status.go

package iris

import (
	"regexp"
	"sync"
)

// HTTP status codes.
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
	StatusUnprocessableEntity          = 422 // RFC 4918, 11.2
	StatusLocked                       = 423 // RFC 4918, 11.3
	StatusFailedDependency             = 424 // RFC 4918, 11.4
	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
)

var statusText = map[int]string{
	StatusContinue:           "Continue",
	StatusSwitchingProtocols: "Switching Protocols",
	StatusProcessing:         "Processing",

	StatusOK:                   "OK",
	StatusCreated:              "Created",
	StatusAccepted:             "Accepted",
	StatusNonAuthoritativeInfo: "Non-Authoritative Information",
	StatusNoContent:            "No Content",
	StatusResetContent:         "Reset Content",
	StatusPartialContent:       "Partial Content",
	StatusMultiStatus:          "Multi-Status",
	StatusAlreadyReported:      "Already Reported",
	StatusIMUsed:               "IM Used",

	StatusMultipleChoices:   "Multiple Choices",
	StatusMovedPermanently:  "Moved Permanently",
	StatusFound:             "Found",
	StatusSeeOther:          "See Other",
	StatusNotModified:       "Not Modified",
	StatusUseProxy:          "Use Proxy",
	StatusTemporaryRedirect: "Temporary Redirect",
	StatusPermanentRedirect: "Permanent Redirect",

	StatusBadRequest:                   "Bad Request",
	StatusUnauthorized:                 "Unauthorized",
	StatusPaymentRequired:              "Payment Required",
	StatusForbidden:                    "Forbidden",
	StatusNotFound:                     "Not Found",
	StatusMethodNotAllowed:             "Method Not Allowed",
	StatusNotAcceptable:                "Not Acceptable",
	StatusProxyAuthRequired:            "Proxy Authentication Required",
	StatusRequestTimeout:               "Request Timeout",
	StatusConflict:                     "Conflict",
	StatusGone:                         "Gone",
	StatusLengthRequired:               "Length Required",
	StatusPreconditionFailed:           "Precondition Failed",
	StatusRequestEntityTooLarge:        "Request Entity Too Large",
	StatusRequestURITooLong:            "Request URI Too Long",
	StatusUnsupportedMediaType:         "Unsupported Media Type",
	StatusRequestedRangeNotSatisfiable: "Requested Range Not Satisfiable",
	StatusExpectationFailed:            "Expectation Failed",
	StatusTeapot:                       "I'm a teapot",
	StatusUnprocessableEntity:          "Unprocessable Entity",
	StatusLocked:                       "Locked",
	StatusFailedDependency:             "Failed Dependency",
	StatusUpgradeRequired:              "Upgrade Required",
	StatusPreconditionRequired:         "Precondition Required",
	StatusTooManyRequests:              "Too Many Requests",
	StatusRequestHeaderFieldsTooLarge:  "Request Header Fields Too Large",
	StatusUnavailableForLegalReasons:   "Unavailable For Legal Reasons",

	StatusInternalServerError:           "Internal Server Error",
	StatusNotImplemented:                "Not Implemented",
	StatusBadGateway:                    "Bad Gateway",
	StatusServiceUnavailable:            "Service Unavailable",
	StatusGatewayTimeout:                "Gateway Timeout",
	StatusHTTPVersionNotSupported:       "HTTP Version Not Supported",
	StatusVariantAlsoNegotiates:         "Variant Also Negotiates",
	StatusInsufficientStorage:           "Insufficient Storage",
	StatusLoopDetected:                  "Loop Detected",
	StatusNotExtended:                   "Not Extended",
	StatusNetworkAuthenticationRequired: "Network Authentication Required",
}

// StatusText returns a text for the HTTP status code. It returns the empty
// string if the code is unknown.
func StatusText(code int) string {
	return statusText[code]
}

// ErrorHandlers contains all custom http errors.
// A custom http error handler is just a handler with its status code.
type ErrorHandlers struct {
	// Handlers the map which actually contains the errors.
	// Use the declared functions to get, set or fire an error.
	handlers map[int]Handler
	mu       sync.RWMutex
}

// Register registers a handler to a http status.
func (e *ErrorHandlers) Register(statusCode int, handler Handler) {
	e.mu.Lock()
	if e.handlers == nil {
		e.handlers = make(map[int]Handler)
	}
	func(statusCode int, handler Handler) {
		e.handlers[statusCode] = HandlerFunc(func(ctx *Context) {
			if w, ok := ctx.IsRecording(); ok {
				w.Reset()
			}
			ctx.SetStatusCode(statusCode)
			handler.Serve(ctx)
		})
	}(statusCode, handler)
	e.mu.Unlock()
}

// RegisterRegex same as Register but it receives a third parameter which is the regex expression
// which is running versus the REQUESTED PATH, i.e "/api/users/42".
//
// If the match against the REQUEST PATH and the 'expr' failed then
// the previous registered error handler on this specific 'statusCode' will be executed.
//
// Returns an error if regexp.Compile failed, nothing special.
func (e *ErrorHandlers) RegisterRegex(statusCode int, handler Handler, expr string) error {
	// if expr is empty, skip the validation and set the error handler as it's
	if expr == "" {
		e.Register(statusCode, handler)
		return nil
	}
	r, err := regexp.Compile(expr)
	if err != nil {
		return err
	}

	prevHandler := e.GetOrRegister(statusCode)

	e.Register(statusCode, HandlerFunc(func(ctx *Context) {
		requestPath := ctx.Request.RequestURI

		if r.MatchString(requestPath) {
			handler.Serve(ctx)
			return
		}
		prevHandler.Serve(ctx)
	}))

	return nil
}

// Get returns the handler which is responsible for
// this 'statusCode' http error.
func (e *ErrorHandlers) Get(statusCode int) Handler {
	e.mu.RLock()
	h := e.handlers[statusCode]
	e.mu.RUnlock()
	if h == nil {
		return nil
	}
	return h
}

// GetOrRegister trys to return the handler which is responsible
// for the 'statusCode', if it was nil then it creates
// a new one, registers that to the error list and returns that.
func (e *ErrorHandlers) GetOrRegister(statusCode int) Handler {
	h := e.Get(statusCode)
	if h == nil {
		// create a new one
		h = HandlerFunc(func(ctx *Context) {
			if w, ok := ctx.IsRecording(); ok {
				w.Reset()
			}
			ctx.SetStatusCode(statusCode)
			if _, err := ctx.WriteString(statusText[statusCode]); err != nil {
				ctx.Log(DevMode, "(status code: %d) %s",
					err.Error(), statusCode)
			}
		})
		e.mu.Lock()
		e.handlers[statusCode] = h
		e.mu.Unlock()
	}

	return h
}

// Fire fires an error based on the `statusCode`
func (e *ErrorHandlers) Fire(statusCode int, ctx *Context) {
	h := e.GetOrRegister(statusCode)
	h.Serve(ctx)
}