From: Willy Tarreau <w@1wt.eu>
Date: Thu, 21 Dec 2017 14:13:09 +0000 (+0100)
Subject: MINOR: http: start to compute the transaction's cacheability from the request
X-Git-Tag: v1.9-dev1~555
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=83ece462b433b7b354036e33e810d1e8264d9c1f;p=thirdparty%2Fhaproxy.git

MINOR: http: start to compute the transaction's cacheability from the request

There has always been something odd with the way the cache-control flags
are checked. Since it was made for checking for the risk of leaking cookies
only, all the processing was done in the response. Because of this it is not
possible to reuse the transaction flags correctly for use with the cache.

This patch starts to change this by moving the method check in the request
so that we know very early whether the transaction is expected to be cacheable
and that this status evolves along with checked headers. For now it's not
enough to use from the cache yet but at least it makes the flag more
consistent along the transaction processing.
---

diff --git a/src/proto_http.c b/src/proto_http.c
index 3e17021975..afeb96ee52 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -2163,6 +2163,26 @@ int http_wait_for_request(struct stream *s, struct channel *req, int an_bit)
 	    (msg->body_len || (msg->flags & HTTP_MSGF_TE_CHNK)))
 		req->analysers |= AN_REQ_HTTP_BODY;
 
+	/*
+	 * RFC7234#4:
+	 *   A cache MUST write through requests with methods
+	 *   that are unsafe (Section 4.2.1 of [RFC7231]) to
+	 *   the origin server; i.e., a cache is not allowed
+	 *   to generate a reply to such a request before
+	 *   having forwarded the request and having received
+	 *   a corresponding response.
+	 *
+	 * RFC7231#4.2.1:
+	 *   Of the request methods defined by this
+	 *   specification, the GET, HEAD, OPTIONS, and TRACE
+	 *   methods are defined to be safe.
+	 */
+	if (likely(txn->meth == HTTP_METH_GET ||
+		   txn->meth == HTTP_METH_HEAD ||
+		   txn->meth == HTTP_METH_OPTIONS ||
+		   txn->meth == HTTP_METH_TRACE))
+		txn->flags |= TX_CACHEABLE | TX_CACHE_COOK;
+
 	/* end of job, return OK */
 	req->analysers &= ~an_bit;
 	req->analyse_exp = TICK_ETERNITY;
@@ -5397,6 +5417,8 @@ int http_wait_for_response(struct stream *s, struct channel *rep, int an_bit)
 	case 410:
 	case 414:
 	case 501:
+		break;
+	default:
 		/* RFC7231#6.1:
 		 *   Responses with status codes that are defined as
 		 *   cacheable by default (e.g., 200, 203, 204, 206,
@@ -5406,28 +5428,8 @@ int http_wait_for_response(struct stream *s, struct channel *rep, int an_bit)
 		 *   by the method definition or explicit cache
 		 *   controls [RFC7234]; all other status codes are
 		 *   not cacheable by default.
-		 *
-		 * RFC7234#4:
-		 *   A cache MUST write through requests with methods
-		 *   that are unsafe (Section 4.2.1 of [RFC7231]) to
-		 *   the origin server; i.e., a cache is not allowed
-		 *   to generate a reply to such a request before
-		 *   having forwarded the request and having received
-		 *   a corresponding response.
-		 *
-		 * RFC7231#4.2.1:
-		 *   Of the request methods defined by this
-		 *   specification, the GET, HEAD, OPTIONS, and TRACE
-		 *   methods are defined to be safe.
 		 */
-		if (likely(txn->meth == HTTP_METH_GET ||
-		           txn->meth == HTTP_METH_HEAD ||
-		           txn->meth == HTTP_METH_OPTIONS ||
-		           txn->meth == HTTP_METH_TRACE) &&
-		    ((s->be->options & PR_O_CHK_CACHE) || (s->be->ck_opts & PR_CK_NOC)))
-			txn->flags |= TX_CACHEABLE | TX_CACHE_COOK;
-		break;
-	default:
+		txn->flags &= ~(TX_CACHEABLE | TX_CACHE_COOK);
 		break;
 	}