Previously, we forced the request to "GET" on all fetches for cache

and this prevented users from implementing "purge on POST" semantics
by looking up the POST requests and ditching the object found.

Now we only overwrite the request with "GET" if it is a HEAD, (the
internal "wantbody" flag tells hos how the response should be composed.)

The testcase shold probably be elevated to VCL example, with suitable
footnotes about URL sanitizing etc.

Fixes #444



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4042 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_center.c

@@ -979,7 +979,12 @@ cnt_recv(struct sess *sp)
 		return (0);
 	}
 
-	sp->wantbody = (strcmp(sp->http->hd[HTTP_HDR_REQ].b, "HEAD") != 0);
+	if (!strcmp(sp->http->hd[HTTP_HDR_REQ].b, "HEAD")) {
+		sp->wantbody = 0;
+		http_ForceGet(sp->http);
+	} else
+		sp->wantbody = 1;
+
 	sp->sendbody = 0;
 	switch(sp->handling) {
 	case VCL_RET_LOOKUP:

bin/varnishd/cache_http.c

@@ -555,23 +555,6 @@ http_copyh(struct http *to, const struct http *fm, unsigned n)
 	to->hdf[n] = fm->hdf[n];
 }
 
-static void
-http_copyreq(struct http *to, const struct http *fm, int how)
-{
-
-	CHECK_OBJ_NOTNULL(fm, HTTP_MAGIC);
-	CHECK_OBJ_NOTNULL(to, HTTP_MAGIC);
-
-	if ((how == HTTPH_R_PIPE) || (how == HTTPH_R_PASS)) {
-		http_copyh(to, fm, HTTP_HDR_REQ);
-		http_copyh(to, fm, HTTP_HDR_PROTO);
-	} else {
-		http_SetH(to, HTTP_HDR_REQ, "GET");
-		http_SetH(to, HTTP_HDR_PROTO, "HTTP/1.1");
-	}
-	http_copyh(to, fm, HTTP_HDR_URL);
-}
-
 void
 http_ForceGet(struct http *to)
 {
@@ -660,7 +643,12 @@ http_FilterHeader(const struct sess *sp, unsigned how)
 	CHECK_OBJ_NOTNULL(hp, HTTP_MAGIC);
 	hp->logtag = HTTP_Tx;
 
-	http_copyreq(hp, sp->http, how);
+	http_copyh(hp, sp->http, HTTP_HDR_REQ);
+	http_copyh(hp, sp->http, HTTP_HDR_URL);
+	if (how == HTTPH_R_FETCH)
+		http_SetH(hp, HTTP_HDR_PROTO, "HTTP/1.1");
+	else
+		http_copyh(hp, sp->http, HTTP_HDR_PROTO);
 	http_FilterFields(sp->wrk, sp->fd, hp, sp->http, how);
 	http_PrintfHeader(sp->wrk, sp->fd, hp, "X-Varnish: %u", sp->xid);
 	http_PrintfHeader(sp->wrk, sp->fd, hp,

bin/varnishtest/tests/r00444.vtc

+# $Id$
+
+test "purging on POST"
+
+server s1 {
+	rxreq
+	expect req.request == "GET"
+	txresp -body "1"
+
+	rxreq
+	expect req.request == "POST"
+	txresp -body "22"
+
+	rxreq
+	expect req.request == "POST"
+	txresp -body "333"
+
+	rxreq
+	expect req.request == "GET"
+	txresp -body "4444"
+} -start
+
+varnish v1 -vcl+backend {
+	sub vcl_recv {
+		if (req.request == "POST") {
+			/* Lookup so we find any cached object */
+			lookup;
+		}
+	}
+	sub vcl_hit {
+		if (req.request == "POST") {
+			/* Get rid of this object */
+			set obj.cacheable = false;
+			set obj.ttl = 0s;
+			pass;
+		}
+	}
+	sub vcl_miss {
+		if (req.request == "POST") {
+			/* Make sure we don't cache the POST result */
+			pass;
+		}
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.bodylen == 1
+
+	txreq -req POST
+	rxresp
+	expect resp.bodylen == 2
+
+	txreq -req POST
+	rxresp
+	expect resp.bodylen == 3
+
+	txreq
+	rxresp
+	expect resp.bodylen == 4
+} -run