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Pagination Quickstart For Turbogears2

Status:Work in progress

Prerequisites

We start where the MovieDemo left off. See the ToscaSample tutorial or download the zipped ToscaWidgetsFormsExample (TODO: must be recreated, not currently available).

Populating The Database

To have some sample data to work with, let’s populate the database with some movies. Add these lines to websetup.py (above transaction.commit()):

movieDatas = [["Into the Wild", 2007],
              ["The Big Lebowsky", 1998],
              ["Pulp Fiction", 1994],
              ["Dead Man", 1995],
              ["Night on Earth", 1991],
              ["Genova", 2008],
              ["Snatch", 2000]]

movies = []
for data in movieDatas:
    movie = Movie()
    movie.title = data[0]
    movie.year = data[1]
    model.DBSession.add(movie)

After you set up your application and restart the server you should now have seven movies listed.

paster setup-app development.ini
paster serve --reload development.ini

Basic Pagination

With a model and some data set up, add webhelpers.paginate to your controller, and create an instance of paginate.Page that you pass to the template.

Import paginate in your controllers/root.py and modify the list() method to look like this:

from webhelpers import paginate

@expose("toscasample.templates.movie_list")
def list(self, page=1):
    """List and paginate all movies in the database"""
    movies = DBSession.query(Movie)
    currentPage = paginate.Page(movies, page, items_per_page=5)
    return dict(movies=currentPage.items, page='ToscaSample Movie list', currentPage=currentPage)

This creates and passes a paginate.Page object to our template, so we can use it there to access a pager().

The subset of items that should be displayed for the current page we get from currentPage.items and display them in the template like we normally would.

Now the pagination can be displayed in the template like this:

Template code in templates/movie_list.html:

<p class="pagelist">${currentPage.pager()}</p>

Now we add some padding to the pagelist and make it centered.

Create a file pagination.css in your public/css/ directory with the following contents and include it in style.css:

CSS in public/css/style.css:

@import url("pagination.css");

CSS in public/css/pagination.css:

.pagelist strong {
        padding: 5px;
}

p.pagelist {
        text-align: center;
}

Your movie listing should now look something like this:

../../_images/tg2pagination_fig1.png

Paginate Decorator

TurboGears provides a convenient paginate() decorator that you can combine with expose(). To use it, you simply have to pass it the name of a collection to paginate. In controller/root.py:

from tg.decorators import paginate as paginatedeco
@expose("toscasample.templates.movie_list_deco")
@paginatedeco("movies", items_per_page=5)
def decolist(self):
    """List and paginate all movies in the database using the
    paginate() decorator."""
    movies = DBSession.query(Movie)
    return dict(movies=movies, page='ToscaSample Movie list')

In your template, you can now use the collection direction since it will be trimed to only contain the current page. You will also have have a basic page navigation with ${tmpl_context.paginators.movies.pager()}:

<ol>
   <li py:for="movie in movies" py:content="movie">Movie title and year</li>
</ol>

<p class="pagelist">
  ${tmpl_context.paginators.movies.pager()}
</p>

Advanced Pagination

More Formatting

Demonstrating some more formating arguments:

${currentPage.pager(format='~3~', page_param='page', show_if_single_page=True)}

See http://www.pylonshq.com/docs/en/0.9.7/thirdparty/webhelpers/paginate/ for more details.

Adding Some Arrow Images

Let’s add some images:

../../_images/arrow-left.png ../../_images/arrow-right.png

Note

These images are public domain - feel free to use them any way you like. Different sizes and the source *.psd are included in the project file.)

Change the pagelist code in templates/movie_list.html:

<p class="pagelist">
        <a class="prevPage" href="/list?page=${currentPage.previous_page}">&nbsp;</a>
        ${currentPage.pager(format='~3~', page_param='page', show_if_single_page=True)}
        <a class="nextPage" href="/list?page=${currentPage.next_page}">&nbsp;</a>
</p>

Add this to the CSS in public/css/pagination.css:

a.prevPage {
        background: url("/images/icons/png/32x32/arrow-left.png") no-repeat;
        padding-left: 18px;
        padding-right: 18px;
        padding-top: 12px;
        padding-bottom: 15px;
        text-decoration: none;
        }

.nextPage {
        background: url("/images/icons/png/32x32/arrow-right.png") no-repeat;
        padding-left: 18px;
        padding-right: 18px;
        padding-top: 12px;
        padding-bottom: 15px;
        text-decoration: none;
        }

And this is what the end result looks like:

../../_images/tg2pagination_fig3.png