01
概念
Gin 框架通过调用 Default 函数,返回一个 *gin.Engine,然后调用 Run 方法构建一个服务器。
func gin.Default() *gin.Engine
Run 方法:
func (engine *Engine) Run(addr ...string) (err error) { defer func() { debugPrintError(err) }() address := resolveAddress(addr) debugPrint("Listening and serving HTTP on %s\n", address) err = http.ListenAndServe(address, engine) return }
细心的读者朋友可能已经注意到 Run 方法只能接收一个地址,无法设置服务器的其他配置信息。
通过查看 Run 方法的代码,可以发现 Run 方法实际上是封装了标准库net/http 的 ListenAndServe 函数。
我们接着查看 ListenAndServe 函数的代码:
func ListenAndServe(addr string, handler Handler) error { server := &Server{Addr: addr, Handler: handler} return server.ListenAndServe() }
通过查看 ListenAndServe 函数的代码,可以发现 ListenAndServe 函数实际上是定义了一个 Server 结构的变量,并调用其 ListenAndServe 方法。
02
自定义服务器配置信息
根据 Part 01 的内容铺垫,如果我们想要自定义服务器的配置信息,就需要我们通过定义一个 Server 结构的变量,使用 Server 结构的 ListenAndServe 方法构建服务器。因为 Server 结构包含更多关于服务器配置信息的字段。
Server 结构体的代码:
Server struct { // Addr optionally specifies the TCP address for the server to listen on, // in the form "host:port". If empty, ":http" (port 80) is used. // The service names are defined in RFC 6335 and assigned by IANA. // See net.Dial for details of the address format. Addr string Handler Handler // handler to invoke, http.DefaultServeMux if nil // TLSConfig optionally provides a TLS configuration for use // by ServeTLS and ListenAndServeTLS. Note that this value is // cloned by ServeTLS and ListenAndServeTLS, so it's not // possible to modify the configuration with methods like // tls.Config.SetSessionTicketKeys. To use // SetSessionTicketKeys, use Server.Serve with a TLS Listener // instead. TLSConfig *tls.Config // ReadTimeout is the maximum duration for reading the entire // request, including the body. // // Because ReadTimeout does not let Handlers make per-request // decisions on each request body's acceptable deadline or // upload rate, most users will prefer to use // ReadHeaderTimeout. It is valid to use them both. ReadTimeout time.Duration // ReadHeaderTimeout is the amount of time allowed to read // request headers. The connection's read deadline is reset // after reading the headers and the Handler can decide what // is considered too slow for the body. If ReadHeaderTimeout // is zero, the value of ReadTimeout is used. If both are // zero, there is no timeout. ReadHeaderTimeout time.Duration // WriteTimeout is the maximum duration before timing out // writes of the response. It is reset whenever a new // request's header is read. Like ReadTimeout, it does not // let Handlers make decisions on a per-request basis. WriteTimeout time.Duration // IdleTimeout is the maximum amount of time to wait for the // next request when keep-alives are enabled. If IdleTimeout // is zero, the value of ReadTimeout is used. If both are // zero, there is no timeout. IdleTimeout time.Duration // MaxHeaderBytes controls the maximum number of bytes the // server will read parsing the request header's keys and // values, including the request line. It does not limit the // size of the request body. // If zero, DefaultMaxHeaderBytes is used. MaxHeaderBytes int // TLSNextProto optionally specifies a function to take over // ownership of the provided TLS connection when an ALPN // protocol upgrade has occurred. The map key is the protocol // name negotiated. The Handler argument should be used to // handle HTTP requests and will initialize the Request's TLS // and RemoteAddr if not already set. The connection is // automatically closed when the function returns. // If TLSNextProto is not nil, HTTP/2 support is not enabled // automatically. TLSNextProto map[string]func(*Server, *tls.Conn, Handler) // ConnState specifies an optional callback function that is // called when a client connection changes state. See the // ConnState type and associated constants for details. ConnState func(net.Conn, ConnState) // ErrorLog specifies an optional logger for errors accepting // connections, unexpected behavior from handlers, and // underlying FileSystem errors. // If nil, logging is done via the log package's standard logger. ErrorLog *log.Logger // BaseContext optionally specifies a function that returns // the base context for incoming requests on this server. // The provided Listener is the specific Listener that's // about to start accepting requests. // If BaseContext is nil, the default is context.Background(). // If non-nil, it must return a non-nil context. BaseContext func(net.Listener) context.Context // ConnContext optionally specifies a function that modifies // the context used for a new connection c. The provided ctx // is derived from the base context and has a ServerContextKey // value. ConnContext func(ctx context.Context, c net.Conn) context.Context inShutdown atomicBool // true when when server is in shutdown disableKeepAlives int32 // accessed atomically. nextProtoOnce sync.Once // guards setupHTTP2_* init nextProtoErr error // result of http2.ConfigureServer if used mu sync.Mutex listeners map[*net.Listener]struct{} activeConn map[*conn]struct{} doneChan chan struct{} onShutdown []func() }
通过 Server 结构体的字段,可以设置更多的服务器配置信息,实现我们构建自定义服务器的需求。