### Example Usage of resty.websocket.client (Lua)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

This comprehensive example demonstrates the basic workflow for using the resty.websocket.client. It covers instantiating a client, connecting to a WebSocket server, receiving a frame, sending a text frame, and sending a close frame. It includes basic error handling for each step.

```lua
local client = require "resty.websocket.client"
    local wb, err = client:new()
    local uri = "ws://127.0.0.1:" .. ngx.var.server_port .. "/s"
    local ok, err, res = wb:connect(uri)
    if not ok then
        ngx.say("failed to connect: " .. err)
        return
    end

    local data, typ, err = wb:recv_frame()
    if not data then
        ngx.say("failed to receive the frame: ", err)
        return
    end

    ngx.say("received: ", data, " (", typ, "): ", err)

    local bytes, err = wb:send_text("copy: " .. data)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end

    local bytes, err = wb:send_close()
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end
```

--------------------------------

### Configure lua_package_path for Installation (Nginx)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

This Nginx configuration snippet shows how to set the lua_package_path directive within the http block. It adds the path to the lua-resty-websocket library's 'lib' directory to ngx_lua's search path, allowing Lua code to find and load the library.

```nginx
# nginx.conf
http {
    lua_package_path "/path/to/lua-resty-websocket/lib/?.lua;;";
    ...
}
```

--------------------------------

### Importing resty.websocket.client Module (Lua)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

This snippet shows how to load the resty.websocket.client module into a Lua script, making its functions and methods available for creating and interacting with WebSocket clients.

```lua
local client = require "resty.websocket.client"
```

--------------------------------

### Loading WebSocket Protocol Module (Lua)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Loads the `resty.websocket.protocol` module, providing functions for building and receiving raw WebSocket frames.

```Lua
local protocol = require "resty.websocket.protocol"
```

--------------------------------

### Handling WebSocket Connections with resty.websocket.server in Lua

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

This snippet demonstrates how to initialize a WebSocket server instance, receive frames, handle different frame types (close, ping, pong, text, binary), send frames, and manage timeouts using the `resty.websocket.server` module. It includes error handling for initialization and frame reception/sending, showing how to respond to control frames like ping and close.

```Lua
    local server = require "resty.websocket.server"

    local wb, err = server:new{
        timeout = 5000,  -- in milliseconds
        max_payload_len = 65535,
    }
    if not wb then
        ngx.log(ngx.ERR, "failed to new websocket: ", err)
        return ngx.exit(444)
    end

    local data, typ, err = wb:recv_frame()

    if not data then
        if not string.find(err, "timeout", 1, true) then
            ngx.log(ngx.ERR, "failed to receive a frame: ", err)
            return ngx.exit(444)
        end
    end

    if typ == "close" then
        -- for typ "close", err contains the status code
        local code = err

        -- send a close frame back:

        local bytes, err = wb:send_close(1000, "enough, enough!")
        if not bytes then
            ngx.log(ngx.ERR, "failed to send the close frame: ", err)
            return
        end
        ngx.log(ngx.INFO, "closing with status code ", code, " and message ", data)
        return
    end

    if typ == "ping" then
        -- send a pong frame back:

        local bytes, err = wb:send_pong(data)
        if not bytes then
            ngx.log(ngx.ERR, "failed to send frame: ", err)
            return
        end
    elseif typ == "pong" then
        -- just discard the incoming pong frame

    else
        ngx.log(ngx.INFO, "received a frame of type ", typ, " and payload ", data)
    end

    wb:set_timeout(1000)  -- change the network timeout to 1 second

    bytes, err = wb:send_text("Hello world")
    if not bytes then
        ngx.log(ngx.ERR, "failed to send a text frame: ", err)
        return ngx.exit(444)
    end

    bytes, err = wb:send_binary("blah blah blah...")
    if not bytes then
        ngx.log(ngx.ERR, "failed to send a binary frame: ", err)
        return ngx.exit(444)
    end

    local bytes, err = wb:send_close(1000, "enough, enough!")
    if not bytes then
        ngx.log(ngx.ERR, "failed to send the close frame: ", err)
        return
    end
```

--------------------------------

### Require lua-resty-websocket Library (Lua)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

This Lua code snippet demonstrates how to load the 'resty.websocket.server' module into a local variable. This is done after configuring the lua_package_path in Nginx, making the library's functions available for use in your Lua scripts.

```lua
local server = require "resty.websocket.server"
```

--------------------------------

### Connect to WebSocket with Options (wss) - lua-resty-websocket - Lua

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Connects the WebSocket client to a remote service using the `wss://` scheme for secure connections, providing an `options` table to customize connection parameters like protocols, origin, pooling, headers, SSL verification, client certificates, etc. Returns `ok` (boolean), `err` (string), and the handshake response (string) or 'connection reused'.

```Lua
ok, err, res = wb:connect("wss://<host>:<port>/<path>", options)
```

--------------------------------

### Connect to WebSocket with Options (ws) - lua-resty-websocket - Lua

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Connects the WebSocket client to a remote service using the `ws://` scheme, providing an `options` table to customize connection parameters like protocols, origin, pooling, headers, etc. Returns `ok` (boolean), `err` (string), and the handshake response (string) or 'connection reused'.

```Lua
ok, err, res = wb:connect("ws://<host>:<port>/<path>", options)
```

--------------------------------

### Sending Binary Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sends a binary frame over the WebSocket connection. Identical to the `send_binary` method for `resty.websocket.server` objects. Returns bytes sent or error.

```Lua
bytes, err = wb:send_binary(data)
```

--------------------------------

### Building Raw WebSocket Frame (lua-resty-websocket Protocol)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Builds a raw WebSocket frame byte string based on the final flag, opcode, payload length, payload data, and masking flag.

```Lua
frame = protocol.build_frame(fin, opcode, payload_len, payload, masking)
```

--------------------------------

### Connect to WebSocket (wss) - lua-resty-websocket - Lua

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Connects the WebSocket client to a remote service using the `wss://` scheme for secure connections. This method performs the handshake and may reuse existing connections from the pool. Returns `ok` (boolean), `err` (string), and the handshake response (string) or 'connection reused'.

```Lua
ok, err, res = wb:connect("wss://<host>:<port>/<path>")
```

--------------------------------

### Connect to WebSocket (ws) - lua-resty-websocket - Lua

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Connects the WebSocket client to a remote service using the `ws://` scheme. This method performs the handshake and may reuse existing connections from the pool. Returns `ok` (boolean), `err` (string), and the handshake response (string) or 'connection reused'.

```Lua
ok, err, res = wb:connect("ws://<host>:<port>/<path>")
```

--------------------------------

### Setting WebSocket Keepalive (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Puts the connection into the `ngx_lua` cosocket pool. Configures max idle timeout (ms) and pool size per worker. Returns `1` on success or `nil` and an error string on failure. Calling this makes the object enter the `closed` state.

```Lua
ok, err = wb:set_keepalive(max_idle_timeout, pool_size)
```

--------------------------------

### Setting WebSocket Timeout (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sets the timeout for the WebSocket connection, identical to the `set_timeout` method for `resty.websocket.server` objects.

```Lua
wb:set_timeout(ms)
```

--------------------------------

### Sending Pong Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sends a pong frame over the WebSocket connection, optionally with a message. Identical to the `send_pong` method for `resty.websocket.server` objects. Returns bytes sent or error.

```Lua
bytes, err = wb:send_pong()
```

```Lua
bytes, err = wb:send_pong(msg)
```

--------------------------------

### Sending Ping Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sends a ping frame over the WebSocket connection, optionally with a message. Identical to the `send_ping` method for `resty.websocket.server` objects. Returns bytes sent or error.

```Lua
bytes, err = wb:send_ping()
```

```Lua
bytes, err = wb:send_ping(msg)
```

--------------------------------

### Sending Text Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sends a text frame over the WebSocket connection. Identical to the `send_text` method for `resty.websocket.server` objects. Returns bytes sent or error.

```Lua
bytes, err = wb:send_text(text)
```

--------------------------------

### Receiving WebSocket Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Receives a WebSocket frame from the connection. Identical to the `recv_frame` method for `resty.websocket.server` objects. Returns the payload data, frame type, and error.

```Lua
data, typ, err = wb:recv_frame()
```

--------------------------------

### Receiving Raw WebSocket Frame (lua-resty-websocket Protocol)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Receives a raw WebSocket frame directly from a socket object. Allows specifying max payload length and forcing masking. Returns the payload data, frame type, and error.

```Lua
data, typ, err = protocol.recv_frame(socket, max_payload_len, force_masking)
```

--------------------------------

### Sending Raw WebSocket Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sends a raw WebSocket frame with specified final flag, opcode, and payload. Identical to the `send_frame` method for `resty.websocket.server` objects. Unmasked frames can be sent by setting `send_unmasked` in the constructor. Returns bytes sent or error.

```Lua
bytes, err = wb:send_frame(fin, opcode, payload)
```

--------------------------------

### Sending Close Frame (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Sends a close frame over the WebSocket connection, optionally with a status code and message. Identical to the `send_close` method for `resty.websocket.server` objects. Returns bytes sent or error.

```Lua
bytes, err = wb:send_close()
```

```Lua
bytes, err = wb:send_close(code, msg)
```

--------------------------------

### Closing WebSocket Connection (lua-resty-websocket Client)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

Closes the current WebSocket connection. Automatically sends a `close` frame if one hasn't been sent already. Returns `ok` (1 on success) and `err` (string on error).

```Lua
ok, err = wb:close()
```

--------------------------------

### Disable ngx_lua Socket Error Logging (Nginx)

Source: https://github.com/openresty/lua-resty-websocket/blob/master/README.markdown

This Nginx configuration directive disables the automatic error logging performed by ngx_lua for socket errors. It is recommended to turn this off if you are implementing custom error handling within your Lua code to avoid duplicate logging.

```nginx
lua_socket_log_errors off;
```

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