WebSocket Lianja Reference Documentation

WebSocket

Current Version: 9.5.0.73

Provides an API for implementing the client side of the WebSocket protocol.

Object Creation

loObject = createobject("CkWebSocket")

Properties

CloseAutoRespond
CloseAutoRespond As Boolean
Introduced in version 9.5.0.70

If .T., then a Close control frame is automatically sent in response to receiving a Close control frame (assuming that we did not initiate the Close in the first place). When the Close frame has both been received and sent, the underlying connection is automatically closed (as per the WebSocket protocol RFC specifications). Thus, if this property is .T., then two things automatically happen when a Close frame is received: (1) a Close frame is sent in response, and (2) the connection is closed.

The default value of this property is .T..

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CloseReason
CloseReason As Character (read-only)
Introduced in version 9.5.0.70

The reason string received with the Close frame, if any.

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CloseReceived
CloseReceived As Boolean (read-only)
Introduced in version 9.5.0.70

If .T., then a Close frame was already received on this websocket connection. If CloseAutoRespond is .F., then an application can check this property value to determine if a Close frame should be sent in response.

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CloseStatusCode
CloseStatusCode As Numeric (read-only)
Introduced in version 9.5.0.70

The status code received with the Close frame. If no status code was provided, or no Close frame has yet been received, then this property will be 0.

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DebugLogFilePath
DebugLogFilePath As Character

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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FinalFrame
FinalFrame As Boolean (read-only)
Introduced in version 9.5.0.70

.T. if the last data frame received by calling ReadFrame was a final frame. Otherwise .F..

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FrameDataLen
FrameDataLen As Numeric (read-only)
Introduced in version 9.5.0.70

The number of bytes accumulated from one or more calls to ReadFrame. Accumulated incoming frame data can be retrieved by calling GetFrameData, GetFrameDataSb, or GetFrameDataBd.

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FrameOpcode
FrameOpcode As Character (read-only)
Introduced in version 9.5.0.70

Indicates the type of frame received in the last call to ReadFrame. Possible values are "Continuation", "Text", "Binary", "Close", "Ping", or "Pong". Initially this property is set to the empty string because nothing has yet been received.

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FrameOpcodeInt
FrameOpcodeInt As Numeric (read-only)
Introduced in version 9.5.0.70

The integer value of the opcode (type of frame) received in the last call to ReadFrame. Possible values are:

0 - Continuation
1 - Text
2 - Binary
8 - Close
9 - Ping
10 - Pong

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IdleTimeoutMs
IdleTimeoutMs As Numeric

The maximum amount of time to wait for additional incoming data when receiving, or the max time to wait to send additional data. The default value is 30000 (30 seconds). This is not an overall max timeout. Rather, it is the maximum time to wait when receiving or sending has halted.

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IsConnected
IsConnected As Boolean (read-only)
Introduced in version 9.5.0.70

Returns .T. if the websocket is connected. Otherwise returns .F..

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LastErrorHtml
LastErrorHtml As Character (read-only)

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
LastErrorText As Character (read-only)

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
LastErrorXml As Character (read-only)

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
LastMethodSuccess As Boolean
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of .T. indicates success, a value of .F. indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = .T. and failure = .F..
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to .T.. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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NeedSendPong
NeedSendPong As Boolean (read-only)
Introduced in version 9.5.0.70

If .T., then a Ping frame was received, but no Pong frame has yet been sent in response. The application should send a Pong frame by calling SendPong as soon as possible.

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PingAutoRespond
PingAutoRespond As Boolean
Introduced in version 9.5.0.70

If .T., then a Pong frame is automatically sent when a Ping frame is received. If set to .F., then the application may check the NeedSendPong property to determine if a Pong response is needed, and if so, may call the SendPong method to send a Pong.

Note: If this property is .T., then the ReadFrame method will auto-consume incoming Ping frames. In other words, ReadFrame will continue with reading the next incoming frame (thus Ping frames will never be returned to the application). This relieves the application from having to worry about receiving and handling spurious Ping frames.

The default value is .T..

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PongAutoConsume
PongAutoConsume As Boolean
Introduced in version 9.5.0.70

If .T., then incoming Pong frames are automatically consumed, and a call to ReadFrame will continue reading until it receives a non-Pong frame. The PongConsumed property can be checked to see if the last ReadFrame method call auto-consumed a Pong frame.

The default value is .T..

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PongConsumed
PongConsumed As Boolean (read-only)
Introduced in version 9.5.0.70

Is .T. if the last call to ReadFrame auto-consumed a Pong frame. This property is reset to .F. each time a ReadFrame method is called, and will get set to .T. if (1) the PongAutoConsume property is .T. and (2) a Pong frame was consumed within the ReadFrame method.

The purpose of PongAutoConsume and PongConsumed is to eliminate the concern for unanticipated Pong frames in the stream. In the websocket protocol, both sides (client and server) may send Pong frames at any time. In addition, if a Ping frame is sent, the corresponding Pong response frame can arrive at some unanticipated point later in the conversation. It's also possible, if several Ping frames are sent, that a Pong response frame is only sent for the most recent Ping frame. The default behavior of Chilkat's WebSocket API is to auto-consume incoming Pong frames and set this property to .T.. This allows the application to call a ReadFrame method for whatever application data frame it may be expecting, without needing to be concerned if the next incoming frame is a Pong frame.

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ReadFrameFailReason
ReadFrameFailReason As Numeric (read-only)
Introduced in version 9.5.0.70

If the ReadFrame method returns .F., this property holds the fail reason. It can have one of the following values:

0 - No failure.
1 - Read Timeout.
2 - Aborted by Application Callback.
3 - Fatal Socket Error (Lost Connection).
4 - Received invalid WebSocket frame bytes.
99 - A catch-all for any unknown failure.  (Should not ever occur.  If it does, contact Chilkat.)

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VerboseLogging
VerboseLogging As Boolean

If set to .T., then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is .F.. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Version As Character (read-only)

Version of the component/library, such as "9.5.0.63"

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Methods

AddClientHeaders
AddClientHeaders() As Boolean
Introduced in version 9.5.0.70

Adds the required WebSocket client-side open handshake headers. The headers specifically added to the previously specified REST object (in the call to UseConnection) are:

Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: ...
Sec-WebSocket-Version: 13

Returns .T. for success, .F. for failure.

More Information and Examples
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CloseConnection
CloseConnection() As Boolean
Introduced in version 9.5.0.70

Forcibly closes the underlying connection. This is a non-clean way to close the connection, but may be used if needed. The clean way to close a websocket is to send a Close frame, and then receive the Close response.

Returns .T. for success, .F. for failure.

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GetFrameData
GetFrameData() As Character
Introduced in version 9.5.0.70

Returns the accumulated received frame data as a string. Calling GetFrameData clears the internal receive buffer.

Returns .F. on failure

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GetFrameDataBd
GetFrameDataBd(binData As CkBinData) As Boolean
Introduced in version 9.5.0.70

Returns the accumulated received frame data in a BinData object. The received data is appended to the binData.

Calling this method clears the internal receive buffer.

More Information and Examples
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GetFrameDataSb
GetFrameDataSb(sb As CkStringBuilder) As Boolean
Introduced in version 9.5.0.70

Returns the accumulated received frame data in a StringBuilder object. The received data is appended to the sb.

Calling this method clears the internal receive buffer.

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PollDataAvailable
PollDataAvailable() As Boolean
Introduced in version 9.5.0.70

Check to see if data is available for reading on the websocket. Returns .T. if data is waiting and .F. if no data is waiting to be read.

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ReadFrame
ReadFrame() As Boolean
Introduced in version 9.5.0.70

Reads a single frame from the connected websocket. If a frame was successfuly received, then the following properties are set: FrameOpcode, FrameDataLen, FinalFrame, and the received frame data can be retrieved by calling GetFrameData, GetFrameDataSb, or GetFrameDataBd.

Returns .T. for success, .F. for failure.

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ReadFrameAsync (1)
ReadFrameAsync() As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the ReadFrame method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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SaveLastError
SaveLastError(path As Character) As Boolean

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns .T. for success, .F. for failure.

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SendClose
SendClose(includeStatus As Boolean, statusCode As Numeric, reason As Character) As Boolean
Introduced in version 9.5.0.70

Sends a Close control frame. If includeStatus is .T., then the statusCode is sent in the application data part of the Close frame. A Close reason may be provided only if includeStatus is .T.. If this Close was sent to satisfy an already-received Close frame, then the underlying connection will also automatically be closed.

Note: If a status code and reason are provided, the utf-8 representation of the reason string must be 123 bytes or less. Chilkat will automatically truncate the reason to 123 bytes if necessary. Also, the status code must be an integer in the range 0 to 16383.

The WebSocket protocol specifies some pre-defined status codes at WebSocket Status Codes. For a normal closure, a status code value of 1000 should be used. The reason can be any string, as long as it is 123 bytes or less.

Returns .T. for success, .F. for failure.

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SendCloseAsync (1)
SendCloseAsync(includeStatus As Boolean, statusCode As Numeric, reason As Character) As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the SendClose method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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SendFrame
SendFrame(stringToSend As Character, finalFrame As Boolean) As Boolean
Introduced in version 9.5.0.70

Sends a single data frame containing a string. If this is the final frame in a message, then finalFrame should be set to .T.. Otherwise set finalFrame equal to .F..

Returns .T. for success, .F. for failure.

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SendFrameAsync (1)
SendFrameAsync(stringToSend As Character, finalFrame As Boolean) As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the SendFrame method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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SendFrameBd
SendFrameBd(bdToSend As CkBinData, finalFrame As Boolean) As Boolean
Introduced in version 9.5.0.70

Sends a single data frame containing binary data (the contents of bdToSend). If this is the final frame in a message, then finalFrame should be set to .T.. Otherwise set finalFrame equal to .F..

Returns .T. for success, .F. for failure.

More Information and Examples
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SendFrameBdAsync (1)
SendFrameBdAsync(bdToSend As CkBinData, finalFrame As Boolean) As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the SendFrameBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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SendFrameSb
SendFrameSb(sbToSend As CkStringBuilder, finalFrame As Boolean) As Boolean
Introduced in version 9.5.0.70

Sends a single data frame containing a string (the contents of sbToSend). If this is the final frame in a message, then finalFrame should be set to .T.. Otherwise set finalFrame equal to .F..

Returns .T. for success, .F. for failure.

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SendFrameSbAsync (1)
SendFrameSbAsync(sbToSend As CkStringBuilder, finalFrame As Boolean) As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the SendFrameSb method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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SendPing
SendPing(pingData As Character) As Boolean
Introduced in version 9.5.0.70

Sends a Ping control frame, optionally including text data. If pingData is non-empty, the utf-8 representation of the string must be 125 bytes or less. Chilkat will automatically truncate the pingData to 125 bytes if necessary.

Returns .T. for success, .F. for failure.

More Information and Examples
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SendPingAsync (1)
SendPingAsync(pingData As Character) As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the SendPing method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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SendPong
SendPong() As Boolean
Introduced in version 9.5.0.70

Sends a Pong control frame. If this Pong frame is sent to satisfy an unresponded-to Ping frame, then the previously received Ping data is automatically sent in this Pong frame.

Returns .T. for success, .F. for failure.

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SendPongAsync (1)
SendPongAsync() As CkTask
Introduced in version 9.5.0.70

Creates an asynchronous task to call the SendPong method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

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UseConnection
UseConnection(connection As CkRest) As Boolean
Introduced in version 9.5.0.70

Initializes the connection for a WebSocket session. All WebSocket sessions begin with a call to UseConnection. A Chilkat REST object is used for the connection because the WebSocket handshake begins with an HTTP GET request. The Chilkat REST API provides the ability to add custom headers, authentication, etc. to the opening GET handshake. It also provides the ability to establish connections over TLS or SSH and to benefit from the rich set of features already present relating to HTTP proxies, SOCKS proxies, bandwidth throttling, IPv6, socket options, etc.

Returns .T. for success, .F. for failure.

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ValidateServerHandshake
ValidateServerHandshake() As Boolean
Introduced in version 9.5.0.70

Called after sending the opening handshake from the Rest object. Validates the server's response to the opening handshake message. If validation is successful, the application may begin sending and receiving data and control frames.

Returns .T. for success, .F. for failure.

More Information and Examples
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