3:遍历层次结构

Objects with subobjects and views, all via URLs.

背景

在 2：有立地根的基本导线测量

在这一步中，我们保持简单，但建立一个基本的层次结构：

/
   doc1
   doc2
   folder1/
      doc1

目标

• 使用Python对象的多级嵌套层次结构。

• 展示如何 __name__ 和 __parent__

• 使用在请求之间持续的对象。

步骤

1. 我们将使用前面的步骤作为起点：

   $ cd ..; cp -r siteroot hierarchy; cd hierarchy
   $ $VENV/bin/python setup.py develop
   

2. Provide a richer set of objects in hierarchy/tutorial/resources.py ：

   class Folder(dict):
       def __init__(self, name, parent, title):
           self.__name__ = name
           self.__parent__ = parent
           self.title = title
   
   
   class Root(Folder):
       pass
   
   
   class Document(object):
       def __init__(self, name, parent, title):
           self.__name__ = name
           self.__parent__ = parent
           self.title = title
   
   # Done outside bootstrap to persist from request to request
   root = Root('', None, 'My Site')
   
   
   def bootstrap(request):
       if not root.values():
           # No values yet, let's make:
           # /
           #   doc1
           #   doc2
           #   folder1/
           #      doc1
           doc1 = Document('doc1', root, 'Document 01')
           root['doc1'] = doc1
           doc2 = Document('doc2', root, 'Document 02')
           root['doc2'] = doc2
           folder1 = Folder('folder1', root, 'Folder 01')
           root['folder1'] = folder1
   
           # Only has to be unique in folder
           doc11 = Document('doc1', folder1, 'Document 01')
           folder1['doc1'] = doc11
   
       return root
   

3. 有 hierarchy/tutorial/views.py

   from pyramid.location import lineage
   from pyramid.view import view_config
   
   
   class TutorialViews:
       def __init__(self, context, request):
           self.context = context
           self.request = request
           self.parents = reversed(list(lineage(context)))
   
       @view_config(renderer='templates/home.jinja2')
       def home(self):
           page_title = 'Quick Tutorial: Home'
           return dict(page_title=page_title)
   
       @view_config(name='hello', renderer='templates/hello.jinja2')
       def hello(self):
           page_title = 'Quick Tutorial: Hello'
           return dict(page_title=page_title)
   

4. 更新 hierarchy/tutorial/templates/home.jinja2 查看模板：

   {% extends "templates/layout.jinja2" %}
   {% block content %}
   
     <ul>
       <li><a href="/">Site Folder</a></li>
       <li><a href="/doc1">Document 01</a></li>
       <li><a href="/doc2">Document 02</a></li>
       <li><a href="/folder1">Folder 01</a></li>
       <li><a href="/folder1/doc1">Document 01 in Folder 01</a></li>
     </ul>
   
     <h2>{{ context.title }}</h2>
   
     <p>Welcome to {{ context.title }}. Visit
       <a href="{{ request.resource_url(context, 'hello') }}">hello</a>
     </p>
   
   {% endblock content %}
   

5. 这个 hierarchy/tutorial/templates/breadcrumbs.jinja2

   {% for p in view.parents %}
   <span>
     <a href="{{ request.resource_url(p) }}">{{ p.title }}</a>
   >> </span>
   {% endfor %}
   

6. Update the tests in hierarchy/tutorial/tests.py ：

   import unittest
   
   from pyramid.testing import DummyRequest
   from pyramid.testing import DummyResource
   
   
   class TutorialViewsUnitTests(unittest.TestCase):
       def test_home_view(self):
           from .views import TutorialViews
   
           request = DummyRequest()
           title = 'Dummy Context'
           context = DummyResource(title=title, __name__='dummy')
           inst = TutorialViews(context, request)
           result = inst.home()
           self.assertIn('Home', result['page_title'])
   
   
   class TutorialFunctionalTests(unittest.TestCase):
       def setUp(self):
           from tutorial import main
           app = main({})
           from webtest import TestApp
           self.testapp = TestApp(app)
   
       def test_home(self):
           result = self.testapp.get('/', status=200)
           self.assertIn(b'Site Folder', result.body)
   

7. 现在运行测试：

   $ $VENV/bin/nosetests tutorial
   ..
   ----------------------------------------------------------------------
   Ran 2 tests in 0.141s
   
   OK
   

8. 运行 Pyramid 应用程序时使用：

   $ $VENV/bin/pserve development.ini --reload
   

9. 在浏览器中打开http://localhost:6543/。

分析

__name__ as an identifier on each child, and __parent__ as a reference to the parent. The template used now shows different information based on the object URL to which you traversed.

@view_config can set a "default" view on a context by omitting the @name 属性。Thus, if you visit http://localhost:6543/folder1/

Extra Credit

1. 在 resources.py root out to global scope. 为什么？

2. 如果你去一个不存在的资源， Pyramid 会优雅地处理它吗？

3. 如果您请求一个资源的默认视图，但未配置任何视图， Pyramid 会处理得当吗？