Difference between revisions of "Session Module"

From BaseX Documentation
Jump to navigation Jump to search
Line 2: Line 2:
  
 
=Conventions=
 
=Conventions=
 +
 +
{{Mark|Updated with Version 9.0}}:
  
 
* The {{Code|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.
 
* The {{Code|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 are assigned to the <code><nowiki>http://basex.org/modules/session</nowiki></code> namespace. The module must be imported in the query prolog:
+
* All functions and errors are assigned to the <code><nowiki>http://basex.org/modules/session</nowiki></code> namespace. The module must be imported in the query prolog:
 
<pre class="brush:xquery">
 
<pre class="brush:xquery">
 
import module namespace session = "http://basex.org/modules/session";
 
import module namespace session = "http://basex.org/modules/session";
 
...
 
...
 
</pre>
 
</pre>
* In this documentation, the namespace is bound to the {{Code|session}} prefix.
+
* If any of the functions is called outside the servlet context, the error {{Error|basex:http|XQuery Errors}} is raised.
* Errors are assigned to the <code><nowiki>http://basex.org/errors</nowiki></code> namespace, which is statically bound to the {{Code|bxerr}} prefix.
+
* 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.
* If any of the functions is called outside the servlet context, the error {{Error|BXSE0003|#Errors}} is raised.
 
* As sessions are side-effecting operations, all functions are flagged as ''non-deterministic''. This means that the functions will not be reordered by the compiler.
 
  
 
=Functions=
 
=Functions=
  
 
==session:id==
 
==session:id==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 34: Line 35:
  
 
==session:created==
 
==session:created==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 44: Line 46:
  
 
==session:accessed==
 
==session:accessed==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 54: Line 57:
  
 
==session:names==
 
==session:names==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 71: Line 75:
  
 
==session:get==
 
==session:get==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 80: Line 85:
 
|-
 
|-
 
| '''Errors'''
 
| '''Errors'''
|{{Error|BXSE0002|#Errors}} the value of a session variable could not be retrieved.
+
|{{Error|get|#Errors}} the value of a session variable could not be retrieved.
 
|-
 
|-
 
| '''Examples'''
 
| '''Examples'''
Line 101: Line 106:
 
|-
 
|-
 
| '''Errors'''
 
| '''Errors'''
|{{Error|BXSE0001|#Errors}} a function item was specified as value of a session variable.
+
|{{Error|set|#Errors}} a function item was specified as value of a session variable.
 
|-
 
|-
 
| '''Examples'''
 
| '''Examples'''
Line 112: Line 117:
  
 
==session:delete==
 
==session:delete==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 129: Line 135:
  
 
==session:close==
 
==session:close==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
Line 139: Line 146:
  
 
=Errors=
 
=Errors=
 +
 +
{{Mark|Updated with Version 9.0}}:
  
 
{| class="wikitable" width="100%"
 
{| class="wikitable" width="100%"
Line 144: Line 153:
 
|Description
 
|Description
 
|-
 
|-
|{{Code|BXSE0001}}
+
|{{Code|set}}
|A function item was specified as value of a session attribute.
+
|Function items cannot be stored.
|-
 
|{{Code|BXSE0002}}
 
|An error occurred while retrieving the value of a session attribute.
 
 
|-
 
|-
|{{Code|BXSE0003}}
+
|{{Code|get}}
|A function was called outside the servlet context.
+
|The stored attribute is no XQuery value.
 
|}
 
|}
  
 
=Changelog=
 
=Changelog=
 +
 +
;Version 9.0
 +
 +
* Updated: error codes updated; errors now use the module namespace
  
 
;Version 8.0
 
;Version 8.0
 +
 
* Updated: Allow sequences as session values.
 
* Updated: Allow sequences as session values.
  
 
This module was introduced with Version 7.5.
 
This module was introduced with Version 7.5.

Revision as of 19:09, 21 November 2017

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

Template:Mark:

  • 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, the error 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 $name bound to the current session. If the specified variable is unknown, an empty sequence or the optionally specified default value is returned instead.
Errors get: 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($name as xs:string, $value as item()*) as empty-sequence()
Summary Binds the specified name/value pair to a session.
Errors set: a function item was specified as value of a session variable.
Examples Running the server-side XQuery file set.xq via http://localhost:8984/set.xq?key=user&value=john:
import module namespace session = "http://basex.org/modules/session";
session:set($key, $value), 'Variable was set.'

session:delete

Signatures session:delete($name as xs:string) as empty-sequence()
Summary Deletes a session value bound to $name.
Examples Running the server-side XQuery file delete.xq via http://localhost:8984/delete.xq?key=user:
import module namespace session = "http://basex.org/modules/session";
session:delete($key), 'Variable was deleted.'

session:close

Signatures session:close() as empty-sequence()
Summary Unregisters a session and all data associated with it.

Errors

Template:Mark:

Code Description
set Function items cannot be stored.
get The stored attribute is no XQuery value.

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.