def remove(self, table, key, value=None):
"""
Function to remove the value for a key in a lmdb table
Parameters:
- table is the name of lmdb table in which
the key-value pair need to be removed.
- key is the primary key of the table.
- value is data to be removed, If the database does not support
sorted duplicate data items (MDB_DUPSORT) the data parameter
is ignored. If the database supports sorted duplicates and
the data parameter is NULL, all of the duplicate data items
for the key will be deleted. Otherwise, if the data parameter is
non-NULL only the matching data item will be deleted.
"""
# Remove, table, key
request = "R\n" + escape(table) + "\n" + escape(key)
if value is not None:
request = "\n" + request + value.replace("\n", "\\n")
response = self.__uri_client._postmsg(request).decode("utf-8")
args = response.split("\n")
# Remove successful (returned True)
if args[0] == "t" and len(args) == 1:
return True
# Remove unsuccessful (returned False)
elif args[0] == "f" and len(args) == 1:
return False
# Error
elif args[0] == "e":
if len(args) != 2:
logger.error("Unknown error format")
else:
logger.error("Request error: %s", args[1])
else:
logger.error("Unknown response format")
def get(self, table, key):
"""
Function to get the value for a key in a lmdb table
Parameters:
- table is the name of lmdb table from which
the key-value pair needs to be retrieved.
- key is the primary key of the table.
"""
# Get, table, key
request = "G\n" + escape(table) + "\n" + escape(key)
response = self.__uri_client._postmsg(request).decode("utf-8")
args = response.split("\n")
# Value found
if args[0] == "v" and len(args) == 2:
return unescape(args[1])
# Value not found
elif args[0] == "n" and len(args) == 1:
return None
# Error
elif args[0] == "e":
if len(args) != 2:
logger.error("Unknown error format")
else:
logger.error("Request error: %s", args[1])
else:
logger.error("Unknown response format")
def set(self, table, key, value):
"""
Function to set a key-value pair in a lmdb table
Parameters:
- table is the name of lmdb table in which
the key-value pair needs to be inserted.
- key is the primary key of the table.
- value is the value that needs to be inserted in the table.
"""
# Set, table, key, value
request = "S\n" + escape(table) + "\n" + escape(key) + \
"\n" + escape(value)
response = self.__uri_client._postmsg(request).decode("utf-8")
args = response.split("\n")
# Set successful (returned True)
if args[0] == "t" and len(args) == 1:
return True
# Set unsuccessful (returned False)
elif args[0] == "f" and len(args) == 1:
return False
# Error
elif args[0] == "e":
if len(args) != 2:
logger.error("Unknown error format")
else:
logger.error("Request error: %s", args[1])
else:
logger.error("Unknown response format")
def lookup(self, table):
"""
Function to get all the keys in a lmdb table
Parameters:
- table is the name of the lmdb table.
"""
result = []
# Lookup, table
request = "L\n" + escape(table)
response = self.__uri_client._postmsg(request).decode("utf-8")
args = response.split("\n")
# Lookup result found
if args[0] == "l":
if len(args) == 2:
# Result is a list of keys separated by commas
result = unescape(args[1]).split(",")
else:
logger.error("Unknown response format")
# Lookup result not found
elif args[0] == "n" and len(args) == 1:
return result
# Error
elif args[0] == "e":
if len(args) != 2:
logger.error("Unknown error format")
else:
logger.error("Request error: %s", args[1])
else:
logger.error("Unknown response format")
return result
def _process_request(self, request):
response = ""
logger.info(request.encode('utf-8'))
args = request.split('\n')
for i in range(len(args)):
args[i] = unescape(args[i])
logger.info(args)
cmd = args[0]
# Lookup
if (cmd == "L"):
if len(args) == 2:
result_list = self.kv_helper.lookup(args[1])
result = ""
for key in result_list:
if result == "":
result = key
else:
result = result + "," + key
# Lookup result found
if result != "":
response = "l\n" + escape(result)
# No result found
else:
response = "n"
# Error
else:
logger.error("Invalid args for cmd Lookup")
response = "e\nInvalid args for cmd Lookup"
# Get
elif (cmd == "G"):
if len(args) == 3:
result = self.kv_helper.get(args[1], args[2])
# Value found
if result is not None:
response = "v\n" + escape(result)
# Value not found
else:
response = "n"
# Error
else:
logger.error("Invalid args for cmd Get")
response = "e\nInvalid args for cmd Get"
# Set
elif (cmd == "S"):
if len(args) == 4:
result = self.kv_helper.set(args[1], args[2], args[3])
# Set successful (returned True)
if result:
response = "t"
# Set unsuccessful (returned False)
else:
response = "f"
# Error
else:
logger.error("Invalid args for cmd Set")
response = "e\nInvalid args for cmd Set"
# Remove
elif (cmd == "R"):
if len(args) == 3 or len(args) == 4:
if len(args) == 3:
result = self.kv_helper.remove(args[1], args[2])
else:
result = self.kv_helper.remove(args[1],
args[2],
value=args[3])
# Remove successful (returned True)
if result:
response = "t"
# Remove unsuccessful (returned False)
else:
response = "f"
# Error
else:
logger.error("Invalid args for cmd Remove")
response = "e\nInvalid args for cmd Remove"
# Error
else:
logger.error("Unknown cmd")
response = "e\nUnknown cmd"
return response