Changes between Initial Version and Version 1 of goflow:leave

Timestamp:

Mar 25, 2008, 8:15:59 AM (18 years ago)

Author:

goflow

Comment:

moved from goflow main page

goflow:leave

@@ +1 @@
+== The Leave workflow application ==
+(not up to date)
+
+Follow instructions in the [https://opensvn.csie.org/goflow/trunk/INSTALL.TXT INSTALL.TXT] file included in the [https://opensvn.csie.org/goflow/trunk/goflow goflow distribution].
+You can then play with the leave demo application (available [wiki:GoFlow:demo online] too).
+ 
+You will find here some details of the leave application implementation.
+
+=== defining the workflow process ===
+First, let's take a look at the process definition; the process is stored in the database, by using entities like Process, Activities, Transitions, Application (see workflow/models.py, and the [http://goflow.alwaysdata.net/images/workflow.png goflow data model] generated by modelviz/graphviz). In the leavedemo project, the process is dumped with the django dumpdata utility, and provided as a fixture. Typically, when you want to define a process, you will use the admin web console.
+
+So, the process is the following:
+http://goflow.alwaysdata.net/leavedemo/media/img/leaveactivities.png
+
+below, the process translated as django entities, with a python syntax (it is not a real code, it's just more readable by humans):
+{{{
+Process(title='leave', begin='Begin', end='End')
+
+Activity(title='Begin', application='checkstatus',
+         pushApplication='route_to_secretary',
+         splitMode='xor', roles=('secretary',))
+
+Activity(title='Approval', application='approvalform',
+         pushApplication='route_to_supervisor',
+         splitMode='xor', roles=('secretary',))
+
+Activity(title='Refinement', application='refine',
+         pushApplication='route_to_customer',
+         joinMode='xor', splitMode='xor')
+
+Activity(title='UpdateHR', application='hrform',
+         pushApplication='route_to_secretary',
+         roles=('supervisor',))
+
+Activity(title='End', application='finalinfo',
+         pushApplication='route_to_customer',
+         joinMode='xor', roles=('secretary',),
+         autoFinish=False)
+
+Transition(name='send_to_approval',
+           input = 'Begin', output='Approval',
+           condition="instance.condition=='OK: Forward to supervisor'")
+
+Transition(name='send_to_refinement',
+           input = 'Begin', output='Refinement',
+           condition="instance.condition=='Denied: Back to requester'")
+
+Transition(name='request_approved',
+           input = 'Approval', output='UpdateHR',
+           condition="instance.condition=='OK: Forward to secretary'")
+
+Transition(name='not_approved',
+           input = 'Approval', output='Refinement',
+           condition="instance.condition=='Denied: Back to requester'")
+
+Transition(name='tell_employee',
+           input = 'UpdateHR', output='End')
+
+Transition(name='cancel_request',
+           input = 'Refinement', output='End',
+           condition="instance.condition=='Withdraw request'")
+
+Transition(name='re_request',
+           input = 'Refinement', output='Begin',
+           condition="instance.condition=='Re-request'")
+}}}
+this [http://goflow.alwaysdata.net/images/leave.png diagram] is a graphviz dot representation. It has
+written by hand, but soon, it should be generated.
+
+'''Some definitions:'''
+[[BR]]A ''transition'' is a path from an ''Activity'' to another one.
+[[BR]]An ''Activity'' is a task that a person (or an automatic process) with a specific role must achieve: it is linked to an ''Application'' which is typically an URL declared in the ''urls.py'' file.
+[[BR]]A ''push application'' is a handler that return a user, given the context of process instance (in fact the parameter of the handler is a ''workitem'', we will see this later) 
+
+=== settings file ===
+''(a little obsolete since rev 14)''
+==== standard settings ====
+First, tell Django you want to use the workflow engine:
+{{{
+INSTALLED_APPS = (
+    ....
+    'leavedemo.leave',     # the leave application
+    'goflow.workflow',     # goflow workflow engine
+)
+}}}
+
+If you use ''send_mail'' application, you should define these:
+{{{
+DEFAULT_FROM_EMAIL = email sender
+EMAIL_HOST = smtp server
+}}}
+==== specific settings ====
+
+{{{
+WF_APPS_PREFIX = 'leavedemo'
+}}}
+This is the url prefix for workflow application definition;
+for example, in the workflow definition the application ''app1'' is
+mapped on the url ''/leavedemo/app1''
+
+{{{
+WF_PUSH_APPS_PREFIX = 'leavedemo.leave.pushapplications'
+}}}
+this is the module containing the push applications functions;
+for example, the push application ''pushapp1'' is a function defined as
+following in the ''leavedemo/leave/pushapplications.py'' module:
+{{{
+def pushapp1(workitem):
+    ...
+    return aUser
+}}}
+
+If you use ''send_mail'' application, you should define these:
+{{{
+EMAIL_SUBJECT_PREFIX = '[Goflow notification]'
+}}}
+
+=== urls.py file ===
+
+==== Starting a workflow instance ====
+
+the ''start_application'' is a handler that display a form used to create an instance of the workflow process:
+
+usage:
+{{{
+    (r'^leave/start/(app)/(model)/$', 'goflow.workflow.applications.start_application'),
+}}}
+This above is the simplest way to start: the default process has the same name as app, and the default template used is "start_[model].html".
+
+other usage:
+{{{
+    (r'^leave/request/$',
+     'goflow.workflow.applications.start_application',
+     {'process_name':'leave', 'form_class':RequestForm, 'template':'start_leave.html'}),
+}}}
+
+''New:''
+see ''workflow urls'' below: an instance can be started with just a model (see also leave demo)
+
+==== Simple info application ====
+the only parameter is a template; this application just shows an inf panel to a user.
+{{{
+    (r'^leave/finalinfo/$', 'goflow.workflow.applications.simple_application', {'template':'finalinfo.html'}),
+}}}
+
+
+==== Form application ====
+this application displays a form to the user: by clicking on a submit button, the activity is terminated with
+ the instance condition set to the submit button value (label displayed)
+{{{
+    (r'^leave/checkstatus/$', 'goflow.workflow.applications.application_form', {'form_class':ApprovalForm,
+                                                                                'template':'checkstatus.html',
+                                                                                'submit_name':'approval'}),
+}}}
+
+==== Custom applications ====
+for more advanced usages, you may write your own applications: for this, take a look at the application form code (see above) and copy-paste the code in your project (in an applications.py file) and customize it; one advantage is that the urls.py file can be quite simpler (less parameters on the application url line).
+
+
+=== workflow urls ===
+Some urls are workflow standard tasks,  managed by the engine itself; like CRUD urls managed by admin,  the workflow standard tasks  are available with the following line in the ''urls.py'' file:
+{{{
+    (r'^leave/', include('goflow.workflow.urls')),
+}}}
+
+So the workflow engine provides handlers and default templates below:
+{{{
+    (r'^mywork/$', 'goflow.workflow.views.mywork', {'template':'mywork.html'}),
+    (r'^otherswork/$', 'goflow.workflow.views.otherswork', {'template':'otherswork.html'}),
+    (r'^otherswork/instancehistory/$', 'goflow.workflow.views.instancehistory', {'template':'instancehistory.html'}),
+    (r'^myrequests/$', 'goflow.workflow.views.myrequests', {'template':'myrequests.html'}),
+    (r'^myrequests/instancehistory/$', 'goflow.workflow.views.instancehistory', {'template':'instancehistory.html'}),
+    (r'^mywork/activate/$', 'goflow.workflow.views.activate', {'template':'activate.html'}),
+    (r'^mywork/complete/$', 'goflow.workflow.views.complete', {'template':'complete.html'}),
+    (r'^start/(?P<app_label>.*)/(?P<model_name>.*)/$', 'goflow.workflow.applications.start_application'),
+    (r'^cron/$','django.contrib.workflow.views.cron'),
+}}}
+
+ * ''mywork'': displays the tasks list of the current user
+ * ....
+ * ''start'': start a new instance given a model
+ * ''cron'': cron simulation task for timeout management
+
+''next soon''
+
+=== Application templates ===
+You can (may) redefine the templates associated with standard workflow views.
+
+For each application, a specific template has to be built. The context available has following variales:
+  * ''form'': form (newforms framework)
+  * ''instance'': instance object
+  * ''ob'': object (application-defined) linked to instance
+  * ''instance_props'': properties of instance
+
+The application developper should insert submit input fields when he inserts forms; the ''application_form'' handler then will update ''instance.condition'' with the value of the submit button pressed.