Файл: pyramid.pdf

37. SQLALCHEMY + URL DISPATCH WIKI TUTORIAL

37.2 Design

Following is a quick overview of the design of our wiki application, to help us understand the changes that we will be making as we work through the tutorial.

37.2.1 Overall

We choose to use reStructuredText markup in the wiki text. Translation from reStructuredText to HTML is provided by the widely used docutils Python module. We will add this module in the dependency list on the project setup.py file.

37.2.2 Models

We’ll be using a SQLite database to hold our wiki data, and we’ll be using SQLAlchemy to access the data in this database.

Within the database, we define a single table named tables, whose elements will store the wiki pages. There are two columns: name and data.

URLs like /PageName will try to find an element in the table that has a corresponding name.

To add a page to the wiki, a new row is created and the text is stored in data.

A page named FrontPage containing the text This is the front page, will be created when the storage is initialized, and will be used as the wiki home page.

37.2.3 Views

There will be four views to handle the normal operations of adding and editing wiki pages, and viewing pages and the wiki front page. Two additional views will handle the login and logout tasks related to security.

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37.2. DESIGN

37.2.4 Security

We’ll eventually be adding security to our application. The components we’ll use to do this are below.

• USERS, a dictionary mapping users names to their corresponding passwords.

• GROUPS, a dictionary mapping user names to a list of groups they belong to.

• groupfinder, an authorization callback that looks up USERS and GROUPS. It will be provided

37.2.5 Summary

The URL, actions, template and permission associated to each view are listed in the following table:

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37. SQLALCHEMY + URL DISPATCH WIKI TUTORIAL

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37.3. INSTALLATION

37.3 Installation

This tutorial assumes that Python and virtualenv are already installed and working in your system. If you need help setting this up, you should refer to the chapters on Installing Pyramid.

37.3.1 Preparation

Please take the following steps to prepare for the tutorial. The steps are slightly different depending on whether you’re using UNIX or Windows.

Preparation, UNIX

1.Install SQLite3 and its development packages if you don’t already have them installed. Usually this is via your system’s package manager. For example, on a Debian Linux system, do sudo apt-get install libsqlite3-dev.

2.Use your Python’s virtualenv to make a workspace:

$path/to/my/Python-2.6/bin/virtualenv --no-site-packages pyramidtut

3.Switch to the pyramidtut directory:

$cd pyramidtut

4.Use easy_install to get Pyramid and its direct dependencies installed:

$bin/easy_install pyramid

Preparation, Windows

1. Use your Python’s virtualenv to make a workspace:

c:\> c:\Python26\Scripts\virtualenv --no-site-packages pyramidtut

2. Switch to the pyramidtut directory:

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37. SQLALCHEMY + URL DISPATCH WIKI TUTORIAL

c:\> cd pyramidtut

3. Use easy_install to get Pyramid and its direct dependencies installed:

c:\pyramidtut> Scripts\easy_install pyramid

37.3.2 Making a Project

Your next step is to create a project. Pyramid supplies a variety of scaffolds to generate sample projects. We will use the alchemy scaffold, which generates an application that uses SQLAlchemy and URL dispatch.

The below instructions assume your current working directory is the “virtualenv” named “pyramidtut”.

On UNIX:

$ bin/pcreate -s alchemy tutorial

On Windows:

c:\pyramidtut> Scripts\pcreate -s alchemy tutorial

latex-note.png

If you are using Windows, the alchemy scaffold may not deal gracefully with installation into a location that contains spaces in the path. If you experience startup problems, try putting both the virtualenv and the project into directories that do not contain spaces in their paths.

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37.3. INSTALLATION

37.3.3 Installing the Project in “Development Mode”

In order to do development on the project easily, you must “register” the project as a development egg in your workspace using the setup.py develop command. In order to do so, cd to the “tutorial” directory you created in Making a Project, and run the “setup.py develop” command using virtualenv Python interpreter.

On UNIX:

$ cd tutorial

$ ../bin/python setup.py develop

On Windows:

c:\pyramidtut> cd tutorial

c:\pyramidtut\tutorial> ..\Scripts\python setup.py develop

Success executing this command will end with a line to the console something like:

Finished processing dependencies for tutorial==0.0

37.3.4 Running the Tests

After you’ve installed the project in development mode, you may run the tests for the project.

On UNIX:

$ ../bin/python setup.py test -q

On Windows:

c:\pyramidtut\tutorial> ..\Scripts\python setup.py test -q

For a successful test run, you should see output that ends like this:

.

----------------------------------------------------------------------

Ran 1 test in 0.094s

OK

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37. SQLALCHEMY + URL DISPATCH WIKI TUTORIAL

37.3.5 Exposing Test Coverage Information

You can run the nosetests command to see test coverage information. This runs the tests in the same way that setup.py test does but provides additional “coverage” information, exposing which lines of your project are “covered” (or not covered) by the tests.

To get this functionality working, we’ll need to install a couple of other packages into our virtualenv: nose and coverage:

On UNIX:

$ ../bin/easy_install nose coverage

On Windows:

c:\pyramidtut\tutorial> ..\Scripts\easy_install nose coverage

Once nose and coverage are installed, we can actually run the coverage tests. On UNIX:

$ ../bin/nosetests --cover-package=tutorial --cover-erase --with-coverage

On Windows:

c:\pyramidtut\tutorial> ..\Scripts\nosetests --cover-package=tutorial ^ --cover-erase --with-coverage

If successful, you will see output something like this:

----------------------------------------------------------------------

Ran 1 test in 0.459s

OK

Looks like our package doesn’t quite have 100% test coverage.

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