1  The nghttp Instruction
 2  =============================
 3  
 4  This is an implementation of the Hypertext Transfer Protocol version 2 in C.
 5  
 6  The framing layer of HTTP/2 is implemented as a reusable C library.
 7  
 8  An HPACK encoder and decoder are available as a public API.
 9  
10  -   The nghttp support many different processor, but for the most part you only need the following functions:
11  
12      **nghttp2_session_callbacks_new**: Initializes \*callbacks_ptr with NULL values
13  
14      **nghttp2_session_client_new**: Initializes \*session_ptr for client use
15  
16      **nghttp2_session_callbacks_del**: Frees any resources allocated for callbacks
17  
18      **nghttp2_submit_settings**: Stores local settings and submits SETTINGS frame
19  
20      **nghttp2_submit_request**: Submits HEADERS frame and optionally one or more DATA frames
21  
22      **nghttp2_session_want_read**: Returns nonzero value if session wants to receive data from the remote peer
23  
24      **nghttp2_session_want_write**: Returns nonzero value if session wants to send data to the remote peer
25  
26      **nghttp2_session_recv**: Receives frames from the remote peer
27  
28      **nghttp2_session_send**: Sends pending frames to the remote peer
29  
30      **nghttp2_session_del**: Frees any resources allocated for session
31  
32  If you are following TLS related RFC, you know that NPN is not the standardized way to negotiate HTTP/2. NPN itself is not even published as RFC. 
33  
34  The standard way to negotiate HTTP/2 is ALPN, Application-Layer Protocol Negotiation Extension, defined in RFC 7301. 
35  
36  -   The following endpoints are available to try out the nghttp2 implementation:
37  
38      https://nghttp2.org/ (TLS + ALPN/NPN)
39  
40      This endpoint supports h2, h2-16, h2-14, spdy/3.1 and http/1.1 via ALPN/NPN and requires TLSv1.2 for HTTP/2 connection.
41  
42  More information about nghttp library can be found at https://nghttp2.org
43  
44  An introductory article on protocol is available on RFC 7540 HTTP/2 and RFC 7541 HPACK - Header Compression for HTTP/2