Pool v0.0.2 → Overview → Pool → Transport

Pool.Transport behaviour

Specification for transport layers to implement for interacting with acceptors.

Source

Types ↑

port_number :: non_neg_integer

opts :: Keyword.t

socket :: :inet.socket

length :: non_neg_integer

packet :: any

Callbacks

accept/2
(callback) # ↑

Specs:

Accepts an incoming connection request on a listen socket. socket must be a socket returned from listen/2. timeout specifies a timeout value in milliseconds, defaults to :infinity.

Returns {:ok, socket} if a connection is established, or {:error, :closed} if socket is closed, or {:error, :timeout} if no connection is established within the specified time, or {:error, :system_limit} if all available ports in the Erlang emulator are in use. May also return a POSIX error value if something else goes wrong.

Packets can be sent to the returned socket using send/2. Packets sent from the peer are delivered as messages:

{:tcp, socket, data}

unless {:active, false} was specified in the option list for the listen socket, in which case packets are retrieved by calling receive/2.

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close/1
(callback) # ↑

Specs:

Closes a socket.

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controlling_process/2
(callback) # ↑

Specs:

  • controlling_process(socket, pid) :: :ok | {:error, atom}

Assigns a new controlling process pid to socket. The controlling process is the process which receives messages from the socket. If called by any other process than the current controlling process, {:error, :not_owner} is returned.

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listen/2
(callback) # ↑

Specs:

Sets up a socket to listen on the port Port on the local host.

If port == 0, the underlying OS assigns an available port number, use :inet.port/1 to retrieve it.

The available options are:

  • list: true - Received packet is delivered as a list.
  • binary: true - Received packet is delivered as a binary.
  • backlog: b - b is an integer >= 0. The backlog value defaults to 5. The backlog value defines the maximum length that the queue of pending connections may grow to.
  • ip: ip_address - If the host has several network interfaces, this option specifies which one to listen on.
  • port: port - Specify which local port number to use.
  • fd: fd - If a socket has somehow been connected without using :gen_tcp, use this option to pass the file descriptor for it.
  • ifaddr: ip_address - Same as ip: ip_address. If the host has several network interfaces, this option specifies which one to use.
  • inet6: true - Set up the socket for IPv6.
  • inet: true - Set up the socket for IPv4.
  • tcp_module: module - Override which callback module is used. Defaults to:inet_tcp for IPv4 and :inet6_tcp for IPv6.
  • opt - See :inet.setopts/2 for other options.

The returned socket socket can only be used in calls to accept/2.

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name/0
(callback) # ↑

Specs:

  • name :: atom

Returns an identifier for the transport.

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receive/3
(callback) # ↑

Specs:

  • receive(socket, length, timeout) :: {:ok, any} | {:error, atom}

This function receives a packet from a socket in passive mode. A closed socket is indicated by a return value {:error, :closed}.

The length argument is only meaningful when the socket is in raw mode and denotes the number of bytes to read. If length == 0, all available bytes are returned. If length > 0, exactly length bytes are returned, or an error; possibly discarding less than length bytes of data when the socket gets closed from the other side.

The optional timeout parameter specifies a timeout in milliseconds. The default value is :infinity.

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send/2
(callback) # ↑

Specs:

Sends a packet on a socket.

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