Hi List, At last I braced myself and completed a patch which, I hope, makes httpd a bit closer to RFCs. Trailers was declared decades ago but they are still only a theory. Though don't think this an academic patch. I need this feature in a practical job.
The patch allows a client to send trailing headers to an origin server through an httpd in the proxy mode. It filters headers which are not declared in the Trailer header. The patch is in the scope of the following ticket. https://bz.apache.org/bugzilla/show_bug.cgi?id=58177 There are 2 patches for 2.4.16 and trunk. I tested only 2.4.16. Trunk doesn't have the configure script. I read that buildconf can generate it, but ubuntu currently has some issue with the libtool package. -- Daneel Yaitskov
Index: modules/proxy/mod_proxy_http.c
===================================================================
--- modules/proxy/mod_proxy_http.c (revision 1710345)
+++ modules/proxy/mod_proxy_http.c (working copy)
@@ -196,6 +196,39 @@
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}
+static void add_trailer_line(const char * key, const char *val, apr_pool_t *p,
+ apr_bucket_alloc_t *bucket_alloc,
+ apr_bucket_brigade *bb)
+{
+ apr_bucket *e;
+ char *buf;
+
+ buf = apr_pstrcat(p, key, ": ", val, CRLF, NULL);
+ ap_xlate_proto_to_ascii(buf, strlen(buf));
+
+ e = apr_bucket_immortal_create(buf, strlen(buf), bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, e);
+}
+
+static void forward_declared_trailers(apr_pool_t *p, const request_rec *r,
+ apr_bucket_alloc_t *bucket_alloc,
+ apr_bucket_brigade *bb)
+{
+ const char *declared_trailers = apr_table_get(r->headers_in, "Trailer");
+ if (declared_trailers) {
+ char *mod_trailers = apr_pstrcat(p, declared_trailers, NULL);
+ char *key;
+ char *last = NULL;
+ while ((key = apr_strtok(mod_trailers, ", ", &last))) {
+ const char *value = apr_table_get(r->trailers_in, key);
+ if (value) {
+ add_trailer_line(key, value, p, bucket_alloc, bb);
+ }
+ mod_trailers = last;
+ }
+ }
+}
+
static void add_cl(apr_pool_t *p,
apr_bucket_alloc_t *bucket_alloc,
apr_bucket_brigade *header_brigade,
@@ -357,10 +390,18 @@
bb = input_brigade;
}
- e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
- /* <trailers> */
- ASCII_CRLF,
- 5, bucket_alloc);
+ if (apr_is_empty_table(r->trailers_in)) {
+ e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
+ /* <trailers> */
+ ASCII_CRLF,
+ 5, bucket_alloc);
+ } else {
+ e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF,
+ 3, bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, e);
+ forward_declared_trailers(p, r, bucket_alloc, bb);
+ e = apr_bucket_immortal_create(ASCII_CRLF, 2, bucket_alloc);
+ }
APR_BRIGADE_INSERT_TAIL(bb, e);
if (apr_table_get(r->subprocess_env, "proxy-sendextracrlf")) {
@@ -982,6 +1023,18 @@
e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}
+ /** pass tailer header and enforce chunked */
+ if (*old_te_val) {
+ const char *trailer = apr_table_get(r->headers_in, "Trailer");
+ if (trailer) {
+ char *buf = apr_pstrcat(p, "Trailer: ", trailer, CRLF, NULL);
+ ap_xlate_proto_to_ascii(buf, strlen(buf));
+ APR_BRIGADE_INSERT_TAIL(header_brigade,
+ apr_bucket_pool_create(buf, strlen(buf),
+ p, bucket_alloc));
+ *rb_method = RB_STREAM_CHUNKED;
+ }
+ }
return OK;
}
diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index 319721f..36912ed 100644
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -196,6 +196,39 @@ static void add_te_chunked(apr_pool_t *p,
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}
+static void add_trailer_line(const char * key, const char *val, apr_pool_t *p,
+ apr_bucket_alloc_t *bucket_alloc,
+ apr_bucket_brigade *bb)
+{
+ apr_bucket *e;
+ char *buf;
+
+ buf = apr_pstrcat(p, key, ": ", val, CRLF, NULL);
+ ap_xlate_proto_to_ascii(buf, strlen(buf));
+
+ e = apr_bucket_immortal_create(buf, strlen(buf), bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, e);
+}
+
+static void forward_declared_trailers(apr_pool_t *p, const request_rec *r,
+ apr_bucket_alloc_t *bucket_alloc,
+ apr_bucket_brigade *bb)
+{
+ const char *declared_trailers = apr_table_get(r->headers_in, "Trailer");
+ if (declared_trailers) {
+ char *mod_trailers = apr_pstrcat(p, declared_trailers, NULL);
+ char *key;
+ char *last = NULL;
+ while ((key = apr_strtok(mod_trailers, ", ", &last))) {
+ const char *value = apr_table_get(r->trailers_in, key);
+ if (value) {
+ add_trailer_line(key, value, p, bucket_alloc, bb);
+ }
+ mod_trailers = last;
+ }
+ }
+}
+
static void add_cl(apr_pool_t *p,
apr_bucket_alloc_t *bucket_alloc,
apr_bucket_brigade *header_brigade,
@@ -344,10 +377,18 @@ static int stream_reqbody_chunked(apr_pool_t *p,
bb = input_brigade;
}
- e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
+ if (apr_is_empty_table(r->trailers_in)) {
+ e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
/* <trailers> */
ASCII_CRLF,
5, bucket_alloc);
+ } else {
+ e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF,
+ 3, bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, e);
+ forward_declared_trailers(p, r, bucket_alloc, bb);
+ e = apr_bucket_immortal_create(ASCII_CRLF, 2, bucket_alloc);
+ }
APR_BRIGADE_INSERT_TAIL(bb, e);
if (apr_table_get(r->subprocess_env, "proxy-sendextracrlf")) {
@@ -932,7 +973,18 @@ skip_body:
e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}
-
+ /** pass tailer header and enforce chunked */
+ if (old_te_val) {
+ const char *trailer = apr_table_get(r->headers_in, "Trailer");
+ if (trailer) {
+ char *buf = apr_pstrcat(p, "Trailer: ", trailer, CRLF, NULL);
+ ap_xlate_proto_to_ascii(buf, strlen(buf));
+ APR_BRIGADE_INSERT_TAIL(header_brigade,
+ apr_bucket_pool_create(buf, strlen(buf),
+ p, bucket_alloc));
+ rb_method = RB_STREAM_CHUNKED;
+ }
+ }
/* send the request body, if any. */
switch(rb_method) {
case RB_STREAM_CHUNKED:
chunked-request.sh
Description: Bourne shell script
