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PyAMS site management

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PyAMS site management is based on the ZODB.

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On application startup, if PyAMS_utils package is included into Pyramid configuration, several operations take -place:

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  • a custom site factory is defined
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  • custom request methods are defined
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  • a custom traverser handling namespaces is defined
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  • a custom subscribers predicate based on interfaces support is defined
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  • several adapters are registered, to handle annotations and key references
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  • custom TALES extensions are registered.
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The site factory is an important component in this process. It is this factory which will define the application root -and create a local site manager.

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Pyramid application is loaded from ZODB’s root via a key defined in Pyramid’s configuration file; the key is named -pyams.application_name and it’s default value is application.

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If the application can’t be found, PyAMS is looking for an application class name in Pyramid’s configuration file; the -class name configuration key is called pyams.application_factory and defined by default as -pyams_utils.site.BaseSiteRoot. PyAMS default site factory will then create the application, and add a local site -manager to it (see Managing ZCA with PyAMS).

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After application creation, a NewLocalSiteCreatedEvent is -notified. Custom packages can subscribe to this event to register custom components.

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pyams_upgrade command line script

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Pyramid allows to define custom command line scripts for application management. A script called pyams_upgrade is -provided by PyAMS_utils package; this script apply the same process as PyAMS site factory, but can also be used to -manage database generations. The idea behind this is just to allow custom packages to provide a way to check and -upgrade database configuration away from application startup process:

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# ./bin/pyams_upgrade webapp/development.ini
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A site generation checker is just a named utility providing pyams_utils.interfaces.site.ISiteGenerations -interface. For example, pyams_security package provides such utility, to make sure that local site manager -contains a PyAMS security manager and a principal annotation utility:

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from pyams_utils.site import check_required_utilities
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-REQUIRED_UTILITIES = ((ISecurityManager, '', SecurityManager, 'Security manager'),
-                      (IPrincipalAnnotationUtility, '', PrincipalAnnotationUtility, 'User profiles'))
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-@utility_config(name='PyAMS security', provides=ISiteGenerations)
-class SecurityGenerationsChecker(object):
-"""I18n generations checker"""
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-    generation = 1
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-    def evolve(self, site, current=None):
-        """Check for required utilities"""
-        check_required_utilities(site, REQUIRED_UTILITIES)
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check_required_utilities is a PyAMS_utils utility function which -can to used to verify that a set of local utilities are correctly registered with the given names and interfaces.

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