This class is used to layer over top of SQLAlchemy models to provide access to a Grid-like API

Grid.py

from sqlalchemy import desc, func

from libs.database import Session

def importer(name):
    mod = __import__(name)
    components = name.split('.')
    for comp in components[1:]:
        mod = getattr(mod, comp)
    return mod

class Grid():

  def __init__(self, model):
		# Set the page 
		self.page = 0
		# Set the ordering column
		self.sort_param = "id"
		# Set the ordering direction 
		self.sort_dir = "DESC"
		# Set the number of items per page
		self.items_per_page = 10

		# Set what model we're using
		self.model = model

	def get(self, cfg):
		pkg = "libs.models.%s" % (self.model)
		module = __import__(pkg, fromlist=[self.model])
		model = getattr(module, self.model)

		page = cfg['page'] - 1

		sess = Session()

		# Calculate offset
		offset = page*cfg['items_per_page']

		q = sess.query(model)

		order = "%s.%s" % (model.__dict__['__tablename__'], sort_param)

		if filters is not None:
			for key in filters.keys():
				param = "%s.%s = %s" % (model.__dict__['__tablename__'], key, filters[key])
				order = order.where(param)

		if sort_dir == "DESC":
			order = "%s DESC" % (order)
			q = q.order_by(order)
		else:
			order = "%s ASC" % (order)
			q = q.order_by(order)
		q = q.limit(items_per_page)
		q = q.offset(offset)

		total_items = sess.query(func.count(model.id)).scalar()
		total_pages = 1
		if items_per_page < total_items:
			total_pages = int(round(float(total_items)/float(items_per_page), 0))
			total_pages = total_page + 1

		data = {
			"items": [i.serialize for i in q.all()],
			"success": True,
			"page": page,
			"sort_param": sort_param,
			"sort_dir": sort_dir,
			"items_per_page": items_per_page,
			"total_pages": total_pages,
			"total_items": total_items
		}

		sess.close()

		return data