| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Database.Memcache.Client
Contents
Description
A memcached client. Supports the binary protocol (only) and SASL authentication.
A client can connect to a single memcached server or a cluster of them. In the later case, consistent hashing is used to route requests to the appropriate server.
Expected return values (like misses) are returned as part of the return type, while unexpected errors are thrown as exceptions.
- newClient :: [ServerSpec] -> Options -> IO Client
- type Client = Cluster
- data ServerSpec = ServerSpec {}
- defaultServerSpec :: ServerSpec
- data Options = Options {
- optsCmdFailure :: !FailureMode
- optsServerFailure :: !FailureMode
- optsServerRetries :: !Int
- defaultOptions :: Options
- data Authentication
- type Username = ByteString
- type Password = ByteString
- quit :: Cluster -> IO ()
- get :: Cluster -> Key -> IO (Maybe (Value, Flags, Version))
- gat :: Cluster -> Key -> Expiration -> IO (Maybe (Value, Flags, Version))
- touch :: Cluster -> Key -> Expiration -> IO (Maybe Version)
- set :: Cluster -> Key -> Value -> Flags -> Expiration -> IO Version
- set' :: Cluster -> Key -> Value -> Flags -> Expiration -> Version -> IO (Maybe Version)
- add :: Cluster -> Key -> Value -> Flags -> Expiration -> IO (Maybe Version)
- replace :: Cluster -> Key -> Value -> Flags -> Expiration -> Version -> IO (Maybe Version)
- delete :: Cluster -> Key -> Version -> IO Bool
- flush :: Cluster -> Maybe Expiration -> IO ()
- increment :: Cluster -> Key -> Initial -> Delta -> Expiration -> Version -> IO (Maybe (Word64, Version))
- decrement :: Cluster -> Key -> Initial -> Delta -> Expiration -> Version -> IO (Maybe (Word64, Version))
- append :: Cluster -> Key -> Value -> Version -> IO (Maybe Version)
- prepend :: Cluster -> Key -> Value -> Version -> IO (Maybe Version)
- version :: Cluster -> IO ByteString
- stats :: Cluster -> Maybe Key -> IO [(Server, Maybe StatResults)]
- type StatResults = [(ByteString, ByteString)]
- data MemcacheError
- data ClientError = NotEnoughBytes
Cluster and connection handling
newClient :: [ServerSpec] -> Options -> IO Client Source
Establish a new connection to a group of memcached servers.
data ServerSpec Source
ServerSpec specifies a server configuration to connect to.
Constructors
| ServerSpec | |
Fields
| |
defaultServerSpec :: ServerSpec Source
Provides a default value for a server cconnection config.
Options specifies how a memcached cluster should be configured.
Constructors
| Options | |
Fields
| |
defaultOptions :: Options Source
Provides recommended default for a cluster Options.
type Username = ByteString Source
Username for authentication.
type Password = ByteString Source
Password for authentication.
Get operations
get :: Cluster -> Key -> IO (Maybe (Value, Flags, Version)) Source
Retrieve the value for the given key from memcache.
gat :: Cluster -> Key -> Expiration -> IO (Maybe (Value, Flags, Version)) Source
Get-and-touch: Retrieve the value for the given key from memcache, and also update the stored key-value pairs expiration time at the server.
touch :: Cluster -> Key -> Expiration -> IO (Maybe Version) Source
Update the expiration time of a stored key-value pair, returning its version identifier.
Set operations
set :: Cluster -> Key -> Value -> Flags -> Expiration -> IO Version Source
Store a new (or overwrite exisiting) key-value pair, returning its version identifier.
set' :: Cluster -> Key -> Value -> Flags -> Expiration -> Version -> IO (Maybe Version) Source
Store a key-value pair, but only if the version specified by the client
matches the version of the key-value pair at the server. The version
identifier of the stored key-value pair is returned, or if the version match
fails, Nothing is returned.
add :: Cluster -> Key -> Value -> Flags -> Expiration -> IO (Maybe Version) Source
Store a new key-value pair, returning it's version identifier. If the
key-value pair already exists, then fail (return Nothing).
replace :: Cluster -> Key -> Value -> Flags -> Expiration -> Version -> IO (Maybe Version) Source
Update the value of an existing key-value pair, returning it's new version identifier. If the key doesn't already exist, the fail and return Nothing.
Delete operations
delete :: Cluster -> Key -> Version -> IO Bool Source
Delete a key-value pair at the server, returning true if successful.
flush :: Cluster -> Maybe Expiration -> IO () Source
Remove (delete) all currently stored key-value pairs from the cluster.
Modify operations
increment :: Cluster -> Key -> Initial -> Delta -> Expiration -> Version -> IO (Maybe (Word64, Version)) Source
Increment a numeric value stored against a key, returning the incremented value and the version identifier of the key-value pair.
decrement :: Cluster -> Key -> Initial -> Delta -> Expiration -> Version -> IO (Maybe (Word64, Version)) Source
Decrement a numeric value stored against a key, returning the decremented value and the version identifier of the key-value pair.
append :: Cluster -> Key -> Value -> Version -> IO (Maybe Version) Source
Append a value to an existing key-value pair, returning the new version identifier of the key-value pair when successful.
prepend :: Cluster -> Key -> Value -> Version -> IO (Maybe Version) Source
Prepend a value to an existing key-value pair, returning the new version identifier of the key-value pair when successful.
Information operations
version :: Cluster -> IO ByteString Source
Version returns the version string of the memcached cluster. We just query one server and assume all servers in the cluster are the same version.
stats :: Cluster -> Maybe Key -> IO [(Server, Maybe StatResults)] Source
Return statistics on the stored key-value pairs at each server in the cluster.
type StatResults = [(ByteString, ByteString)] Source
StatResults are a list of key-value pairs.
Error handling
data MemcacheError Source
Exceptions that may be thrown by Memcache. These are expected error codes returned by a memcached server.
data ClientError Source
Errors that occur between the client and server in communicating. These are unexpected exceptions, such as network failures or garbage data.
Constructors
| NotEnoughBytes |
Instances