注：本文是基于Windos系统上Go SDK v1.8进行讲解
1.net/http包介绍
Go语言内置的net/http包提供了HTTP客户端和服务端的实现。
超文本传输协议（HTTP，HyperText Transfer Protocol)是互联网上应用最为广泛的一种网络传输协议，所有的WWW文件都必须遵守这个标准
2.http.ListenAndServe函数
ListenAndServe使用指定的监听地址和处理器启动一个HTTP服务端。处理器参数通常是nil，这表示采用包变量DefaultServeMux作为处理器。
func ListenAndServe(addr string, handler Handler) error {
server := &Server{Addr: addr, Handler: handler}
return server.ListenAndServe()
}
3.http.Handle函数
Handle可以向DefaultServeMux添加处理器
func Handle(pattern string, handler Handler) {
DefaultServeMux.Handle(pattern, handler)
}
4.http.HandleFunc函数
HandleFunc函数可以向DefaultServeMux添加处理器。
func HandleFunc(pattern string, handler func(ResponseWriter, *Request)) {
DefaultServeMux.HandleFunc(pattern, handler)
}
5.gin.const常量
const (
StatusContinue = 100 // RFC 7231, 6.2.1
StatusSwitchingProtocols = 101 // RFC 7231, 6.2.2
StatusProcessing = 102 // RFC 2518, 10.1
StatusEarlyHints = 103 // RFC 8297
StatusOK = 200 // RFC 7231, 6.3.1
StatusCreated = 201 // RFC 7231, 6.3.2
StatusAccepted = 202 // RFC 7231, 6.3.3
StatusNonAuthoritativeInfo = 203 // RFC 7231, 6.3.4
StatusNoContent = 204 // RFC 7231, 6.3.5
StatusResetContent = 205 // RFC 7231, 6.3.6
StatusPartialContent = 206 // RFC 7233, 4.1
StatusMultiStatus = 207 // RFC 4918, 11.1
StatusAlreadyReported = 208 // RFC 5842, 7.1
StatusIMUsed = 226 // RFC 3229, 10.4.1
StatusMultipleChoices = 300 // RFC 7231, 6.4.1
StatusMovedPermanently = 301 // RFC 7231, 6.4.2
StatusFound = 302 // RFC 7231, 6.4.3
StatusSeeOther = 303 // RFC 7231, 6.4.4
StatusNotModified = 304 // RFC 7232, 4.1
StatusUseProxy = 305 // RFC 7231, 6.4.5
_ = 306 // RFC 7231, 6.4.6 (Unused)
StatusTemporaryRedirect = 307 // RFC 7231, 6.4.7
StatusPermanentRedirect = 308 // RFC 7538, 3
StatusBadRequest = 400 // RFC 7231, 6.5.1
StatusUnauthorized = 401 // RFC 7235, 3.1
StatusPaymentRequired = 402 // RFC 7231, 6.5.2
StatusForbidden = 403 // RFC 7231, 6.5.3
StatusNotFound = 404 // RFC 7231, 6.5.4
StatusMethodNotAllowed = 405 // RFC 7231, 6.5.5
StatusNotAcceptable = 406 // RFC 7231, 6.5.6
StatusProxyAuthRequired = 407 // RFC 7235, 3.2
StatusRequestTimeout = 408 // RFC 7231, 6.5.7
StatusConflict = 409 // RFC 7231, 6.5.8
StatusGone = 410 // RFC 7231, 6.5.9
StatusLengthRequired = 411 // RFC 7231, 6.5.10
StatusPreconditionFailed = 412 // RFC 7232, 4.2
StatusRequestEntityTooLarge = 413 // RFC 7231, 6.5.11
StatusRequestURITooLong = 414 // RFC 7231, 6.5.12
StatusUnsupportedMediaType = 415 // RFC 7231, 6.5.13
StatusRequestedRangeNotSatisfiable = 416 // RFC 7233, 4.4
StatusExpectationFailed = 417 // RFC 7231, 6.5.14
StatusTeapot = 418 // RFC 7168, 2.3.3
StatusMisdirectedRequest = 421 // RFC 7540, 9.1.2
StatusUnprocessableEntity = 422 // RFC 4918, 11.2
StatusLocked = 423 // RFC 4918, 11.3
StatusFailedDependency = 424 // RFC 4918, 11.4
StatusTooEarly = 425 // RFC 8470, 5.2.
StatusUpgradeRequired = 426 // RFC 7231, 6.5.15
StatusPreconditionRequired = 428 // RFC 6585, 3
StatusTooManyRequests = 429 // RFC 6585, 4
StatusRequestHeaderFieldsTooLarge = 431 // RFC 6585, 5
StatusUnavailableForLegalReasons = 451 // RFC 7725, 3
StatusInternalServerError = 500 // RFC 7231, 6.6.1
StatusNotImplemented = 501 // RFC 7231, 6.6.2
StatusBadGateway = 502 // RFC 7231, 6.6.3
StatusServiceUnavailable = 503 // RFC 7231, 6.6.4
StatusGatewayTimeout = 504 // RFC 7231, 6.6.5
StatusHTTPVersionNotSupported = 505 // RFC 7231, 6.6.6
StatusVariantAlsoNegotiates = 506 // RFC 2295, 8.1
StatusInsufficientStorage = 507 // RFC 4918, 11.5
StatusLoopDetected = 508 // RFC 5842, 7.2
StatusNotExtended = 510 // RFC 2774, 7
StatusNetworkAuthenticationRequired = 511 // RFC 6585, 6
)
6.http.Request结构体
//简化版
type Request struct {
Method string
URL *url.URL
Proto string // "HTTP/1.0"
ProtoMajor int // 1
ProtoMinor int // 0
Header Header
Body io.ReadCloser
GetBody func() (io.ReadCloser, error)
ContentLength int64
TransferEncoding []string
Close bool
Host string
Form url.Values
PostForm url.Values
MultipartForm *multipart.Form
Trailer Header
RemoteAddr string
RequestURI string
TLS *tls.ConnectionState
Cancel <-chan struct{}
Response *Response
ctx context.Context
}
//详细版
// A Request represents an HTTP request received by a server
// or to be sent by a client.
//
// The field semantics differ slightly between client and server
// usage. In addition to the notes on the fields below, see the
// documentation for Request.Write and RoundTripper.
type Request struct {
// Method specifies the HTTP method (GET, POST, PUT, etc.).
// For client requests, an empty string means GET.
//
// Go's HTTP client does not support sending a request with
// the CONNECT method. See the documentation on Transport for
// details.
Method string
// URL specifies either the URI being requested (for server
// requests) or the URL to access (for client requests).
//
// For server requests, the URL is parsed from the URI
// supplied on the Request-Line as stored in RequestURI. For
// most requests, fields other than Path and RawQuery will be
// empty. (See RFC 7230, Section 5.3)
//
// For client requests, the URL's Host specifies the server to
// connect to, while the Request's Host field optionally
// specifies the Host header value to send in the HTTP
// request.
URL *url.URL
// The protocol version for incoming server requests.
//
// For client requests, these fields are ignored. The HTTP
// client code always uses either HTTP/1.1 or HTTP/2.
// See the docs on Transport for details.
Proto string // "HTTP/1.0"
ProtoMajor int // 1
ProtoMinor int // 0
// Header contains the request header fields either received
// by the server or to be sent by the client.
//
// If a server received a request with header lines,
//
// Host: example.com
// accept-encoding: gzip, deflate
// Accept-Language: en-us
// fOO: Bar
// foo: two
//
// then
//
// Header = map[string][]string{
// "Accept-Encoding": {"gzip, deflate"},
// "Accept-Language": {"en-us"},
// "Foo": {"Bar", "two"},
// }
//
// For incoming requests, the Host header is promoted to the
// Request.Host field and removed from the Header map.
//
// HTTP defines that header names are case-insensitive. The
// request parser implements this by using CanonicalHeaderKey,
// making the first character and any characters following a
// hyphen uppercase and the rest lowercase.
//
// For client requests, certain headers such as Content-Length
// and Connection are automatically written when needed and
// values in Header may be ignored. See the documentation
// for the Request.Write method.
Header Header
// Body is the request's body.
//
// For client requests, a nil body means the request has no
// body, such as a GET request. The HTTP Client's Transport
// is responsible for calling the Close method.
//
// For server requests, the Request Body is always non-nil
// but will return EOF immediately when no body is present.
// The Server will close the request body. The ServeHTTP
// Handler does not need to.
//
// Body must allow Read to be called concurrently with Close.
// In particular, calling Close should unblock a Read waiting
// for input.
Body io.ReadCloser
// GetBody defines an optional func to return a new copy of
// Body. It is used for client requests when a redirect requires
// reading the body more than once. Use of GetBody still
// requires setting Body.
//
// For server requests, it is unused.
GetBody func() (io.ReadCloser, error)
// ContentLength records the length of the associated content.
// The value -1 indicates that the length is unknown.
// Values >= 0 indicate that the given number of bytes may
// be read from Body.
//
// For client requests, a value of 0 with a non-nil Body is
// also treated as unknown.
ContentLength int64
// TransferEncoding lists the transfer encodings from outermost to
// innermost. An empty list denotes the "identity" encoding.
// TransferEncoding can usually be ignored; chunked encoding is
// automatically added and removed as necessary when sending and
// receiving requests.
TransferEncoding []string
// Close indicates whether to close the connection after
// replying to this request (for servers) or after sending this
// request and reading its response (for clients).
//
// For server requests, the HTTP server handles this automatically
// and this field is not needed by Handlers.
//
// For client requests, setting this field prevents re-use of
// TCP connections between requests to the same hosts, as if
// Transport.DisableKeepAlives were set.
Close bool
// For server requests, Host specifies the host on which the
// URL is sought. For HTTP/1 (per RFC 7230, section 5.4), this
// is either the value of the "Host" header or the host name
// given in the URL itself. For HTTP/2, it is the value of the
// ":authority" pseudo-header field.
// It may be of the form "host:port". For international domain
// names, Host may be in Punycode or Unicode form. Use
// golang.org/x/net/idna to convert it to either format if
// needed.
// To prevent DNS rebinding attacks, server Handlers should
// validate that the Host header has a value for which the
// Handler considers itself authoritative. The included
// ServeMux supports patterns registered to particular host
// names and thus protects its registered Handlers.
//
// For client requests, Host optionally overrides the Host
// header to send. If empty, the Request.Write method uses
// the value of URL.Host. Host may contain an international
// domain name.
Host string
// Form contains the parsed form data, including both the URL
// field's query parameters and the PATCH, POST, or PUT form data.
// This field is only available after ParseForm is called.
// The HTTP client ignores Form and uses Body instead.
Form url.Values
// PostForm contains the parsed form data from PATCH, POST
// or PUT body parameters.
//
// This field is only available after ParseForm is called.
// The HTTP client ignores PostForm and uses Body instead.
PostForm url.Values
// MultipartForm is the parsed multipart form, including file uploads.
// This field is only available after ParseMultipartForm is called.
// The HTTP client ignores MultipartForm and uses Body instead.
MultipartForm *multipart.Form
// Trailer specifies additional headers that are sent after the request
// body.
//
// For server requests, the Trailer map initially contains only the
// trailer keys, with nil values. (The client declares which trailers it
// will later send.) While the handler is reading from Body, it must
// not reference Trailer. After reading from Body returns EOF, Trailer
// can be read again and will contain non-nil values, if they were sent
// by the client.
//
// For client requests, Trailer must be initialized to a map containing
// the trailer keys to later send. The values may be nil or their final
// values. The ContentLength must be 0 or -1, to send a chunked request.
// After the HTTP request is sent the map values can be updated while
// the request body is read. Once the body returns EOF, the caller must
// not mutate Trailer.
//
// Few HTTP clients, servers, or proxies support HTTP trailers.
Trailer Header
// RemoteAddr allows HTTP servers and other software to record
// the network address that sent the request, usually for
// logging. This field is not filled in by ReadRequest and
// has no defined format. The HTTP server in this package
// sets RemoteAddr to an "IP:port" address before invoking a
// handler.
// This field is ignored by the HTTP client.
RemoteAddr string
// RequestURI is the unmodified request-target of the
// Request-Line (RFC 7230, Section 3.1.1) as sent by the client
// to a server. Usually the URL field should be used instead.
// It is an error to set this field in an HTTP client request.
RequestURI string
// TLS allows HTTP servers and other software to record
// information about the TLS connection on which the request
// was received. This field is not filled in by ReadRequest.
// The HTTP server in this package sets the field for
// TLS-enabled connections before invoking a handler;
// otherwise it leaves the field nil.
// This field is ignored by the HTTP client.
TLS *tls.ConnectionState
// Cancel is an optional channel whose closure indicates that the client
// request should be regarded as canceled. Not all implementations of
// RoundTripper may support Cancel.
//
// For server requests, this field is not applicable.
//
// Deprecated: Set the Request's context with NewRequestWithContext
// instead. If a Request's Cancel field and context are both
// set, it is undefined whether Cancel is respected.
Cancel <-chan struct{}
// Response is the redirect response which caused this request
// to be created. This field is only populated during client
// redirects.
Response *Response
// ctx is either the client or server context. It should only
// be modified via copying the whole Request using WithContext.
// It is unexported to prevent people from using Context wrong
// and mutating the contexts held by callers of the same request.
ctx context.Context
}
7.http.Response结构体
//简化版
type Response struct {
Status string // e.g. "200 OK"
StatusCode int // e.g. 200
Proto string // e.g. "HTTP/1.0"
ProtoMajor int // e.g. 1
ProtoMinor int // e.g. 0
Header Header
Body io.ReadCloser
ContentLength int64
TransferEncoding []string
Close bool
Uncompressed bool
Trailer Header
Request *Request
TLS *tls.ConnectionState
}
//详细版
// Response represents the response from an HTTP request.
//
// The Client and Transport return Responses from servers once
// the response headers have been received. The response body
// is streamed on demand as the Body field is read.
type Response struct {
Status string // e.g. "200 OK"
StatusCode int // e.g. 200
Proto string // e.g. "HTTP/1.0"
ProtoMajor int // e.g. 1
ProtoMinor int // e.g. 0
// Header maps header keys to values. If the response had multiple
// headers with the same key, they may be concatenated, with comma
// delimiters. (RFC 7230, section 3.2.2 requires that multiple headers
// be semantically equivalent to a comma-delimited sequence.) When
// Header values are duplicated by other fields in this struct (e.g.,
// ContentLength, TransferEncoding, Trailer), the field values are
// authoritative.
//
// Keys in the map are canonicalized (see CanonicalHeaderKey).
Header Header
// Body represents the response body.
//
// The response body is streamed on demand as the Body field
// is read. If the network connection fails or the server
// terminates the response, Body.Read calls return an error.
//
// The http Client and Transport guarantee that Body is always
// non-nil, even on responses without a body or responses with
// a zero-length body. It is the caller's responsibility to
// close Body. The default HTTP client's Transport may not
// reuse HTTP/1.x "keep-alive" TCP connections if the Body is
// not read to completion and closed.
//
// The Body is automatically dechunked if the server replied
// with a "chunked" Transfer-Encoding.
//
// As of Go 1.12, the Body will also implement io.Writer
// on a successful "101 Switching Protocols" response,
// as used by WebSockets and HTTP/2's "h2c" mode.
Body io.ReadCloser
// ContentLength records the length of the associated content. The
// value -1 indicates that the length is unknown. Unless Request.Method
// is "HEAD", values >= 0 indicate that the given number of bytes may
// be read from Body.
ContentLength int64
// Contains transfer encodings from outer-most to inner-most. Value is
// nil, means that "identity" encoding is used.
TransferEncoding []string
// Close records whether the header directed that the connection be
// closed after reading Body. The value is advice for clients: neither
// ReadResponse nor Response.Write ever closes a connection.
Close bool
// Uncompressed reports whether the response was sent compressed but
// was decompressed by the http package. When true, reading from
// Body yields the uncompressed content instead of the compressed
// content actually set from the server, ContentLength is set to -1,
// and the "Content-Length" and "Content-Encoding" fields are deleted
// from the responseHeader. To get the original response from
// the server, set Transport.DisableCompression to true.
Uncompressed bool
// Trailer maps trailer keys to values in the same
// format as Header.
//
// The Trailer initially contains only nil values, one for
// each key specified in the server's "Trailer" header
// value. Those values are not added to Header.
//
// Trailer must not be accessed concurrently with Read calls
// on the Body.
//
// After Body.Read has returned io.EOF, Trailer will contain
// any trailer values sent by the server.
Trailer Header
// Request is the request that was sent to obtain this Response.
// Request's Body is nil (having already been consumed).
// This is only populated for Client requests.
Request *Request
// TLS contains information about the TLS connection on which the
// response was received. It is nil for unencrypted responses.
// The pointer is shared between responses and should not be
// modified.
TLS *tls.ConnectionState
}
8.http.HandleFunc函数类型
// The HandlerFunc type is an adapter to allow the use of
// ordinary functions as HTTP handlers. If f is a function
// with the appropriate signature, HandlerFunc(f) is a
// Handler that calls f.
type HandlerFunc func(ResponseWriter, *Request)