example of model w/ model graph, multi-tenancy, record versioning (incl auth tables), and record uid

[Peter Etchells]

I was playing around with impressive model graph feature, & thought you may be interested in the following simple model, with these features:

• multi-tenancy 
  
• record versioning (including auth tables)
  
• unique id for each record (eg for syncing across multiple dbs)

total code is about 14 lines, all in model db.py in a new empty application

#this goes after auth=Auth(db) 

#model code to implement multi-tenancy and tenant name table, record versioning (including for auth tables), uid for all tables( for syncing multiple dbs)

#this field in a table triggers multi-tenancy

request_tenant=Field('request_tenant', default=request.env.http_host, writable=False) #try request.env.server_port on local machine for local demo

#this field is a unique id for any record, anywhere. could/should be unique=True

unique_id=Field('uuid', length=64, default=lambda: str(uuid.uuid4()), writable=False)

#extra fields for auth & all tables

extra_fields=[request_tenant, auth.signature, unique_id]

#example of adding extra fields to various auth tables

#auth_user gets two extra fields as below. auth_event gets no extra fields. other auth tables get the extra_fields defined above.

auth.settings.extra_fields['auth_user']=[   Field('country'),   Field('tz_offset', 'double', default=0.0),   ]+extra_fields

#example of extra fields for multiple auth tables

#this is to exclude auth_event from getting versioning and archive

for auth_table in 'cas membership permission group'.split():

   auth.settings.extra_fields['auth_'+auth_table]=extra_fields

#auth.settings.extra_fields['auth_event']=[unique_id] # if we wanted unique events across multiple dbs  

#instead of the above, we could just do auth.define_tables after common_fields if we wanted *all* auth_ tables to also have versioning and archive

auth.define_tables(username=False, signature=False)

## configure email

#...

#use_janrain(auth, filename='private/janrain.key')

#this at end of model 

#example of extra fields for all other tables except auth tables, which have already been defined above. this implements record versioning

for f in extra_fields:

    db._common_fields.append(f)

    

#the tenant table below will have only one visible record, depending on tenant (if record exists)...

#eg tenant_name=db().select(db.tenant.name, cacheable=True, cache=(cache.ram, 1000)).first().name)

db.define_table('tenant',

    Field('name', label='tenant name'), #could/should be unique=True

    )

#sample basic table to demonstrate links to web2py tables

db.define_table('mytable',

    Field('name'),

    )

#here define more tables that will have record versioning

auth.enable_record_versioning(db)

#now define any tables that won't have record versioning (eg event logs)

[Massimo Di Pierro]

Nice example!

[Massimo Di Pierro]

Can you post a web2pyslice about this?

[Gene]

Regarding the appending of common fields, seems to work for me when its declared at the beginning of the model file, not end. Does the placement matter, can anyone confirm/deny?

[Massimo Di Pierro]

Yes, it matters.