API Documentation

Classes

TransientObjectContainer , TransientObject , MaxTransientObjectsExceeded

Transient Objects

class TransientObjectContainer

TransientObjectContainers hold transient objects, most often, session data.

You will rarely have to script a transient object container. You'll almost always deal with a TransientObject itself which you'll usually get as REQUEST.SESSION.

__module__ = __builtin__

Methods

getDelNotificationTarget(self):

Returns the current before destruction function, or None.

Permission

View management screens

getAddNotificationTarget(self):

Returns the current after add function, or None.

Permission

View management screens

get(self, k, default=None):

Return value associated with key k. If value associated with k does not exist, return default.

Permission

Access Transient Objects

new_or_existing(self, k):

If an object already exists in the container with key "k", it is returned.

Otherwiser, create a new subobject of the type supported by this container with key "k" and return it.

"k" must be a string, else a TypeError is raised.

If the container is full, a MaxTransientObjectsExceeded exception be raised.

Permission

Create Transient Objects

getId(self):

Returns a meaningful unique id for the object.

Permission

Always available

setAddNotificationTarget(self, f):

Cause the after add function to be f.

If f is not callable and is a string, treat it as a Zope path to a callable function.

after add functions need accept a single argument: item, which is the item being added to the container.

Permission

Manage Transient Object Container

has_key(self, k):

Return true if container has value associated with key k, else return false.

Permission

Access Transient Objects

getTimeoutMinutes(self):

Return the number of minutes allowed for subobject inactivity before expiration.

Permission

View management screens

setTimeoutMinutes(self, timeout_mins, period=20):

Set the number of minutes of inactivity allowable for subobjects before they expire (timeout_mins) as well as the timeout resolution in seconds (period). timeout_mins * 60 must be evenly divisible by the period. Period must be less than timeout_mins * 60.

Permission

Manage Transient Object Container

new(self, k):

Creates a new subobject of the type supported by this container with key "k" and returns it.

If an object already exists in the container with key "k", a KeyError is raised.

"k" must be a string, else a TypeError is raised.

If the container is full, a MaxTransientObjectsExceeded will be raised.

Permission

Create Transient Objects

getPeriodSeconds(self):

Return the timeout resolution in seconds.

Permission

View management screens

setDelNotificationTarget(self, f):

Cause the before destruction function to be f.

If f is not callable and is a string, treat it as a Zope path to a callable function.

before destruction functions need accept a single argument: item, which is the item being destroyed.

Permission

Manage Transient Object Container

class TransientObject

A transient object is a temporary object contained in a transient object container.

Most of the time you'll simply treat a transient object as a dictionary. You can use Python sub-item notation:

  SESSION['foo']=1
  foo=SESSION['foo']
  del SESSION['foo']

When using a transient object from Python-based Scripts or DTML you can use the get, set, and delete methods instead.

Methods of transient objects are not protected by security assertions.

It's necessary to reassign mutuable sub-items when you change them. For example:

  l=SESSION['myList']
  l.append('spam')
  SESSION['myList']=l

This is necessary in order to save your changes. Note that this caveat is true even for mutable subitems which inherit from the Persistence.Persistent class.

__module__ = __builtin__

Methods

getContainerKey(self):

Returns the key under which the object is "filed" in its container. getContainerKey will often return a differnt value than the value returned by getId.

Permission

Always available

set(self, k, v):

Call __setitem__ with key k, value v.

Permission

Always available

invalidate(self):

Invalidate (expire) the transient object.

Causes the transient object container's "before destruct" method related to this object to be called as a side effect.

Permission

Always available

keys(self):

Return sequence of key elements.

Permission

Always available

items(self):

Return sequence of (key, value) elements.

Permission

Always available

clear(self):

Remove all key/value pairs.

Permission

Always available

get(self, k, default=marker):

Return value associated with key k. If k does not exist and default is not marker, return default, else raise KeyError.

Permission

Always available

update(self, d):

Merge dictionary d into ourselves.

Permission

Always available

getId(self):

Returns a meaningful unique id for the object.

Permission

Always available

getLastAccessed(self):

Return the time the transient object was last accessed in integer seconds-since-the-epoch form.

Permission

Always available

has_key(self, k):

Return true if item referenced by key k exists.

Permission

Always available

values(self):

Return sequence of value elements.

Permission

Always available

getCreated(self):

Return the time the transient object was created in integer seconds-since-the-epoch form.

Permission

Always available

setLastAccessed(self):

Cause the last accessed time to be set to now.

Permission

Always available

delete(self, k):

Call __delitem__ with key k.

Permission

Always available

class MaxTransientObjectsExceeded

An exception importable from the Products.Transience.Transience module which is raised when an attempt is made to add an item to a TransientObjectContainer that is full.

This exception may be caught in PythonScripts through a normal import. A successful import of the exception can be achieved via:

  from Products.Transience import MaxTransientObjectsExceeded

__module__ = __builtin__