def map_data():
"""
Given a specific cuisine and a latitude, longitude, and diagonal bound
in meters, return a dictionary mapping the ID of the restaurant to a
pair of (longitude, latitude).
Arguments:
cuisine - A string representing the given restaurant type, e.g. 'pizza'.
latitude - A float representing the latitude of the center of the map.
longitude - A float representing the longitude of the center of the map.
diag - The distance, in meters, from the northwest corner of the map to the
southeast corner of the map.
"""
cuisine = request.args.get('cuisine') # Required
latitude = request.args.get('lat') # Required
longitude = request.args.get('lng') # Required
diag = request.args.get('diag') # Required
response = {}
r = get_redis_client()
################################## TODO ###################################
# https://redis.io/commands/georadius
# GEORADIUS key longitude latitude radius m|km|ft|mi [WITHCOORD] [WITHDIST] [WITHHASH] [COUNT count] [ASC|DESC] [STORE key] [STOREDIST key]
response.update(r.georadius('geo:'+cuisine, longitude, latitude, float(diag)/2, unit='m', withcoord=True))
############################### END TODO ###################################
return json.dumps(response)
def cuisine_ratings():
"""
Return JSON mapping each rating value (1-5) to the number of restaurants that
have been rated with this rating.
"""
cuisine = request.args.get('cuisine') # Required
response = {}
r = get_redis_client()
pipe = r.pipeline(transaction=False) # Batch together multiple requests
################################## TODO ####################################
# https://redis.io/commands/zcount
# ZCOUNT key min max
# Set up the pipeline
for i in range(1, 6):
pipe.zcount('ratings:' + cuisine, i, i)
results = pipe.execute()
# Store the results into the response dictionary
i = 1
for item in results:
response[i] = item
i += 1
############################### END TODO ###################################
return json.dumps(response, sort_keys=True)
def rating():
"""
Get or set the restaurant's rating. If a rating is provided in input, set
the rating for each cuisine sorted set and return it. Otherwise, look up
the rating and return it as a string.
"""
id = request.args.get('id') # Required
rating = request.args.get('rating') # Optional
r = get_redis_client()
# Fetch the cuisine for the restaurant
data = get_restaurant_data(r, id, 'tag:cuisine')
if 'tag:cuisine' not in data:
return "0"
cuisine = data['tag:cuisine']
# Set the rating if provided
if rating:
set_rating(r, cuisine, id, rating)
# Always look up rating at the end to make sure it's set
rating = get_rating(r, cuisine, id)
if rating:
return str(rating)
else:
return "0"
def restaurant_list():
"""
Return JSON mapping restaurant identifiers to their public-facing names.
To filter the set of restaurants, a cuisine type is provided, as well as
the map's diagonal distance.
Arguments:
cuisine - A string representing the given restaurant type, e.g. 'pizza'.
latitude - A float representing the latitude of the center of the map.
longitude - A float representing the longitude of the center of the map.
diag - The distance, in meters, from the northwest corner of the map to the
southeast corner of the map.
"""
cuisine = request.args.get('cuisine') # Required
longitude = request.args.get('lng') # Required
latitude = request.args.get('lat') # Required
diag = request.args.get('diag') # Required
response = {}
r = get_redis_client()
# Use this LUA template and fill in the function calls to return id, name
# pairs for entries that are geographically close.
lua_script_template = Template('''
local results = {}
for i, id in ipairs($redis_function_call1) do
local name = $redis_function_call2
table.insert(results, id)
table.insert(results, name)
end
return results''')
################################## TODO ####################################
# https://redis.io/commands/eval
# EVAL script numkeys key [key ...] arg [arg ...]
#
# The restaurant's name is stored in the property 'tag:name'
lua_script = lua_script_template.substitute(
redis_function_call1="redis.call('GEORADIUS', KEYS[1], ARGV[1], ARGV[2], ARGV[3], 'm')",
redis_function_call2="redis.call('HGET', id, 'tag:name')"
)
# EVAL call to Redis goes here and returns a list
members = r.eval(lua_script, 1, 'geo:'+cuisine, longitude, latitude, float(diag)/2)
############################### END TODO ###################################
it = iter(members)
for item in it:
name = next(it)
# Some restaurants may not have a name - handle this gracefully
if name is None:
name = "Unknown "+cuisine
response[item] = name
return json.dumps(response, sort_keys=True)
def restaurant_detail():
id = request.args.get('id') # Required
field = request.args.get('field') # Optional
r = get_redis_client()
response = get_restaurant_data(r, id, field)
return json.dumps(response, sort_keys=True)
def import_data(filename):
"""Parse the restaurant information from the given OSM XML data file and store in Redis"""
print(filename)
global progress
global stop
r = get_redis_client()
r.flushall()
total_size = os.path.getsize(filename)
print(total_size)
with open(filename, 'r') as f:
context = ET.iterparse(f, events=('start', 'end'))
context = iter(context)
event, root = next(context)
cuisine_item = False # Whether the current item has a tag with key 'cuisine'
node_item = False # Whether the current item has a 'node' tag
for event, item in context:
if stop:
break
# Process all nodes and their children
progress = float(f.tell()) / total_size
if event == 'start':
if item.tag == 'node':
node_item = True # Currently parsing a node
continue
elif not node_item:
root.clear() # GC
continue
if item.tag == 'tag' and item.attrib['k'] == 'cuisine':
cuisine_item = True
if item.tag == 'node':
if cuisine_item:
cuisine_item = False
process_node(r, item)
root.clear()
node_item = False
if not stop:
progress = 1
stop = False
def restaurant_frequencies():
"""
Return JSON mapping cuisine to the number of restaurants serving that
cuisine. The dictionary should contain the top cuisines in order by
frequency.
"""
response = OrderedDict() # Dictionary that maintains order added
r = get_redis_client()
################################## TODO ####################################
# https://redis.io/commands/zcount
# ZREVRANGEBYSCORE key max min [WITHSCORES] [LIMIT offset count]
response.update(r.zrevrangebyscore('cuisine_rankings', '+inf', '-inf', withscores=True))
############################### END TODO ###################################
return json.dumps(response)
def clear_ratings():
"""
Clear all ratings, leaving other data intact.
"""
r = get_redis_client()
################################## TODO ####################################
# https://redis.io/commands/scan
# SCAN cursor [MATCH pattern] [COUNT count]
# https://redis.io/commands/del
# DEL key [key ...]
for key in r.scan_iter('ratings:*'):
r.delete(key)
############################### END TODO ###################################
return json.dumps({
"result": "ok",
})