Pagelets are way to specify a template without the O-wrap.
Project description
Pagelets are Zope 3 UI components. In particular they allow the developer to specify content templates without worrying about the UI O-wrap.
Pagelets
This package provides a very flexible base implementation that can be used to write view components which can be higly customized later in custom projects. This is needed if you have to write reusable components like those needed in a framework. Pagelets are BrowserPages made differently and can be used to replace them.
What does this mean?
We separate the python view code from the template implementation. And we also separate the template in at least two different templates - the content template and the layout template.
This package uses z3c.template and offers an implementaton for this template pattern. Additionaly this package offers a pagelet directive wich can be used to register pagelets.
Pagelets are views which can be called and support the update and render pattern.
How do they work
A pagelet returns the rendered content without layout in the render method and returns the layout code if we call it. See also z3c.template which shows how the template works. These samples will only show how the base implementation located in the z3c.pagelet.browser module get used.
BrowserPagelet
The base implementation called BrowserPagelet offers builtin __call__ and render methods which provide the different template lookups. Take a look at the BrowserPagelet class located in z3c.pagelet.browser and you can see that the render method returns a IContentTemplate and the __call__ method a ILayoutTemplate defined in the z3c.layout package.
>>> import os, tempfile >>> temp_dir = tempfile.mkdtemp()>>> import zope.interface >>> import zope.component >>> from z3c.pagelet import interfaces >>> from z3c.pagelet import browser
We start by defining a page template rendering the pagelet content.
>>> contentTemplate = os.path.join(temp_dir, 'contentTemplate.pt')
>>> with open(contentTemplate, 'w') as file:
... _ = file.write('''
... <div class="content">
... my template content
... </div>
... ''')
And we also define a layout template rendering the layout for a pagelet. This template will call the render method from a pagelet:
>>> layoutTemplate = os.path.join(temp_dir, 'layoutTemplate.pt')
>>> with open(layoutTemplate, 'w') as file:
... _ = file.write('''
... <html>
... <body>
... <div class="layout" tal:content="structure view/render">
... here comes the content
... </div>
... </body>
... </html>
... ''')
Let’s now register the template for the view and the request. We use the TemplateFactory directly from the z3c.template package. This is commonly done using the ZCML directive called z3c:template. Note that we do use the generic Interface as the view base interface to register the template. This allows us to register a more specific template in the next sample:
>>> from zope.publisher.interfaces.browser import IDefaultBrowserLayer >>> from z3c.template.interfaces import IContentTemplate >>> from z3c.template.template import TemplateFactory >>> factory = TemplateFactory(contentTemplate, 'text/html') >>> zope.component.provideAdapter( ... factory, (zope.interface.Interface, IDefaultBrowserLayer), ... IContentTemplate)
And register the layout template using the Interface as registration base:
>>> from z3c.template.interfaces import ILayoutTemplate >>> factory = TemplateFactory(layoutTemplate, 'text/html') >>> zope.component.provideAdapter(factory, ... (zope.interface.Interface, IDefaultBrowserLayer), ILayoutTemplate)
Now define a view marker interface. Such a marker interface is used to let us register our templates:
>>> class IMyView(zope.interface.Interface): ... pass
And we define a view class inherited from BrowserPagelet and implementing the view marker interface:
>>> @zope.interface.implementer(IMyView) ... class MyView(browser.BrowserPagelet): ... pass
Now test the view class providing the view and check the output:
>>> from zope.publisher.browser import TestRequest
>>> request = TestRequest()
>>> myView = MyView(root, request)
>>> print(myView())
<html>
<body>
<div class="layout">
<div class="content">
my template content
</div>
</div>
</body>
</html>
You can see the render method generates only the content:
>>> print(myView.render()) <div class="content"> my template content </div>
Redirection
The pagelet doesn’t bother rendering itself and its layout when request is a redirection as the rendering doesn’t make any sense with browser requests in that case. Let’s create a view that does a redirection in its update method.
>>> class RedirectingView(MyView):
... def update(self):
... self.request.response.redirect('.')
It will return an empty string when called as a browser page.
>>> redirectRequest = TestRequest() >>> redirectView = RedirectingView(root, redirectRequest) >>> redirectView() == '' True
However, the render method will render pagelet’s template as usual:
>>> print(redirectView.render()) <div class="content"> my template content </div>
PageletRenderer
There is also a standard pattern for calling the render method on pagelet. Using the pagelet renderer which is a IContentProvider makes it possible to reuse existing layout template without the pagelet. If you want to reuse a layout template without a pagelet you simply have to provide another content provider. It’s flexible isn’t it? As next let’s show a sample using the pagelet renderer.
We define a new layout template using the content provider called `pagelet
>>> providerLayout = os.path.join(temp_dir, 'providerLayout.pt')
>>> with open(providerLayout, 'w') as file:
... _ = file.write('''
... <html>
... <body>
... <div class="layout" tal:content="structure provider:pagelet">
... here comes the content
... </div>
... </body>
... </html>
... ''')
and register them. Now we use the specific interface defined in the view:
>>> factory = TemplateFactory(providerLayout, 'text/html') >>> zope.component.provideAdapter(factory, ... (zope.interface.Interface, IDefaultBrowserLayer), ILayoutTemplate)
Now let’s call the view:
>>> try: ... myView() ... except Exception as e: ... print(repr(e)) ContentProviderLookupError(u'pagelet',)
That’s right, we need to register the content provider pagelet before we can use it.
>>> from zope.contentprovider.interfaces import IContentProvider >>> from z3c.pagelet import provider >>> zope.component.provideAdapter(provider.PageletRenderer, ... provides=IContentProvider, name='pagelet')
Now let’s call the view again:
>>> print(myView())
<html>
<body>
<div class="layout">
<div class="content">
my template content
</div>
</div>
</body>
</html>
Context-specific templates
Pagelets are also able to lookup templates using their context object as an additional discriminator, via (self, self.request, self.context) lookup. It’s useful when you want to provide a custom template for some specific content objects. Let’s check that out.
First, let’s define a custom content type and make an object to work with:
>>> class IContent(zope.interface.Interface): ... pass >>> @zope.interface.implementer(IContent) ... class Content(object): ... pass>>> content = Content()
Let’s use our view class we defined earlier. Currently, it will use the layout and content templates we defined for (view, request) before:
>>> myView = MyView(content, request)
>>> print(myView())
<html>
<body>
<div class="layout">
<div class="content">
my template content
</div>
</div>
</body>
</html>
Let’s create context-specific layout and content templates and register them for our IContent interface:
>>> contextLayoutTemplate = os.path.join(temp_dir, 'contextLayoutTemplate.pt') >>> with open(contextLayoutTemplate, 'w') as file: ... _ = file.write(''' ... <html> ... <body> ... <div class="context-layout" tal:content="structure provider:pagelet"> ... here comes the context-specific content ... </div> ... </body> ... </html> ... ''') >>> factory = TemplateFactory(contextLayoutTemplate, 'text/html') >>> zope.component.provideAdapter( ... factory, (zope.interface.Interface, IDefaultBrowserLayer, IContent), ... ILayoutTemplate)>>> contextContentTemplate = os.path.join(temp_dir, 'contextContentTemplate.pt') >>> with open(contextContentTemplate, 'w') as file: ... _ = file.write(''' ... <div class="context-content"> ... my context-specific template content ... </div> ... ''') >>> factory = TemplateFactory(contextContentTemplate, 'text/html') >>> zope.component.provideAdapter( ... factory, (zope.interface.Interface, IDefaultBrowserLayer, IContent), ... IContentTemplate)
Now, our view should use context-specific templates for rendering:
>>> print(myView())
<html>
<body>
<div class="context-layout">
<div class="context-content">
my context-specific template content
</div>
</div>
</body>
</html>
Add, Edit and Display forms (formlib)
What would the pagelet be without any formlib based implementations? We offer base implementations for add, edit and display forms based on the formlib. Note: To make sure these classes get defined, you should have zope.formlib already installed, as z3c.pagelet does not directly depend on zope.formlib because there are other form libraries.
For the next tests we provide a generic form template like those used in formlib. This template is registered within this package as a default for the formlib based mixin classes:
>>> from z3c import pagelet >>> baseDir = os.path.split(pagelet.__file__)[0] >>> formTemplate = os.path.join(baseDir, 'form.pt') >>> factory = TemplateFactory(formTemplate, 'text/html') >>> zope.component.provideAdapter( ... factory, ... (interfaces.IPageletForm, IDefaultBrowserLayer), IContentTemplate)
And we define a new interface including a text attribute:
>>> import zope.schema >>> class IDocument(zope.interface.Interface): ... """A document.""" ... text = zope.schema.TextLine(title=u'Text', description=u'Text attr.')
Also define a content object which implements the interface:
>>> @zope.interface.implementer(IDocument) ... class Document(object): ... text = None >>> document = Document()
PageletAddForm
Now let’s define an add from based on the PageletAddForm class:
>>> from zope.formlib import form
>>> class MyAddForm(browser.PageletAddForm):
... form_fields = form.Fields(IDocument)
... def createAndAdd(self, data):
... title = data.get('title', u'')
... doc = Document()
... doc.title = title
... root['document'] = doc
... return doc
Now render the form:
>>> addForm = MyAddForm(root, request)
>>> print(addForm())
<html>
<body>
<div class="layout">
<form action="http://127.0.0.1" method="post"
enctype="multipart/form-data" class="edit-form"
id="zc.page.browser_form">
<table class="form-fields">
<tr>
<td class="label">
<label for="form.text">
<span class="required">*</span><span>Text</span>
</label>
</td>
<td class="field">
<div class="form-fields-help"
id="field-help-for-form.text">Text attr.</div>
<div class="widget"><input class="textType" id="form.text"
name="form.text" size="20" type="text" value="" /></div>
</td>
</tr>
</table>
<div class="form-controls">
<input type="submit" id="form.actions.add" name="form.actions.add"
value="Add" class="button" />
</div>
</form>
</div>
</body>
</html>
PageletEditForm
Now let’s define an edit form based on the PageletEditForm class:
>>> class MyEditForm(browser.PageletEditForm): ... form_fields = form.Fields(IDocument)
and render the form:
>>> document.text = u'foo'
>>> editForm = MyEditForm(document, request)
>>> print(editForm())
<html>
<body>
<div class="layout">
<form action="http://127.0.0.1" method="post"
enctype="multipart/form-data" class="edit-form"
id="zc.page.browser_form">
<table class="form-fields">
<tr>
<td class="label">
<label for="form.text">
<span class="required">*</span><span>Text</span>
</label>
</td>
<td class="field">
<div class="form-fields-help"
id="field-help-for-form.text">Text attr.</div>
<div class="widget"><input class="textType" id="form.text"
name="form.text" size="20" type="text" value="foo"
/></div>
</td>
</tr>
</table>
<div class="form-controls">
<input type="submit" id="form.actions.apply"
name="form.actions.apply" value="Apply" class="button" />
</div>
</form>
</div>
</body>
</html>
PageletDisplayForm
Now let’s define a display form based on the PageletDisplayForm class…
>>> class MyDisplayForm(browser.PageletDisplayForm): ... form_fields = form.Fields(IDocument)
and render the form:
>>> document.text = u'foo'
>>> displayForm = MyDisplayForm(document, request)
>>> print(displayForm())
<html>
<body>
<div class="layout">
<form action="http://127.0.0.1" method="post"
enctype="multipart/form-data" class="edit-form"
id="zc.page.browser_form">
<table class="form-fields">
<tr>
<td class="label">
<label for="form.text">
<span>Text</span>
</label>
</td>
<td class="field">
<div class="form-fields-help"
id="field-help-for-form.text">Text attr.</div>
<div class="widget">foo</div>
</td>
</tr>
</table>
</form>
</div>
</body>
</html>
Cleanup
>>> import shutil >>> shutil.rmtree(temp_dir)
CHANGES
2.0.0a1 (2013-02-28)
Added support for Python 3.3.
Replaced deprecated zope.interface.implements usage with equivalent zope.interface.implementer decorator.
Dropped support for Python 2.4 and 2.5.
1.3.1 (2012-09-15)
Fix IPageletDirective after a change in zope.component.zcml.IBasicViewInformation
1.3.0 (2011-10-29)
Moved z3c.pt include to extras_require chameleon. This makes the package independent from chameleon and friends and allows to include this dependencies in your own project.
Upgrade to chameleon 2.0 template engine and use the newest z3c.pt and z3c.ptcompat packages adjusted to work with chameleon 2.0.
See the notes from the z3c.ptcompat package:
Update z3c.ptcompat implementation to use component-based template engine configuration, plugging directly into the Zope Toolkit framework.
The z3c.ptcompat package no longer provides template classes, or ZCML directives; you should import directly from the ZTK codebase.
Note that the PREFER_Z3C_PT environment option has been rendered obsolete; instead, this is now managed via component configuration.
Also note that the chameleon CHAMELEON_CACHE environment value changed from True/False to a path. Skip this property if you don’t like to use a cache. None or False defined in buildout environment section doesn’t work. At least with chameleon <= 2.5.4
Attention: You need to include the configure.zcml file from z3c.ptcompat for enable the z3c.pt template engine. The configure.zcml will plugin the template engine. Also remove any custom built hooks which will import z3c.ptcompat in your tests or other places.
1.2.2 (2011-08-18)
Change request interface in pagelet adapter signature e.g. (context, request, pagelet). Switch from IBrowserRequest to IHTTPRequest. This allows to use the pagelet pattern for jsonrpc request which doesn’t provide IBrowserRequest. Also reflect the changes in configure.zcml
1.2.1 (2010-07-29)
zope.app.pagetemplate.metaconfigure.registerType was moved to zope.browserpage, so it gets now imported from there.
Dropped test dependency on zope.app.security, it is no longer needed.
Using python’s doctest instead of deprecated zope.testing.doctest[unit].
1.2.0 (2009-08-27)
Fix untrusted redirect to google.com in tests. It’s now forbidden by default by newer zope.publisher versions.
Change zope.app.publisher dependency to new zope.browserpage, as it has much less dependencies.
1.1.0 (2009-05-28)
Got rid of dependency on zope.app.component by requiring zope.component >= 3.7.
Removed hard dependency on zope.formlib: the pagelet forms now only get defined when zope.formlib is available. Tests still depend on zope.formlib, so it got a test dependency.
Made sure long_description renders fine on pypi.
1.0.3 (2009-02-27)
Allow use of z3c.pt using z3c.ptcompat compatibility layer.
Add support for context-specific layout and content template lookup, using (view, request, context) discriminator. This is compatible with context-specific templates introduced in z3c.template 1.2.0.
Don’t do rendering in pagelet’s __call__ method when request is a redirection.
Add sphinx-based HTML documentation building part to the buildout.
1.0.2 (2008-01-21)
Added a form.zcml which can be included to have a template for PageletAddForm, PageletEditForm and PageletDisplayForm.
1.0.1 (2007-10-08)
Added update() and render() method to IPagelet which was not specified but used.
Fixed a infinite recursion bug when a layout template was registered for “*” but no content template was registered for a pagelet.
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