# SWOOLE\_KEEP建立TCP长连接
[TOC]
swoole\_client支持在`php-fpm/apache`中创建一个TCP长连接到服务器端。使用方法：
~~~
$client = new swoole_client(SWOOLE_SOCK_TCP | SWOOLE_KEEP);
$client->connect('127.0.0.1', 9501);
~~~
启用`SWOOLE_KEEP`选项后，一个请求结束不会关闭`socket`，下一次再进行`connect`时会自动复用上次创建的连接。如果执行`connect`发现连接已经被服务器关闭，那么`connect`会创建新的连接。
## SWOOLE\_KEEP的优势
* `TCP`长连接可以减少`connect``3`次握手/`close``4`次挥手带来的额外IO消耗
* 降低服务器端`close`/`connect`次数
- 序言
- 入门指引
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- 进程隔离
- 版本更新记录
- 4.3.1
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- 向下不兼容改动
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- 1.7.5 在Server中使用swoole_table
- 1.7.5 swoole_client支持sendfile接口
- 1.7.4 SSL隧道加密TCP-Server
- 1.7.4 task进程中使用毫秒定时器
- 1.7.3 固定包头+包体协议自动分包
- 1.7.3 onTask直接return取代finish函数
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- swoole与node.js相比有哪些优势
- swoole与golang相比有哪些优势
- pcre.h: No such file or directory
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- 学习Swoole需要掌握哪些基础知识
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- 可选参数
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- onStart
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- Server内存管理机制
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- 在php-fpm/apache中使用task功能
- 常见问题
- 为什么不要send完后立即close
- 如何在回调函数中访问外部的变量
- 是否可以共用1个redis或mysql连接
- 关于onConnect/onReceive/onClose顺序
- 4种PHP回调函数风格
- 不同的Server程序实例间如何通信
- 错误信息：ERROR (9006)
- eventLoop has already been created. unable to create swoole_server
- 压力测试
- 并发10万TCP连接的测试
- PHP7+Swoole/Nginx/Golang性能对比
- 全球Web框架权威性能测试 Techempower Web Framework Benchmarks
- Coroutine
- Coroutine
- Coroutine::set
- Coroutine::stats
- Coroutine::create
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- Coroutine::getaddrinfo
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- Coroutine::statvfs
- Coroutine\Channel
- Coroutine\Channel->__construct
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- Coroutine\Channel->$capacity
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- Coroutine\Client
- Coroutine\Client->connect
- Coroutine\Client->send
- Coroutine\Client->recv
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- Coroutine\Client->peek
- Coroutine\Http\Client
- 属性列表
- Coroutine\Http\Client->get
- Coroutine\Http\Client->post
- Coroutine\Http\Client->upgrade
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- Coroutine\Http\Client->addFile
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- Coroutine\Http2\Client->__construct
- Coroutine\Http2\Client->set
- Coroutine\Http2\Client->connect
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- Coroutine\Socket->sendto
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- Coroutine\MySQL
- 属性列表
- Coroutine\MySQL->connect
- Coroutine\MySQL->query
- Coroutine\MySQL->prepare
- Coroutine\MySQL->escape
- Coroutine\MySQL->begin
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- Coroutine\MySQL\Statement->fetchAll
- Coroutine\MySQL\Statement->nextResult
- Coroutine\PostgreSQL
- Coroutine\PostgreSQL->connect
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- Coroutine\PostgreSQL->fetchObject
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- Coroutine\PostgreSQL->fetchArray
- Coroutine\PostgreSQL->fetchRow
- Coroutine\PostgreSQL->metaData
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- Server
- 并发调用
- setDefer 机制
- 子协程+通道
- 实现原理
- 协程与线程
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- 协程内存开销
- 4.0 协程实现原理
- 协程客户端超时规则
- 协程执行流程
- 常见问题
- 运行中出现 Fatal error: Maximum function nesting level of '1000' reached, aborting!
- 为什么只能在回调函数中使用协程客户端
- 支持协程的回调方法列表
- 错误信息： XXXX client has already been bound to another coroutine
- Swoole4 协程与 PHP 的 Yield/Generator 协程有什么区别
- Swoole4 协程与 Go 协程有哪些区别
- 编程须知
- 在多个协程间共用同一个协程客户端
- 禁止使用协程 API 的场景（2.x 版本）
- 使用类静态变量/全局变量保存上下文
- 退出协程
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- MongoDB
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- Runtime
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- Timer
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- Memory
- Lock
- swoole_lock->__construct
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- Buffer
- swoole_buffer->__construct
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- Table
- Table->__construct
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- Atomic
- swoole_atomic->__construct
- swoole_atomic->add
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- mmap
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- Channel
- Channel->__construct
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- Serialize
- swoole_serialize::pack
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- Http\Server
- Http\Server
- Http\Server->on
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- Http\Request
- Http\Request->$header
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- Http\Response
- Http\Response->header
- Http\Response->cookie
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- Http\Response->gzip
- Http\Response->redirect
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- Http\Response->sendfile
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- Http\Response::create
- 配置选项
- upload_tmp_dir
- http_parse_post
- document_root
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- 常见问题
- CURL发送POST请求服务器端超时
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- GET/POST请求的最大尺寸
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- 回调函数
- onHandShake
- onOpen
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- 函数列表
- WebSocket\Server->push
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- 常见问题
- 配置选项
- WebSocket\Frame
- Redis\Server
- 方法
- Redis\Server->setHandler
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- 常量
- Process
- Process::__construct
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- Client
- 方法列表
- swoole_client::__construct
- swoole_client->set
- swoole_client->on
- swoole_client->connect
- swoole_client->isConnected
- swoole_client->getSocket
- swoole_client->getSockName
- swoole_client->getPeerName
- swoole_client->getPeerCert
- swoole_client->send
- swoole_client->sendto
- swoole_client->sendfile
- swoole_client->recv
- swoole_client->close
- swoole_client->sleep
- swoole_client->wakeup
- swoole_client->enableSSL
- 回调函数
- onConnect
- onError
- onReceive
- onClose
- onBufferFull
- onBufferEmpty
- 属性列表
- swoole_client->errCode
- swoole_client->sock
- swoole_client->reuse
- 并行
- swoole_client_select
- TCP客户端异步连接
- SWOOLE_KEEP建立TCP长连接
- 常量
- 配置选项
- ssl_verify_peer
- ssl_host_name
- ssl_cafile
- ssl_capath
- package_length_func
- http_proxy_host
- 常见问题
- Event
- swoole_event_add
- swoole_event_set
- swoole_event_isset
- swoole_event_write
- swoole_event_del
- swoole_event_exit
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- swoole_event_cycle
- swoole_event_wait
- swoole_event_dispatch
- 常见问题
- epoll_wait 偶尔会用很长时间
- 异步回调
- 异步文件系统IO
- swoole_async_readfile
- swoole_async_writefile
- swoole_async_read
- swoole_async_write
- swoole_async_dns_lookup
- swoole_async::exec
- 异步MySQL客户端
- swoole_mysql->__construct
- swoole_mysql->on
- swoole_mysql->connect
- swoole_mysql->escape
- swoole_mysql->query
- swoole_mysql->begin
- swoole_mysql->commit
- swoole_mysql->rollback
- swoole_mysql->close
- 异步Redis客户端
- swoole_redis->__construct
- swoole_redis->on
- swoole_redis->connect
- swoole_redis->__call
- swoole_redis->close
- 异步Http/WebSocket客户端
- swoole_http_client->__construct
- swoole_http_client->set
- swoole_http_client->setMethod
- swoole_http_client->setHeaders
- swoole_http_client->setCookies
- swoole_http_client->setData
- swoole_http_client->addFile
- swoole_http_client->get
- swoole_http_client->post
- swoole_http_client->upgrade
- swoole_http_client->push
- swoole_http_client->execute
- swoole_http_client->download
- swoole_http_client->close
- 异步Http2.0客户端
- swoole_http2_client->__construct
- swoole_http2_client->get
- swoole_http2_client->post
- swoole_http2_client->setHeaders
- swoole_http2_client->setCookies
- 高级
- Swoole的实现
- Reactor线程
- Manager进程
- Worker进程
- Reactor、Worker、TaskWorker的关系
- Task/Finish特性的用途
- 在php-fpm或apache中使用swoole
- Swoole异步与同步的选择
- TCP/UDP压测工具
- swoole服务器如何做到无人值守100%可用
- MySQL的连接池、异步、断线重连
- PHP中哪些函数是同步阻塞的
- 守护进程程序常用数据结构
- 队列（Queue）
- 堆（Heap）
- 定长数组（SplFixedArray）
- 使用jemalloc优化swoole内存分配性能
- C开发者如何使用Swoole
- C++开发者如何使用Swoole
- 使用systemd管理swoole服务
- 网卡中断设置
- 将Swoole静态编译内嵌到PHP
- 异步回调程序内存管理
- 日志等级控制
- 使用 asan 内存检测
- Windows编译
- Swoole协程之旅-前篇
- Swoole协程之旅-中篇
- Swoole协程之旅-后篇
- 协程CPU密集场景调度实现
- 其他
- 函数列表
- swoole_set_process_name
- swoole_version
- swoole_strerror
- swoole_errno
- swoole_get_local_ip
- swoole_clear_dns_cache
- swoole_get_local_mac
- swoole_cpu_num
- swoole_last_error
- Swoole社区
- Swoole技术会议
- 工作组（Working Groups）
- 参与开源项目指引
- 捐赠Swoole项目
- 加入Swoole开发组
- 非协程特性独立扩展 （swoole_async）
- 附录：Linux信号列表
- 附录：Linux错误码(errno)列表
- 附录：Swoole错误码列表
- 附录：TCP连接的状态
- 附录：tcpdump抓包工具的使用
- 附录：strace工具的使用
- 附录：gdb工具的使用
- 附录：lsof工具的使用
- 附录：perf工具的使用
- 附录：编译PHP扩展的相关工具
- 备用：已移除的历史特性
- swoole_server->handler
- task_worker_max
- swoole_server->addtimer
- swoole_server->deltimer
- onTimer
- swoole_timer_add
- swoole_timer_del
- swoole_get_mysqli_sock
- swoole_mysql_query
- onMasterConnect
- onMasterClose
- Nginx/Golang/Swoole/Node.js的性能对比
- Coroutine::call_user_func
- Coroutine::call_user_func_array
- Coroutine\Channel::select
- task_async
- 历史：版本更新记录（1.x）
- 1.10.3
- 1.10.2
- 1.10.1
- 1.10.0
- 1.9.23
- 1.9.22
- 1.9.19
- 1.9.18
- 1.9.17
- 1.9.16
- 1.9.15
- 1.9.14
- 1.9.12
- 1.9.11
- 1.9.9
- 1.9.7
- 1.9.6
- 1.9.5
- 1.9.4
- 1.9.3
- 1.9.2
- 1.9.1
- 1.9.0
- 1.8.13
- 1.8.12
- 1.8.11
- 1.8.10
- 1.8.9
- 1.8.8
- 1.8.7
- 1.8.6
- 1.8.5
- 1.8.4
- 1.8.3
- 1.8.2
- 1.8.1
- 1.8.0
- 1.7.22
- 1.7.21
- 1.7.20
- 1.7.19
- 1.7.18
- 1.7.17
- 1.7.16
- 1.7.15
- 1.7.14
- 1.7.13
- 1.7.12
- 1.7.11
- 1.7.10
- 1.7.9
- 1.7.8
- 1.7.7
- 1.7.6
- 1.7.5
- v1.5
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