Difference between revisions of "Session Module"

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| '''Errors'''
 
| '''Errors'''
|{{Error|get|#Errors}} the value of a session variable could not be retrieved.
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|{{Error|get|#Errors}} the value of an attribute could not be retrieved.
 
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| '''Examples'''
 
| '''Examples'''

Revision as of 13:13, 27 September 2018

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

  • The basex-api package must be included in the classpath. This is always the case if you use one of the complete distributions (zip, exe, war) of BaseX.
  • All functions and errors are assigned to the http://basex.org/modules/session namespace. The module must be imported in the query prolog:
import module namespace session = "http://basex.org/modules/session";
...
  • If any of the functions is called outside the servlet context, basex:http is raised.
  • As sessions are side-effecting operations, all functions are flagged as non-deterministic. As a result, the functions will not be reordered by the compiler.

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:created

Signatures session:created() as xs:dateTime
Summary Returns the creation time of a session.

session:accessed

Signatures session:accessed() as xs:dateTime
Summary Returns the last access time of a session.

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($name as xs:string) as item()*
session:get($name as xs:string, $default as item()*) as item()*
Summary Returns the value of a session attribute with the specified $name. If the attribute is unknown, an empty sequence or the optionally specified $default value will be returned instead.
Errors get: the value of an attribute 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($name as xs:string, $value as item()*) as empty-sequence()
Summary Binds the specified $value to the session attribute with the specified $name.
Errors set: The supplied value cannot be materialized.
Examples Running the server-side XQuery file set.xq via http://localhost:8984/set.xq?key=user&value=john:
import module namespace session = "http://basex.org/modules/session";
session:set($key, $value), 'Variable was set.'

session:delete

Signatures session:delete($name as xs:string) as empty-sequence()
Summary Deletes a session attribute with the specified $name.
Examples Running the server-side XQuery file delete.xq via http://localhost:8984/delete.xq?key=user:
import module namespace session = "http://basex.org/modules/session";
session:delete($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
get The stored attribute is no XQuery value.
set The supplied value cannot be materialized.

Changelog

Version 9.0
  • Updated: error codes updated; errors now use the module namespace
Version 8.0
  • Updated: Allow sequences as session values.

This module was introduced with Version 7.5.