arguments = parser.parse_args()
# write JSON with REJSON
rj.jsonset('some_json', Path.rootPath(), json.loads(arguments.json[0].read()))
# get a single (string) value from the JSON
value_of_myjson = rj.jsonget('some_json', Path('myjson'))
print('myjson in some_json: {}'.format(value_of_myjson))
# create an array
rj.jsonset('some_json', Path('secondary.spanishNumbers'), ["uno"])
# Append some values to the Array
rj.jsonarrappend('some_json', Path('secondary.spanishNumbers'), "tres",
"cuatro")
# insert a value to the Array
rj.jsonarrinsert('some_json', Path('secondary.spanishNumbers'), '1', 'dos')
# get the array back
value_of_spanishNumbers = rj.jsonget('some_json',
Path('secondary.spanishNumbers'))
print(value_of_spanishNumbers)
# Append to the a string value
rj.jsonstrappend('some_json', 'well', Path('myjson'))
# Get the whole json object back
value_of_some_json = rj.jsonget('some_json', Path.rootPath())
print('some_json: ' + json.dumps(value_of_some_json, indent=1))
class RejsonDb(KeyValueStorage):
def __init__(self, conf):
"""
arguments:
conf -- a dictionary containing 'settings' module compatible configuration of the plug-in
"""
self._host = conf['host']
self._port = int(conf['port'])
self._db = int(conf['id'])
self.redis = Client(host=self._host,
port=self._port,
db=self._db,
decode_responses=True)
self._scan_chunk_size = 50
try:
self.redis.jsonget('-')
except ResponseError as e:
if 'unknown command' in str(e):
logging.fatal(
"Rejson DB Plug-in requires Redis with RedisJSON module enabled"
)
else:
raise e
def rename(self, key, new_key):
return self.redis.rename(key, new_key)
def list_get(self, key, from_idx=0, to_idx=-1):
"""
Returns a stored list. If there is a non-list value stored with the passed key
then TypeError is raised.
arguments:
key -- data access key
from_idx -- optional start index
to_idx -- optional (default is -1) end index (including, i.e. unlike Python);
negative values are supported (-1 = last, -2 = penultimate,...)
"""
data = self.get(key, [])
if isinstance(data, list):
if to_idx == -1:
return data[from_idx:]
return data[from_idx:to_idx + 1]
raise TypeError('Object is not a list')
def list_append(self, key, value):
"""
Add a value at the end of a list
arguments:
key -- data access key
value -- value to be pushed
"""
if not self.exists(key):
self.set(key, [])
self.redis.jsonarrappend(key, Path.rootPath(), value)
def list_pop(self, key):
"""
Removes and returns the first element of the list stored at key.
arguments:
key -- list access key
"""
return self.redis.jsonarrpop(key)
def list_len(self, key):
"""
Returns length of a list. If there is a non-list value stored with the passed key
then TypeError is raised.
arguments:
key -- data access key
"""
if not self.exists(key):
return 0
return self.redis.jsonarrlen(key)
def list_set(self, key, idx, value):
"""
Sets the list element at index to value
arguments:
key -- list access key
idx -- a zero based index where the set should be performed
value -- a JSON-serializable value to be inserted
"""
# TODO the operation pair should be atomic to avoid possible race conditions
self.redis.jsonarrpop(key, Path.rootPath(), idx)
return self.redis.jsonarrinsert(key, Path.rootPath(), idx, value)
def list_trim(self, key, keep_left, keep_right):
"""
Trims the list from the beginning to keep_left - 1 and from keep_right to the end.
The function does not return anything.
arguments:
key -- data access key
keep_left -- the first value to be kept
keep_right -- the last value to be kept
"""
self.redis.jsonarrtrim(key, Path.rootPath(), keep_left, keep_right)
def hash_get(self, key, field):
"""
Gets a value from a hash table stored under the passed key
arguments:
key -- data access key
field -- hash table entry key
"""
if self.redis.jsontype(key, Path(f'["{field}"]')) is None:
return None
return self.redis.jsonget(key, Path(f'["{field}"]'), no_escape=True)
def hash_set(self, key, field, value):
"""
Puts a value into a hash table stored under the passed key
arguments:
key -- data access key
field -- hash table entry key
value -- a value to be stored
"""
if not self.exists(key):
self.set(key, {})
self.redis.jsonset(key, Path(f'["{field}"]'), value)
def hash_del(self, key, field):
"""
Removes a field from a hash item
arguments:
key -- hash item access key
field -- the field to be deleted
"""
self.redis.jsondel(key, Path(f'["{field}"]'))
def hash_get_all(self, key):
"""
Returns a complete hash object (= Python dict) stored under the passed
key. If the provided key is not present then an empty dict is returned.
arguments:
key -- data access key
"""
return self.get(key)
def get(self, key, default=None):
"""
Gets a value stored with passed key and returns its JSON decoded form.
arguments:
key -- data access key
default -- a value to be returned in case there is no such key
"""
data = self.redis.jsonget(key, Path.rootPath(), no_escape=True)
if data is None:
return default
return data
def set(self, key, data):
"""
Saves 'data' with 'key'.
arguments:
key -- an access key
data -- a dictionary containing data to be saved
"""
self.redis.jsonset(key, Path.rootPath(), data)
def set_ttl(self, key, ttl):
"""
Set auto expiration timeout in seconds.
arguments:
key -- data access key
ttl -- number of seconds to wait before the value is removed
(please note that update actions reset the timer to zero)
"""
self.redis.expire(key, ttl)
def get_ttl(self, key):
return self.redis.ttl(key)
def clear_ttl(self, key):
self.redis.persist(key)
def remove(self, key):
"""
Removes a value specified by a key
arguments:
key -- key of the data to be removed
"""
self.redis.jsondel(key)
def exists(self, key):
"""
Tests whether there is a value with the specified key
arguments:
key -- the key to be tested
returns:
boolean value
"""
return self.redis.exists(key)
def setnx(self, key, value):
"""
An atomic operation "set if not exists".
returns:
1 if the key was set
0 if the key was not set
"""
return self.redis.jsonset(key, Path.rootPath(), value, nx=True)
def getset(self, key, value):
"""
An atomic operation which obtains current key first and then
sets a new value under that key
returns:
previous key if any or None
"""
data = self.get(key)
self.set(key, value)
return data
def incr(self, key, amount=1):
"""
Increments the value of 'key' by 'amount'. If no key exists,
the value will be initialized as 'amount'
"""
if not self.exists(key):
self.set(key, 0)
return self.redis.jsonnumincrby(key, Path.rootPath(), amount)
def hash_set_map(self, key, mapping):
"""
Set key to value within hash 'name' for each corresponding
key and value from the 'mapping' dict.
Before setting, the values are json-serialized
"""
return self.set(key, mapping)
