nghttp2_submit_push_promise

Synopsis

#include <nghttp2/nghttp2.h>

int32_t nghttp2_submit_push_promise(nghttp2_session *session, uint8_t flags, int32_t stream_id, const nghttp2_nv *nva, size_t nvlen, void *promised_stream_user_data)

Submits PUSH_PROMISE frame.

The flags is currently ignored. The library handles the CONTINUATION frame internally and it correctly sets END_HEADERS to the last sequence of the PUSH_PROMISE or CONTINUATION frame.

The stream_id must be client initiated stream ID.

The nva is an array of name/value pair nghttp2_nv with nvlen elements. The application is responsible to include required pseudo-header fields (header field whose name starts with ":") in nva and must place pseudo-headers before regular header fields.

This function creates copies of all name/value pairs in nva. It also lower-cases all names in nva. The order of elements in nva is preserved. For header fields with NGHTTP2_NV_FLAG_NO_COPY_NAME and NGHTTP2_NV_FLAG_NO_COPY_VALUE are set, header field name and value are not copied respectively. With NGHTTP2_NV_FLAG_NO_COPY_NAME, application is responsible to pass header field name in lowercase. The application should maintain the references to them until nghttp2_on_frame_send_callback or nghttp2_on_frame_not_send_callback is called.

The promised_stream_user_data is a pointer to an arbitrary data which is associated to the promised stream this frame will open and make it in reserved state. It is available using nghttp2_session_get_stream_user_data(). The application can access it in nghttp2_before_frame_send_callback and nghttp2_on_frame_send_callback of this frame.

The client side is not allowed to use this function.

To submit response headers and data, use nghttp2_submit_response().

This function returns assigned promised stream ID if it succeeds, or one of the following negative error codes:

NGHTTP2_ERR_NOMEM
Out of memory.
NGHTTP2_ERR_PROTO
This function was invoked when session is initialized as client.
NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE
No stream ID is available because maximum stream ID was reached.
NGHTTP2_ERR_INVALID_ARGUMENT
The stream_id is 0; The stream_id does not designate stream that peer initiated.
NGHTTP2_ERR_STREAM_CLOSED
The stream was already closed; or the stream_id is invalid.

Warning

This function returns assigned promised stream ID if it succeeds. As of 1.16.0, stream object for pushed resource is created when this function succeeds. In that case, the application can submit push response for the promised frame.

In 1.15.0 or prior versions, pushed stream is not opened yet when this function succeeds. The application must not submit frame to that stream ID before nghttp2_before_frame_send_callback is called for this frame.