frappe/frappe/model/document.py

# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# MIT License. See license.txt

from __future__ import unicode_literals
import frappe
from frappe import _, msgprint
from frappe.utils import flt, cstr, now, get_datetime_str
from frappe.utils.background_jobs import enqueue
from frappe.model.base_document import BaseDocument, get_controller
from frappe.model.naming import set_new_name
from werkzeug.exceptions import NotFound, Forbidden
import hashlib, json
from frappe.model import optional_fields

# once_only validation
# methods

def get_doc(arg1, arg2=None):
	"""returns a frappe.model.Document object.

	:param arg1: Document dict or DocType name.
	:param arg2: [optional] document name.

	There are two ways to call `get_doc`

		# will fetch the latest user object (with child table) from the database
		user = get_doc("User", "test@example.com")

		# create a new object
		user = get_doc({
			"doctype":"User"
			"email_id": "test@example.com",
			"user_roles: [
				{"role": "System Manager"}
			]
		})
	"""
	if isinstance(arg1, BaseDocument):
		return arg1
	elif isinstance(arg1, basestring):
		doctype = arg1
	else:
		doctype = arg1.get("doctype")

	controller = get_controller(doctype)
	if controller:
		return controller(arg1, arg2)

	raise ImportError, arg1

class Document(BaseDocument):
	"""All controllers inherit from `Document`."""
	def __init__(self, arg1, arg2=None):
		"""Constructor.

		:param arg1: DocType name as string or document **dict**
		:param arg2: Document name, if `arg1` is DocType name.

		If DocType name and document name are passed, the object will load
		all values (including child documents) from the database.
		"""
		self.doctype = self.name = None
		self._default_new_docs = {}
		self.flags = frappe._dict()

		if arg1 and isinstance(arg1, basestring):
			if not arg2:
				# single
				self.doctype = self.name = arg1
			else:
				self.doctype = arg1
				if isinstance(arg2, dict):
					# filter
					self.name = frappe.db.get_value(arg1, arg2, "name")
					if self.name is None:
						frappe.throw(_("{0} {1} not found").format(_(arg1), arg2), frappe.DoesNotExistError)
				else:
					self.name = arg2

			self.load_from_db()

		elif isinstance(arg1, dict):
			super(Document, self).__init__(arg1)
			self.init_valid_columns()

		else:
			# incorrect arguments. let's not proceed.
			raise frappe.DataError("Document({0}, {1})".format(arg1, arg2))

	def reload(self):
		"""Reload document from database"""
		self.load_from_db()

	def load_from_db(self):
		"""Load document and children from database and create properties
		from fields"""
		if not getattr(self, "_metaclass", False) and self.meta.issingle:
			single_doc = frappe.db.get_singles_dict(self.doctype)
			if not single_doc:
				single_doc = frappe.new_doc(self.doctype).as_dict()
				single_doc["name"] = self.doctype
				del single_doc["__islocal"]

			super(Document, self).__init__(single_doc)
			self.init_valid_columns()
			self._fix_numeric_types()

		else:
			d = frappe.db.get_value(self.doctype, self.name, "*", as_dict=1)
			if not d:
				frappe.throw(_("{0} {1} not found").format(_(self.doctype), self.name), frappe.DoesNotExistError)

			super(Document, self).__init__(d)

		if self.name=="DocType" and self.doctype=="DocType":
			from frappe.model.meta import doctype_table_fields
			table_fields = doctype_table_fields
		else:
			table_fields = self.meta.get_table_fields()

		for df in table_fields:
			children = frappe.db.get_values(df.options,
				{"parent": self.name, "parenttype": self.doctype, "parentfield": df.fieldname},
				"*", as_dict=True, order_by="idx asc")
			if children:
				self.set(df.fieldname, children)
			else:
				self.set(df.fieldname, [])

		# sometimes __setup__ can depend on child values, hence calling again at the end
		if hasattr(self, "__setup__"):
			self.__setup__()

	def get_latest(self):
		if not getattr(self, "latest", None):
			self.latest = frappe.get_doc(self.doctype, self.name)
		return self.latest

	def check_permission(self, permtype, permlabel=None):
		"""Raise `frappe.PermissionError` if not permitted"""
		if not self.has_permission(permtype):
			self.raise_no_permission_to(permlabel or permtype)

	def has_permission(self, permtype="read", verbose=False):
		"""Call `frappe.has_permission` if `self.flags.ignore_permissions`
		is not set.

		:param permtype: one of `read`, `write`, `submit`, `cancel`, `delete`"""
		if self.flags.ignore_permissions:
			return True
		return frappe.has_permission(self.doctype, permtype, self, verbose=verbose)

	def has_website_permission(self, permtype="read", verbose=False):
		"""Call `frappe.has_website_permission` if `self.flags.ignore_permissions`
		is not set.

		:param permtype: one of `read`, `write`, `submit`, `cancel`, `delete`"""
		if self.flags.ignore_permissions:
			return True

		return (frappe.has_website_permission(self.doctype, permtype, self, verbose=verbose)
			or self.has_permission(permtype, verbose=verbose))

	def raise_no_permission_to(self, perm_type):
		"""Raise `frappe.PermissionError`."""
		msg = _("No permission to {0} {1} {2}".format(perm_type, self.doctype, self.name or ""))
		frappe.msgprint(msg)
		raise frappe.PermissionError(msg)

	def lock(self):
		'''Will set docstatus to 3 + the current docstatus and mark it as queued

		3 = queued for saving
		4 = queued for submission
		5 = queued for cancellation
		'''
		self.db_set('docstatus', 3 + self.docstatus, update_modified = False)

	def unlock(self):
		'''set the original docstatus at the time it was locked in the controller'''
		current_docstatus = self.db_get('docstatus') - 4
		if current_docstatus < 0:
			current_docstatus = 0

		self.db_set('docstatus', current_docstatus, update_modified = False)

	def insert(self, ignore_permissions=None):
		"""Insert the document in the database (as a new document).
		This will check for user permissions and execute `before_insert`,
		`validate`, `on_update`, `after_insert` methods if they are written.

		:param ignore_permissions: Do not check permissions if True."""
		if self.flags.in_print:
			return

		if ignore_permissions!=None:
			self.flags.ignore_permissions = ignore_permissions

		self.set("__islocal", True)

		self.check_permission("create")
		self._set_defaults()
		self.set_user_and_timestamp()
		self.set_docstatus()
		self.check_if_latest()
		self.run_method("before_insert")
		self.set_new_name()
		self.set_parent_in_children()
		self.validate_higher_perm_levels()

		self.flags.in_insert = True
		self.run_before_save_methods()
		self._validate()
		self.set_docstatus()
		self.flags.in_insert = False

		# run validate, on update etc.

		# parent
		if getattr(self.meta, "issingle", 0):
			self.update_single(self.get_valid_dict())
		else:
			self.db_insert()

		# children
		for d in self.get_all_children():
			d.db_insert()

		self.run_method("after_insert")
		self.flags.in_insert = True
		self.run_post_save_methods()
		self.flags.in_insert = False

		# delete __islocal
		if hasattr(self, "__islocal"):
			delattr(self, "__islocal")

		return self

	def save(self, *args, **kwargs):
		"""Wrapper for _save"""
		return self._save(*args, **kwargs)

	def _save(self, ignore_permissions=None):
		"""Save the current document in the database in the **DocType**'s table or
		`tabSingles` (for single types).

		This will check for user permissions and execute
		`validate` before updating, `on_update` after updating triggers.

		:param ignore_permissions: Do not check permissions if True."""
		if self.flags.in_print:
			return

		if ignore_permissions!=None:
			self.flags.ignore_permissions = ignore_permissions

		if self.get("__islocal") or not self.get("name"):
			self.insert()
			return

		self.check_permission("write", "save")

		self.set_user_and_timestamp()
		self.set_docstatus()
		self.check_if_latest()
		self.set_parent_in_children()
		self.validate_higher_perm_levels()
		self.run_before_save_methods()

		if self._action != "cancel":
			self._validate()

		if self._action == "update_after_submit":
			self.validate_update_after_submit()

		self.set_docstatus()

		# parent
		if self.meta.issingle:
			self.update_single(self.get_valid_dict())
		else:
			self.db_update()

		self.update_children()
		self.run_post_save_methods()

		return self

	def update_children(self):
		'''update child tables'''
		for df in self.meta.get_table_fields():
			self.update_child_table(df.fieldname, df)

	def update_child_table(self, fieldname, df=None):
		'''sync child table for given fieldname'''
		rows = []
		if not df:
			df = self.meta.get_field(fieldname)

		for d in self.get(df.fieldname):
			d.db_update()
			rows.append(d.name)

		if df.options in (self.flags.ignore_children_type or []):
			# do not delete rows for this because of flags
			# hack for docperm :(
			return

		if rows:
			# delete rows that do not match the ones in the
			# document
			frappe.db.sql("""delete from `tab{0}` where parent=%s
				and parenttype=%s and parentfield=%s
				and name not in ({1})""".format(df.options, ','.join(['%s'] * len(rows))),
					[self.name, self.doctype, fieldname] + rows)
		else:
			# no rows found, delete all rows
			frappe.db.sql("""delete from `tab{0}` where parent=%s
				and parenttype=%s and parentfield=%s""".format(df.options),
				(self.name, self.doctype, fieldname))

	def set_new_name(self):
		"""Calls `frappe.naming.se_new_name` for parent and child docs."""
		set_new_name(self)
		# set name for children
		for d in self.get_all_children():
			set_new_name(d)

	def set_title_field(self):
		"""Set title field based on template"""
		def get_values():
			values = self.as_dict()
			# format values
			for key, value in values.iteritems():
				if value==None:
					values[key] = ""
			return values

		if self.meta.get("title_field")=="title":
			df = self.meta.get_field(self.meta.title_field)

			if df.options:
				self.set(df.fieldname, df.options.format(**get_values()))
			elif self.is_new() and not self.get(df.fieldname) and df.default:
				# set default title for new transactions (if default)
				self.set(df.fieldname, df.default.format(**get_values()))

	def update_single(self, d):
		"""Updates values for Single type Document in `tabSingles`."""
		frappe.db.sql("""delete from tabSingles where doctype=%s""", self.doctype)
		for field, value in d.iteritems():
			if field != "doctype":
				frappe.db.sql("""insert into tabSingles(doctype, field, value)
					values (%s, %s, %s)""", (self.doctype, field, value))

		if self.doctype in frappe.db.value_cache:
			del frappe.db.value_cache[self.doctype]

	def set_user_and_timestamp(self):
		self._original_modified = self.modified
		self.modified = now()
		self.modified_by = frappe.session.user
		if not self.creation:
			self.creation = self.modified
		if not self.owner:
			self.owner = self.modified_by

		for d in self.get_all_children():
			d.modified = self.modified
			d.modified_by = self.modified_by
			if not d.owner:
				d.owner = self.owner
			if not d.creation:
				d.creation = self.creation

		frappe.flags.currently_saving.append((self.doctype, self.name))

	def set_docstatus(self):
		if self.docstatus==None:
			self.docstatus=0

		for d in self.get_all_children():
			d.docstatus = self.docstatus

	def _validate(self):
		self._validate_mandatory()
		self._validate_links()
		self._validate_selects()
		self._validate_constants()
		self._validate_length()
		self._sanitize_content()
		self._save_passwords()

		children = self.get_all_children()
		for d in children:
			d._validate_selects()
			d._validate_constants()
			d._validate_length()
			d._sanitize_content()
			d._save_passwords()

		if self.is_new():
			# don't set fields like _assign, _comments for new doc
			for fieldname in optional_fields:
				self.set(fieldname, None)

		# extract images after validations to save processing if some validation error is raised
		self._extract_images_from_text_editor()
		for d in children:
			d._extract_images_from_text_editor()

	def apply_fieldlevel_read_permissions(self):
		'''Remove values the user is not allowed to read (called when loading in desk)'''
		has_higher_permlevel = False
		for p in self.get_permissions():
			if p.permlevel > 0:
				has_higher_permlevel = True
				break

		if not has_higher_permlevel:
			return

		has_access_to = self.get_permlevel_access('read')

		for df in self.meta.fields:
			if df.permlevel and not df.permlevel in has_access_to:
				self.set(df.fieldname, None)

		for table_field in self.meta.get_table_fields():
			for df in frappe.get_meta(table_field.options).fields or []:
				if df.permlevel and not df.permlevel in has_access_to:
					for child in self.get(table_field.fieldname) or []:
						child.set(df.fieldname, None)

	def validate_higher_perm_levels(self):
		"""If the user does not have permissions at permlevel > 0, then reset the values to original / default"""
		if self.flags.ignore_permissions or frappe.flags.in_install:
			return

		has_access_to = self.get_permlevel_access()
		high_permlevel_fields = self.meta.get_high_permlevel_fields()

		if high_permlevel_fields:
			self.reset_values_if_no_permlevel_access(has_access_to, high_permlevel_fields)

		# check for child tables
		for df in self.meta.get_table_fields():
			high_permlevel_fields = frappe.get_meta(df.options).meta.get_high_permlevel_fields()
			if high_permlevel_fields:
				for d in self.get(df.fieldname):
					d.reset_values_if_no_permlevel_access(has_access_to, high_permlevel_fields)

	def get_permlevel_access(self, permission_type='write'):
		if not hasattr(self, "_has_access_to"):
			user_roles = frappe.get_roles()
			self._has_access_to = []
			for perm in self.get_permissions():
				if perm.role in user_roles and perm.permlevel > 0 and perm.get(permission_type):
					if perm.permlevel not in self._has_access_to:
						self._has_access_to.append(perm.permlevel)

		return self._has_access_to

	def has_permlevel_access_to(self, fieldname, df=None, permission_type='read'):
		if not df:
			df = self.meta.get_field(fieldname)

		return df.permlevel in self.get_permlevel_access()

	def get_permissions(self):
		if self.meta.istable:
			# use parent permissions
			permissions = frappe.get_meta(self.parenttype).permissions
		else:
			permissions = self.meta.permissions

		return permissions

	def _set_defaults(self):
		if frappe.flags.in_import:
			return

		new_doc = frappe.new_doc(self.doctype, as_dict=True)
		self.update_if_missing(new_doc)

		# children
		for df in self.meta.get_table_fields():
			new_doc = frappe.new_doc(df.options, as_dict=True)
			value = self.get(df.fieldname)
			if isinstance(value, list):
				for d in value:
					d.update_if_missing(new_doc)

	def check_if_latest(self):
		"""Checks if `modified` timestamp provided by document being updated is same as the
		`modified` timestamp in the database. If there is a different, the document has been
		updated in the database after the current copy was read. Will throw an error if
		timestamps don't match.

		Will also validate document transitions (Save > Submit > Cancel) calling
		`self.check_docstatus_transition`."""
		conflict = False
		self._action = "save"
		if not self.get('__islocal'):
			if self.meta.issingle:
				modified = frappe.db.get_value(self.doctype, self.name, "modified")
				if cstr(modified) and cstr(modified) != cstr(self._original_modified):
					conflict = True
			else:
				tmp = frappe.db.sql("""select modified, docstatus from `tab{0}`
					where name = %s for update""".format(self.doctype), self.name, as_dict=True)

				if not tmp:
					frappe.throw(_("Record does not exist"))
				else:
					tmp = tmp[0]

				modified = cstr(tmp.modified)

				if modified and modified != cstr(self._original_modified):
					conflict = True

				self.check_docstatus_transition(tmp.docstatus)

			if conflict:
				frappe.msgprint(_("Error: Document has been modified after you have opened it") \
				+ (" (%s, %s). " % (modified, self.modified)) \
				+ _("Please refresh to get the latest document."),
					raise_exception=frappe.TimestampMismatchError)
		else:
			self.check_docstatus_transition(0)

	def check_docstatus_transition(self, docstatus):
		"""Ensures valid `docstatus` transition.
		Valid transitions are (number in brackets is `docstatus`):

		- Save (0) > Save (0)
		- Save (0) > Submit (1)
		- Submit (1) > Submit (1)
		- Submit (1) > Cancel (2)

		If docstatus is > 2, it will throw exception as document is deemed queued
		"""

		if self.docstatus > 2:
			frappe.throw(_('This document is currently queued for execution. Please try again'),
				title=_('Document Queued'), indicator='red')

		if not self.docstatus:
			self.docstatus = 0
		if docstatus==0:
			if self.docstatus==0:
				self._action = "save"
			elif self.docstatus==1:
				self._action = "submit"
				self.check_permission("submit")
			else:
				raise frappe.DocstatusTransitionError, _("Cannot change docstatus from 0 to 2")

		elif docstatus==1:
			if self.docstatus==1:
				self._action = "update_after_submit"
				self.check_permission("submit")
			elif self.docstatus==2:
				self._action = "cancel"
				self.check_permission("cancel")
			else:
				raise frappe.DocstatusTransitionError, _("Cannot change docstatus from 1 to 0")

		elif docstatus==2:
			raise frappe.ValidationError, _("Cannot edit cancelled document")

	def set_parent_in_children(self):
		"""Updates `parent` and `parenttype` property in all children."""
		for d in self.get_all_children():
			d.parent = self.name
			d.parenttype = self.doctype

	def validate_update_after_submit(self):
		if self.flags.ignore_validate_update_after_submit:
			return

		self._validate_update_after_submit()
		for d in self.get_all_children():
			if d.is_new() and self.meta.get_field(d.parentfield).allow_on_submit:
				# in case of a new row, don't validate allow on submit, if table is allow on submit
				continue

			d._validate_update_after_submit()

		# TODO check only allowed values are updated

	def _validate_mandatory(self):
		if self.flags.ignore_mandatory:
			return

		missing = self._get_missing_mandatory_fields()
		for d in self.get_all_children():
			missing.extend(d._get_missing_mandatory_fields())

		if not missing:
			return

		for fieldname, msg in missing:
			msgprint(msg)

		if frappe.flags.print_messages:
			print self.as_json().encode("utf-8")

		raise frappe.MandatoryError('[{doctype}, {name}]: {fields}'.format(
			fields=", ".join((each[0] for each in missing)),
			doctype=self.doctype,
			name=self.name))

	def _validate_links(self):
		if self.flags.ignore_links:
			return

		invalid_links, cancelled_links = self.get_invalid_links()

		for d in self.get_all_children():
			result = d.get_invalid_links(is_submittable=self.meta.is_submittable)
			invalid_links.extend(result[0])
			cancelled_links.extend(result[1])

		if invalid_links:
			msg = ", ".join((each[2] for each in invalid_links))
			frappe.throw(_("Could not find {0}").format(msg),
				frappe.LinkValidationError)

		if cancelled_links:
			msg = ", ".join((each[2] for each in cancelled_links))
			frappe.throw(_("Cannot link cancelled document: {0}").format(msg),
				frappe.CancelledLinkError)

	def get_all_children(self, parenttype=None):
		"""Returns all children documents from **Table** type field in a list."""
		ret = []
		for df in self.meta.get("fields", {"fieldtype": "Table"}):
			if parenttype:
				if df.options==parenttype:
					return self.get(df.fieldname)
			value = self.get(df.fieldname)
			if isinstance(value, list):
				ret.extend(value)
		return ret

	def run_method(self, method, *args, **kwargs):
		"""run standard triggers, plus those in hooks"""
		if "flags" in kwargs:
			del kwargs["flags"]

		if hasattr(self, method) and hasattr(getattr(self, method), "__call__"):
			fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
		else:
			# hack! to run hooks even if method does not exist
			fn = lambda self, *args, **kwargs: None

		fn.__name__ = method.encode("utf-8")
		return Document.hook(fn)(self, *args, **kwargs)

	@staticmethod
	def whitelist(f):
		f.whitelisted = True
		return f

	@whitelist.__func__
	def _submit(self):
		"""Submit the document. Sets `docstatus` = 1, then saves."""
		self.docstatus = 1
		self.save()

	@whitelist.__func__
	def _cancel(self):
		"""Cancel the document. Sets `docstatus` = 2, then saves."""
		self.docstatus = 2
		self.save()

	@whitelist.__func__
	def submit(self):
		"""Submit the document. Sets `docstatus` = 1, then saves."""
		self._submit()

	@whitelist.__func__
	def cancel(self):
		"""Cancel the document. Sets `docstatus` = 2, then saves."""
		self._cancel()

	def delete(self):
		"""Delete document."""
		frappe.delete_doc(self.doctype, self.name, flags=self.flags)

	def run_before_save_methods(self):
		"""Run standard methods before  `INSERT` or `UPDATE`. Standard Methods are:

		- `validate`, `before_save` for **Save**.
		- `validate`, `before_submit` for **Submit**.
		- `before_cancel` for **Cancel**
		- `before_update_after_submit` for **Update after Submit**

		Will also update title_field if set"""
		self.set_title_field()
		self.reset_seen()

		if self.flags.ignore_validate:
			return

		if self._action=="save":
			self.run_method("validate")
			self.run_method("before_save")
		elif self._action=="submit":
			self.run_method("validate")
			self.run_method("before_submit")
		elif self._action=="cancel":
			self.run_method("before_cancel")
		elif self._action=="update_after_submit":
			self.run_method("before_update_after_submit")

	def run_post_save_methods(self):
		"""Run standard methods after `INSERT` or `UPDATE`. Standard Methods are:

		- `on_update` for **Save**.
		- `on_update`, `on_submit` for **Submit**.
		- `on_cancel` for **Cancel**
		- `update_after_submit` for **Update after Submit**"""
		if self._action=="save":
			self.run_method("on_update")
		elif self._action=="submit":
			self.run_method("on_update")
			self.run_method("on_submit")
			if not self.flags.ignore_submit_comment:
				self.add_comment("Submitted")
		elif self._action=="cancel":
			self.run_method("on_cancel")
			self.check_no_back_links_exist()
			if not self.flags.ignore_submit_comment:
				self.add_comment("Cancelled")
		elif self._action=="update_after_submit":
			self.run_method("on_update_after_submit")

		self.run_method('on_change')

		self.update_timeline_doc()
		self.clear_cache()
		self.notify_update()

		if (self.doctype, self.name) in frappe.flags.currently_saving:
			frappe.flags.currently_saving.remove((self.doctype, self.name))

		self.latest = None

	def clear_cache(self):
		frappe.cache().hdel("last_modified", self.doctype)
		self.clear_linked_with_cache()

	def clear_linked_with_cache(self):
		cache = frappe.cache()
		def _clear_cache(d):
			for df in (d.meta.get_link_fields() + d.meta.get_dynamic_link_fields()):
				if d.get(df.fieldname):
					doctype = df.options if df.fieldtype=="Link" else d.get(df.options)
					name = d.get(df.fieldname)

					if df.fieldtype=="Dynamic Link":
						# clear linked doctypes list
						cache.hdel("linked_doctypes", doctype)

					# for all users, delete linked with cache and per doctype linked with cache
					cache.delete_value("user:*:linked_with:{doctype}:{name}".format(doctype=doctype, name=name))
					cache.delete_value("user:*:linked_with:{doctype}:{name}:*".format(doctype=doctype, name=name))

		_clear_cache(self)
		for d in self.get_all_children():
			_clear_cache(d)

	def reset_seen(self):
		'''Clear _seen property and set current user as seen'''
		if getattr(self.meta, 'track_seen', False):
			self._seen = json.dumps([frappe.session.user])

	def notify_update(self):
		"""Publish realtime that the current document is modified"""
		frappe.publish_realtime("doc_update", {"modified": self.modified, "doctype": self.doctype, "name": self.name},
			doctype=self.doctype, docname=self.name, after_commit=True)

		if not self.meta.get("read_only") and not self.meta.get("issingle") and \
			not self.meta.get("istable"):
			frappe.publish_realtime("list_update", {"doctype": self.doctype}, after_commit=True)


	def check_no_back_links_exist(self):
		"""Check if document links to any active document before Cancel."""
		from frappe.model.delete_doc import check_if_doc_is_linked, check_if_doc_is_dynamically_linked
		if not self.flags.ignore_links:
			check_if_doc_is_linked(self, method="Cancel")
			check_if_doc_is_dynamically_linked(self, method="Cancel")

	@staticmethod
	def whitelist(f):
		"""Decorator: Whitelist method to be called remotely via REST API."""
		f.whitelisted = True
		return f

	@staticmethod
	def hook(f):
		"""Decorator: Make method `hookable` (i.e. extensible by another app).

		Note: If each hooked method returns a value (dict), then all returns are
		collated in one dict and returned. Ideally, don't return values in hookable
		methods, set properties in the document."""
		def add_to_return_value(self, new_return_value):
			if isinstance(new_return_value, dict):
				if not self.get("_return_value"):
					self._return_value = {}
				self._return_value.update(new_return_value)
			else:
				self._return_value = new_return_value or self.get("_return_value")

		def compose(fn, *hooks):
			def runner(self, method, *args, **kwargs):
				add_to_return_value(self, fn(self, *args, **kwargs))
				for f in hooks:
					add_to_return_value(self, f(self, method, *args, **kwargs))

				return self._return_value

			return runner

		def composer(self, *args, **kwargs):
			hooks = []
			method = f.__name__
			doc_events = frappe.get_doc_hooks()
			for handler in doc_events.get(self.doctype, {}).get(method, []) \
				+ doc_events.get("*", {}).get(method, []):
				hooks.append(frappe.get_attr(handler))

			composed = compose(f, *hooks)
			return composed(self, method, *args, **kwargs)

		return composer

	def is_whitelisted(self, method):
		fn = getattr(self, method, None)
		if not fn:
			raise NotFound("Method {0} not found".format(method))
		elif not getattr(fn, "whitelisted", False):
			raise Forbidden("Method {0} not whitelisted".format(method))

	def validate_value(self, fieldname, condition, val2, doc=None, raise_exception=None):
		"""Check that value of fieldname should be 'condition' val2
			else throw Exception."""
		error_condition_map = {
			"in": _("one of"),
			"not in": _("none of"),
			"^": _("beginning with"),
		}

		if not doc:
			doc = self

		val1 = doc.get_value(fieldname)

		df = doc.meta.get_field(fieldname)
		val2 = doc.cast(val2, df)

		if not frappe.compare(val1, condition, val2):
			label = doc.meta.get_label(fieldname)
			condition_str = error_condition_map.get(condition, condition)
			if doc.parentfield:
				msg = _("Incorrect value in row {0}: {1} must be {2} {3}".format(doc.idx, label, condition_str, val2))
			else:
				msg = _("Incorrect value: {0} must be {1} {2}".format(label, condition_str, val2))

			# raise passed exception or True
			msgprint(msg, raise_exception=raise_exception or True)

	def validate_table_has_rows(self, parentfield, raise_exception=None):
		"""Raise exception if Table field is empty."""
		if not (isinstance(self.get(parentfield), list) and len(self.get(parentfield)) > 0):
			label = self.meta.get_label(parentfield)
			frappe.throw(_("Table {0} cannot be empty").format(label), raise_exception or frappe.EmptyTableError)

	def round_floats_in(self, doc, fieldnames=None):
		"""Round floats for all `Currency`, `Float`, `Percent` fields for the given doc.

		:param doc: Document whose numeric properties are to be rounded.
		:param fieldnames: [Optional] List of fields to be rounded."""
		if not fieldnames:
			fieldnames = (df.fieldname for df in
				doc.meta.get("fields", {"fieldtype": ["in", ["Currency", "Float", "Percent"]]}))

		for fieldname in fieldnames:
			doc.set(fieldname, flt(doc.get(fieldname), self.precision(fieldname, doc.parentfield)))

	def get_url(self):
		"""Returns Desk URL for this document. `/desk#Form/{doctype}/{name}`"""
		return "/desk#Form/{doctype}/{name}".format(doctype=self.doctype, name=self.name)

	def add_comment(self, comment_type, text=None, comment_by=None, link_doctype=None, link_name=None):
		"""Add a comment to this document.

		:param comment_type: e.g. `Comment`. See Communication for more info."""

		comment = frappe.get_doc({
			"doctype":"Communication",
			"communication_type": "Comment",
			"sender": comment_by or frappe.session.user,
			"comment_type": comment_type,
			"reference_doctype": self.doctype,
			"reference_name": self.name,
			"content": text or comment_type,
			"link_doctype": link_doctype,
			"link_name": link_name
		}).insert(ignore_permissions=True)
		return comment

	def add_seen(self, user=None):
		'''add the given/current user to list of users who have seen this document (_seen)'''
		if not user:
			user = frappe.session.user

		if self.meta.track_seen:
			if self._seen:
				_seen = json.loads(self._seen)
			else:
				_seen = []

			if user not in _seen:
				_seen.append(user)
				self.db_set('_seen', json.dumps(_seen), update_modified=False)
				frappe.local.flags.commit = True

	def get_signature(self):
		"""Returns signature (hash) for private URL."""
		return hashlib.sha224(get_datetime_str(self.creation)).hexdigest()

	def get_liked_by(self):
		liked_by = getattr(self, "_liked_by", None)
		if liked_by:
			return json.loads(liked_by)
		else:
			return []

	def set_onload(self, key, value):
		if not self.get("__onload"):
			self.set("__onload", frappe._dict())
		self.get("__onload")[key] = value

	def update_timeline_doc(self):
		if frappe.flags.in_install or not self.meta.get("timeline_field"):
			return

		timeline_doctype = self.meta.get_link_doctype(self.meta.timeline_field)
		timeline_name = self.get(self.meta.timeline_field)

		if not (timeline_doctype and timeline_name):
			return

		# update timeline doc in communication if it is different than current timeline doc
		frappe.db.sql("""update `tabCommunication`
			set timeline_doctype=%(timeline_doctype)s, timeline_name=%(timeline_name)s
			where
				reference_doctype=%(doctype)s and reference_name=%(name)s
				and (timeline_doctype is null or timeline_doctype != %(timeline_doctype)s
					or timeline_name is null or timeline_name != %(timeline_name)s)""",
				{
					"doctype": self.doctype,
					"name": self.name,
					"timeline_doctype": timeline_doctype,
					"timeline_name": timeline_name
				})

	def queue_action(self, action, **kwargs):
		'''Run an action in background. If the action has an inner function,
		like _submit for submit, it will call that instead'''

		if action in ('save', 'submit', 'cancel'):
			# set docstatus explicitly again due to inconsistent action
			self.docstatus = {'save':0, 'submit':1, 'cancel': 2}[action]
		else:
			raise 'Action must be one of save, submit, cancel'

		# call _submit instead of submit, so you can override submit to call
		# run_delayed based on some action
		# See: Stock Reconciliation
		if hasattr(self, '_' + action):
			action = '_' + action

		self.lock()
		enqueue('frappe.model.document.execute_action', doctype=self.doctype, name=self.name,
			action=action, **kwargs)

def execute_action(doctype, name, action, **kwargs):
	'''Execute an action on a document (called by background worker)'''
	doc = frappe.get_doc(doctype, name)
	doc.unlock()
	try:
		getattr(doc, action)(**kwargs)
	except frappe.ValidationError:
		# add a comment (?)
		if frappe.local.message_log:
			msg = json.loads(frappe.local.message_log[-1]).get('message')
		else:
			msg = '<pre><code>' + frappe.get_traceback() + '</pre></code>'
		
		doc.add_comment('Comment', _('Action Failed') + '<br><br>' + msg)

		doc.notify_update()
	except Exception:
		# add a comment (?)
		doc.add_comment('Comment',
			_('Action Failed') + '<pre><code>' + frappe.get_traceback() + '</pre></code>')

		doc.notify_update()