hs.socket

Talk to custom protocols using asynchronous TCP sockets.

For UDP sockets see hs.socket.udp.

hs.socket is implemented with CocoaAsyncSocket. CocoaAsyncSocket's tagging features provide a handy way to implement custom protocols.

For example, you can easily implement a basic HTTP client as follows (though using hs.http is recommended for the real world):

local TAG_HTTP_HEADER, TAG_HTTP_CONTENT = 1, 2
local body = ""
local function httpCallback(data, tag)
  if tag == TAG_HTTP_HEADER then
    print(tag, "TAG_HTTP_HEADER"); print(data)
    local contentLength = data:match("\r\nContent%-Length: (%d+)\r\n")
    client:read(tonumber(contentLength), TAG_HTTP_CONTENT)
  elseif tag == TAG_HTTP_CONTENT then
    print(tag, "TAG_HTTP_CONTENT"); print(data)
    body = data
  end
end

client = hs.socket.new(httpCallback):connect("google.com", 80)
client:write("GET /index.html HTTP/1.0\r\nHost: google.com\r\n\r\n")
client:read("\r\n\r\n", TAG_HTTP_HEADER)

Resulting in the following console output (adjust log verbosity with hs.socket.setLogLevel()) :

            LuaSkin: (secondary thread): TCP socket connected
            LuaSkin: (secondary thread): Data written to TCP socket
            LuaSkin: (secondary thread): Data read from TCP socket
1 TAG_HTTP_HEADER
HTTP/1.0 301 Moved Permanently
Location: http://www.google.com/index.html
Content-Type: text/html; charset=UTF-8
Date: Thu, 03 Mar 2016 08:38:02 GMT
Expires: Sat, 02 Apr 2016 08:38:02 GMT
Cache-Control: public, max-age=2592000
Server: gws
Content-Length: 229
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN

            LuaSkin: (secondary thread): Data read from TCP socket
2 TAG_HTTP_CONTENT
&lt;HTML&gt;&lt;HEAD&gt;&lt;meta http-equiv=&quot;content-type&quot; content=&quot;text/html;charset=utf-8&quot;&gt;
&lt;TITLE&gt;301 Moved&lt;/TITLE&gt;&lt;/HEAD&gt;&lt;BODY&gt;
&lt;H1&gt;301 Moved&lt;/H1&gt;
The document has moved
&lt;A HREF=&quot;http://www.google.com/index.html&quot;&gt;here&lt;/A&gt;.
&lt;/BODY&gt;&lt;/HTML&gt;
            LuaSkin: (secondary thread): TCP socket disconnected Socket closed by remote peer

Submodules

hs.socket.udp

API Overview

Variables - Configurable values

timeout

Functions - API calls offered directly by the extension

parseAddress

Constructors - API calls which return an object, typically one that offers API methods

new
server

Methods - API calls which can only be made on an object returned by a constructor

connect
connected
connections
disconnect
info
listen
read
receive
send
setCallback
setTimeout
startTLS
write

API Documentation

Variables

timeout


Signature	`hs.socket.timeout`
Type	Variable
Description	Timeout for the socket operations, in seconds.
Notes	New `hs.socket` objects will be created with this timeout value, but can individually change it with the `hs.socket:setTimeout` method. If the timeout value is negative, the operations will not use a timeout. The default value is `-1`.
Source	extensions/socket/socket.lua line 162

Functions

parseAddress


Signature	`hs.socket.parseAddress(sockaddr) -> table or nil`
Type	Function
Description	Parses a binary socket address structure into a readable table.
Parameters	`sockaddr` - A binary socket address structure, usually obtained from the `info` method or in `hs.socket.udp`'s read callback.
Returns	A table describing the address with the following keys or `nil`: host - A string containing the host IP. port - A number containing the port. addressFamily - A number containing the address family.
Notes	Some address family definitions from `<sys/socket.h>`: address family	number	description :---	:---	: AF_UNSPEC	0	unspecified AF_UNIX	1	local to host (pipes) AF_LOCAL	AF_UNIX	backward compatibility AF_INET	2	internetwork: UDP, TCP, etc. AF_NS	6	XEROX NS protocols AF_CCITT	10	CCITT protocols, X.25 etc AF_APPLETALK	16	Apple Talk AF_ROUTE	17	Internal Routing Protocol AF_LINK	18	Link layer interface AF_INET6	30	IPv6
Examples	None
Source	extensions/socket/libsocket.m line 187

Constructors

new


Signature	`hs.socket.new([fn]) -> hs.socket object`
Type	Constructor
Description	Creates an unconnected asynchronous TCP socket object.
Parameters	`fn` - An optional callback function for reading data from the socket, settable here for convenience.
Returns	An `hs.socket` object.
Notes	None
Examples	None
Source	extensions/socket/libsocket.m line 154

server


Signature	`hs.socket.server(port \| path [, fn]) -> hs.socket object`
Type	Constructor
Description	Creates a TCP socket, and binds it to either a port or path (Unix domain socket) for listening.
Parameters	`port` - A port number [0-65535]. Ports [1-1023] are privileged. Port 0 allows the OS to select any available port. `path` - A string containing the path to the Unix domain socket. `fn` - An optional callback function for reading data from the socket, settable here for convenience.
Returns	An `hs.socket` object.
Notes	None
Examples	None
Source	extensions/socket/socket.lua line 190

Methods

connect


Signature	`hs.socket:connect(host, port \| path [, fn]) -> self or nil`
Type	Method
Description	Connects an unconnected socket.
Parameters	`host` - A string containing the hostname or IP address. `port` - A port number [1-65535]. `path` - A string containing the path to the Unix domain socket. `fn` - An optional single-use callback function to execute after establishing the connection. The callback receives no parameters.
Returns	The `hs.socket` object, or `nil` if an error occurred.
Notes	Either a host/port pair OR a Unix domain socket path must be supplied. If no port is passed, the first parameter is assumed to be a path to the socket file.
Examples	None
Source	extensions/socket/libsocket.m line 234

connected


Signature	`hs.socket:connected() -> bool`
Type	Method
Description	Returns the connection status of the socket.
Parameters	None
Returns	`true` if the socket is connected, otherwise `false`.
Notes	If the socket is bound for listening, this method returns `true` if there is at least one connection.
Examples	None
Source	extensions/socket/libsocket.m line 572

connections


Signature	`hs.socket:connections() -> number`
Type	Method
Description	Returns the number of connections to the socket.
Parameters	None
Returns	The number of connections to the socket.
Notes	This method returns at most 1 for default (non-listening) sockets.
Examples	None
Source	extensions/socket/libsocket.m line 593

disconnect


Signature	`hs.socket:disconnect() -> self`
Type	Method
Description	Disconnects the socket, freeing it for reuse.
Parameters	None
Returns	The `hs.socket` object.
Notes	If called on a listening socket with multiple connections, each client is disconnected.
Examples	None
Source	extensions/socket/libsocket.m line 345

info


Signature	`hs.socket:info() -> table`
Type	Method
Description	Returns information about the socket.
Parameters	None
Returns	A table containing the following keys: connectedAddress - `string` (`sockaddr` struct) connectedHost - `string` connectedPort - `number` connectedURL - `string` connections - `number` isConnected - `boolean` isDisconnected - `boolean` isIPv4 - `boolean` isIPv4Enabled - `boolean` isIPv4PreferredOverIPv6 - `boolean` isIPv6 - `boolean` isIPv6Enabled - `boolean` isSecure - `boolean` localAddress - `string` (`sockaddr` struct) localHost - `string` localPort - `number` timeout - `number` unixSocketPath - `string` userData - `string`
Notes	None
Examples	None
Source	extensions/socket/libsocket.m line 614

listen


Signature	`hs.socket:listen(port\|path) -> self or nil`
Type	Method
Description	Binds an unconnected socket to either a port or path (Unix domain socket) for listening.
Parameters	`port` - A port number [0-65535]. Ports [1-1023] are privileged. Port 0 allows the OS to select any available port. `path` - A string containing the path to the Unix domain socket.
Returns	The `hs.socket` object, or `nil` if an error occurred.
Notes	None
Examples	None
Source	extensions/socket/libsocket.m line 297

read


Signature	`hs.socket:read(delimiter[, tag]) -> self or nil`
Type	Method
Description	Read data from the socket.
Parameters	`delimiter` - Either a number of bytes to read, or a string delimiter such as "\n" or "\r\n". Data is read up to and including the delimiter. `tag` - An optional integer to assist with labeling reads. It is passed to the callback to assist with implementing state machines for processing complex protocols.
Returns	The `hs.socket` object, or `nil` if an error occurred.
Notes	Results are passed to the socket's callback function, which must be set to use this method. If called on a listening socket with multiple connections, data is read from each of them.
Examples	None
Source	extensions/socket/libsocket.m line 369

receive


Signature	`hs.socket:receive(delimiter[, tag]) -> self`
Type	Method
Description	Alias for `hs.socket:read`
Parameters
Returns
Notes	None
Source	extensions/socket/socket.lua line 225

send


Signature	`hs.socket:send(message[, tag]) -> self`
Type	Method
Description	Alias for `hs.socket:write`
Parameters
Returns
Notes	None
Source	extensions/socket/socket.lua line 231

setCallback

| | | | --------------------------------------------|-------------------------------------------------------------------------------------| | Signature | hs.socket:setCallback([fn]) -> self | | Type | Method | | Description | Sets the read callback for the socket. | | Parameters |

fn - An optional callback function to process data read from the socket. nil or no argument clears the callback. The callback receives 2 parameters: data - The data read from the socket as a string. tag - The integer tag associated with the read call, which defaults to -1.

| | Returns |

The hs.socket object.

| | Notes |

A callback must be set in order to read data from the socket.

setTimeout


Signature	`hs.socket:setTimeout(timeout) -> self`
Type	Method
Description	Sets the timeout for the socket operations.
Parameters	`timeout` - A number containing the timeout duration, in seconds.
Returns	The `hs.socket` object.
Notes	If the timeout value is negative, the operations will not use a timeout, which is the default.
Examples	None
Source	extensions/socket/libsocket.m line 503

startTLS


Signature	`hs.socket:startTLS([verify][, peerName]) -> self`
Type	Method
Description	Secures the socket with TLS.
Parameters	`verify` - An optional boolean that, if `false`, allows TLS handshaking with servers with self-signed certificates and does not evaluate the chain of trust. Defaults to `true` and omitted if `peerName` is supplied `peerName` - An optional string containing the fully qualified domain name of the peer to validate against — for example, `store.apple.com`. It should match the name in the X.509 certificate given by the remote party. See the important security note below.
Returns	The `hs.socket` object.
Notes	The socket will disconnect immediately if TLS negotiation fails. IMPORTANT SECURITY NOTE: The default settings will check to make sure the remote party's certificate is signed by a trusted 3rd party certificate agency (e.g. verisign) and that the certificate is not expired. However it will not verify the name on the certificate unless you give it a name to verify against via `peerName`. The security implications of this are important to understand. Imagine you are attempting to create a secure connection to MySecureServer.com, but your socket gets directed to MaliciousServer.com because of a hacked DNS server. If you simply use the default settings, and MaliciousServer.com has a valid certificate, the default settings will not detect any problems since the certificate is valid. To properly secure your connection in this particular scenario you should set `peerName` to "MySecureServer.com".
Examples	None
Source	extensions/socket/libsocket.m line 527

write


Signature	`hs.socket:write(message[, tag, fn]) -> self`
Type	Method
Description	Write data to the socket.
Parameters	`message` - A string containing data to be sent on the socket. `tag` - An optional integer to assist with labeling writes. `fn` - An optional single-use callback function to execute after writing data to the socket. The callback receives the tag parameter provided here.
Returns	The `hs.socket` object.
Notes	If called on a listening socket with multiple connections, data is broadcast to all connected sockets.
Examples	None
Source	extensions/socket/libsocket.m line 429