170 lines
6.1 KiB
Go
170 lines
6.1 KiB
Go
// Copyright 2012 Gary Burd
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License"): you may
|
|
// not use this file except in compliance with the License. You may obtain
|
|
// a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
// License for the specific language governing permissions and limitations
|
|
// under the License.
|
|
|
|
// Package redis is a client for the Redis database.
|
|
//
|
|
// The Redigo FAQ (https://github.com/garyburd/redigo/wiki/FAQ) contains more
|
|
// documentation about this package.
|
|
//
|
|
// Connections
|
|
//
|
|
// The Conn interface is the primary interface for working with Redis.
|
|
// Applications create connections by calling the Dial, DialWithTimeout or
|
|
// NewConn functions. In the future, functions will be added for creating
|
|
// sharded and other types of connections.
|
|
//
|
|
// The application must call the connection Close method when the application
|
|
// is done with the connection.
|
|
//
|
|
// Executing Commands
|
|
//
|
|
// The Conn interface has a generic method for executing Redis commands:
|
|
//
|
|
// Do(commandName string, args ...interface{}) (reply interface{}, err error)
|
|
//
|
|
// The Redis command reference (http://redis.io/commands) lists the available
|
|
// commands. An example of using the Redis APPEND command is:
|
|
//
|
|
// n, err := conn.Do("APPEND", "key", "value")
|
|
//
|
|
// The Do method converts command arguments to binary strings for transmission
|
|
// to the server as follows:
|
|
//
|
|
// Go Type Conversion
|
|
// []byte Sent as is
|
|
// string Sent as is
|
|
// int, int64 strconv.FormatInt(v)
|
|
// float64 strconv.FormatFloat(v, 'g', -1, 64)
|
|
// bool true -> "1", false -> "0"
|
|
// nil ""
|
|
// all other types fmt.Print(v)
|
|
//
|
|
// Redis command reply types are represented using the following Go types:
|
|
//
|
|
// Redis type Go type
|
|
// error redis.Error
|
|
// integer int64
|
|
// simple string string
|
|
// bulk string []byte or nil if value not present.
|
|
// array []interface{} or nil if value not present.
|
|
//
|
|
// Use type assertions or the reply helper functions to convert from
|
|
// interface{} to the specific Go type for the command result.
|
|
//
|
|
// Pipelining
|
|
//
|
|
// Connections support pipelining using the Send, Flush and Receive methods.
|
|
//
|
|
// Send(commandName string, args ...interface{}) error
|
|
// Flush() error
|
|
// Receive() (reply interface{}, err error)
|
|
//
|
|
// Send writes the command to the connection's output buffer. Flush flushes the
|
|
// connection's output buffer to the server. Receive reads a single reply from
|
|
// the server. The following example shows a simple pipeline.
|
|
//
|
|
// c.Send("SET", "foo", "bar")
|
|
// c.Send("GET", "foo")
|
|
// c.Flush()
|
|
// c.Receive() // reply from SET
|
|
// v, err = c.Receive() // reply from GET
|
|
//
|
|
// The Do method combines the functionality of the Send, Flush and Receive
|
|
// methods. The Do method starts by writing the command and flushing the output
|
|
// buffer. Next, the Do method receives all pending replies including the reply
|
|
// for the command just sent by Do. If any of the received replies is an error,
|
|
// then Do returns the error. If there are no errors, then Do returns the last
|
|
// reply. If the command argument to the Do method is "", then the Do method
|
|
// will flush the output buffer and receive pending replies without sending a
|
|
// command.
|
|
//
|
|
// Use the Send and Do methods to implement pipelined transactions.
|
|
//
|
|
// c.Send("MULTI")
|
|
// c.Send("INCR", "foo")
|
|
// c.Send("INCR", "bar")
|
|
// r, err := c.Do("EXEC")
|
|
// fmt.Println(r) // prints [1, 1]
|
|
//
|
|
// Concurrency
|
|
//
|
|
// Connections do not support concurrent calls to the write methods (Send,
|
|
// Flush) or concurrent calls to the read method (Receive). Connections do
|
|
// allow a concurrent reader and writer.
|
|
//
|
|
// Because the Do method combines the functionality of Send, Flush and Receive,
|
|
// the Do method cannot be called concurrently with the other methods.
|
|
//
|
|
// For full concurrent access to Redis, use the thread-safe Pool to get and
|
|
// release connections from within a goroutine.
|
|
//
|
|
// Publish and Subscribe
|
|
//
|
|
// Use the Send, Flush and Receive methods to implement Pub/Sub subscribers.
|
|
//
|
|
// c.Send("SUBSCRIBE", "example")
|
|
// c.Flush()
|
|
// for {
|
|
// reply, err := c.Receive()
|
|
// if err != nil {
|
|
// return err
|
|
// }
|
|
// // process pushed message
|
|
// }
|
|
//
|
|
// The PubSubConn type wraps a Conn with convenience methods for implementing
|
|
// subscribers. The Subscribe, PSubscribe, Unsubscribe and PUnsubscribe methods
|
|
// send and flush a subscription management command. The receive method
|
|
// converts a pushed message to convenient types for use in a type switch.
|
|
//
|
|
// psc := redis.PubSubConn{c}
|
|
// psc.Subscribe("example")
|
|
// for {
|
|
// switch v := psc.Receive().(type) {
|
|
// case redis.Message:
|
|
// fmt.Printf("%s: message: %s\n", v.Channel, v.Data)
|
|
// case redis.Subscription:
|
|
// fmt.Printf("%s: %s %d\n", v.Channel, v.Kind, v.Count)
|
|
// case error:
|
|
// return v
|
|
// }
|
|
// }
|
|
//
|
|
// Reply Helpers
|
|
//
|
|
// The Bool, Int, Bytes, String, Strings and Values functions convert a reply
|
|
// to a value of a specific type. To allow convenient wrapping of calls to the
|
|
// connection Do and Receive methods, the functions take a second argument of
|
|
// type error. If the error is non-nil, then the helper function returns the
|
|
// error. If the error is nil, the function converts the reply to the specified
|
|
// type:
|
|
//
|
|
// exists, err := redis.Bool(c.Do("EXISTS", "foo"))
|
|
// if err != nil {
|
|
// // handle error return from c.Do or type conversion error.
|
|
// }
|
|
//
|
|
// The Scan function converts elements of a array reply to Go types:
|
|
//
|
|
// var value1 int
|
|
// var value2 string
|
|
// reply, err := redis.Values(c.Do("MGET", "key1", "key2"))
|
|
// if err != nil {
|
|
// // handle error
|
|
// }
|
|
// if _, err := redis.Scan(reply, &value1, &value2); err != nil {
|
|
// // handle error
|
|
// }
|
|
package redis // import "github.com/garyburd/redigo/redis"
|