(See the README.md file in the upper level 'examples' directory for more information about examples.)
This example demonstrates the HTTPD server using the WebSocket feature.
## How to Use Example
The example starts a WS server on a local network, so a WS client is needed to interact with the server (an example test
ws_server_example_test.py could be used as a simple WS client).
The server registers WebSocket handler which echoes back the received WebSocket frame. It also demonstrates
use of asynchronous send, which is triggered on reception of a certain message.
### Hardware Required
This example can be executed on any common development board, the only required interface is WiFi or Ethernet connection to a local network.
### Configure the project
* Open the project configuration menu (`idf.py menuconfig`)
* Configure Wi-Fi or Ethernet under "Example Connection Configuration" menu. See "Establishing Wi-Fi or Ethernet Connection" section in [examples/protocols/README.md](../../README.md) for more details.
### Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
```
idf.py -p PORT flash monitor
```
(To exit the serial monitor, type ``Ctrl-]``.)
See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
## Example Output
```
I (4932) example_connect: Got IPv6 event!
I (4942) example_connect: Connected to Espressif
I (4942) example_connect: IPv4 address: 192.168.4.2
I (4952) example_connect: IPv6 address: fe80:xxxx
I (4962) ws_echo_server: Starting server on port: '80'
I (4962) ws_echo_server: Registering URI handlers
D (4962) httpd: httpd_thread: web server started
D (4972) httpd: httpd_server: doing select maxfd+1 = 56
D (4982) httpd_uri: httpd_register_uri_handler: [0] installed /ws
D (17552) httpd: httpd_server: processing listen socket 54
D (17552) httpd: httpd_accept_conn: newfd = 57
D (17552) httpd_sess: httpd_sess_new: fd = 57
D (17562) httpd: httpd_accept_conn: complete
D (17562) httpd: httpd_server: doing select maxfd+1 = 58
D (17572) httpd: httpd_server: processing socket 57
D (17572) httpd_sess: httpd_sess_process: httpd_req_new
D (17582) httpd_parse: httpd_req_new: New request, has WS? No, sd->ws_handler valid? No, sd->ws_close? No
D (17592) httpd_txrx: httpd_recv_with_opt: requested length = 128
D (17592) httpd_txrx: httpd_recv_with_opt: received length = 128
D (17602) httpd_parse: read_block: received HTTP request block size = 128
D (17612) httpd_parse: cb_url: message begin
D (17612) httpd_parse: cb_url: processing url = /ws
D (17622) httpd_parse: verify_url: received URI = /ws
D (17622) httpd_parse: cb_header_field: headers begin
D (17632) httpd_txrx: httpd_unrecv: length = 110
D (17632) httpd_parse: pause_parsing: paused
D (17632) httpd_parse: cb_header_field: processing field = Host
D (17642) httpd_txrx: httpd_recv_with_opt: requested length = 128
D (17652) httpd_txrx: httpd_recv_with_opt: pending length = 110
D (17652) httpd_parse: read_block: received HTTP request block size = 110
D (17662) httpd_parse: continue_parsing: skip pre-parsed data of size = 5
D (17672) httpd_parse: continue_parsing: un-paused
D (17682) httpd_parse: cb_header_field: processing field = Upgrade
D (17682) httpd_parse: cb_header_value: processing value = websocket
D (17692) httpd_parse: cb_header_field: processing field = Connection
D (17702) httpd_parse: cb_header_value: processing value = Upgrade
D (17702) httpd_parse: cb_header_field: processing field = Sec-WebSocket-Key
D (17712) httpd_parse: cb_header_value: processing value = gfhjgfhjfj
D (17722) httpd_parse: cb_header_field: processing field = Sec-WebSocket-Proto
D (17722) httpd_parse: parse_block: parsed block size = 110
D (17732) httpd_txrx: httpd_recv_with_opt: requested length = 128
D (17742) httpd_txrx: httpd_recv_with_opt: received length = 40
D (17742) httpd_parse: read_block: received HTTP request block size = 40
D (17752) httpd_parse: cb_header_field: processing field = col
D (17752) httpd_parse: cb_header_value: processing value = echo
D (17762) httpd_parse: cb_header_field: processing field = Sec-WebSocket-Version
D (17772) httpd_parse: cb_header_value: processing value = 13
D (17772) httpd_parse: cb_headers_complete: bytes read = 169
D (17782) httpd_parse: cb_headers_complete: content length = 0
D (17792) httpd_parse: cb_headers_complete: Got an upgrade request
D (17792) httpd_parse: pause_parsing: paused
D (17802) httpd_parse: cb_no_body: message complete
D (17802) httpd_parse: httpd_parse_req: parsing complete
D (17812) httpd_uri: httpd_uri: request for /ws with type 1
D (17812) httpd_uri: httpd_find_uri_handler: [0] = /ws
D (17822) httpd_uri: httpd_uri: Responding WS handshake to sock 57
D (17822) httpd_ws: httpd_ws_respond_server_handshake: Server key before encoding: gfhjgfhjfj258EAFA5-E914-47DA-95CA-C5AB0DC85B11
D (17842) httpd_ws: httpd_ws_respond_server_handshake: Generated server key: Jg/fQVRsgwdDzYeG8yNBHRajUxw=
D (17852) httpd_sess: httpd_sess_process: httpd_req_delete
D (17852) httpd_sess: httpd_sess_process: success
D (17862) httpd: httpd_server: doing select maxfd+1 = 58
D (17892) httpd: httpd_server: processing socket 57
D (17892) httpd_sess: httpd_sess_process: httpd_req_new
D (17892) httpd_parse: httpd_req_new: New request, has WS? Yes, sd->ws_handler valid? Yes, sd->ws_close? No
D (17902) httpd_parse: httpd_req_new: New WS request from existing socket
D (17902) httpd_txrx: httpd_recv_with_opt: requested length = 1
D (17912) httpd_txrx: httpd_recv_with_opt: received length = 1
D (17912) httpd_ws: httpd_ws_get_frame_type: First byte received: 0x81
D (17922) httpd_txrx: httpd_recv_with_opt: requested length = 1
D (17932) httpd_txrx: httpd_recv_with_opt: received length = 1
D (17932) httpd_txrx: httpd_recv_with_opt: requested length = 4
D (17942) httpd_txrx: httpd_recv_with_opt: received length = 4
D (17942) httpd_txrx: httpd_recv_with_opt: requested length = 13
D (17952) httpd_txrx: httpd_recv_with_opt: received length = 13
I (17962) ws_echo_server: Got packet with message: Trigger async
I (17962) ws_echo_server: Packet type: 1
D (17972) httpd_sess: httpd_sess_process: httpd_req_delete
D (17972) httpd_sess: httpd_sess_process: success
D (17982) httpd: httpd_server: doing select maxfd+1 = 58
D (17982) httpd: httpd_server: processing ctrl message
D (17992) httpd: httpd_process_ctrl_msg: work
D (18002) httpd: httpd_server: doing select maxfd+1 = 58
