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Command-Line Pyramid

Your :app:`Pyramid` application can be controlled and inspected using a variety of command-line utilities. These utilities are documented in this chapter.

Displaying Matching Views for a Given URL

For a big application with several views, it can be hard to keep the view configuration details in your head, even if you defined all the views yourself. You can use the paster pviews command in a terminal window to print a summary of matching routes and views for a given URL in your application. The paster pviews command accepts two arguments. The first argument to pviews is the path to your application's .ini file and section name inside the .ini file which points to your application. This should be of the format config_file#section_name. The second argument is the URL to test for matching views. The section_name may be omitted; if it is, it's considered to be main.

Here is an example for a simple view configuration using :term:`traversal`:

The output always has the requested URL at the top and below that all the views that matched with their view configuration details. In this example only one view matches, so there is just a single View section. For each matching view, the full code path to the associated view callable is shown, along with any permissions and predicates that are part of that view configuration.

A more complex configuration might generate something like this:

In this case, we are dealing with a :term:`URL dispatch` application. This specific URL has two matching routes. The matching route information is displayed first, followed by any views that are associated with that route. As you can see from the second matching route output, a route can be associated with more than one view.

For a URL that doesn't match any views, paster pviews will simply print out a Not found message.

The Interactive Shell

Once you've installed your program for development using setup.py develop, you can use an interactive Python shell to execute expressions in a Python environment exactly like the one that will be used when your application runs "for real". To do so, use the paster pshell command.

The argument to pshell follows the format config_file#section_name where config_file is the path to your application's .ini file and section_name is the app section name inside the .ini file which points to your application. For example, if your application .ini file might have a [app:main] section that looks like so:

If so, you can use the following command to invoke a debug shell using the name MyProject as a section name:

chrism@thinko env26]$ bin/paster pshell starter/development.ini#MyProject
Python 2.6.5 (r265:79063, Apr 29 2010, 00:31:32)
[GCC 4.4.3] on linux2
Type "help" for more information.

Environment:
  app          The WSGI application.
  registry     Active Pyramid registry.
  request      Active request object.
  root         Root of the default resource tree.
  root_factory Default root factory used to create `root`.

>>> root
<myproject.resources.MyResource object at 0x445270>
>>> registry
<Registry myproject>
>>> registry.settings['pyramid.debug_notfound']
False
>>> from myproject.views import my_view
>>> from pyramid.request import Request
>>> r = Request.blank('/')
>>> my_view(r)
{'project': 'myproject'}

The WSGI application that is loaded will be available in the shell as the app global. Also, if the application that is loaded is the :app:`Pyramid` app with no surrounding middleware, the root object returned by the default :term:`root factory`, registry, and request will be available.

You can also simply rely on the main default section name by omitting any hash after the filename:

chrism@thinko env26]$ bin/paster pshell starter/development.ini

Press Ctrl-D to exit the interactive shell (or Ctrl-Z on Windows).

Extending the Shell

It is convenient when using the interactive shell often to have some variables significant to your application already loaded as globals when you start the pshell. To facilitate this, pshell will look for a special [pshell] section in your INI file and expose the subsequent key/value pairs to the shell. Each key is a variable name that will be global within the pshell session; each value is a :term:`dotted Python name`. If specified, the special key setup should be a :term:`dotted Python name` pointing to a callable that accepts the dictionary of globals that will be loaded into the shell. This allows for some custom initializing code to be executed each time the pshell is run. The setup callable can also be specified from the commandline using the --setup option which will override the key in the INI file.

For example, you want to expose your model to the shell, along with the database session so that you can mutate the model on an actual database. Here, we'll assume your model is stored in the myapp.models package.

By defining the setup callable, we will create the module myapp.lib.pshell containing a callable named setup that will receive the global environment before it is exposed to the shell. Here we mutate the environment's request as well as add a new value containing a WebTest version of the application to which we can easily submit requests.

When this INI file is loaded, the extra variables m, session and t will be available for use immediately. Since a setup callable was also specified, it is executed and a new variable testapp is exposed, and the request is configured to generate urls from the host http://www.example.com. For example:

chrism@thinko env26]$ bin/paster pshell starter/development.ini
Python 2.6.5 (r265:79063, Apr 29 2010, 00:31:32)
[GCC 4.4.3] on linux2
Type "help" for more information.

Environment:
  app          The WSGI application.
  registry     Active Pyramid registry.
  request      Active request object.
  root         Root of the default resource tree.
  root_factory Default root factory used to create `root`.
  testapp      <webtest.TestApp object at ...>

Custom Variables:
  m            myapp.models
  session      myapp.models.DBSession
  t            transaction

>>> testapp.get('/')
<200 OK text/html body='<!DOCTYPE...l>\n'/3337>
>>> request.route_url('home')
'https://www.example.com/'

IPython

If you have IPython installed in the interpreter you use to invoke the paster command, the pshell command will use an IPython interactive shell instead of a standard Python interpreter shell. If you don't want this to happen, even if you have IPython installed, you can pass the --disable-ipython flag to the pshell command to use a standard Python interpreter shell unconditionally.

[chrism@vitaminf shellenv]$ ../bin/paster pshell --disable-ipython \
                             development.ini#MyProject

Displaying All Application Routes

You can use the paster proutes command in a terminal window to print a summary of routes related to your application. Much like the paster pshell command (see :ref:`interactive_shell`), the paster proutes command accepts one argument with the format config_file#section_name. The config_file is the path to your application's .ini file, and section_name is the app section name inside the .ini file which points to your application. By default, the section_name is main and can be omitted.

For example:

paster proutes generates a table. The table has three columns: a Name column, a Pattern column, and a View column. The items listed in the Name column are route names, the items listed in the Pattern column are route patterns, and the items listed in the View column are representations of the view callable that will be invoked when a request matches the associated route pattern. The view column may show None if no associated view callable could be found. If no routes are configured within your application, nothing will be printed to the console when paster proutes is executed.

Displaying "Tweens"

A :term:`tween` is a bit of code that sits between the main Pyramid application request handler and the WSGI application which calls it. A user can get a representation of both the implicit tween ordering (the ordering specified by calls to :meth:`pyramid.config.Configurator.add_tween`) and the explicit tween ordering (specified by the pyramid.tweens configuration setting) orderings using the paster ptweens command. Tween factories will show up represented by their standard Python dotted name in the paster ptweens output.

For example, here's the paster pwteens command run against a system configured without any explicit tweens:

Here's the paster pwteens command run against a system configured with explicit tweens defined in its development.ini file:

Here's the application configuration section of the development.ini used by the above paster ptweens command which reprorts that the explicit tween chain is used:

See :ref:`registering_tweens` for more information about tweens.

Writing a Script

All web applications are, at their hearts, systems which accept a request and return a response. When a request is accepted by a :app:`Pyramid` application, the system receives state from the request which is later relied on by your application code. For example, one :term:`view callable` may assume it's working against a request that has a request.matchdict of a particular composition, while another assumes a different composition of the matchdict.

In the meantime, it's convenient to be able to write a Python script that can work "in a Pyramid environment", for instance to update database tables used by your :app:`Pyramid` application. But a "real" Pyramid environment doesn't have a completely static state independent of a request; your application (and Pyramid itself) is almost always reliant on being able to obtain information from a request. When you run a Python script that simply imports code from your application and tries to run it, there just is no request data, because there isn't any real web request. Therefore some parts of your application and some Pyramid APIs will not work.

For this reason, :app:`Pyramid` makes it possible to run a script in an environment much like the environment produced when a particular :term:`request` reaches your :app:`Pyramid` application. This is achieved by using the :func:`pyramid.paster.bootstrap` command in the body of your script.

Note

This feature is new as of :app:`Pyramid` 1.1.

In the simplest case, :func:`pyramid.paster.bootstrap` can be used with a single argument, which accepts the :term:`PasteDeploy` .ini file representing Pyramid your application configuration as a single argument:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini')
print env['request'].route_url('home')

:func:`pyramid.paster.bootstrap` returns a dictionary containing framework-related information. This dictionary will always contain a :term:`request` object as its request key.

The following keys are available in the env dictionary returned by :func:`pyramid.paster.bootstrap`:

request

A :class:`pyramid.request.Request` object implying the current request state for your script.

app

The :term:`WSGI` application object generated by bootstrapping.

root

The :term:`resource` root of your :app:`Pyramid` application. This is an object generated by the :term:`root factory` configured in your application.

registry

The :term:`application registry` of your :app:`Pyramid` application.

closer

A parameterless callable that can be used to pop an internal :app:`Pyramid` threadlocal stack (used by :func:`pyramid.threadlocal.get_current_registry` and :func:`pyramid.threadlocal.get_current_request`) when your scripting job is finished.

Let's assume that the /path/to/my/development.ini file used in the example above looks like so:

[pipeline:main]
pipeline = translogger
           another

[filter:translogger]
filter_app_factory = egg:Paste#translogger
setup_console_handler = False
logger_name = wsgi

[app:another]
use = egg:MyProject

The configuration loaded by the above bootstrap example will use the configuration implied by the [pipeline:main] section of your configuration file by default. Specifying /path/to/my/development.ini is logically equivalent to specifying /path/to/my/development.ini#main. In this case, we'll be using a configuration that includes an app object which is wrapped in the Paste "translogger" middleware (which logs requests to the console).

You can also specify a particular section of the PasteDeploy .ini file to load instead of main:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini#another')
print env['request'].route_url('home')

The above example specifies the another app, pipeline, or composite section of your PasteDeploy configuration file. The app object present in the env dictionary returned by :func:`pyramid.paster.bootstrap` will be a :app:`Pyramid` :term:`router`.

Changing the Request

By default, Pyramid will generate a request object in the env dictionary for the URL http://localhost:80/. This means that any URLs generated by Pyramid during the execution of your script will be anchored here. This is generally not what you want.

So how do we make Pyramid generate the correct URLs?

Assuming that you have a route configured in your application like so:

config.add_route('verify', '/verify/{code}')

You need to inform the Pyramid environment that the WSGI application is handling requests from a certain base. For example, we want to mount our application at example.com/prefix and the generated URLs should use HTTPS. This can be done by mutating the request object:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini#another')
env['request'].host = 'example.com'
env['request'].scheme = 'https'
env['request'].script_name = '/prefix'
print env['request'].application_url
# will print 'https://example.com/prefix/another/url'

Now you can readily use Pyramid's APIs for generating URLs:

env['request'].route_url('verify', code='1337')
# will return 'https://example.com/prefix/verify/1337'

Cleanup

When your scripting logic finishes, it's good manners (but not required) to call the closer callback:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini')

# .. do stuff ...

env['closer']()

Setting Up Logging

By default, :func:`pyramid.paster.bootstrap` does not configure logging parameters present in the configuration file. If you'd like to configure logging based on [logger] and related sections in the configuration file, use the following command:

import logging.config
logging.config.fileConfig('/path/to/my/development.ini')
Something went wrong with that request. Please try again.