websockets: remodeled API to support 63 bit frame sizes

curl_ws_recv() now receives data to fill up the provided buffer, but can
return a partial fragment. The function now also get a pointer to a
curl_ws_frame struct with metadata that also mentions the offset and
total size of the fragment (of which you might be receiving a smaller
piece). This way, large incoming fragments will be "streamed" to the
application. When the curl_ws_frame struct field 'bytesleft' is 0, the
final fragment piece has been delivered.

curl_ws_recv() was also adjusted to work with a buffer size smaller than
the fragment size. (Possibly needless to say as the fragment size can
now be 63 bit large).

curl_ws_send() now supports sending a piece of a fragment, in a
streaming manner, in addition to sending the entire fragment in a single
call if it is small enough. To send a huge fragment, curl_ws_send() can
be used to send it in many small calls by first telling libcurl about
the total expected fragment size, and then send the payload in N number
of separate invokes and libcurl will stream those over the wire.

The struct curl_ws_meta() returns is now called 'curl_ws_frame' and it
has been extended with two new fields: *offset* and *bytesleft*. To help
describe the passed on data chunk when a fragment is delivered in many
smaller pieces.

The documentation has been updated accordingly.

Closes #9636

1 files changed, 1 insertions, 12 deletions

diff --git a/lib/http.h b/lib/http.h
index 4ba4b2bbb..f7cbb3424 100644
--- a/lib/http.h
+++ b/lib/http.h
@@ -202,17 +202,6 @@ struct h3out; /* see ngtcp2 */
 #endif /* _WIN32 */
 #endif /* USE_MSH3 */
 
-struct websockets {
-  bool contfragment; /* set TRUE if the previous fragment sent was not final */
-  unsigned char mask[4]; /* 32 bit mask for this connection */
-  struct Curl_easy *data; /* used for write callback handling */
-  struct dynbuf buf;
-  size_t usedbuf; /* number of leading bytes in 'buf' the most recent complete
-                     websocket frame uses */
-  struct curl_ws_metadata handout; /* the struct storage used for
-                                      curl_ws_meta() returns */
-};
-
 /****************************************************************************
  * HTTP unique setup
  ***************************************************************************/
@@ -240,7 +229,7 @@ struct HTTP {
   } sending;
 
 #ifdef USE_WEBSOCKETS
-  struct websockets ws;
+  struct websocket ws;
 #endif
 
 #ifndef CURL_DISABLE_HTTP