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- // 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
- import (
- "errors"
- "time"
- )
- // Error represents an error returned in a command reply.
- type Error string
- func (err Error) Error() string { return string(err) }
- // Conn represents a connection to a Redis server.
- type Conn interface {
- // Close closes the connection.
- Close() error
- // Err returns a non-nil value when the connection is not usable.
- Err() error
- // Do sends a command to the server and returns the received reply.
- Do(commandName string, args ...interface{}) (reply interface{}, err error)
- // Send writes the command to the client's output buffer.
- Send(commandName string, args ...interface{}) error
- // Flush flushes the output buffer to the Redis server.
- Flush() error
- // Receive receives a single reply from the Redis server
- Receive() (reply interface{}, err error)
- }
- // Argument is the interface implemented by an object which wants to control how
- // the object is converted to Redis bulk strings.
- type Argument interface {
- // RedisArg returns a value to be encoded as a bulk string per the
- // conversions listed in the section 'Executing Commands'.
- // Implementations should typically return a []byte or string.
- RedisArg() interface{}
- }
- // Scanner is implemented by an object which wants to control its value is
- // interpreted when read from Redis.
- type Scanner interface {
- // RedisScan assigns a value from a Redis value. The argument src is one of
- // the reply types listed in the section `Executing Commands`.
- //
- // An error should be returned if the value cannot be stored without
- // loss of information.
- RedisScan(src interface{}) error
- }
- // ConnWithTimeout is an optional interface that allows the caller to override
- // a connection's default read timeout. This interface is useful for executing
- // the BLPOP, BRPOP, BRPOPLPUSH, XREAD and other commands that block at the
- // server.
- //
- // A connection's default read timeout is set with the DialReadTimeout dial
- // option. Applications should rely on the default timeout for commands that do
- // not block at the server.
- //
- // All of the Conn implementations in this package satisfy the ConnWithTimeout
- // interface.
- //
- // Use the DoWithTimeout and ReceiveWithTimeout helper functions to simplify
- // use of this interface.
- type ConnWithTimeout interface {
- Conn
- // Do sends a command to the server and returns the received reply.
- // The timeout overrides the read timeout set when dialing the
- // connection.
- DoWithTimeout(timeout time.Duration, commandName string, args ...interface{}) (reply interface{}, err error)
- // Receive receives a single reply from the Redis server. The timeout
- // overrides the read timeout set when dialing the connection.
- ReceiveWithTimeout(timeout time.Duration) (reply interface{}, err error)
- }
- var errTimeoutNotSupported = errors.New("redis: connection does not support ConnWithTimeout")
- // DoWithTimeout executes a Redis command with the specified read timeout. If
- // the connection does not satisfy the ConnWithTimeout interface, then an error
- // is returned.
- func DoWithTimeout(c Conn, timeout time.Duration, cmd string, args ...interface{}) (interface{}, error) {
- cwt, ok := c.(ConnWithTimeout)
- if !ok {
- return nil, errTimeoutNotSupported
- }
- return cwt.DoWithTimeout(timeout, cmd, args...)
- }
- // ReceiveWithTimeout receives a reply with the specified read timeout. If the
- // connection does not satisfy the ConnWithTimeout interface, then an error is
- // returned.
- func ReceiveWithTimeout(c Conn, timeout time.Duration) (interface{}, error) {
- cwt, ok := c.(ConnWithTimeout)
- if !ok {
- return nil, errTimeoutNotSupported
- }
- return cwt.ReceiveWithTimeout(timeout)
- }
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