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This [[Module Library|XQuery Module]] contains functions for accessing specific WebSocket functions. This module is mainly useful in the context of [[WebSockets]].
Within the WebSocket module you can access functions in the context of the specific client. You can access the clientid, the clientpath and broadcast a message to all connected clients without the caller/client. If you have to access functions with more rights, like getting the clientids of other connected clients, you should checkout the [[WebSockets Module]]
=Conventions=
* The module will be available if the {{Code|basex-api}} package must be included library is found in the classpath. This is always the case if you use one of the complete distributions of BaseX (zip, exe, war) of BaseX.* All functions and errors are assigned to the <code><nowiki>http://basex.org/modules/websocketws</nowiki></code> namespace. The module must be imported in , which is statically bound to the query prolog:<pre class="brush:xquery">import module namespace websocket = "http://basex{{Code|ws}} prefix.org/modules/Websocket";* As sessions are side-effecting operations, all functions are flagged as ''non-deterministic''.As a result, some query optimizations will be suppressed..</pre>
=General Functions= ==ws:id== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:id||xs:string}}|-| '''Summary'''|Returns the ID of the current WebSocket.|-| '''Errors'''|{{Error|not-found|#Errors}} No WebSocket with the specified id exists.|} ==ws:ids== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:ids||xs:string*}}|-| '''Summary'''|Returns the ids of all currently registered WebSockets.|} ==ws:path== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:path|$id as xs:string|xs:string}}|-| '''Summary'''|Returns the path of the WebSocket with the specified {{Code|$id}}.|-| '''Errors'''|{{Error|not-found|#Errors}} No WebSocket with the specified id exists.|} ==ws:close== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:close|$id as xs:string|empty-sequence()}}|-| '''Summary'''|Closes the connection of the WebSocket with the specified {{Code|$id}}.|-| '''Errors'''|{{Error|not-found|#Errors}} No WebSocket with the specified id exists.|} =Sending Data= ==ws:send== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:send|$message as item(), $ids as xs:string*|empty-sequence()}}|-| '''Summary'''|Sends a <code>$message</code> to the clients with the specified <code>$ids</code>. Ids that cannot be assigned to clients will be ignored. The message will be handled as follows:* Items of type {{Code|xs:base64Binary}} and {{Code|xs:hexBinary}} will be transmitted as binary messages.* Function items (maps, arrays) will be serialized as JSON and transmitted as string messages.* All other items will be serialized with the default serialization options and transmitted as string messages.|} ==ws:broadcast== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:broadcast|$message as xs:anyAtomicType|empty-sequence()}}|-| '''Summary'''|Broadcasts a <code>$message</code> to all connected clients except to the caller. Invocations of this convenience function are equivalent to <code>ws:send($message, ws:ids()[. != ws:id()])</code>. See [[#ws:send|ws:send]] for more details on the message handling.|} ==ws:emit== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:emit|$message as xs:anyAtomicType|empty-sequence()}}|-| '''Summary'''|Emits a <code>$message</code> to all connected clients. Invocations of this function are equivalent to <code>ws:send($message, ws:ids())</code>. See [[#ws:send|ws:send]] for more details on the message handling.|} ==ws:eval==
==websocket:broadcast==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|websocketws:broadcasteval|$message query as xs:anyAtomicTypeanyAtomicItem|empty-sequencexs:string}}<br />{{Func|ws:eval|$query as xs:anyAtomicItem, $bindings as map(*)?|xs:string}}<br />{{Func|ws:eval|$query as xs:anyAtomicItem, $bindings as map(*)?, $options as map(*)?|xs:string}}<br />
|-
| '''Summary'''
|Broadcasts Schedules the evaluation of the supplied {{Code|$query}} and returns the result to the calling WebSocket client. The query can be a URI or a string, and variables and context items can be declared via {{Code|$bindings}} (see {{Function|XQuery|xquery:eval}} for more details). The following {{Code|$options}} can be supplied:* {{Code|base-uri}}: sets the [https://www.w3.org/TR/xquery-31/#dt-static-base-uri base-uri property] for the query. This URI will be used when resolving relative URIs, such as with {{Code|fn:doc}}.* {{Code|id}}: sets a custom job id. The id must not start with the standard <code>messagejob</code> which may prefix, and it can only be of type xsassigned if no job with the same name exists.Query scheduling is recommendable if the immediate query execution might be too time consuming and lead to a timeout.|-| '''Errors'''|{{Error|overflow|#Errors}} Query execution is rejected, because too many jobs are queued or being executed. <br/>{{Error|id|#Errors}} The specified id is invalid or has already been assigned.|-| '''Examples'''|* Schedule a second query that will notify the client 10 seconds later that a message was processed:<syntaxhighlight lang="xquery">declare %ws:stringmessage('/tasks', xs'{$message}')function local:message($message) { ws:eval('prof:base64Binarysleep(10000), or xs:hexBinary to all connected members except to the caller"Your message has been processed. "')}; </syntaxhighlight>
|}
=WebSocket Attributes=websocket ==ws:idget== 
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|websocketws:get|$idas xs:string, $name as xs:string|item()*}}<br/>{{Func|ws:get|$id as xs:string, $name as xs:string, $default as item()*|item()*}}
|-
| '''Summary'''
|Returns the ID value of an attribute with the current specified {{Code|$name}} from the WebSocket with the specified {{Code|$id}}. If the attribute is unknown, an empty sequence or the optionally specified {{Code|$default}} value will be returned instead.|-| '''Errors'''|{{Error|not-found|#Errors}} No WebSocket connectionwith the specified id exists.
|}
==websocketws:pathset== 
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|websocketws:path|set|$id as xs:string, $name as xs:string, $value as item()*|empty-sequence()}}
|-
| '''Summary'''
|Returns the path specified {{Code|value}} of the current WebSocketClient. If attribute with the <code>specified {{Code|$id</code> parameter is set, name}} from the path of a specific user WebSocket with the ID <code>specified {{Mono|$id}}.|-| '''Errors'''|{{Error|not-found|#Errors}} No WebSocket with the specified id exists.</codebr> will {{Error|set|#Errors}} The supplied value cannot be returnedmaterialized.
|}
=Usage Tips=ws:delete== * <code>websocket{| width='100%'|-| width='120' | '''Signatures'''|{{Func|ws:delete|$id</code> returns your current session as xs:string, $name as xs:string|empty-sequence()}}|-| '''Summary'''|Deletes an attribute with the specified {{Code|$name}} from the WebSocket with the specified {{Mono|$id}}. You can use all [[Session Module]] and [[Sessions Module]] functions within |-| '''Errors'''|{{Error|not-found|#Errors}} No WebSocket with the websocket contextspecified id exists.|}
=Examples=
 ==CodeExample 1== <pre classsyntaxhighlight lang="brushxquery">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($message)};</syntaxhighlight> '''Explanation:''' * The function has a <code>%ws:connect</code> annotation. It gets called if a client successfully creates a WebSocket connection to the path <code>/</code> (check out [[WebSockets]] for further information).* A JSON response is generated, which contains the new client id and a <code>Connect</code> string.* This response will be sent to all other connected clients. ==Example 2== <syntaxhighlight lang="xquery">import module namespace ws = "http://basex.org/modules/ws"; 
declare
module namespace websocketexample %ws:message('/', '{$message}')function local:message( $message as xs:string) as empty-sequence() { let $message := json:serialize(map { 'message'http:$message }) return ws:emit($message)};</syntaxhighlight> '''Explanation:''' * The function has a <code>%ws:message</basexcode> annotation. It gets called if a client sends a new message.* A JSON response is generated, which contains the message string.org/modules/web-page';* This response will be sent to all connected clients (: Import including the WebSocket module :calling client). import module namespace websocket = Errors= {| class="wikitable"http://basexwidth="100%"! width="110"|Code|Description|-|{{Code|set}}|The supplied value cannot be materialized.|-|{{Code|not-found}}|No WebSocket with the specified id exists.org/modules/Websocket"|} =Changelog= ;Version 9.2 * Added: [[#ws:eval|ws:eval]]
%ws:connect("/") function websocketexample:connect( ) { let $client-id := websocket:id() let $client-path := websocket:path() let $response := json:serialize( <json type="object"> <messageType>UserConnected</messageType> <clientId>{$client-id}</clientId> <clientPath>{$client-path}</clientPath> </json> ) return websocket:broadcast($response) };</pre>==Explanation==* First of all: include the websocket This module* The <code>$ws:connect("/")</code> annotation gets called if a client successfully creates a websocket to the path "/"* Get the <code>client-id</code> and the <code>client-path</code> was introduced with <code>websocket:id()</code> and <code>websocket:path()</code>* Create a json-result * Broadcast the result to all connected clients without the calling clientVersion 9.1.
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