ServerZen.Net

The Form Class

We begin by creating a new file, browser.py, which will need to live in ploneexample.formlib/ploneexample/formlib/. The browser.py file will comprise the bulk of the necessary work. Lets start by adding the necessary imports.

from zope import interface, schema
from zope.formlib import form
from Products.CMFCore import utils as cmfutils
from Products.Five.browser import pagetemplatefile
from Products.Five.formlib import formbase

Next we’ll construct our first Zope 3 interface:

class ISearch(interface.Interface):
    text = schema.TextLine(title=u'Search Text',
                           description=u'The text to search for',
                           required=False)

    description = schema.TextLine(title=u'Description',
                                  required=False)

The purpose of the interface in this case is not to describe a particular content object but instead to define the fields that formlib will use. Later on we’ll discover how tradtional interfaces used to describe actual content classes can be used in combination with formlib to autogenerate proper add and edit forms for content.

And now for the form view class itself. We will start with the first part of the class definition.

class SearchForm(formbase.PageForm):
    form_fields = form.FormFields(ISearch)
    result_template = pagetemplatefile.ZopeTwoPageTemplateFile('search-results.pt')

We use the PageForm class as our super class to inherit functionality from formlib itself. By default, PageForm knows how to generate all the HTML that will make up of our finished form. But in order to do this, formlib needs to know what fields we want. We do this by providing the form_fields attribute. FormFields is a formlib helper class that generates the appropriate field items from any Zope 3 schema (in this case, the schema interface we just defined).

The result_template attribute defines a new page template that we will use to iterate over all of the results of our search.

Next we define an action for our form:

@form.action("search")
def action_search(self, action, data):
    catalog = cmfutils.getToolByName(self.context, 'portal_catalog')

    kwargs = {}
    if data['text']:
        kwargs['SearchableText'] = data['text']
    if data['description']:
        kwargs['description'] = data['description']

    self.search_results = catalog(**kwargs)
    self.search_results_count = len(self.search_results)
    return self.result_template()

This is where the real work takes place. A formlib action is generally a handler that will somehow get invoked by submitting an HTML form. In this case we create a new action labeled search, that will be used to handle when a user hits the search button. Our formlib-based class will automatically understand how to hook in an search button on the HTML form itself. This particular action handler will return our result template as a result.

The Result Page Template

In order to display the results of our search form we need to setup a simple page template. We will name this template, search-results.pt. Most the of template is pretty uninteresting. But for purposes of this writing we will demonstrate the result printing portion.

<tal:block tal:repeat="single view/search_results">
<div class="single-result">
  <h4>
    <span tal:replace="repeat/single/number"></span>.
    <a tal:content="single/Title" tal:attributes="href single/getURL" href=""></a>
  </h4>
  <p tal:content="single/Description"></p>
</div>
</tal:block>

Since our previous formlib based class was a regular view, it gets treated that way inside the page templates. And we are able to assign simple attributes to our view that can get picked up within the template.

Tying It All Together With ZCML

Now that we’ve defined the form class and the result page template to go along with it we need to glue this all into Zope. We do this in configure.zcml.

So we need to add the appropriate ZCML snippet:

<browser:page
    name="search.html"
    for="Products.CMFPlone.Portal.PloneSite"
    class=".browser.SearchForm"
    permission="zope.Public"
    />

Again, since formlib is all based on regular Zope 3 view components, we register them the same way in the ZCML.