collective.z3cform.wizard 1.1

This is a library for creating multi-page wizards using z3c.form. Values are stored in a session until the wizard is finished.

Introduction

This library implements a simple z3c.form-based wizard. The wizard is composed of multiple steps. Each step is a form. Data is stored in a session until the user clicks the Finish button on the last step.

In order to make good use of this library you’ll need to be reasonably familiar with z3c.form first. Here are some places to start:

• Official documentation: http://docs.zope.org/z3c.form

• Slides from Stephan Richter’s tutorial at Plone Conference 2008: http://svn.zope.org/*checkout*/z3c.talk/trunk/Z3CForms/Z3CForms.html?rev=92118

Wizard Step

A wizard step is a normal z3c.form form with a few additional features.

By default, the content accessed by this form will be a dictionary within the wizard’s session, with a key equal to the step’s prefix.

Additional attributes:

wizard

The wizard this step is being used in.

available

Boolean indicating whether the current step can be accessed via the wizard navigation links. By default, only steps for which there is already data stored in the session can be accessed. (The next and previous steps can always be accessed via the respective buttons regardless of the value of this property.)

completed

Boolean indicating whether the user should be allowed to move on to the next step. Defaults to True. If False, the Continue button will be disabled.

Additional methods:

applyChanges(data)

Saves changes from this step to its content (typically a PersistentDict in the wizard’s session.)

load(context):

Loads the session data for this step based on a context.

apply(context):

Updates a context based on the session data for this step.

Wizard

The wizard is also a form, with a list of steps and built-in logic for moving between those steps.

Class attributes. Override these to affect how the wizard behaves:

steps

A sequence of step classes that will be instantiated when the wizard’s update method is called.

sessionKey

Returns the unique session key used by this wizard instance. By default, this is a tuple of ‘collective.z3cform.wizard’ and the URL path to the wizard.

Attributes set during the update method:

activeSteps

A sequence of wizard step instances.

currentStep

The wizard step instance currently being displayed.

currentIndex

The (0-based) index of the current step within the activeSteps sequence.

session

The session where data for this wizard is persisted.

onFirstStep

Boolean. True if the first step of the wizard is being displayed.

onLastStep

Boolean. True if the last step of the wizard is being displayed.

allStepsFinished

Boolean. True if the ‘available’ attribute of each wizard step is True.

finished

Boolean. True if the wizard has been completed.

absolute_url

The URL of the wizard.

Methods:

initialize()

Called the first time a wizard is viewed in a given session.

This method may be used to populate the session with data from some source.

The default implementation calls the loadSteps method.

loadSteps(context)

Loads the wizard session data from a context.

The default implementation calls the ‘load’ method of each wizard step.

finish()

Called when a wizard is successfully completed, after validation of the final step.

Use this method to carry out some actions based on the values that have been filled out during completion of the wizard.

The default implementation calls the applySteps method.

applySteps(context)

Updates a context based on the wizard session data.

The default implementation calls the ‘apply’ method of each wizard step.

sync()

Mark the session as having changed, to ensure that changes get persisted. This is required since we aren’t using a persistence-aware dictionary class for our session variables.

Compatibility

This package has been tested in Zope 2.10 with Plone 3.3, and in Zope 2.12 with Plone 4.

It should be pretty easy to get it to work in other environments supported by z3c.form, such as Zope 3, but I’ll need someone familiar with those environments to tell me how sessions work there, for example.

Credits

This package is inspired by and based on the non-session-based z3c.form wizard included in the collective.singing package, which was implemented by Daniel Nouri.

Session support, miscellaneous improvements, and repackaging by David Glick.

Changelog

1.1 (2010-03-01)

• Make sure that the Next button is the default if a step is submitted by pressing enter.

1.0 (2010-01-19)

• Include the form’s enctype in the form tag.

• Don’t clear the session when traversing over the form to other things (such as a widget).

1.0b2 (2009-06-25)

• Moved the default wizard CSS to a browser resource which is available but not pulled in by anything by default.

• Adjusted the criteria for visibility of the Finish button so that it shows up on any step as long as data is stored in the session for all steps. Previously it was only shown on the final step.

• Added wizard navigation which lists the wizard’s steps and links to ones that are available.

• Added support in the Wizard class for jumping to a particular step based on an index passed in the request (but only if that step is available).

• Adjusted the URL check that triggers session invalidation to not pay attention to the query string or fragment.

• Changed the updateCurrentStep method of the Wizard class (not part of the public API) to take a single parameter, the target step index.

• Added ‘allStepsFinished’ property to the Wizard class.

• Added ‘available’ property to the Step class.

• Added ‘absolute_url’ property to the Wizard class.

• Reset the wizard session if you leave it before finishing.

1.0b1 (2009-05-12)

• Initial release

Example and tests

Define a wizard with three steps

To define a form that uses the wizard, we’ll need to define steps. These steps represent individual forms that are processed sequentially. Only when the last step is completed will the data be submitted through a user-defined method.

>>> from zope import schema
>>> from z3c.form import field, form
>>> from collective.z3cform.wizard import wizard

>>> class StepOne(wizard.Step):
...     prefix = 'one'
...     fields = field.Fields(
...         schema.Int(__name__='age', title=u"Age"))

By default, the steps will get/set values in the session. If we want to initialize these values or do something with them once the wizard is completed, we need to implement the load and apply methods for our step.

>>> from pprint import pprint
>>> class StepTwo(wizard.Step):
...     prefix = 'two'
...     fields = field.Fields(
...         schema.TextLine(__name__='name', title=u"Name", required=True))
...
...     def load(self, context):
...         data = self.getContent()
...         data['name'] = 'David'
...
...     def apply(self, context):
...         data = self.getContent()
...         pprint('Name from step 2: %s' % data['name'])

>>> class StepThree(wizard.Step):
...     prefix = 'three'
...     fields = field.Fields(
...         schema.TextLine(__name__='color', title=u'Favorite Color', required=False))

We can now define our minimal wizard:

>>> class Wizard(wizard.Wizard):
...     label = u"My silly wizard"
...     steps = StepOne, StepTwo, StepThree

Render the form

Let’s render the form for the first time now:

>>> request = TestRequest()
>>> wizard = Wizard(None, request)
>>> print wizard()
<...
<div class="form" id="wizard-step-one">
  <form action="http://127.0.0.1" method="post"
        class="enableUnloadProtection"
        enctype="multipart/form-data">
      <p class="discreet"></p>
  <div class="row">
      <div class="field">
        <label for="one-widgets-age">
          <span>Age</span>
        </label>...
        <span class="fieldRequired"
              title="Required">
          (Required)
        </span>
        <div class="widget">
          <input id="one-widgets-age" name="one.widgets.age"
                 class="text-widget required int-field" value=""
                 type="text" />
        </div>
      </div>
  </div>
  <hr />
  <div class="wizard-buttons">
      <div class="action">
          <input id="form-buttons-continue"
                 name="form.buttons.continue"
                 class="submit-widget button-field" value="Continue"
                 type="submit" />
      </div>
  </div>
  </form>
</div>

Submit with an error

Remember that our first step requires the age.

>>> request.form = {
...     'form.buttons.continue': u'Continue',
... }
>>> wizard = Wizard(None, request)
>>> print wizard()
<...
<div class="form" id="wizard-step-one">
...There were errors...
...Required input is missing...

Submit the first step successfully

>>> request.form['one.widgets.age'] = u'27'
>>> wizard = Wizard(None, request)
>>> print wizard()
<...
<div class="form" id="wizard-step-two">
  <form action="http://127.0.0.1" method="post"
        class="enableUnloadProtection"
        enctype="multipart/form-data">
      <p class="discreet"></p>
  <div class="row">
      <div class="field">
        <label for="two-widgets-name">
          <span>Name</span>
        </label>
        <span class="fieldRequired"
              title="Required">
          (Required)
        </span>
        <div class="widget">
          <input id="two-widgets-name" name="two.widgets.name"
                 class="text-widget required textline-field"
                 value="David" type="text" />
        </div>
      </div>
  </div>
    <hr />
    <div class="wizard-buttons">
        <div class="action">
          <input id="form-buttons-back" name="form.buttons.back"
                 class="submit-widget button-field" value="Back"
                 type="submit" />
        </div>
        <div class="action">
          <input id="form-buttons-continue"
                 name="form.buttons.continue"
                 class="submit-widget button-field" value="Continue"
                 type="submit" />
        </div>
    </div>
  </form>
</div>

Submitting step two

Step two works similarly:

>>> request.form['two.widgets.name'] = u'David'
>>> wizard = Wizard(None, request)
>>> html = wizard()
>>> 'three' in html, 'Finish' in html
(True, True)

Step three: Slaying the dragon

Now let’s press the Finish button. We expect this to print out the value from step 2, thanks to the ‘apply’ method we implemented for that step.

Remembering that in our wizard, we implemented finish to print out the data that it receives. Here’s the finishing move:

>>> request.form['form.buttons.finish'] = u'Finish'
>>> wizard = Wizard(None, request)
>>> html = wizard()
'Name from step 2: David'

>>> print html
<...
<div class="form">
  <div class="portalMessage">Information submitted successfully.</div>
</div>...

Example

See the collective.megaphone package for an example of this library in use.