From ee0cb2dae07281430b784880284999b9c806f7e7 Mon Sep 17 00:00:00 2001
From: kindly <kindly@gmail.com>
Date: Wed, 25 Jul 2012 00:38:24 +0100
Subject: [PATCH] [2733] add engines and basic transaction scaffolding for
 create

---
 ckanext/datastore/db.py                  | 76 +++++++++++++++++++++++-
 ckanext/datastore/logic/action/create.py | 17 +++---
 2 files changed, 84 insertions(+), 9 deletions(-)

diff --git a/ckanext/datastore/db.py b/ckanext/datastore/db.py
index 19845d05361..4951987e660 100644
--- a/ckanext/datastore/db.py
+++ b/ckanext/datastore/db.py
@@ -1,6 +1,57 @@
+import sqlalchemy
+from pylons import config
 
+_pg_types = {}
+_type_names = set()
+_engines = {}
 
-def create(resource_id, fields, rows):
+def _get_engine(context, data_dict):
+    ''' Get either read or write engine'''
+    connection_type = data_dict.get('connection_type', 'write')
+    engine = _engines.get(connection_type)
+
+    if not engine:
+        config_option = 'ckan.datastore_{}_url'.format(connection_type)
+        url = config.get(config_option)
+        assert url, 'Config option ' + config_option + ' not defined'
+        engine = sqlalchemy.create_engine(url)
+        _engines[connection_type] = engine
+    return engine
+
+def _cache_types(context, data_dict=None):
+    if not _pg_types:
+        connection = context['connection']
+        results = connection.execute(
+            'select oid, typname from pg_type;'
+        )
+        for result in results:
+            _pg_types[result[0]] = result[1]
+            _type_names.add(result[1])
+
+def _get_type(context, oid):
+    _cache_types(context)
+    return _pg_types[oid]
+
+def check_fields(context, fields):
+    _cache_types(context)
+    ## check if fieds are in in _type_names
+    pass
+
+def create_table(context, data_dict):
+    '''create table from combination of fields and first row of data'''
+    check_fields(context, data_dict.get('fields'))
+    pass
+
+def alter_table(context, data_dict):
+    '''alter table from combination of fields and first row of data'''
+    check_fields(context, data_dict.get('fields'))
+    pass
+
+def insert_data(context, data_dict):
+    '''insert all data from records'''
+    pass
+
+def create(context, data_dict):
     '''
     The first row will be used to guess types not in the fields and the
     guessed types will be added to the headers permanently.
@@ -22,4 +73,25 @@ def create(resource_id, fields, rows):
     Any error results in total failure! For now pass back the actual error.
     Should be transactional.
     '''
-    pass
+
+    engine = _get_engine(context, {'connection_type': 'write'})
+    context['connection'] = engine.connect()
+    ## close connection at all cost.
+    try:
+        ## check if table already existes
+        trans = context['connection'].begin()
+        result = context['connection'].execute(
+            'select * from pg_tables where tablename = %s',
+             data_dict['resource_id']
+        ).fetchone()
+        if not result:
+            create_table(context, data_dict)
+        else:
+            alter_table(context, data_dict)
+        insert_data(context, data_dict)
+    except:
+        trans.rollback()
+        raise
+    finally:
+        context['connection'].close()
+
diff --git a/ckanext/datastore/logic/action/create.py b/ckanext/datastore/logic/action/create.py
index c7e02d70237..ca0321bf8fb 100644
--- a/ckanext/datastore/logic/action/create.py
+++ b/ckanext/datastore/logic/action/create.py
@@ -30,14 +30,17 @@ def datastore_create(context, data_dict):
     model = _get_or_bust(context, 'model')
     resource_id = _get_or_bust(data_dict, 'resource_id')
     fields = data_dict.get('fields')
-    records = _get_or_bust(data_dict, 'records')
+    records = data_dict.get('records')
 
     _check_access('datastore_create', context, data_dict)
 
-    schema = ckanext.datastore.logic.schema.default_datastore_create_schema()
-    data, errors = _validate(data_dict, schema, context)
-    if errors:
-        model.Session.rollback()
-        raise p.toolkit.ValidationError(errors)
+    # Not sure need schema as will be too dificulut to make 
+    # as records could be deeply nested..
 
-    return db.create(resource_id, fields, records)
+    #schema = ckanext.datastore.logic.schema.default_datastore_create_schema()
+    #data, errors = _validate(data_dict, schema, context)
+    #if errors:
+    #    model.Session.rollback()
+    #    raise p.toolkit.ValidationError(errors)
+
+    return db.create(context, data_dict)