Edit me on GitHub

pyramid_jinja2

Overview

pyramid_jinja2 is a set of bindings that make templates written for the Jinja2 templating system work under the Pyramid web framework.

Installation

Install using setuptools, e.g. (within a virtualenv):

$ $VENV/bin/easy_install pyramid_jinja2

Setup

Note

If you start a project from scratch, consider using the project template which comes with a working setup and sensible defaults.

There are multiple ways to make sure that pyramid_jinja2 is active. All are completely equivalent:

  1. Use the includeme() function via include():

    config = Configurator()
    config.include('pyramid_jinja2')
    
  2. Add pyramid_jinja2 to the list of your pyramid.includes in your .ini settings file:

    pyramid.includes =
        pyramid_jinja2
  3. If you’re using pyramid_zcml instead of imperative configuration, ensure that some ZCML file with an analogue of the following contents is executed by your Pyramid application:

    <include package="pyramid_jinja2"/>
    

Once activated either of these says, the following happens:

  1. Files with the .jinja2 extension are considered to be Jinja2 templates.
  2. The pyramid_jinja2.add_jinja2_renderer() directive is added to the Configurator instance.
  3. The pyramid_jinja2.add_jinja2_search_path() directive is added to the Configurator instance.
  4. The pyramid_jinja2.add_jinja2_extension() directive is added to the Configurator instance.
  5. The pyramid_jinja2.get_jinja2_environment() directive is added to the Configurator instance.
  6. jinja2.Environment is constructed and registered globally.

To setup the Jinja2 search path either one of the following steps must be taken:

  1. Add jinja2.directories to your .ini settings file using a Pyramid asset spec:

    jinja2.directories = yourapp:templates
  2. Or Alternatively by using the add_jinja2_search_path() directive attached to your application’s Configurator instance also using a Pyramid asset spec:

    config.add_jinja2_search_path("yourapp:templates")
    

Warning

If you do not explicitly configure your Jinja2 search path it will default to the root of your application. If the specified template is not found in the root of your application and you did not specify a package on the template path it will then try to load the template path relative to the module’s caller package. For example:

Without the search path configured:

@view_config(renderer='templates/mytemplate.jinja2')

With the search path configured:

@view_config(renderer='mytemplate.jinja2')

If your view module is in app.module.view and your template is under app/module/templates/mytemplate.jinja2 you can access that asset in a few different ways.

Using the full path:

@view_config(renderer="module/templates/mytemplate.jinja2")

Using the package:

@view_config(renderer="app.module:templates/mytemplate.jinja2")

Using the relative path to current package:

@view_config(renderer="templates/mytemplate.jinja2")

You need to be careful when using relative paths though, if there is an app/templates/mytemplate.jinja2 this will be used instead as Jinja2 lookup will first try the path relative to the root of the app and then it will try the path relative to the current package.

Finally, to make sure your .jinja2 template files are included in your package’s source distribution (e.g. when using python setup.py sdist), add *.jinja2 to your MANIFEST.in:

recursive-include yourapp *.ico *.png *.css *.gif *.jpg *.pt *.txt *.mak *.mako *.jinja2 *.js *.html *.xml

Usage

Once pyramid_jinja2 been activated .jinja2 templates can be loaded either by looking up names that would be found on the Jinja2 search path or by looking up asset specifications.

Template Lookups

The default lookup mechanism for templates uses the Jinja2 search path (specified with jinja2.directories or by using the add_jinja2_search_path() directive on the Configurator instance).

Rendering Jinja2 templates with a view like this is typically done as follows (where the templates directory is expected to live in the search path):

1
2
3
4
5
from pyramid.view import view_config

@view_config(renderer='mytemplate.jinja2')
def myview(request):
    return {'foo':1, 'bar':2}

Rendering templates outside of a view (and without a request) can be done using the renderer api:

1
2
from pyramid.renderers import render_to_response
render_to_response('mytemplate.jinja2', {'foo':1, 'bar':2})

Template Inheritance

Template inheritance can use asset specs in the same manner as regular template lookups. An example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<!-- templates/layout.jinja2 -->

<html lang="en">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <link rel="stylesheet" href="style.css" />
</head>
<body>
  <div id="content">{% block content %}{% endblock %}</div>
</body>
1
2
3
4
5
6
7
8
<!-- templates/root.jinja2 -->
{% extends "templates/layout.jinja2" %}
{% block content %}
<h1>Yes</h1>
<p>
  Some random paragraph.
</p>
{% endblock %}

For further information on Template Inheritance in Jinja2 templates please see Template Inheritance in Jinja2 documentation.

Asset Specification Lookups

Looking up templates via asset specification is a feature specific to Pyramid. For further info please see Understanding Asset Specifications. Overriding templates in this style uses the standard pyramid asset overriding technique.

Internalization (i18n)

When pyramid_jinja2 is included as pyramid application, jinja2.ext.i18n is automatically activated.

Be sure to configure jinja2.i18n.domain according to setup.cfg domain settings. By default, jinja2.i18n.domain is set to the package name of the pyramid application.

Supporting Alternate File Extensions and Settings

By default, only templates ending in the .jinja2 file extension are supported. However, it is very easy to add support for alternate file extensions using the pyramid_jinja2.add_jinja2_renderer() directive.

config.include('pyramid_jinja2')
config.add_jinja2_renderer('.html')

It would now be possible to use templates named foo.html and foo.jinja2. Each renderer extension will use its own jinja2.Environment. These alternate renderers can be extended at runtime using the name parameter to the other directives such as pyramid_jinja2.get_jinja2_environment().

config.include('pyramid_jinja2')
config.add_jinja2_renderer('.html')
config.add_jinja2_search_path('myapp:templates', name='.html')

It is also possible to setup different renderers that use different search paths, configuration settings and environments if necessary. This technique can come in handy when different defaults are required for rendering templates with different content types. For example, a plain text email body versus an html page. For this reason, pyramid_jinja2.add_jinja2_renderer() accepts an optional parameter settings_prefix which can point a renderer at a different group of settings.

settings = {
    'jinja2.directories': 'myapp:html_templates',
    'mail.jinja2.directories': 'myapp:email_templates',
}

config = Configurator(settings=settings)
config.include('pyramid_jinja2')
config.add_jinja2_renderer('.email', settings_prefix='mail.jinja2.')

Now foo.email will be rendered using the mail.jinja2.* settings.

Settings

Jinja2 derives additional settings to configure its template renderer. Many of these settings are optional and only need to be set if they should be different from the default. The below values can be present in the .ini file used to configure the Pyramid application (in the app section representing your Pyramid app) or they can be passed directly within the settings argument passed to a Pyramid Configurator.

Generic Settings

These settings correspond to the ones documented in Jinja2. Set them accordingly.

For reference please see: http://jinja.pocoo.org/docs/api/#high-level-api

Note

For the boolean settings please use true or false

jinja2.block_start_string

jinja2.block_end_string

jinja2.variable_start_string

jinja2.variable_end_string

jinja2.comment_start_string

jinja2.comment_end_string

jinja2.line_statement_prefix

jinja2.line_comment_prefix

jinja2.trim_blocks

jinja2.newline_sequence

jinja2.optimized

jinja2.cache_size

jinja2.autoescape

Jinja2 autoescape setting.

Possible values: true or false.

Warning

By default Jinja2 sets autoescaping to False.

pyramid_jinja2 sets it to true as it is considered a good security practice.

pyramid.reload_templates

For usage see Pyramid: Automatically Reloading Templates.

true or false representing whether Jinja2 templates should be reloaded when they change on disk. Useful for development to be true. This setting sets the Jinja2 auto_reload setting.

reload_templates

Warning

Deprecated as of version 1.5, use pyramid.reload_templates instead

jinja2.auto_reload

Use Pyramid pyramid.reload_templates setting.

jinja2.directories

A list of directory names or a newline-delimited string with each line representing a directory name. These locations are where Jinja2 will search for templates. Each can optionally be an absolute resource specification (e.g. package:subdirectory/).

jinja2.input_encoding

The input encoding of templates. Defaults to utf-8.

jinja2.undefined

Changes the undefined types that are used when a variable name lookup fails. If unset, defaults to Undefined (silent ignore). Setting it to strict will trigger StrictUndefined behavior (raising an error, this is recommended for development). Setting it to debug will trigger DebugUndefined, which outputs debug information in some cases. See Undefined Types

jinja2.extensions

A list of extension objects or a newline-delimited set of dotted import locations where each line represents an extension. jinja2.ext.i18n is automatically activated.

jinja2.i18n.domain

Pyramid domain for translations. See Translation Domain in Pyramid documentation. Defaults to the package name of the pyramid application.

jinja2.filters

A dictionary mapping filter name to filter object, or a newline-delimted string with each line in the format:

name = dotted.name.to.filter

representing Jinja2 filters.

jinja2.globals

A dictionary mapping global name to global template object, or a newline-delimited string with each line in the format:

name = dotted.name.to.globals

representing Jinja2 globals

jinja2.tests

A dictionary mapping test name to test object, or a newline-delimted string with each line in the format:

name = dotted.name.to.test

representing Jinja2 tests.

jinja2.bytecode_caching

If set to true, a filesystem bytecode cache will be configured (in a directory determined by jinja2.bytecode_caching_directory.) To configure other types of bytecode caching, jinja2.bytecode_caching may also be set directly to an instance of jinja2.BytecodeCache (This can not be done in a paste .ini file, however, it must be done programatically.) By default, no bytecode cache is configured.

Changed in version 1.10: Previously, jinja2.bytecode_caching defaulted to true.

Note that configuring a filesystem bytecode cache will (not surprisiningly) generate files in the cache directory. As templates are changed, some of these will become stale, pointless wastes of disk space. You are advised to consider a clean up strategy (such as a cron job) to check for and remove such files.

See the Jinja2 Documentation for more information on bytecode caching.

Changed in version 1.10: Previously, an atexit callback which called jinja2.BytecodeCache.clear() was registered in an effort to delete the cache files. This is no longer done.

jinja2.bytecode_caching_directory

Absolute path to directory to store bytecode cache files. Defaults to the system temporary directory. This is only used if jinja2.bytecode_caching is set to true.

jinja2.newstyle

true or false to enable the use of newstyle gettext calls. Defaults to false.

See Newstyle Gettext http://jinja.pocoo.org/docs/extensions/#newstyle-gettext

Jinja2 Filters

pyramid_jinja2 provides following filters.

pyramid_jinja2.filters.model_url_filter(ctx, model, *elements, **kw)

A filter from model to a string representing the absolute URL. This filter calls pyramid.url.resource_url().

pyramid_jinja2.filters.route_url_filter(ctx, route_name, *elements, **kw)

A filter from route_name to a string representing the absolute URL. This filter calls pyramid.url.route_url().

pyramid_jinja2.filters.static_url_filter(ctx, path, **kw)

A filter from path to a string representing the absolute URL. This filter calls pyramid.url.static_url().

pyramid_jinja2.filters.route_path_filter(ctx, route_name, *elements, **kw)

A filter from route_name to a string representing the relative URL. This filter calls pyramid.url.route_path().

pyramid_jinja2.filters.static_path_filter(ctx, path, **kw)

A filter from path to a string representing the relative URL. This filter calls pyramid.url.static_path().

To use these filters, configure the settings of jinja2.filters:

1
2
3
4
5
6
[app:yourapp]
# ... other stuff ...
jinja2.filters =
    model_url = pyramid_jinja2.filters:model_url_filter
    route_url = pyramid_jinja2.filters:route_url_filter
    static_url = pyramid_jinja2.filters:static_url_filter

And use the filters in template.

<a href="{{context|model_url('edit')}}">Edit</a>

<a href="{{'top'|route_url}}">Top</a>

<link rel="stylesheet" href="{{'yourapp:static/css/style.css'|static_url}}" />

Creating a Jinja2 Pyramid Project

After you’ve got pyramid_jinja2 installed, you can invoke one of the following commands to create a Jinja2-based Pyramid project.

On Pyramid 1.0, 1.1, or 1.2:

$ $VENV/bin/paster create -t pyramid_jinja2_starter myproject

On Pyramid 1.3+:

$ $VENV/bin/pcreate -s pyramid_jinja2_starter myproject

After it’s created, you can visit the myproject directory and run setup.py develop. At that point you can start the application like any other Pyramid application.

This is a good way to see a working Pyramid application that uses Jinja2, even if you wind up not using the result.

Paster Template I18N

The paster template automatically sets up pot/po/mo locale files for use with the generated project.

The usual pattern for working with i18n in pyramid_jinja2 is as follows:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
# make sure Babel is installed
easy_install Babel

# extract translatable strings from *.jinja2 / *.py
python setup.py extract_messages
python setup.py update_catalog

# Translate strings in <mypackage>/locale/<mylocale>/LC_MESSAGES/<myproject>.po
# and re-compile *.po files
python setup.py compile_catalog

More Information

Reporting Bugs / Development Versions

Visit http://github.com/Pylons/pyramid_jinja2 to download development or tagged versions.

Visit http://github.com/Pylons/pyramid_jinja2/issues to report bugs.