Session Module
This XQuery Module contains functions for accessing and modifying server-side session information. This module is mainly useful in the context of Web Applications.
Conventions
As sessions are side-effecting operations, all functions in this module are flagged as non-deterministic. This means that the evaluation order of the functions will not be influenced by the compiler.
All functions are assigned to the http://basex.org/modules/session
namespace, which must be dynamically imported. In this documentation, the namespace is bound to the session
prefix. Errors are assigned to the http://basex.org/errors
namespace, which is statically bound to the bxerr
prefix.
If the module is called outside the servlet context, the error BXSE0003 is raised.
Functions
session:id
Signatures | session:id() as xs:string
|
Summary | Returns the session ID of a servlet request. |
Examples | Running the server-side XQuery file id.xq via http://localhost:8984/id.xq :
import module namespace session = "http://basex.org/modules/session"; 'Session ID: ' || session:id() |
session:names
Signatures | session:names() as xs:string*
|
Summary | Returns the names of all variables bound to the current session. |
Examples | Running the server-side XQuery file names.xq via http://localhost:8984/names.xq :
import module namespace session = "http://basex.org/modules/session"; session:names() ! element variable { . } |
session:get
Signatures | session:get($key as xs:string) as xs:string? session:get($key as xs:string, $default as xs:string) as xs:string
|
Summary | Returns the value of a variable bound to the current session. If the variable does not exist, an empty sequence or the optionally specified default value is returned instead. |
Errors | BXSE0002 : the value of a session variable could not be retrieved.
|
Examples | Running the server-side XQuery file get.xq via http://localhost:8984/get.xq?key=user :
import module namespace session = "http://basex.org/modules/session"; 'Value of ' || $key || ': ' || session:get($key) |
session:set
Signatures | session:set($key as xs:string, $value as xs:string) as empty-sequence()
|
Summary | Assigns a value to a session variable. |
Errors | BXSE0001 : a function item was specified as value of a session variable.
|
Examples | Running the server-side XQuery file set.xq via http://localhost:8984/set.xq?key=user&value=john :
import module namespace session = "http://basex.org/modules/session"; session:set($key, $value), 'Variable was set.' |
session:delete
Signatures | session:delete($key as xs:string) as empty-sequence()
|
Summary | Deletes a session variable. |
Examples | Running the server-side XQuery file delete.xq via http://localhost:8984/delete.xq?key=user :
import module namespace session = "http://basex.org/modules/session"; session:delete($key), 'Variable was deleted.' |
session:close
Signatures | session:close() as empty-sequence()
|
Summary | Unregisters a session and all data associated with it. |
Errors
Code | Description |
---|---|
BXSE0001
|
A function item was specified as value of a session attribute. |
BXSE0002
|
An error occurred while retrieving the value of a session attribute. |
Changelog
This module was introduced with Version 7.5.