# Serving Wiki Pages

We are now able to create, edit and delete Wiki Pages, but we are still unable to serve them.

Without serving pages our wiki is actually useless, so we are going to add a controller and template to make them available.

## WebSite Index

To make our wiki navigable we are going to create a new index page with a sidebar containing all the available wiki pages, so the user can easily move around.

### Pages Slug and Content

To create links to the pages and display their content we are going to add url and html_content properties to the page model. The first property will create the slug for the model and provide the url where the page is available, while the second will give back the page content parsed accordingly to the Markdown language.

To generate the slugs we are going to use `tgext.datahelpers`, so the first thing we are going to do is add it to our project `setup.py` file inside the `install_requires` list:

    install_requires=[
        "TurboGears2 >= 2.3.4",
        "Genshi",
        "zope.sqlalchemy >= 0.4",
        "sqlalchemy",
        "alembic",
        "repoze.who",
        "tw2.forms",
        "tgext.admin >= 0.6.1",
        "webhelpers",
        "tgext.datahelpers"
    ]

Then we need to run again `pip install -e .` to install our new project dependency:

    (tg22env)$ pip install -e .
    Successfully installed tgext.datahelpers wikir
    Cleaning up...

Now that we installed the datahelpers we can add the url and html_content properties to our WikiPage model. Our model should end up looking like:

    #all the other sqlalchemy imports here...
    import tg
    from tgext.datahelpers.utils import slugify
    from webhelpers.html.converters import markdown

    class WikiPage(DeclarativeBase):
        __tablename__ = 'page'

        uid = Column(Integer, primary_key=True)
        updated_at = Column(DateTime, default=datetime.utcnow, nullable=False)
        title = Column(Unicode(255), nullable=False, unique=True)
        data = Column(Unicode(4096), nullable=False, default='')

        @property
        def url(self):
            return tg.url('/'+slugify(self, self.title))

        @property
        def html_content(self):
            return markdown(self.data)

        class __sprox__(object):
            hide_fields =  ['updated_at']
            field_widget_args = {'data': {'rows':15}}

### Index Controller

Now that we are able to retrieve the url for each wiki page, we need to retrieve the list of the wiki pages with their urls so that our index page can display the sidebar.

Our index page is a wiki page itself, so we are also going to load up it’s content from the page titled “index”.

To do so we must edit the `RootController` class inside the `wikir/controllers/root.py` file and look for the index method. When you found it change it to look like:

    @expose('wikir.templates.index')
    def index(self):
        wikipages = [(w.url, w.title) for w in DBSession.query(model.WikiPage).filter(model.WikiPage.title!='index')]

        indexpage = DBSession.query(model.WikiPage).filter_by(title='index').first()
        if not indexpage:
            content = 'Index page not available, please create a page titled index'
        else:
            content = indexpage.html_content

        return dict(page='index', wikipages=wikipages, content=content)

TurboGears2 controllers are just plain python methods with an `@expose` decorator. The @expose decorator tells to TurboGears2 which template the controller is going to display and make so that all the data that our controller returns will be available inside the template itself.

If you are still asking yourself why connecting to http://localhost:8080/ you ended up being served by the RootController.index method you probably want to take a look at TurboGears2 documentation about Writing Controllers and try to understand how Object Dispatch routing works.

### Index Template

Now, if you reloaded to your index page you probably already noticed that nothing changed. This is because our controller retrieved the wiki pages, but we didn’t expose them in the index template in any place.

The index template is available as `wikir/templates/index.html` which is exactly the same path written inside the @expose decorator but with / replaced by dots and without the template extension.

We are going to provide a really simple template, so what is currently available inside the file is going to just be removed and replaced with:

    <html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:py="http://genshi.edgewall.org/"
          xmlns:xi="http://www.w3.org/2001/XInclude">

      <xi:include href="master.html" />

    <head>
      <title>TurboGears2 Wikier Index</title>
    </head>

    <body>
      <div class="row">
        <div class="col-md-3">
          <ul>
           <li py:for="url, title in wikipages">
              <a href="${url}">${title}</a>
           </li>
          </ul>
        </div>
        <div class="col-md-9">
          <div>
           ${Markup(content)}
          </div>
        </div>
      </div>
    </body>
    </html>

## Serving all Wiki pages

If you tried clicking on any link in our sidebar your probably noticed that they all lead to a 404 page. This is because we still haven’t implemented any controller method that is able to serve them.

### Page Template

First we are going to create a template for our wiki pages and save it as `wikir/templates/page.html`. The content of our template will look like:

    <html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:py="http://genshi.edgewall.org/"
          xmlns:xi="http://www.w3.org/2001/XInclude">

      <xi:include href="master.html" />

    <head>
      <title>${title}</title>
    </head>

    <body>
      <div class="row">
        <div class="col-md-12">
          <h2>${title}</h2>
          ${Markup(content)}
          <a py:if="request.identity and 'managers' in request.identity['groups']"
             href="${tg.url('/admin/wikipages/%s/edit' % page_id)}">
             edit
          </a>
        </div>
      </div>
    </body>
    </html>

### Page Controller

Now that we have our template we just need to bind it a controller which is going to render the page. To do this we are going to use the special `_default` controller method. This is a method that turbogears will call if it’s unable to find the exact method request by the url.

As our wiki pages have a all different names they will all end up in _default and we will be able to serve them from there. Just edit `wikir/controller/root.py` and add the `_default` method to the `RootController`:

    from tg import validate
    from tgext.datahelpers.validators import SQLAEntityConverter
    from tgext.datahelpers.utils import fail_with

    @expose('wikir.templates.page')
    @validate({'page':SQLAEntityConverter(model.WikiPage, slugified=True)},
              error_handler=fail_with(404))
    def _default(self, page, *args, **kw):
        return dict(page_id=page.uid, title=page.title, content=page.html_content)

The `@validate` decorator makes possible to apply validators to the incoming parameters and if validation fails the specified error_handler is called. In this case we are checking if there is a web page with the given slug. If it fails to find one it will just return a 404 page.

If the page is available the page instance is returned, so our controller ends just returning the data of the page to the template.

If you now point your browser to the index and click any of the links in the sidebar you will see that they now lead to the linked page instead of failing with a 404 like before.

Note

If you don’t have any links in the left bar, just go to the admin page and create as many pages as you like.

Our wiki is actually finished, but in the upcoming sections we are going to see how we can improve it by introducing caching.