This CKAN Extension demonstrates some common patterns for customising a CKAN instance. | This CKAN Extension demonstrates some common patterns for customising a CKAN instance. |
It comprises: | It comprises: |
* A CKAN Extension "plugin" at ``ckanext/example/plugin.py`` which, when | * A CKAN Extension "plugin" at ``ckanext/example/plugin.py`` which, when |
loaded, overrides various settings in the core ``ini``-file to provide: | loaded, overrides various settings in the core ``ini``-file to provide: |
* A path to local customisations of the core templates and stylesheets | * A path to local customisations of the core templates and stylesheets |
* A "stream filter" that replaces arbitrary strings in rendered templates | * A "stream filter" that replaces arbitrary strings in rendered templates |
* A "route" to override and extend the default behaviour of a core CKAN page | * A "route" to override and extend the default behaviour of a core CKAN page |
* A custom Pylons controller for overriding some core CKAN behaviour | * A custom Pylons controller for overriding some core CKAN behaviour |
* A custom Package edit form | * A custom Package edit form |
* A custom Group edit form | |
* A plugin that allows for custom forms to be used for datasets based on | |
their "type". | |
* A custom User registration and edition form | * A custom User registration and edition form |
* Some simple template customisations | * Some simple template customisations |
Installation | Installation |
============ | ============ |
To install this package, from your CKAN virtualenv, run the following from your CKAN base folder (e.g. ``pyenv/``):: | To install this package, from your CKAN virtualenv, run the following from your CKAN base folder (e.g. ``pyenv/``):: |
pip install -e git+https://github.com/okfn/ckanext-example#egg=ckanext-example | pip install -e git+https://github.com/okfn/ckanext-example#egg=ckanext-example |
Then activate it by setting ``ckan.plugins = example`` in your main ``ini``-file. | Then activate it by setting ``ckan.plugins = example`` in your main ``ini``-file. |
Orientation | Orientation |
=========== | =========== |
* Examine the source code, starting with ``ckanext/example/plugin.py`` | * Examine the source code, starting with ``ckanext/example/plugin.py`` |
* To understand the nuts and bolts of this file, which is a CKAN | * To understand the nuts and bolts of this file, which is a CKAN |
*Extension*, read in conjunction with the "Extension | *Extension*, read in conjunction with the "Extension |
documentation": http://docs.ckan.org/en/latest/plugins.html | documentation": http://docs.ckan.org/en/latest/plugins.html |
* One thing the extension does is set the values of | * One thing the extension does is set the values of |
``extra_public_paths`` and ``extra_template_paths`` in the CKAN | ``extra_public_paths`` and ``extra_template_paths`` in the CKAN |
config, which are "documented | config, which are "documented |
here": http://docs.ckan.org/en/latest/configuration.html#extra-template-paths | here": http://docs.ckan.org/en/latest/configuration.html#extra-template-paths |
* These are set to point at directories within | * These are set to point at directories within |
``ckanext/example/theme/`` (in this package). Here we: | ``ckanext/example/theme/`` (in this package). Here we: |
* override the home page HTML ``ckanext/example/theme/templates/home/index.html`` | * override the home page HTML ``ckanext/example/theme/templates/home/index.html`` |
* provide some extra style by serving ``extra.css`` (which is loaded using the ``ckan.template_head_end`` option | * provide some extra style by serving ``extra.css`` (which is loaded using the ``ckan.template_head_end`` option |
* customise the navigation and header of the main template in the file ``layout.html``. | * customise the navigation and header of the main template in the file ``layout.html``. |
The latter file is a great place to make global theme alterations. | The latter file is a great place to make global theme alterations. |
It uses the _layout template_ pattern "described in the Genshi | It uses the _layout template_ pattern "described in the Genshi |
documentation":http://genshi.edgewall.org/wiki/GenshiTutorial#AddingaLayoutTemplate. | documentation":http://genshi.edgewall.org/wiki/GenshiTutorial#AddingaLayoutTemplate. |
This allows you to use Xpath selectors to override snippets of HTML | This allows you to use Xpath selectors to override snippets of HTML |
globally. | globally. |
* The custom package edit form at ``package_form.py`` follows a deprecated | |
way to make a form (using FormAlchemy). This part of the Example Theme needs | |
updating. In the meantime, follow the instructions at: | |
http://readthedocs.org/docs/ckan/en/latest/forms.html | |
from ckan import model | |
from ckan.lib.cli import CkanCommand | |
from ckan.logic import get_action, NotFound | |
import forms | |
import logging | |
log = logging.getLogger() | |
class ExampleCommand(CkanCommand): | |
''' | |
CKAN Example Extension | |
Usage:: | |
paster example create-example-vocab -c <path to config file> | |
paster example clean -c <path to config file> | |
- Remove all data created by ckanext-example | |
The commands should be run from the ckanext-example directory. | |
''' | |
summary = __doc__.split('\n')[0] | |
usage = __doc__ | |
def command(self): | |
''' | |
Parse command line arguments and call appropriate method. | |
''' | |
if not self.args or self.args[0] in ['--help', '-h', 'help']: | |
print ExampleCommand.__doc__ | |
return | |
cmd = self.args[0] | |
self._load_config() | |
if cmd == 'create-example-vocab': | |
self.create_example_vocab() | |
else: | |
log.error('Command "%s" not recognized' % (cmd,)) | |
def create_example_vocab(self): | |
''' | |
Adds an example vocabulary to the database if it doesn't | |
already exist. | |
''' | |
user = get_action('get_site_user')({'model': model, 'ignore_auth': True}, {}) | |
context = {'model': model, 'session': model.Session, 'user': user['name']} | |
data = {'id': forms.EXAMPLE_VOCAB} | |
try: | |
get_action('vocabulary_show')(context, data) | |
log.info("Example tag vocabulary already exists, skipping.") | |
except NotFound: | |
log.info("Creating example vocab %s" % forms.EXAMPLE_VOCAB) | |
data = {'name': forms.EXAMPLE_VOCAB} | |
vocab = get_action('vocabulary_create')(context, data) | |
log.info("Adding tag %s to vocab %s" % ('vocab-tag-example-1', forms.EXAMPLE_VOCAB)) | |
data = {'name': 'vocab-tag-example-1', 'vocabulary_id': vocab['id']} | |
get_action('tag_create')(context, data) | |
log.info("Adding tag %s to vocab %s" % ('vocab-tag-example-2', forms.EXAMPLE_VOCAB)) | |
data = {'name': 'vocab-tag-example-2', 'vocabulary_id': vocab['id']} | |
get_action('tag_create')(context, data) | |
import os | |
import logging | |
from ckan.authz import Authorizer | |
from ckan.logic.converters import convert_to_extras,\ | |
convert_from_extras, convert_to_tags, convert_from_tags, free_tags_only | |
from ckan.logic import get_action, NotFound | |
from ckan.logic.schema import package_form_schema, group_form_schema | |
from ckan.lib.base import c, model | |
from ckan.plugins import IDatasetForm, IGroupForm, IConfigurer | |
from ckan.plugins import implements, SingletonPlugin | |
from ckan.lib.navl.validators import ignore_missing, keep_extras | |
log = logging.getLogger(__name__) | |
EXAMPLE_VOCAB = u'example_vocab' | |
class ExampleGroupForm(SingletonPlugin): | |
"""This plugin demonstrates how a class packaged as a CKAN | |
extension might extend CKAN behaviour by providing custom forms | |
based on the type of a Group. | |
In this case, we implement two extension interfaces to provide custom | |
forms for specific types of group. | |
- ``IConfigurer`` allows us to override configuration normally | |
found in the ``ini``-file. Here we use it to specify where the | |
form templates can be found. | |
- ``IGroupForm`` allows us to provide a custom form for a dataset | |
based on the 'type' that may be set for a group. Where the | |
'type' matches one of the values in group_types then this | |
class will be used. | |
""" | |
implements(IGroupForm, inherit=True) | |
implements(IConfigurer, inherit=True) | |
def update_config(self, config): | |
""" | |
This IConfigurer implementation causes CKAN to look in the | |
```templates``` directory when looking for the group_form() | |
""" | |
here = os.path.dirname(__file__) | |
rootdir = os.path.dirname(os.path.dirname(here)) | |
template_dir = os.path.join(rootdir, 'ckanext', | |
'example', 'theme', 'templates') | |
config['extra_template_paths'] = ','.join([template_dir, | |
config.get('extra_template_paths', '')]) | |
def group_form(self): | |
""" | |
Returns a string representing the location of the template to be | |
rendered. e.g. "forms/group_form.html". | |
""" | |
return 'forms/group_form.html' | |
def group_types(self): | |
""" | |
Returns an iterable of group type strings. | |
If a request involving a group of one of those types is made, then | |
this plugin instance will be delegated to. | |
There must only be one plugin registered to each group type. Any | |
attempts to register more than one plugin instance to a given group | |
type will raise an exception at startup. | |
""" | |
return ["testgroup"] | |
def is_fallback(self): | |
""" | |
Returns true iff this provides the fallback behaviour, when no other | |
plugin instance matches a group's type. | |
As this is not the fallback controller we should return False. If | |
we were wanting to act as the fallback, we'd return True | |
""" | |
return False | |
def form_to_db_schema(self): | |
""" | |
Returns the schema for mapping group data from a form to a format | |
suitable for the database. | |
""" | |
return group_form_schema() | |
def db_to_form_schema(self): | |
""" | |
Returns the schema for mapping group data from the database into a | |
format suitable for the form (optional) | |
""" | |
return {} | |
def check_data_dict(self, data_dict): | |
""" | |
Check if the return data is correct. | |
raise a DataError if not. | |
""" | |
def setup_template_variables(self, context, data_dict): | |
""" | |
Add variables to c just prior to the template being rendered. | |
""" | |
class ExampleDatasetForm(SingletonPlugin): | |
"""This plugin demonstrates how a theme packaged as a CKAN | |
extension might extend CKAN behaviour. | |
In this case, we implement three extension interfaces: | |
- ``IConfigurer`` allows us to override configuration normally | |
found in the ``ini``-file. Here we use it to specify where the | |
form templates can be found. | |
- ``IDatasetForm`` allows us to provide a custom form for a dataset | |
based on the type_name that may be set for a package. Where the | |
type_name matches one of the values in package_types then this | |
class will be used. | |
""" | |
implements(IDatasetForm, inherit=True) | |
implements(IConfigurer, inherit=True) | |
def update_config(self, config): | |
""" | |
This IConfigurer implementation causes CKAN to look in the | |
```templates``` directory when looking for the package_form() | |
""" | |
here = os.path.dirname(__file__) | |
rootdir = os.path.dirname(os.path.dirname(here)) | |
template_dir = os.path.join(rootdir, 'ckanext', | |
'example', 'theme', 'templates') | |
config['extra_template_paths'] = ','.join([template_dir, | |
config.get('extra_template_paths', '')]) | |
def package_form(self): | |
""" | |
Returns a string representing the location of the template to be | |
rendered. e.g. "package/new_package_form.html". | |
""" | |
return 'forms/dataset_form.html' | |
def is_fallback(self): | |
""" | |
Returns true iff this provides the fallback behaviour, when no other | |
plugin instance matches a package's type. | |
As this is not the fallback controller we should return False. If | |
we were wanting to act as the fallback, we'd return True | |
""" | |
return True | |
def package_types(self): | |
""" | |
Returns an iterable of package type strings. | |
If a request involving a package of one of those types is made, then | |
this plugin instance will be delegated to. | |
There must only be one plugin registered to each package type. Any | |
attempts to register more than one plugin instance to a given package | |
type will raise an exception at startup. | |
""" | |
return ["example_dataset_form"] | |
def setup_template_variables(self, context, data_dict=None): | |
""" | |
Adds variables to c just prior to the template being rendered that can | |
then be used within the form | |
""" | |
c.licences = [('', '')] + model.Package.get_license_options() | |
c.publishers = [('Example publisher', 'Example publisher 2')] | |
c.is_sysadmin = Authorizer().is_sysadmin(c.user) | |
c.resource_columns = model.Resource.get_columns() | |
try: | |
c.vocab_tags = get_action('tag_list')(context, {'vocabulary_id': EXAMPLE_VOCAB}) | |
except NotFound: | |
c.vocab_tags = None | |
## This is messy as auths take domain object not data_dict | |
pkg = context.get('package') or c.pkg | |
if pkg: | |
c.auth_for_change_state = Authorizer().am_authorized( | |
c, model.Action.CHANGE_STATE, pkg) | |
def form_to_db_schema(self): | |
""" | |
Returns the schema for mapping package data from a form to a format | |
suitable for the database. | |
""" | |
schema = package_form_schema() | |
schema.update({ | |
'published_by': [ignore_missing, unicode, convert_to_extras], | |
'vocab_tags': [ignore_missing, convert_to_tags(EXAMPLE_VOCAB)], | |
}) | |
return schema | |
def db_to_form_schema(self): | |
""" | |
Returns the schema for mapping package data from the database into a | |
format suitable for the form (optional) | |
""" | |
schema = package_form_schema() | |
schema.update({ | |
'tags': { | |
'__extras': [keep_extras, free_tags_only] | |
}, | |
'vocab_tags_selected': [convert_from_tags(EXAMPLE_VOCAB), ignore_missing], | |
'published_by': [convert_from_extras, ignore_missing], | |
}) | |
return schema | |
def check_data_dict(self, data_dict): | |
""" | |
Check if the return data is correct and raises a DataError if not. | |
""" | |
return | |
import os | import os |
from logging import getLogger | from logging import getLogger |
from pylons import request | |
from genshi.input import HTML | |
from genshi.filters.transform import Transformer | from genshi.filters.transform import Transformer |
from ckan.plugins import implements, SingletonPlugin | from ckan.plugins import implements, SingletonPlugin |
from ckan.plugins import IConfigurer | from ckan.plugins import IConfigurer |
from ckan.plugins import IGenshiStreamFilter | from ckan.plugins import IGenshiStreamFilter |
from ckan.plugins import IRoutes | from ckan.plugins import IRoutes |
log = getLogger(__name__) | log = getLogger(__name__) |
class ExamplePlugin(SingletonPlugin): | class ExamplePlugin(SingletonPlugin): |
"""This plugin demonstrates how a theme packaged as a CKAN | """This plugin demonstrates how a theme packaged as a CKAN |
extension might extend CKAN behaviour. | extension might extend CKAN behaviour. |
In this case, we implement three extension interfaces: | In this case, we implement three extension interfaces: |
- ``IConfigurer`` allows us to override configuration normally | - ``IConfigurer`` allows us to override configuration normally |