introduce LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER
This adds a callback to protocols[0] which happens when the
Client HTTP handshake packet is being composed. After all the
headers for the websocket handshake to the server have been
added, the callback is called with a pointer to a char *
that allows extra headers to be added. See the comments in
libwebsocket.h or the api documentation for example code.
Signed-off-by: Andy Green <andy@warmcat.com>
diff --git a/lib/libwebsockets.c b/lib/libwebsockets.c
index ba596bf..96d3934 100644
--- a/lib/libwebsockets.c
+++ b/lib/libwebsockets.c
@@ -900,6 +900,12 @@
p += sprintf(p, "Sec-WebSocket-Key2: %s\x0d\x0a",
key_2);
+ /* give userland a chance to append, eg, cookies */
+
+ this->protocols[0].callback(this, wsi,
+ LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
+ NULL, &p, (pkt + sizeof(pkt)) - p - 12);
+
p += sprintf(p, "\x0d\x0a");
read(this->fd_random, p, 8);
@@ -927,9 +933,17 @@
if (wsi->c_protocol)
p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
wsi->c_protocol);
- p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a\x0d\x0a",
+ p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
wsi->ietf_spec_revision);
+ /* give userland a chance to append, eg, cookies */
+
+ this->protocols[0].callback(this, wsi,
+ LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
+ NULL, &p, (pkt + sizeof(pkt)) - p - 12);
+
+ p += sprintf(p, "\x0d\x0a");
+
/* prepare the expected server accept response */
strcpy((char *)buf, wsi->key_b64);
diff --git a/lib/libwebsockets.h b/lib/libwebsockets.h
index a97de07..5d0f047 100644
--- a/lib/libwebsockets.h
+++ b/lib/libwebsockets.h
@@ -47,6 +47,7 @@
LWS_CALLBACK_OPENSSL_LOAD_EXTRA_CLIENT_VERIFY_CERTS,
LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS,
LWS_CALLBACK_OPENSSL_PERFORM_CLIENT_CERT_VERIFICATION,
+ LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
/* external poll() management support */
LWS_CALLBACK_ADD_POLL_FD,
@@ -276,6 +277,30 @@
* the default callback action of returning 0 allows the client
* certificates.
*
+ * LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER: this callback happens
+ * when a client handshake is being compiled. @user is NULL,
+ * @in is a char **, it's pointing to a char * which holds the
+ * next location in the header buffer where you can add
+ * headers, and @len is the remaining space in the header buffer,
+ * which is typically some hundreds of bytes. So, to add a canned
+ * cookie, your handler code might look similar to:
+ *
+ * char **p = (char **)in;
+ *
+ * if (len < 100)
+ * return 1;
+ *
+ * *p += sprintf(*p, "Cookie: a=b\x0d\x0a");
+ *
+ * return 0;
+ *
+ * Notice if you add anything, you just have to take care about
+ * the CRLF on the line you added. Obviously this callback is
+ * optional, if you don't handle it everything is fine.
+ *
+ * Notice the callback is coming to protocols[0] all the time,
+ * because there is no specific protocol handshook yet.
+ *
* The next four reasons are optional and only need taking care of if you
* will be integrating libwebsockets sockets into an external polling
* array.
diff --git a/libwebsockets-api-doc.html b/libwebsockets-api-doc.html
index 966df7d..8cc72c4 100644
--- a/libwebsockets-api-doc.html
+++ b/libwebsockets-api-doc.html
@@ -621,6 +621,32 @@
This also means that if you don't handle this callback then
the default callback action of returning 0 allows the client
certificates.
+</blockquote>
+<h3>LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER</h3>
+<blockquote>
+this callback happens
+when a client handshake is being compiled. <tt><b>user</b></tt> is NULL,
+<tt><b>in</b></tt> is a char **, it's pointing to a char * which holds the
+next location in the header buffer where you can add
+headers, and <tt><b>len</b></tt> is the remaining space in the header buffer,
+which is typically some hundreds of bytes. So, to add a canned
+cookie, your handler code might look similar to:
+<p>
+char **p = (char **)in;
+<p>
+if (len < 100)
+return 1;
+<p>
+*p += sprintf(*p, "Cookie: a=b\x0d\x0a");
+<p>
+return 0;
+<p>
+Notice if you add anything, you just have to take care about
+the CRLF on the line you added. Obviously this callback is
+optional, if you don't handle it everything is fine.
+<p>
+Notice the callback is coming to protocols[0] all the time,
+because there is no specific protocol handshook yet.
<p>
The next four reasons are optional and only need taking care of if you
will be integrating libwebsockets sockets into an external polling