r->main) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"xss skipped in subrequests");
return ngx_http_next_header_filter(r);
}
xlcf = ngx_http_get_module_loc_conf(r, ngx_http_xss_filter_module);
if (!xlcf->get_enabled) {
return ngx_http_next_header_filter(r);
}
if (r->method != NGX_HTTP_GET) {
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"xss skipped due to the unmatched request method: %V",
&r->method_name);
return ngx_http_next_header_filter(r);
}
if (xlcf->check_status) {
if (r->headers_out.status != NGX_HTTP_OK
&& r->headers_out.status != NGX_HTTP_CREATED)
{
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"xss skipped due to unmatched response status "
"\"%ui\"", r->headers_out.status);
return ngx_http_next_header_filter(r);
}
}
if (xlcf->callback_arg.len == 0) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"xss: xss_get is enabled but no xss_callback_arg "
"specified");
return ngx_http_next_header_filter(r);
}
if (ngx_http_test_content_type(r, &xlcf->input_types) == NULL) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"xss skipped due to unmatched Content-Type response "
"header");
return ngx_http_next_header_filter(r);
}
if (ngx_http_arg(r, xlcf->callback_arg.data, xlcf->callback_arg.len,
&callback)
!= NGX_OK)
{
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"xss skipped: no GET argument \"%V\" specified in "
"the request", &xlcf->callback_arg);
return ngx_http_next_header_filter(r);
}
p = ngx_palloc(r->pool, callback.len);
if (p == NULL) {
return NGX_ERROR;
}
src = callback.data; dst = p;
ngx_unescape_uri(&dst, &src, callback.len, NGX_UNESCAPE_URI_COMPONENT);
if (src != callback.data + callback.len) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"xss: unescape uri: input data not consumed completely");
return NGX_ERROR;
}
callback.data = p;
callback.len = dst - p;
if (ngx_http_xss_test_callback(callback.data, callback.len) != NGX_OK) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"xss: bad callback argument: \"%V\"", &callback);
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_xss_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
/*
* set by ngx_pcalloc():
*
* ctx->callback = { 0, NULL };
* ctx->before_body_sent = 0;
*/
ctx->callback = callback;
ngx_http_set_ctx(r, ctx, ngx_http_xss_filter_module);
r->headers_out.content_type = xlcf->output_type;
r->headers_out.content_type_len = xlcf->output_type.len;
r->headers_out.content_type_lowcase = NULL;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"xss output Content-Type header \"%V\"",
&xlcf->output_type);
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (xlcf->override_status
&& r->headers_out.status >= NGX_HTTP_SPECIAL_RESPONSE)
{
r->headers_out.status = NGX_HTTP_OK;
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t ngx_http_dynamic_etags_body_filter(ngx_http_request_t *r, ngx_chain_t *in) {
ngx_chain_t *chain_link;
ngx_http_dynamic_etags_module_ctx_t *ctx;
ngx_int_t rc;
ngx_md5_t md5;
unsigned char digest[16];
ngx_uint_t i;
ctx = ngx_http_get_module_ctx(r, ngx_http_dynamic_etags_module);
if (ctx == NULL) {
return ngx_http_next_body_filter(r, in);
}
ngx_http_dynamic_etags_loc_conf_t *loc_conf;
loc_conf = ngx_http_get_module_loc_conf(r, ngx_http_dynamic_etags_module);
if (1 == loc_conf->enable) {
ngx_md5_init(&md5);
for (chain_link = in; chain_link; chain_link = chain_link->next) {
ngx_md5_update(&md5, chain_link->buf->pos,
chain_link->buf->last - chain_link->buf->pos);
}
ngx_md5_final(digest, &md5);
unsigned char* etag = ngx_pcalloc(r->pool, 34);
etag[0] = etag[33] = '"';
for ( i = 0 ; i < 16; i++ ) {
etag[2*i+1] = hex[digest[i] >> 4];
etag[2*i+2] = hex[digest[i] & 0xf];
}
if(!r->headers_out.etag) {
r->headers_out.etag = ngx_list_push(&r->headers_out.headers);
}
r->headers_out.etag->hash = 1;
r->headers_out.etag->key.len = sizeof("ETag") - 1;
r->headers_out.etag->key.data = (u_char *) "ETag";
r->headers_out.etag->value.len = 34;
r->headers_out.etag->value.data = etag;
/* look for If-None-Match in request headers */
ngx_uint_t found=0;
ngx_list_part_t *part = NULL;
ngx_table_elt_t *header = NULL;
ngx_table_elt_t if_none_match;
part = &r->headers_in.headers.part;
header = part->elts;
for ( i = 0 ; ; i++ ) {
if ( i >= part->nelts) {
if ( part->next == NULL ) {
break;
}
part = part->next;
header = part->elts;
i = 0;
}
if ( ngx_strcmp(header[i].key.data, "If-None-Match") == 0 ) {
if_none_match = header[i];
found = 1;
break;
}
}
if ( found ) {
if ( ngx_strncmp(r->headers_out.etag->value.data, if_none_match.value.data, r->headers_out.etag->value.len) == 0 ) {
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
}
}
}
static ngx_int_t
ngx_http_send_special_response(ngx_http_request_t *r,
ngx_http_core_loc_conf_t *clcf, ngx_uint_t err)
{
u_char *tail;
size_t len;
ngx_int_t rc;
ngx_buf_t *b;
ngx_uint_t msie_padding;
ngx_chain_t out[3];
if (clcf->server_tokens) {
len = sizeof(ngx_http_error_full_tail) - 1;
tail = ngx_http_error_full_tail;
} else {
len = sizeof(ngx_http_error_tail) - 1;
tail = ngx_http_error_tail;
}
msie_padding = 0;
if (ngx_http_error_pages[err].len) {
r->headers_out.content_length_n = ngx_http_error_pages[err].len + len;
if (clcf->msie_padding
&& (r->headers_in.msie || r->headers_in.chrome)
&& r->http_version >= NGX_HTTP_VERSION_10
&& err >= NGX_HTTP_OFF_4XX)
{
r->headers_out.content_length_n +=
sizeof(ngx_http_msie_padding) - 1;
msie_padding = 1;
}
r->headers_out.content_type_len = sizeof("text/html") - 1;
ngx_str_set(&r->headers_out.content_type, "text/html");
r->headers_out.content_type_lowcase = NULL;
} else {
r->headers_out.content_length_n = 0;
}
if (r->headers_out.content_length) {
r->headers_out.content_length->hash = 0;
r->headers_out.content_length = NULL;
}
ngx_http_clear_accept_ranges(r);
ngx_http_clear_last_modified(r);
ngx_http_clear_etag(r);
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || r->header_only) {
return rc;
}
if (ngx_http_error_pages[err].len == 0) {
return ngx_http_send_special(r, NGX_HTTP_LAST);
}
b = ngx_calloc_buf(r->pool);
if (b == NULL) {
return NGX_ERROR;
}
b->memory = 1;
b->pos = ngx_http_error_pages[err].data;
b->last = ngx_http_error_pages[err].data + ngx_http_error_pages[err].len;
out[0].buf = b;
out[0].next = &out[1];
b = ngx_calloc_buf(r->pool);
if (b == NULL) {
return NGX_ERROR;
}
b->memory = 1;
b->pos = tail;
b->last = tail + len;
out[1].buf = b;
out[1].next = NULL;
if (msie_padding) {
b = ngx_calloc_buf(r->pool);
if (b == NULL) {
return NGX_ERROR;
}
b->memory = 1;
b->pos = ngx_http_msie_padding;
b->last = ngx_http_msie_padding + sizeof(ngx_http_msie_padding) - 1;
out[1].next = &out[2];
out[2].buf = b;
out[2].next = NULL;
}
if (r == r->main) {
b->last_buf = 1;
}
b->last_in_chain = 1;
return ngx_http_output_filter(r, &out[0]);
}
static ngx_int_t
ngx_http_zip_set_headers(ngx_http_request_t *r, ngx_http_zip_ctx_t *ctx)
{
time_t if_range, last_modified;
if (ngx_http_zip_add_cache_control(r) == NGX_ERROR) {
return NGX_ERROR;
}
r->headers_out.content_type_len = sizeof(NGX_ZIP_MIME_TYPE) - 1;
ngx_str_set(&r->headers_out.content_type, NGX_ZIP_MIME_TYPE);
ngx_http_clear_content_length(r);
if (ctx->missing_crc32) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: Clearing Accept-Ranges header");
ngx_http_clear_accept_ranges(r);
}
r->headers_out.content_length_n = ctx->archive_size;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: Archive will be %O bytes", ctx->archive_size);
if (r->headers_in.range) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: Range found");
if (ctx->missing_crc32) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: Missing checksums, ignoring Range");
return NGX_OK;
}
if (r->headers_in.if_range && r->upstream) {
if_range = ngx_http_parse_time(r->headers_in.if_range->value.data,
r->headers_in.if_range->value.len);
if (if_range == NGX_ERROR) { /* treat as ETag */
if (r->upstream->headers_in.etag) {
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: If-Range = %V, ETag = %V",
&r->headers_in.if_range->value, &r->upstream->headers_in.etag->value);
if (r->upstream->headers_in.etag->value.len != r->headers_in.if_range->value.len
|| ngx_strncmp(r->upstream->headers_in.etag->value.data,
r->headers_in.if_range->value.data,
r->headers_in.if_range->value.len)) {
return NGX_OK;
}
} else {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: No ETag from upstream");
return NGX_OK;
}
} else { /* treat as modification time */
if (r->upstream->headers_in.last_modified) {
last_modified = ngx_http_parse_time(r->upstream->headers_in.last_modified->value.data,
r->upstream->headers_in.last_modified->value.len);
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: If-Range = %d, Last-Modified = %d",
if_range, last_modified);
if (if_range != last_modified && last_modified != -1) {
return NGX_OK;
}
} else {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: No Last-Modified from upstream");
return NGX_OK;
}
}
}
if (ngx_http_zip_parse_range(r, &r->headers_in.range->value, ctx)
== NGX_ERROR) {
r->headers_out.status = NGX_HTTP_RANGE_NOT_SATISFIABLE;
if (ngx_http_zip_add_full_content_range(r) == NGX_ERROR) {
return NGX_ERROR;
}
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: Range not satisfiable");
ctx->ranges.nelts = 0;
return NGX_HTTP_RANGE_NOT_SATISFIABLE;
}
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"mod_zip: Range is satisfiable");
if (ctx->ranges.nelts == 1) {
if (ngx_http_zip_add_partial_content_range(r, ctx) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
if (ngx_http_zip_init_multipart_range(r, ctx) == NGX_ERROR) {
return NGX_ERROR;
}
}
r->headers_out.status = NGX_HTTP_PARTIAL_CONTENT;
r->headers_out.status_line.len = 0;
}
return NGX_OK;
}
