Defining custom configuration¶
Any code you write using Reahl is packaged as a component even your web application itself.
Each Reahl component used by an application can have its own configuration file located in a common configuration directory.
The tutorial.componentconfigbootstrap example shows how to make a component read configuration from such a file. The example uses its own config setting (componentconfig.showheader) to contol whether AddressBookPanel has a heading or not.
The Configuration for the system is available anywhere in your code
as config of the
current ExecutionContext:
class AddressBookPanel(Div):
def __init__(self, view):
super(AddressBookPanel, self).__init__(view)
config = ExecutionContext.get_context().config
if config.componentconfig.showheader:
self.add_child(H(view, 1, text='Addresses'))
for address in Session.query(Address).all():
self.add_child(AddressBox(view, address))
self.add_child(AddAddressForm(view))
AddressConfig (which inherits from Configuration) defines the
available configuration settings and associated information. Declare
each config setting by assigning an instance of ConfigSetting to a
class attribute of AddressConfig with the name you want:
class AddressConfig(Configuration):
filename = 'componentconfig.config.py'
config_key = 'componentconfig'
showheader = ConfigSetting(default=False, description='Whether the title should be shown as a heading too')
Note
It is good practice to always provide a default value for a setting. If all your settings have sensible defaults, your application can be started up and run without any config file present at all–something a new user will appreciate. Similarly, the description is used to enable useful output when you run, for example:
reahl listconfig -i etc/
In the .reahlproject file, AddressConfig is added as the configuration of the component:
<configuration locator="reahl.doc.examples.tutorial.componentconfigbootstrap.componentconfigbootstrap:AddressConfig"/>
Config files contain Python code. In componentconfig.config.py (the
filename) an
instance of AddressConfig is available as componentconfig (the
config_key):
componentconfig.showheader = True