Creating a Pyramid Project¶
As we saw in Creating Your First Pyramid Application, it’s possible to create a Pyramid application completely manually. However, it’s usually more convenient to use a template to generate a basic Pyramid project.
A project is a directory that contains at least one Python package. You’ll use a template to create a project, and you’ll create your application logic within a package that lives inside the project. Even if your application is extremely simple, it is useful to place code that drives the application within a package, because a package is more easily extended with new code. An application that lives inside a package can also be distributed more easily than one which does not live within a package.
Pyramid comes with a variety of templates that you can use to generate a project. Each template makes different configuration assumptions about what type of application you’re trying to construct.
These templates are rendered using the PasteDeploy paster
script,
and so therefore they are often referred to as “paster templates”.
Paster Templates Included with Pyramid¶
The convenience paster
templates included with Pyramid differ from
each other on a number of axes:
- the persistence mechanism they offer (no persistence mechanism, ZODB, or SQLAlchemy).
- the mechanism they use to map URLs to code (traversal or URL dispatch).
- whether or not the
pyramid_beaker
library is relied upon as the sessioning implementation (as opposed to no sessioning or default sessioning).
The included templates are these:
pyramid_starter
- URL mapping via traversal and no persistence mechanism.
pyramid_zodb
- URL mapping via traversal and persistence via ZODB.
pyramid_routesalchemy
- URL mapping via URL dispatch and persistence via SQLAlchemy
pyramid_alchemy
- URL mapping via traversal and persistence via SQLAlchemy
Note
At this time, each of these templates uses the Chameleon
templating system, which is incompatible with both Jython and PyPy. To
use paster templates to build applications which will run on Jython and
PyPy, you can try the pyramid_jinja2_starter
template which ships as
part of the pyramid_jinja2 package or the pyramid_sqla
paster
template which ships with the pyramid_sqla package (it uses Mako),
both available from PyPI. You can also just use the above paster
templates to build a skeleton and replace the Chameleon template it
includes with a Mako analogue.
Rather than use any of the above templates, Pylons 1 users may feel more
comfortable installing the pyramid_sqla add-on package, which
provides a paster template named pyramid_sqla
. This paster template
configures a Pyramid application in a “Pylons-esque” way, including the use
of a view handler to map URLs to code (it’s much like a Pylons
“controller”).
Creating the Project¶
In Installing Pyramid, you created a virtual Python environment via
the virtualenv
command. To start a Pyramid project, use
the paster
facility installed within the virtualenv. In
Installing Pyramid we called the virtualenv directory env
; the
following command assumes that our current working directory is that
directory.
We’ll choose the pyramid_starter
template for this purpose.
$ bin/paster create -t pyramid_starter
The above command uses the paster
command to create a project using the
pyramid_starter
template. The paster create
command creates project
from a template. To use a different template, such as
pyramid_routesalchemy
, you’d just change the last argument. For example:
$ bin/paster create -t pyramid_routesalchemy
paster create
will ask you a single question: the name of the
project. You should use a string without spaces and with only letters
in it. Here’s sample output from a run of paster create
for a
project we name MyProject
:
$ bin/paster create -t pyramid_starter
Selected and implied templates:
pyramid#pyramid_starter pyramid starter project
Enter project name: MyProject
Variables:
egg: MyProject
package: myproject
project: MyProject
Creating template pyramid
Creating directory ./MyProject
# ... more output ...
Running /Users/chrism/projects/pyramid/bin/python setup.py egg_info
Note
You can skip the interrogative question about a project
name during paster create
by adding the project name to the
command line, e.g. paster create -t pyramid_starter MyProject
.
Note
You may encounter an error when using paster create
if a
dependent Python package is not installed. This will result in a traceback
ending in pkg_resources.DistributionNotFound: <package name>
.
Simply run bin/easy_install
, with the missing package name from the
error message to work around this issue.
As a result of invoking the paster create
command, a project is created
in a directory named MyProject
. That directory is a project
directory. The setup.py
file in that directory can be used to distribute
your application, or install your application for deployment or development.
A PasteDeploy .ini
file named development.ini
will be created
in the project directory. You will use this .ini
file to configure a
server, to run your application, and to and debug your application. It
sports configuration that enables an interactive debugger and settings
optimized for development.
Another PasteDeploy .ini
file named production.ini
will also
be created in the project directory. It sports configuration that disables
any interactive debugger (to prevent inappropriate access and disclosure),
and turns off a number of debugging settings. You can use this file to put
your application into production, and you can modify it to do things like
send email when an exception occurs.
The MyProject
project directory contains an additional subdirectory named
myproject
(note the case difference) representing a Python
package which holds very simple Pyramid sample code. This is
where you’ll edit your application’s Python code and templates.
Installing your Newly Created Project for Development¶
To install a newly created project for development, you should cd
to the
newly created project directory and use the Python interpreter from the
virtualenv you created during Installing Pyramid to invoke the
command python setup.py develop
The file named setup.py
will be in the root of the paster-generated
project directory. The python
you’re invoking should be the one that
lives in the bin
directory of your virtual Python environment. Your
terminal’s current working directory must the the newly created project
directory. For example:
$ ../bin/python setup.py develop
Elided output from a run of this command is shown below:
$ ../bin/python setup.py develop
...
Finished processing dependencies for MyProject==0.0
This will install a distribution representing your project into the
interpreter’s library set so it can be found by import
statements and by
PasteDeploy commands such as paster serve
and paster pshell
.
Running The Tests For Your Application¶
To run unit tests for your application, you should invoke them using the
Python interpreter from the virtualenv you created during
Installing Pyramid (the python
command that lives in the bin
directory of your virtualenv):
$ ../bin/python setup.py test -q
Here’s sample output from a test run:
$ python setup.py test -q
running test
running egg_info
writing requirements to MyProject.egg-info/requires.txt
writing MyProject.egg-info/PKG-INFO
writing top-level names to MyProject.egg-info/top_level.txt
writing dependency_links to MyProject.egg-info/dependency_links.txt
writing entry points to MyProject.egg-info/entry_points.txt
reading manifest file 'MyProject.egg-info/SOURCES.txt'
writing manifest file 'MyProject.egg-info/SOURCES.txt'
running build_ext
..
----------------------------------------------------------------------
Ran 1 test in 0.108s
OK
Note
The -q
option is passed to the setup.py test
command to limit the
output to a stream of dots. If you don’t pass -q
, you’ll see more
verbose test result output (which normally isn’t very useful).
The tests themselves are found in the tests.py
module in your paster
create
-generated project. Within a project generated by the
pyramid_starter
template, a single sample test exists.
The Interactive Shell¶
Once you’ve installed your program for development using setup.py
develop
, you can use an interactive Python shell to examine your
Pyramid project’s resource and view objects from a
Python prompt. To do so, use your virtualenv’s paster pshell
command.
The first argument to pshell
is the path to your application’s .ini
file. The second is the app
section name inside the .ini
file which
points to your application as opposed to any other section within the
.ini
file. For example, if your application .ini
file might have a
[app:MyProject]
section that looks like so:
1 2 3 4 5 6 7 | [app:MyProject]
use = egg:MyProject
reload_templates = true
debug_authorization = false
debug_notfound = false
debug_templates = true
default_locale_name = en
|
If so, you can use the following command to invoke a debug shell using the
name MyProject
as a section name:
[chrism@vitaminf shellenv]$ ../bin/paster pshell development.ini MyProject
Python 2.4.5 (#1, Aug 29 2008, 12:27:37)
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
Type "help" for more information. "root" is the Pyramid app root object,
"registry" is the Pyramid registry object.
>>> root
<myproject.resources.MyResource object at 0x445270>
>>> registry
<Registry myproject>
>>> registry.settings['debug_notfound']
False
>>> from myproject.views import my_view
>>> from pyramid.request import Request
>>> r = Request.blank('/')
>>> my_view(r)
{'project': 'myproject'}
Two names are made available to the pshell user as globals: root
and
registry
. root
is the the object returned by the default root
factory in your application. registry
is the application
registry object associated with your project’s application (often accessed
within view code as request.registry
).
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
You should always use a section name argument that refers to the actual
app
section within the Paste configuration file that points at your
Pyramid application without any middleware wrapping. In particular,
a section name is inappropriate as the second argument to pshell
if the
configuration section it names is a pipeline
rather than an app
. For
example, if you have the following .ini
file content:
1 2 3 4 5 6 7 8 9 10 11 12 | [app:MyProject]
use = egg:MyProject
reload_templates = true
debug_authorization = false
debug_notfound = false
debug_templates = true
default_locale_name = en
[pipeline:main]
pipeline =
egg:WebError#evalerror
MyProject
|
Use MyProject
instead of main
as the section name argument to
pshell
against the above .ini
file (e.g. paster pshell
development.ini MyProject
). If you use main
instead, an error will
occur. Use the most specific reference to your application within the
.ini
file possible as the section name argument.
Press Ctrl-D
to exit the interactive shell (or Ctrl-Z
on Windows).
Running The Project Application¶
Once a project is installed for development, you can run the application it
represents using the paster serve
command against the generated
configuration file. In our case, this file is named development.ini
:
$ ../bin/paster serve development.ini
Here’s sample output from a run of paster serve
:
$ ../bin/paster serve development.ini
Starting server in PID 16601.
serving on 0.0.0.0:6543 view at http://127.0.0.1:6543
By default, Pyramid applications generated from a paster
template
will listen on TCP port 6543. You can shut down a server started this way by
pressing Ctrl-C
.
During development, it’s often useful to run paster serve
using its
--reload
option. When --reload
is passed to paster serve
,
changes to any Python module your project uses will cause the server to
restart. This typically makes development easier, as changes to Python code
made within a Pyramid application is not put into effect until the
server restarts.
For example:
$ ../bin/paster serve development.ini --reload
Starting subprocess with file monitor
Starting server in PID 16601.
serving on 0.0.0.0:6543 view at http://127.0.0.1:6543
For more detailed information about the startup process, see Startup. For more information about environment variables and configuration file settings that influence startup and runtime behavior, see Environment Variables and .ini File Settings.
Viewing the Application¶
Once your application is running via paster serve
, you may visit
http://localhost:6543/
in your browser. You will see something in your
browser like what is displayed in the following image:
This is the page shown by default when you visit an unmodified paster
create
-generated pyramid_starter
application in a browser.
The Project Structure¶
The pyramid_starter
template generated a project (named
MyProject
), which contains a Python package. The package is
also named myproject
, but it’s lowercased; the paster template
generates a project which contains a package that shares its name except for
case.
All Pyramid paster
-generated projects share a similar structure.
The MyProject
project we’ve generated has the following directory
structure:
MyProject/
|-- CHANGES.txt
|-- development.ini
|-- MANIFEST.in
|-- myproject
| |-- __init__.py
| |-- resources.py
| |-- static
| | |-- favicon.ico
| | |-- logo.png
| | `-- pylons.css
| |-- templates
| | `-- mytemplate.pt
| |-- tests.py
| `-- views.py
|-- production.ini
|-- README.txt
|-- setup.cfg
`-- setup.py
The MyProject
Project¶
The MyProject
project directory is the distribution and
deployment wrapper for your application. It contains both the myproject
package representing your application as well as files used to
describe, run, and test your application.
CHANGES.txt
describes the changes you’ve made to the application. It is conventionally written in ReStructuredText format.README.txt
describes the application in general. It is conventionally written in ReStructuredText format.development.ini
is a PasteDeploy configuration file that can be used to execute your application during development.production.ini
is a PasteDeploy configuration file that can be used to execute your application in a production configuration.setup.cfg
is a setuptools configuration file used bysetup.py
.MANIFEST.in
is a distutils “manifest” file, naming which files should be included in a source distribution of the package whenpython setup.py sdist
is run.setup.py
is the file you’ll use to test and distribute your application. It is a standard setuptoolssetup.py
file.
development.ini
¶
The development.ini
file is a PasteDeploy configuration file.
Its purpose is to specify an application to run when you invoke paster
serve
, as well as the deployment settings provided to that application.
The generated development.ini
file looks like so:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | [app:MyProject]
use = egg:MyProject
reload_templates = true
debug_authorization = false
debug_notfound = false
debug_routematch = false
debug_templates = true
default_locale_name = en
[pipeline:main]
pipeline =
egg:WebError#evalerror
MyProject
[server:main]
use = egg:Paste#http
host = 0.0.0.0
port = 6543
# Begin logging configuration
[loggers]
keys = root, myproject
[handlers]
keys = console
[formatters]
keys = generic
[logger_root]
level = INFO
handlers = console
[logger_myproject]
level = DEBUG
handlers =
qualname = myproject
[handler_console]
class = StreamHandler
args = (sys.stderr,)
level = NOTSET
formatter = generic
[formatter_generic]
format = %(asctime)s %(levelname)-5.5s [%(name)s] %(message)s
# End logging configuration
|
This file contains several “sections” including [app:MyProject]
,
[pipeline:main]
, and [server:main]
.
The [app:MyProject]
section represents configuration for your
application. This section name represents the MyProject
application (and
it’s an app
-lication, thus app:MyProject
)
The use
setting is required in the [app:MyProject]
section. The
use
setting points at a setuptools entry point named
MyProject
(the egg:
prefix in egg:MyProject
indicates that this
is an entry point URI specifier, where the “scheme” is “egg”).
egg:MyProject
is actually shorthand for a longer spelling:
egg:MyProject#main
. The #main
part is omitted for brevity, as it is
the default.
The use
setting is the only setting required in the [app:MyProject]
section unless you’ve changed the callable referred to by the
egg:MyProject
entry point to accept more arguments: other settings you
add to this section are passed as keywords arguments to the callable
represented by this entry point (main
in our __init__.py
module).
You can provide startup-time configuration parameters to your application by
adding more settings to this section.
The reload_templates
setting in the [app:MyProject]
section is a
Pyramid -specific setting which is passed into the framework. If it
exists, and its value is true
, Chameleon and Mako
template changes will not require an application restart to be detected. See
Automatically Reloading Templates for more information.
Warning
The reload_templates
option should be turned off for
production applications, as template rendering is slowed when it is
turned on.
The debug_templates
setting in the [app:MyProject]
section is a
Pyramid -specific setting which is passed into the framework. If it
exists, and its value is true
, Chameleon template exceptions will
contained more detailed and helpful information about the error than when
this value is false
. See Nicer Exceptions in Chameleon Templates for more
information.
Warning
The debug_templates
option should be turned off for
production applications, as template rendering is slowed when it is
turned on.
Various other settings may exist in this section having to do with debugging or influencing runtime behavior of a Pyramid application. See Environment Variables and .ini File Settings for more information about these settings.
[pipeline:main]
, has the name main
signifying that this is the
default ‘application’ (although it’s actually a pipeline of middleware and an
application) run by paster serve
when it is invoked against this
configuration file. The name main
is a convention used by PasteDeploy
signifying that it is the default application.
The [server:main]
section of the configuration file configures a WSGI
server which listens on TCP port 6543. It is configured to listen on all
interfaces (0.0.0.0
). The Paste#http
server will create a new thread
for each request.
Note
In general, Pyramid applications generated from paster templates should be threading-aware. It is not required that a Pyramid application be nonblocking as all application code will run in its own thread, provided by the server you’re using.
See the PasteDeploy documentation for more information about other
types of things you can put into this .ini
file, such as other
applications, middleware and alternate WSGI server
implementations.
Note
You can add a [DEFAULT]
section to your development.ini
file.
Such a section should consists of global parameters that are shared by all
the applications, servers and middleware defined within the
configuration file. The values in a [DEFAULT]
section will be passed
to your application’s main
function as global_values
.
production.ini
¶
The development.ini
file is a PasteDeploy configuration file with
a purpose much like that of development.ini
. However, it disables the
WebError interactive debugger, replacing it with a logger which outputs
exception messages to stderr
by default. It also turns off template
development options such that templates are not automatically reloaded when
changed, and turns off all debugging options. You can use this file instead
of development.ini
when you put your application into production.
setup.py
¶
The setup.py
file is a setuptools setup file. It is meant to be
run directly from the command line to perform a variety of functions, such as
testing your application, packaging, and distributing your application.
Note
setup.py
is the defacto standard which Python developers use to
distribute their reusable code. You can read more about setup.py
files
and their usage in the Setuptools documentation.
Our generated setup.py
looks like this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | import os
from setuptools import setup, find_packages
here = os.path.abspath(os.path.dirname(__file__))
README = open(os.path.join(here, 'README.txt')).read()
CHANGES = open(os.path.join(here, 'CHANGES.txt')).read()
requires = ['pyramid', 'WebError']
setup(name='MyProject',
version='0.0',
description='MyProject',
long_description=README + '\n\n' + CHANGES,
classifiers=[
"Programming Language :: Python",
"Framework :: Pylons",
"Topic :: Internet :: WWW/HTTP",
"Topic :: Internet :: WWW/HTTP :: WSGI :: Application",
],
author='',
author_email='',
url='',
keywords='web pyramid pylons',
packages=find_packages(),
include_package_data=True,
zip_safe=False,
install_requires=requires,
tests_require=requires,
test_suite="myproject",
entry_points = """\
[paste.app_factory]
main = myproject:main
""",
paster_plugins=['pyramid'],
)
|
The setup.py
file calls the setuptools setup
function, which does
various things depending on the arguments passed to setup.py
on the
command line.
Within the arguments to this function call, information about your application is kept. While it’s beyond the scope of this documentation to explain everything about setuptools setup files, we’ll provide a whirlwind tour of what exists in this file in this section.
Your application’s name can be any string; it is specified in the name
field. The version number is specified in the version
value. A short
description is provided in the description
field. The
long_description
is conventionally the content of the README and CHANGES
file appended together. The classifiers
field is a list of Trove classifiers
describing your application. author
and author_email
are text fields
which probably don’t need any description. url
is a field that should
point at your application project’s URL (if any).
packages=find_packages()
causes all packages within the project to be
found when packaging the application. include_package_data
will include
non-Python files when the application is packaged if those files are checked
into version control. zip_safe
indicates that this package is not safe
to use as a zipped egg; instead it will always unpack as a directory, which
is more convenient. install_requires
and tests_require
indicate that
this package depends on the pyramid
package. test_suite
points at
the package for our application, which means all tests found in the package
will be run when setup.py test
is invoked. We examined entry_points
in our discussion of the development.ini
file; this file defines the
main
entry point that represents our project’s application.
Usually you only need to think about the contents of the setup.py
file
when distributing your application to other people, or when versioning your
application for your own use. For fun, you can try this command now:
$ python setup.py sdist
This will create a tarball of your application in a dist
subdirectory
named MyProject-0.1.tar.gz
. You can send this tarball to other people
who want to use your application.
Warning
Without the presence of a MANIFEST.in
file or without checking your
source code into a version control repository, setup.py sdist
places
only Python source files (files ending with a .py
extension) into
tarballs generated by python setup.py sdist
. This means, for example,
if your project was not checked into a setuptools-compatible source
control system, and your project directory didn’t contain a MANIFEST.in
file that told the sdist
machinery to include *.pt
files, the
myproject/templates/mytemplate.pt
file would not be included in the
generated tarball.
Projects generated by Pyramid paster templates include a default
MANIFEST.in
file. The MANIFEST.in
file contains declarations
which tell it to include files like *.pt
, *.css
and *.js
in
the generated tarball. If you include files with extensions other than
the files named in the project’s MANIFEST.in
and you don’t make use of
a setuptools-compatible version control system, you’ll need to edit the
MANIFEST.in
file and include the statements necessary to include your
new files. See http://docs.python.org/distutils/sourcedist.html#principle
for more information about how to do this.
You can also delete MANIFEST.in
from your project and rely on a
setuptools feature which simply causes all files checked into a version
control system to be put into the generated tarball. To allow this to
happen, check all the files that you’d like to be distributed along with
your application’s Python files into Subversion. After you do this, when
you rerun setup.py sdist
, all files checked into the version control
system will be included in the tarball. If you don’t use Subversion, and
instead use a different version control system, you may need to install a
setuptools add-on such as setuptools-git
or setuptools-hg
for this
behavior to work properly.
setup.cfg
¶
The setup.cfg
file is a setuptools configuration file. It
contains various settings related to testing and internationalization:
Our generated setup.cfg
looks like this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | [nosetests]
match = ^test
nocapture = 1
cover-package = myproject
with-coverage = 1
cover-erase = 1
[compile_catalog]
directory = myproject/locale
domain = MyProject
statistics = true
[extract_messages]
add_comments = TRANSLATORS:
output_file = myproject/locale/MyProject.pot
width = 80
[init_catalog]
domain = MyProject
input_file = myproject/locale/MyProject.pot
output_dir = myproject/locale
[update_catalog]
domain = MyProject
input_file = myproject/locale/MyProject.pot
output_dir = myproject/locale
previous = true
|
The values in the default setup file allow various commonly-used internationalization commands and testing commands to work more smoothly.
The myproject
Package¶
The myproject
package lives inside the MyProject
project. It contains:
- An
__init__.py
file signifies that this is a Python package. It also contains code that helps users run the application, including amain
function which is used as a Paste entry point. - A
resources.py
module, which contains resource code. - A
templates
directory, which contains Chameleon (or other types of) templates. - A
tests.py
module, which contains unit test code for the application. - A
views.py
module, which contains view code for the application.
These are purely conventions established by the paster
template:
Pyramid doesn’t insist that you name things in any particular way.
However, it’s generally a good idea to follow Pyramid standards for naming,
so that other Pyramid developers can get up to speed quickly on your code
when you need help.
__init__.py
¶
We need a small Python module that configures our application and which
advertises an entry point for use by our PasteDeploy .ini
file.
This is the file named __init__.py
. The presence of an __init__.py
also informs Python that the directory which contains it is a package.
1 2 3 4 5 6 7 8 9 10 11 12 | from pyramid.config import Configurator
from myproject.resources import Root
def main(global_config, **settings):
""" This function returns a Pyramid WSGI application.
"""
config = Configurator(root_factory=Root, settings=settings)
config.add_view('myproject.views.my_view',
context='myproject.resources.Root',
renderer='myproject:templates/mytemplate.pt')
config.add_static_view('static', 'myproject:static')
return config.make_wsgi_app()
|
Line 1 imports the Configurator class from
pyramid.config
that we use later.Line 2 imports the
Root
class frommyproject.resources
that we use later.Lines 4-12 define a function that returns a Pyramid WSGI application. This function is meant to be called by the PasteDeploy framework as a result of running
paster serve
.Within this function, application configuration is performed.
Lines 8-10 register a “default view” (a view that has no
name
attribute). It is registered so that it will be found when the context of the request is an instance of themyproject.resources.Root
class. The first argument toadd_view
points at a Python function that does all the work for this view, also known as a view callable, via a dotted Python name. The view declaration also names arenderer
, which in this case is a template that will be used to render the result of the view callable. This particular view declaration points atmyproject:templates/mytemplate.pt
, which is a asset specification that specifies themytemplate.pt
file within thetemplates
directory of themyproject
package. The template file it actually points to is a Chameleon ZPT template file.Line 11 registers a static view, which will serve up the files from the
mypackage:static
asset specification (thestatic
directory of themypackage
package).Line 12 returns a WSGI application to the caller of the function (Paste).
views.py
¶
Much of the heavy lifting in a Pyramid application is done by view callables. A view callable is the main tool of a Pyramid web application developer; it is a bit of code which accepts a request and which returns a response.
1 2 | def my_view(request):
return {'project':'MyProject'}
|
This bit of code was registered as the view callable within __init__.py
(via add_view
). add_view
said that the default URL for instances
that are of the class myproject.resources.Root
should run this
myproject.views.my_view()
function.
This view callable function is handed a single piece of information: the
request. The request is an instance of the WebOb
Request
class representing the browser’s request to our server.
This view returns a dictionary. When this view is invoked, a
renderer converts the dictionary returned by the view into HTML, and
returns the result as the response. This view is configured to
invoke a renderer which uses a Chameleon ZPT template
(mypackage:templates/my_template.pt
, as specified in the __init__.py
file call to add_view
).
See Writing View Callables Which Use a Renderer for more information about how views, renderers, and templates relate and cooperate.
Note
Because our development.ini
has a reload_templates =
true
directive indicating that templates should be reloaded when
they change, you won’t need to restart the application server to
see changes you make to templates. During development, this is
handy. If this directive had been false
(or if the directive
did not exist), you would need to restart the application server
for each template change. For production applications, you should
set your project’s reload_templates
to false
to increase
the speed at which templates may be rendered.
resources.py
¶
The resources.py
module provides the resource data and behavior
for our application. Resources are objects which exist to provide site
structure in applications which use traversal to map URLs to code.
We write a class named Root
that provides the behavior for the root
resource.
1 2 3 | class Root(object):
def __init__(self, request):
self.request = request
|
- Lines 1-3 define the Root class. The Root class is a “root resource factory” function that will be called by the Pyramid Router for each request when it wants to find the root of the resource tree.
In a “real” application, the Root object would likely not be such a simple
object. Instead, it might be an object that could access some persistent
data store, such as a database. Pyramid doesn’t make any assumption
about which sort of data storage you’ll want to use, so the sample
application uses an instance of myproject.resources.Root
to
represent the root.
static
¶
This directory contains static assets which support the mytemplate.pt
template. It includes CSS and images.
templates/mytemplate.pt
¶
The single Chameleon template exists in the project. Its contents
are too long to show here, but it displays a default page when rendered. It
is referenced by the call to add_view
as the renderer
attribute in
the __init__
file. See Writing View Callables Which Use a Renderer for more
information about renderers.
Templates are accessed and used by view configurations and sometimes by view functions themselves. See Using Templates Directly and Templates Used as Renderers via Configuration.
tests.py
¶
The tests.py
module includes unit tests for your application.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | import unittest
from pyramid import testing
class ViewTests(unittest.TestCase):
def setUp(self):
self.config = testing.setUp()
def tearDown(self):
testing.tearDown()
def test_my_view(self):
from myproject.views import my_view
request = testing.DummyRequest()
info = my_view(request)
self.assertEqual(info['project'], 'MyProject')
|
This sample tests.py
file has a single unit test defined within it. This
test is executed when you run python setup.py test
. You may add more
tests here as you build your application. You are not required to write
tests to use Pyramid, this file is simply provided as convenience and
example.
See Unit, Integration, and Functional Testing for more information about writing Pyramid unit tests.
Modifying Package Structure¶
It is best practice for your application’s code layout to not stray too much from accepted Pyramid paster template defaults. If you refrain from changing things very much, other Pyramid coders will be able to more quickly understand your application. However, the code layout choices made for you by a paster template are in no way magical or required. Despite the choices made for you by any paster template, you can decide to lay your code out any way you see fit.
For example, the configuration method named
add_view()
requires you to pass a
dotted Python name or a direct object reference as the class or
function to be used as a view. By default, the pyramid_starter
paster
template would have you add view functions to the views.py
module in your
package. However, you might be more comfortable creating a views
directory, and adding a single file for each view.
If your project package name was myproject
and you wanted to arrange all
your views in a Python subpackage within the myproject
package
named views
instead of within a single views.py
file, you might:
- Create a
views
directory inside yourmypackage
package directory (the same directory which holdsviews.py
). - Move the existing
views.py
file to a file inside the newviews
directory named, say,blog.py
. - Create a file within the new
views
directory named__init__.py
(it can be empty, this just tells Python that theviews
directory is a package.
Then change the __init__.py of your myproject project (not the
__init__.py
you just created in the views
directory, the one in its
parent directory). For example, from something like:
1 2 | config.add_view('myproject.views.my_view',
renderer='myproject:templates/mytemplate.pt')
|
To this:
1 2 | config.add_view('myproject.views.blog.my_view',
renderer='myproject:templates/mytemplate.pt')
|
You can then continue to add files to the views
directory, and refer to
view classes or functions within those files via the dotted name passed as
the first argument to add_view
. For example, if you added a file named
anothermodule.py
to the views
subdirectory, and added a view callable
named my_view
to it:
1 2 | config.add_view('myproject.views.anothermodule.my_view',
renderer='myproject:templates/anothertemplate.pt')
|
This pattern can be used to rearrage code referred to by any Pyramid API argument which accepts a dotted Python name or direct object reference.