WebSocket Module

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This XQuery Module contains functions for accessing specific WebSocket functions. This module is mainly useful in the context of WebSockets.

Contents

[edit] Conventions

import module namespace ws = "http://basex.org/modules/ws";
...

[edit] General Functions

[edit] ws:id

Signatures ws:id() as xs:string
Summary Returns the ID of the current WebSocket.
Errors not-found: No WebSocket with the specified id exists.

[edit] ws:ids

Signatures ws:ids() as xs:string*
Summary Returns the ids of all currently registered WebSocket.

[edit] ws:path

Signatures ws:path($id as xs:string) as xs:string
Summary Returns the path of the WebSocket with the specified $id.
Errors not-found: No WebSocket with the specified id exists.

[edit] ws:close

Signatures ws:close($id as xs:string) as empty-sequence()
Summary Closes the connection of the WebSocket with the specified $id.
Errors not-found: No WebSocket with the specified id exists.

[edit] Sending Data

[edit] ws:send

Signatures ws:send($message as item(), $ids as xs:string*) as empty-sequence()
Summary Sends a $message to the clients with the specified $ids. Ids that cannot be assigned to clients will be ignored. The message will be handled as follows:
  • Items of type xs:base64Binary and xs:hexBinary will be transmitted as binary messages.
  • Function items (maps, arrays) will be serialized as JSON and transmitted as string messages.
  • All other items will be serialized with the default serialization options and transmitted as string messages.

[edit] ws:broadcast

Signatures ws:broadcast($message as xs:anyAtomicType) as empty-sequence()
Summary Broadcasts a $message to all connected clients except to the caller. Invocations of this convenience function are equivalent to ws:send($message, ws:ids()[. != ws:id()]). See ws:send for more details on the message handling.

[edit] ws:emit

Signatures ws:emit($message as xs:anyAtomicType) as empty-sequence()
Summary Emits a $message to all connected clients. Invocations of this function are equivalent to ws:send($message, ws:ids()). See ws:send for more details on the message handling.

[edit] WebSocket Attributes

[edit] ws:get

Signatures ws:get($id as xs:string, $name as xs:string) as item()*
ws:get($id as xs:string, $name as xs:string, $default as item()*) as item()*
Summary Returns the value of an attribute with the specified $name from the WebSocket with the specified $id. If the attribute is unknown, an empty sequence or the optionally specified $default value will be returned instead.
Errors not-found: No WebSocket with the specified id exists.

[edit] ws:set

Signatures ws:set($id as xs:string, $name as xs:string, $value as item()*) as empty-sequence()
Summary Returns the specified value of the attribute with the specified $name from the WebSocket with the specified $id.
Errors not-found: No WebSocket with the specified id exists.
set: The supplied value cannot be materialized.

[edit] ws:delete

Signatures ws:delete($id as xs:string, $name as xs:string) as empty-sequence()
Summary Deletes an attribute with the specified $name from the WebSocket with the specified $id.
Errors not-found: No WebSocket with the specified id exists.

[edit] Examples

[edit] Example 1

import module namespace ws = "http://basex.org/modules/ws";

declare
  %ws:connect('/')
function local:connect() as empty-sequence() {
  let $id := ws:id()
  let $message := json:serialize(map {
    'type': 'Connect',
    'id': $id
  })
  return ws:broadcast($message)
};

Explanation:

[edit] Example 2

import module namespace ws = "http://basex.org/modules/ws";

declare
  %ws:message('/', '{$message}')
function local:message(
  $message as xs:string
) as empty-sequence() {
  let $message := json:serialize(map { 'message': $message })
  return ws:emit($message)
};

Explanation:

[edit] Errors

Code Description
set The supplied value cannot be materialized.
not-found No WebSocket with the specified id exists.

[edit] Changelog

This module was introduced with Version 9.1.

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