def exists(path, n=replication):
'''Checks whether a value is stored at a path.'''
n = min(int(n), replication)
key = hash(path, replication - n + 1)
try:
assert n > 0, 'n should be strictly positive.'
# Lookup successor of 'key'
host = node.lookup(key)[0]
if host == None:
if n > 1:
return exists(path, n - 1)
else:
raise KeyError('Unable to access path {}.'.format(path))
elif host == node.host:
# Request internal node
with node.lock:
return jsonify(node.exists(key, path)), 200
else:
# Request external node
url = address(host) + 'exists/{}/{:d}'.format(path, n)
resp = requests.get(url)
return resp.text, resp.status_code
except Exception as e:
return str(e), 500
def remove(path, n=replication):
'''Removes the value stored at a path.'''
n = min(int(n), replication)
key = hash(path, replication - n + 1)
try:
assert n > 0, 'n should be strictly positive.'
# Lookup successor of 'key'
host = node.lookup(key)[0]
if host == None:
if n > 1:
return remove(path, n - 1)
else:
raise KeyError('Unable to access path {}.'.format(path))
elif host == node.host:
# Request internal node
with node.lock:
value = node.pop(key, path)
if n > 1 and value is not None:
remove(path, n - 1)
return 'Value successfully removed from path {}.\n'.format(
path), 200
else:
# Request external node
url = address(host) + 'remove/{}/{:d}'.format(path, n)
resp = requests.get(url)
return resp.text, resp.status_code
except Exception as e:
return str(e), 500
def put(path, n=replication):
'''Stores a value at a path.'''
n = min(int(n), replication)
key = hash(path, replication - n + 1)
value = request.get_json()
try:
assert n > 0, 'n should be strictly positive.'
# Lookup successor of 'key'
host = node.lookup(key)[0]
if host == None:
if n > 1:
# Start again with 'hash(path)'
return put(path, n - 1)
else:
raise KeyError('Unable to access path {}.'.format(path))
elif host == node.host:
# Request internal node
with node.lock:
node.put(key, path, value)
if n > 1:
put(path, n - 1)
return 'Value successfully stored at path {}.\n'.format(path), 200
else:
# Request external node
url = address(host) + 'put/{}/{:d}'.format(path, n)
resp = requests.post(url, json=value)
return resp.text, resp.status_code
except Exception as e:
return str(e), 500
def copy(src, dst):
'''Copies the value at a path to another.'''
try:
# Get value with path 'src'
url = address(node.host) + 'get/{}'.format(src)
resp = requests.get(url)
if resp.status_code != 200:
return resp.text, resp.status_code
# Put value with path 'dst'
url = address(node.host) + 'put/{}'.format(dst)
resp = requests.post(url, json=json.loads(resp.text))
return resp.text, resp.status_code
except Exception as e:
return str(e), 500
def ls():
'''Lists all occupied paths within the network.'''
paths = {j[0] for i in node.hash_table.values() for j in i}
visited = {node.id}
stack = list(node.host_table.items())
# Depth-first search
while stack:
id, host = stack.pop()
id = int(id)
if id in visited:
# If already visited
continue
# Add to visited
visited.add(id)
try:
# Extend stack
url = address(host) + 'network'
resp = requests.get(url)
if resp.status_code != 200:
raise ConnectionError
stack.extend(json.loads(resp.text).items())
# Gather content
url = address(host) + 'content'
resp = requests.get(url)
if resp.status_code != 200:
raise ConnectionError
paths.update(j[0] for i in json.loads(resp.text).values()
for j in i)
except:
pass
return jsonify(sorted(paths)), 200