From 025fa762f644c9c1438c6669c4fe3e1800a112b5 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Tue, 10 Apr 2001 06:49:32 +0000
Subject: [PATCH] Added new CURLOPT_HEADERFUNCTION callback for writing headers
 only

---
 include/curl/curl.h | 4 ++++
 lib/sendf.c         | 9 ++++++++-
 lib/urldata.h       | 3 +++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/curl/curl.h b/include/curl/curl.h
index 0a612c006..5dbd7b447 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -430,6 +430,10 @@ typedef enum {
      phase. [Only works on unix-style/SIGALRM operating systems] */
   CINIT(CONNECTTIMEOUT, LONG, 78),
 
+  /* Function that will be called to store headers (instead of fwrite). The
+   * parameters will use fwrite() syntax, make sure to follow them. */
+  CINIT(HEADERFUNCTION, FUNCTIONPOINT, 79),
+
   CURLOPT_LASTENTRY /* the last unusued */
 } CURLoption;
 
diff --git a/lib/sendf.c b/lib/sendf.c
index 868aa887a..25ccb926d 100644
--- a/lib/sendf.c
+++ b/lib/sendf.c
@@ -236,7 +236,14 @@ CURLcode Curl_client_write(struct UrlData *data,
     }
   }
   if((type & CLIENTWRITE_HEADER) && data->writeheader) {
-    wrote = data->fwrite(ptr, 1, len, data->writeheader);
+    /*
+     * Write headers to the same callback or to the especially setup
+     * header callback function (added after version 7.7.1).
+     */
+    curl_write_callback writeit=
+      data->fwrite_header?data->fwrite_header:data->fwrite;
+
+    wrote = writeit(ptr, 1, len, data->writeheader);
     if(wrote != len) {
       failf (data, "Failed writing header");
       return CURLE_WRITE_ERROR;
diff --git a/lib/urldata.h b/lib/urldata.h
index aef8435c4..5c019946f 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -485,6 +485,9 @@ struct UrlData {
   /* function that stores the output:*/
   curl_write_callback fwrite;
 
+  /* optional function that stores the header output:*/
+  curl_write_callback fwrite_header;
+
   /* function that reads the input:*/
   curl_read_callback fread;