# nghttp2_submit_response2

## Synopsis

#include <nghttp2/nghttp2.h>

int nghttp2_submit_response2(nghttp2_session *session, int32_t stream_id, const nghttp2_nv *nva, size_t nvlen, const nghttp2_data_provider2 *data_prd)

  Submits response HEADERS frame and optionally one or more DATA frames against the stream 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.NGHTTP2_NV_FLAG_NO_COPY_NAME` and `nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set, header field name and value are not copied respectively. With `nghttp2_nv_flag.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.

  HTTP/2 specification has requirement about header fields in the response HEADERS. See the specification for more details.

  If data_prd is not `NULL`, it provides data which will be sent in subsequent DATA frames. This function does not take ownership of the data_prd. The function copies the members of the data_prd. If data_prd is `NULL`, HEADERS will have END_STREAM flag set.

  This method can be used as normal HTTP response and push response. When pushing a resource using this function, the session must be configured using `nghttp2_session_server_new()` or its variants and the target stream denoted by the stream_id must be reserved using `nghttp2_submit_push_promise()`.

  To send non-final response headers (e.g., HTTP status 101), don’t use this function because this function half-closes the outbound stream. Instead, use `nghttp2_submit_headers()` for this purpose.

  This function returns 0 if it succeeds, or one of the following negative error codes:

  `nghttp2_error.NGHTTP2_ERR_NOMEM`

    Out of memory.

  `nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`

    The stream_id is 0.

  `nghttp2_error.NGHTTP2_ERR_DATA_EXIST`

    DATA or HEADERS has been already submitted and not fully processed yet. Normally, this does not happen, but when application wrongly calls `nghttp2_submit_response2()` twice, this may happen.

  `nghttp2_error.NGHTTP2_ERR_PROTO`

    The session is client session.

  Warning

  Calling this function twice for the same stream ID may lead to program crash. It is generally considered to a programming error to commit response twice.