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117 lines
4.1 KiB
117 lines
4.1 KiB
// Copyright 2012 Gary Burd
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//
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// Licensed under the Apache License, Version 2.0 (the "License"): you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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package redis
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import (
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"errors"
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"time"
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)
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// Error represents an error returned in a command reply.
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type Error string
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func (err Error) Error() string { return string(err) }
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// Conn represents a connection to a Redis server.
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type Conn interface {
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// Close closes the connection.
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Close() error
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// Err returns a non-nil value when the connection is not usable.
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Err() error
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// Do sends a command to the server and returns the received reply.
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Do(commandName string, args ...interface{}) (reply interface{}, err error)
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// Send writes the command to the client's output buffer.
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Send(commandName string, args ...interface{}) error
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// Flush flushes the output buffer to the Redis server.
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Flush() error
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// Receive receives a single reply from the Redis server
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Receive() (reply interface{}, err error)
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}
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// Argument is the interface implemented by an object which wants to control how
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// the object is converted to Redis bulk strings.
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type Argument interface {
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// RedisArg returns a value to be encoded as a bulk string per the
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// conversions listed in the section 'Executing Commands'.
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// Implementations should typically return a []byte or string.
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RedisArg() interface{}
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}
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// Scanner is implemented by an object which wants to control its value is
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// interpreted when read from Redis.
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type Scanner interface {
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// RedisScan assigns a value from a Redis value. The argument src is one of
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// the reply types listed in the section `Executing Commands`.
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//
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// An error should be returned if the value cannot be stored without
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// loss of information.
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RedisScan(src interface{}) error
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}
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// ConnWithTimeout is an optional interface that allows the caller to override
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// a connection's default read timeout. This interface is useful for executing
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// the BLPOP, BRPOP, BRPOPLPUSH, XREAD and other commands that block at the
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// server.
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//
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// A connection's default read timeout is set with the DialReadTimeout dial
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// option. Applications should rely on the default timeout for commands that do
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// not block at the server.
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//
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// All of the Conn implementations in this package satisfy the ConnWithTimeout
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// interface.
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//
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// Use the DoWithTimeout and ReceiveWithTimeout helper functions to simplify
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// use of this interface.
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type ConnWithTimeout interface {
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Conn
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// Do sends a command to the server and returns the received reply.
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// The timeout overrides the read timeout set when dialing the
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// connection.
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DoWithTimeout(timeout time.Duration, commandName string, args ...interface{}) (reply interface{}, err error)
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// Receive receives a single reply from the Redis server. The timeout
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// overrides the read timeout set when dialing the connection.
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ReceiveWithTimeout(timeout time.Duration) (reply interface{}, err error)
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}
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var errTimeoutNotSupported = errors.New("redis: connection does not support ConnWithTimeout")
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// DoWithTimeout executes a Redis command with the specified read timeout. If
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// the connection does not satisfy the ConnWithTimeout interface, then an error
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// is returned.
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func DoWithTimeout(c Conn, timeout time.Duration, cmd string, args ...interface{}) (interface{}, error) {
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cwt, ok := c.(ConnWithTimeout)
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if !ok {
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return nil, errTimeoutNotSupported
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}
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return cwt.DoWithTimeout(timeout, cmd, args...)
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}
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// ReceiveWithTimeout receives a reply with the specified read timeout. If the
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// connection does not satisfy the ConnWithTimeout interface, then an error is
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// returned.
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func ReceiveWithTimeout(c Conn, timeout time.Duration) (interface{}, error) {
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cwt, ok := c.(ConnWithTimeout)
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if !ok {
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return nil, errTimeoutNotSupported
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}
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return cwt.ReceiveWithTimeout(timeout)
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}
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