Udp Communication

createUDPSocket

TIP

The API usage is as follows: UDPSocket wx.createUDPSocket()

• Functional description: Create a UDP Socket instance.
• Return value: UDPSocket, a UDP Socket instance.

UDPSocket

Description

A UDP Socket instance uses IPv4 protocol by default.

.bind

TIP

The API usage is as follows: number UDPSocket.bind(number port)

• Functional description: Bind an available port randomly assigned by the system, or bind a specified port number.

• Parameters and descriptions: number port, Specify the port number to bind, if not passed, return the available port randomly assigned by the system.

• Return value: number, The port number of successful binding.

• Sample code:

const udp = wx.createUDPSocket()
const port = udp.bind()

.close

TIP

The API usage is as follows: UDPSocket.close()

• Functional description: Close the UDP Socket instance, which is equivalent to destruction. After closing, the UDP Socket instance can no longer send messages. Each call to UDPSocket.send will trigger an error event, and the message event callback function will no longer be executed. After the UDPSocket instance is created, it will be strongly referenced by Native to ensure that it is not GC. After UDPSocket.close, the strong reference to it will be released to make the UDPSocket instance comply with GC.

.connect

TIP

The API usage is as follows: UDPSocket.connect(Object object)

• Functional description: Pre-connect to the specified IP and port, need to be used with the write method.

• Parameters and descriptions: Object object

  Properties	Type	Default value	Required	Description
  address	string	-	Yes	Address to send the message to
  port	number	-	Yes	Port number to send the message to

• Sample code:

  const udp = wx.createUDPSocket()
  udp.bind()
  udp.connect({
    address: '192.168.193.2',
    port: 8848,
  })
  udp.write({
    address: '192.168.193.2',
    port: 8848,
    message: 'hello, how are you'
  })

.onClose

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The API usage is as follows: UDPSocket.onClose(function listener)

• Functional description: Listen for closing events.
• Parameters and descriptions: function listener Listening function for close event.

.offClose

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The API usage is as follows: UDPSocket.offClose(function listener)

• Functional description: Remove the listener function for closing events.

• Parameters and descriptions: function listener Listening function passed in by onClose, if this parameter is not passed, all listening functions will be removed.

• Sample code:

const listener = function (res) { console.log(res) }

UDPSocket.onClose(listener)
UDPSocket.offClose(listener) // Pass the same function object used for listening.

.onError

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The API usage is as follows: UDPSocket.onError(function listener)

• Functional description: Listen for error events.

• Parameters and descriptions: function listener， Listening function for error events, parameter Object res is as follows

  Properties	Type	Description
  errMsg	string	Error message

.offError

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The API usage is as follows: UDPSocket.offError(function listener)

• Functional description: Remove the listener function for error events.

• Parameters and descriptions: function listener， onError The listening function passed in. If this parameter is not passed, all listening functions will be removed.

• Sample code:

const listener = function (res) { console.log(res) }

UDPSocket.onError(listener)
UDPSocket.offError(listener)  // Pass the same function object used for listening.

.onListening

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The API usage is as follows: UDPSocket.onListening(function listener)

• Functional description: Listen for events that start listening for data packet messages.
• Parameters and descriptions: function listener， The listening function of the event of starting to listen for data packet messages.

.offListening

TIP

The API usage is as follows: UDPSocket.offListening(function listener)

• Functional description: Remove the listener function for events that start listening for data packet messages.

• Parameters and descriptions: function listener， onListening The listening function passed in. If this parameter is not passed, all listening functions will be removed.

• Sample code:

const listener = function (res) { console.log(res) }

UDPSocket.onListening(listener)
UDPSocket.offListening(listener) // Pass the same function object used for listening.

.onMessage

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The API usage is as follows: UDPSocket.onMessage(function listener)

• Functional description: Listen for the event of receiving messages.

• Parameters and descriptions: function listener, the listening function of the event of receiving messages, the parameter Object res is as follows:

  Properties	Type	Description
  message	ArrayBuffer	Received message. The message length needs to be less than 4104
  remoteInfo	Object	Sender address information

  • remoteInfo structure attribute

    Properties	Type	Description
    address	string	The address of the socket to send the message
    family	string	The protocol family used, which is IPv4 or IPv14
    port	number	Port number
    size	number	The size of the message, in bytes

.offMessage

TIP

The API usage is as follows: UDPSocket.offMessage(function listener)

• Functional description: Remove the listener function of the event that receives the message.

• Parameters and descriptions: function listener， onMessage The listening function passed in. If this parameter is not passed, all listening functions will be removed.

• Sample code:

const listener = function (res) { console.log(res) }

UDPSocket.onMessage(listener)
UDPSocket.offMessage(listener)  // Pass the same function object used for listening.

.send

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The API usage is as follows: UDPSocket.send(Object object)

• Functional description: Send a message to the specified IP and port.

• Parameters and descriptions: Object object。

  Properties	Type	Default value	Required	Description
  address	string	-	Yes	The address to send the message.
  port	number	-	Yes	The port number to send the message to
  message	string/ArrayBuffer	-	Yes	The data to send
  offset	number	0	No	The offset of the data to send, valid only when message is of ArrayBuffer type
  length	number	message.byteLength	No	The length of the data to send, valid only when message is of ArrayBuffer type

• Sample code:

const udp = wx.createUDPSocket()
  udp.bind()
  udp.send({
    address: '192.168.193.2',
    port: 8848,
    message: 'hello, how are you'
 })

.setTTL

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The API usage is as follows: UDPSocket.setTTL(number ttl)

• Functional description: Set the IP_TTL socket option to set the maximum number of hops allowed when transmitting an IP data packet.

• Parameters and descriptions: number ttl, The ttl parameter can be between 0 and 255.

• Sample code:

const udp = wx.createUDPSocket()
udp.onListening(function () {
  udp.setTTL(64)
})
udp.bind()

.write

TIP

The API usage is as follows: UDPSocket.write()

• Functional description: The usage is the same as the send method. If connect is not called in advance, there is no difference with send.

Description

Even if connect is called, the address and port parameters need to be filled in this interface.

• Sample code:

  const udp = wx.createUDPSocket()
  udp.bind()
  udp.connect({
    address: '192.168.193.2',
    port: 8848,
  })
  udp.write({
    address: '192.168.193.2',
    port: 8848,
    message: 'hello, how are you'
  })