This post covers various notes taken from the Golang HTTP package, touching upon topics such as pprof.go, the ServeMux struct, and the ServeHTTP function. Additionally, it discusses the Serve, ServeTLS, and ListenAndServe functions, as well as the different HTTP status codes registered with IANA. The post also explores the Request struct and the MultipartForm field, along with the validMethod function.
pprof.go
// Package pprof serves via its HTTP server runtime profiling data // in the format expected by the pprof visualization tool.
Go Server.go
// Patterns name fixed, rooted paths, like "/favicon.ico", // or rooted subtrees, like "/images/" (note the trailing slash). // Longer patterns take precedence over shorter ones, so that // if there are handlers registered for both "/images/" // and "/images/thumbnails/", the latter handler will be // called for paths beginning "/images/thumbnails/" and the // former will receive requests for any other paths in the // "/images/" subtree. //
// If a subtree has been registered and a request is received naming the // subtree root without its trailing slash, ServeMux redirects that // request to the subtree root (adding the trailing slash). This behavior can // be overridden with a separate registration for the path without // the trailing slash. For example, registering "/images/" causes ServeMux // to redirect a request for "/images" to "/images/", unless "/images" has // been registered separately.
// ServeHTTP dispatches the request to the handler whose // pattern most closely matches the request URL. func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) // Handle registers the handler for the given pattern. // If a handler already exists for pattern, Handle panics. func (mux *ServeMux) Handle(pattern string, handler Handler)
// Serve accepts incoming HTTP connections on the listener l, // creating a new service goroutine for each. The service goroutines // read requests and then call handler to reply to them. // // The handler is typically nil, in which case the DefaultServeMux is used. // // HTTP/2 support is only enabled if the Listener returns *tls.Conn // connections and they were configured with "h2" in the TLS // Config.NextProtos. // // Serve always returns a non-nil error. func Serve(l net.Listener, handler Handler) error
// ServeTLS accepts incoming HTTPS connections on the listener l,
// creating a new service goroutine for each. The service goroutines
// read requests and then call handler to reply to them.
// The handler is typically nil, in which case the DefaultServeMux is used.
// Additionally, files containing a certificate and matching private key
// for the server must be provided. If the certificate is signed by a
// certificate authority, the certFile should be the concatenation
// of the server's certificate, any intermediates, and the CA's certificate.
// ServeTLS always returns a non-nil error.
func ServeTLS(l net.Listener, handler Handler, certFile, keyFile string) error
// ListenAndServe listens on the TCP network address srv.Addr and then
// calls Serve to handle requests on incoming connections.
// Accepted connections are configured to enable TCP keep-alives.
// If srv.Addr is blank, ":http" is used.
// ListenAndServe always returns a non-nil error. After Shutdown or Close,
// the returned error is ErrServerClosed.
func (srv *Server) ListenAndServe() error {
if srv.shuttingDown() {
return ErrServerClosed
}
addr := srv.Addr
if addr == "" {
addr = ":http"
}
ln, err := net.Listen("tcp", addr)
if err != nil {
return err
}
return srv.Serve(tcpKeepAliveListener{ln.(*net.TCPListener)})
}
// HTTP status codes as registered with IANA. // See: https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml const ( StatusContinue = 100 // RFC 7231, 6.2.1 StatusSwitchingProtocols = 101 // RFC 7231, 6.2.2 StatusProcessing = 102 // RFC 2518, 10.1 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 )
// 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{}
// 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
func validMethod(method string) bool {
/*
Method = "OPTIONS" ; Section 9.2
| "GET" ; Section 9.3
| "HEAD" ; Section 9.4
| "POST" ; Section 9.5
| "PUT" ; Section 9.6
| "DELETE" ; Section 9.7
| "TRACE" ; Section 9.8
| "CONNECT" ; Section 9.9
| extension-method
extension-method = token
token = 1*<any CHAR except CTLs or separators>
*/
return len(method) > 0 && strings.IndexFunc(method, isNotToken) == -1
}
Sumit Arora 