From 0a80a8dbb27532310dab1bdcf1bd92289140aa33 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Mon, 26 Nov 2012 16:33:37 +0100
Subject: [PATCH] MINOR: http: factor out the content-type checks

Let's only look up the content-type header once. This involves
inverting the condition which is not dramatic.

Also, we now always check the value length before comparing it, and we
always reset the ctx.idx before looking a header up. Otherwise that
could make header lookups depend on their on-wire order. It would be
a minor issue however since at worst it would cause some responses not
to be compressed.
---
 src/proto_http.c | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/proto_http.c b/src/proto_http.c
index f36c7b590..6f1b9d796 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -2064,44 +2064,43 @@ int select_compression_response_header(struct session *s, struct buffer *res)
 	if (txn->status != 200)
 		goto fail;
 
-	ctx.idx = 0;
-
 	/* Content-Length is null */
 	if (!(msg->flags & HTTP_MSGF_TE_CHNK) && msg->body_len == 0)
 		goto fail;
 
 	/* content is already compressed */
+	ctx.idx = 0;
 	if (http_find_header2("Content-Encoding", 16, res->p, &txn->hdr_idx, &ctx))
 		goto fail;
 
 	comp_type = NULL;
 
-	/* if there was a compression content-type option in the backend or the frontend
-	 * The backend have priority.
+	/* we don't want to compress multipart content-types, nor content-types that are
+	 * not listed in the "compression type" directive if any. If no content-type was
+	 * found but configuration requires one, we don't compress either. Backend has
+	 * the priority.
 	 */
-	if ((s->be->comp && (comp_type = s->be->comp->types)) || (s->fe->comp && (comp_type = s->fe->comp->types))) {
-		if (http_find_header2("Content-Type", 12, res->p, &txn->hdr_idx, &ctx)) {
+	ctx.idx = 0;
+	if (http_find_header2("Content-Type", 12, res->p, &txn->hdr_idx, &ctx)) {
+		if (ctx.vlen >= 9 && strncasecmp("multipart", ctx.line+ctx.val, 9) == 0)
+			goto fail;
+
+		if ((s->be->comp && (comp_type = s->be->comp->types)) ||
+		    (s->fe->comp && (comp_type = s->fe->comp->types))) {
 			for (; comp_type; comp_type = comp_type->next) {
-				if (strncasecmp(ctx.line+ctx.val, comp_type->name, comp_type->name_len) == 0)
+				if (ctx.vlen >= comp_type->name_len &&
+				    strncasecmp(ctx.line+ctx.val, comp_type->name, comp_type->name_len) == 0)
 					/* this Content-Type should be compressed */
 					break;
 			}
-		} else {
-			/* there is no Content-Type header */
-			goto fail;
+			/* this Content-Type should not be compressed */
+			if (comp_type == NULL)
+				goto fail;
 		}
-		/* this Content-Type should not be compressed */
-		if (comp_type == NULL)
-			goto fail;
 	}
-
-	ctx.idx = 0;
-
-	/* Don't compress multipart */
-	if (http_find_header2("Content-Type", 12, res->p, &txn->hdr_idx, &ctx)) {
-		if (strncasecmp("multipart", ctx.line+ctx.val, 9) == 0)
-			goto fail;
-
+	else { /* no content-type header */
+		if ((s->be->comp && s->be->comp->types) || (s->fe->comp && s->fe->comp->types))
+			goto fail; /* a content-type was required */
 	}
 
 	/* limit compression rate */
@@ -2120,6 +2119,7 @@ int select_compression_response_header(struct session *s, struct buffer *res)
 	s->flags |= SN_COMP_READY;
 
 	/* remove Content-Length header */
+	ctx.idx = 0;
 	if ((msg->flags & HTTP_MSGF_CNT_LEN) && http_find_header2("Content-Length", 14, res->p, &txn->hdr_idx, &ctx))
 		http_remove_header2(msg, &txn->hdr_idx, &ctx);