def find_path_to_course():
'''Find a path up the location graph to a node with the
specified category.
If no path exists, return None.
If a path exists, return it as a list with target location first, and
the starting location last.
'''
# Standard DFS
# To keep track of where we came from, the work queue has
# tuples (location, path-so-far). To avoid lots of
# copying, the path-so-far is stored as a lisp-style
# list--nested hd::tl tuples, and flattened at the end.
queue = [(location, ())]
while len(queue) > 0:
(loc, path) = queue.pop() # Takes from the end
loc = Location(loc)
# get_parent_locations should raise ItemNotFoundError if location
# isn't found so we don't have to do it explicitly. Call this
# first to make sure the location is there (even if it's a course, and
# we would otherwise immediately exit).
parents = modulestore.get_parent_locations(loc, course_id)
# print 'Processing loc={0}, path={1}'.format(loc, path)
if loc.category == "course":
# confirm that this is the right course
if course_id == CourseDescriptor.location_to_id(loc):
# Found it!
path = (loc, path)
return flatten(path)
# otherwise, add parent locations at the end
newpath = (loc, path)
queue.extend(zip(parents, repeat(newpath)))
# If we're here, there is no path
return None
def find_path_to_course():
'''Find a path up the location graph to a node with the
specified category.
If no path exists, return None.
If a path exists, return it as a list with target location first, and
the starting location last.
'''
# Standard DFS
# To keep track of where we came from, the work queue has
# tuples (location, path-so-far). To avoid lots of
# copying, the path-so-far is stored as a lisp-style
# list--nested hd::tl tuples, and flattened at the end.
queue = [(location, ())]
while len(queue) > 0:
(loc, path) = queue.pop() # Takes from the end
loc = Location(loc)
# get_parent_locations should raise ItemNotFoundError if location
# isn't found so we don't have to do it explicitly. Call this
# first to make sure the location is there (even if it's a course, and
# we would otherwise immediately exit).
parents = modulestore.get_parent_locations(loc, course_id)
# print 'Processing loc={0}, path={1}'.format(loc, path)
if loc.category == "course":
# confirm that this is the right course
if course_id == CourseDescriptor.location_to_id(loc):
# Found it!
path = (loc, path)
return flatten(path)
# otherwise, add parent locations at the end
newpath = (loc, path)
queue.extend(zip(parents, repeat(newpath)))
# If we're here, there is no path
return None
def path_to_location(modulestore, course_id, location):
'''
Try to find a course_id/chapter/section[/position] path to location in
modulestore. The courseware insists that the first level in the course is
chapter, but any kind of module can be a "section".
location: something that can be passed to Location
course_id: Search for paths in this course.
raise ItemNotFoundError if the location doesn't exist.
raise NoPathToItem if the location exists, but isn't accessible via
a chapter/section path in the course(s) being searched.
Return a tuple (course_id, chapter, section, position) suitable for the
courseware index view.
A location may be accessible via many paths. This method may
return any valid path.
If the section is a sequential or vertical, position will be the position
of this location in that sequence. Otherwise, position will
be None. TODO (vshnayder): Not true yet.
'''
def flatten(xs):
'''Convert lisp-style (a, (b, (c, ()))) list into a python list.
Not a general flatten function. '''
p = []
while xs != ():
p.append(xs[0])
xs = xs[1]
return p
def find_path_to_course():
'''Find a path up the location graph to a node with the
specified category.
If no path exists, return None.
If a path exists, return it as a list with target location first, and
the starting location last.
'''
# Standard DFS
# To keep track of where we came from, the work queue has
# tuples (location, path-so-far). To avoid lots of
# copying, the path-so-far is stored as a lisp-style
# list--nested hd::tl tuples, and flattened at the end.
queue = [(location, ())]
while len(queue) > 0:
(loc, path) = queue.pop() # Takes from the end
loc = Location(loc)
# get_parent_locations should raise ItemNotFoundError if location
# isn't found so we don't have to do it explicitly. Call this
# first to make sure the location is there (even if it's a course, and
# we would otherwise immediately exit).
parents = modulestore.get_parent_locations(loc, course_id)
# print 'Processing loc={0}, path={1}'.format(loc, path)
if loc.category == "course":
# confirm that this is the right course
if course_id == CourseDescriptor.location_to_id(loc):
# Found it!
path = (loc, path)
return flatten(path)
# otherwise, add parent locations at the end
newpath = (loc, path)
queue.extend(zip(parents, repeat(newpath)))
# If we're here, there is no path
return None
if not modulestore.has_item(location):
raise ItemNotFoundError
path = find_path_to_course()
if path is None:
raise NoPathToItem(location)
n = len(path)
course_id = CourseDescriptor.location_to_id(path[0])
# pull out the location names
chapter = path[1].name if n > 1 else None
section = path[2].name if n > 2 else None
# Figure out the position
position = None
# This block of code will find the position of a module within a nested tree
# of modules. If a problem is on tab 2 of a sequence that's on tab 3 of a
# sequence, the resulting position is 3_2. However, no positional modules
# (e.g. sequential and videosequence) currently deal with this form of
# representing nested positions. This needs to happen before jumping to a
# module nested in more than one positional module will work.
if n > 3:
position_list = []
for path_index in range(2, n - 1):
category = path[path_index].category
if category == 'sequential' or category == 'videosequence':
section_desc = modulestore.get_instance(
course_id, path[path_index])
child_locs = [c.location for c in section_desc.get_children()]
# positions are 1-indexed, and should be strings to be consistent with
# url parsing.
position_list.append(str(child_locs.index(
path[path_index + 1]) + 1))
position = "_".join(position_list)
return (course_id, chapter, section, position)
def path_to_location(modulestore, course_id, location):
'''
Try to find a course_id/chapter/section[/position] path to location in
modulestore. The courseware insists that the first level in the course is
chapter, but any kind of module can be a "section".
location: something that can be passed to Location
course_id: Search for paths in this course.
raise ItemNotFoundError if the location doesn't exist.
raise NoPathToItem if the location exists, but isn't accessible via
a chapter/section path in the course(s) being searched.
Return a tuple (course_id, chapter, section, position) suitable for the
courseware index view.
A location may be accessible via many paths. This method may
return any valid path.
If the section is a sequential or vertical, position will be the position
of this location in that sequence. Otherwise, position will
be None. TODO (vshnayder): Not true yet.
'''
def flatten(xs):
'''Convert lisp-style (a, (b, (c, ()))) list into a python list.
Not a general flatten function. '''
p = []
while xs != ():
p.append(xs[0])
xs = xs[1]
return p
def find_path_to_course():
'''Find a path up the location graph to a node with the
specified category.
If no path exists, return None.
If a path exists, return it as a list with target location first, and
the starting location last.
'''
# Standard DFS
# To keep track of where we came from, the work queue has
# tuples (location, path-so-far). To avoid lots of
# copying, the path-so-far is stored as a lisp-style
# list--nested hd::tl tuples, and flattened at the end.
queue = [(location, ())]
while len(queue) > 0:
(loc, path) = queue.pop() # Takes from the end
loc = Location(loc)
# get_parent_locations should raise ItemNotFoundError if location
# isn't found so we don't have to do it explicitly. Call this
# first to make sure the location is there (even if it's a course, and
# we would otherwise immediately exit).
parents = modulestore.get_parent_locations(loc, course_id)
# print 'Processing loc={0}, path={1}'.format(loc, path)
if loc.category == "course":
# confirm that this is the right course
if course_id == CourseDescriptor.location_to_id(loc):
# Found it!
path = (loc, path)
return flatten(path)
# otherwise, add parent locations at the end
newpath = (loc, path)
queue.extend(zip(parents, repeat(newpath)))
# If we're here, there is no path
return None
if not modulestore.has_item(course_id, location):
raise ItemNotFoundError
path = find_path_to_course()
if path is None:
raise NoPathToItem(location)
n = len(path)
course_id = CourseDescriptor.location_to_id(path[0])
# pull out the location names
chapter = path[1].name if n > 1 else None
section = path[2].name if n > 2 else None
# Figure out the position
position = None
# This block of code will find the position of a module within a nested tree
# of modules. If a problem is on tab 2 of a sequence that's on tab 3 of a
# sequence, the resulting position is 3_2. However, no positional modules
# (e.g. sequential and videosequence) currently deal with this form of
# representing nested positions. This needs to happen before jumping to a
# module nested in more than one positional module will work.
if n > 3:
position_list = []
for path_index in range(2, n - 1):
category = path[path_index].category
if category == 'sequential' or category == 'videosequence':
section_desc = modulestore.get_instance(
course_id, path[path_index])
child_locs = [c.location for c in section_desc.get_children()]
# positions are 1-indexed, and should be strings to be consistent with
# url parsing.
position_list.append(
str(child_locs.index(path[path_index + 1]) + 1))
position = "_".join(position_list)
return (course_id, chapter, section, position)
