utils.go

// ⚡️ Fiber is an Express inspired web framework written in Go with ☕️
// 🤖 Github Repository: https://github.com/gofiber/fiber
// 📌 API Documentation: https://docs.gofiber.io

package fiber

import (
	"bytes"
	"fmt"
	"hash/crc32"
	"net"
	"os"
	"path/filepath"
	"reflect"
	"runtime"
	"strings"
	"testing"
	"time"
	"unsafe"
)

const toLowerTable = "\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@abcdefghijklmnopqrstuvwxyz[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\u007f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
const toUpperTable = "\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`ABCDEFGHIJKLMNOPQRSTUVWXYZ{|}~\u007f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"

func toLower(b string) string {
	var res = make([]byte, len(b))
	copy(res, b)
	for i := range b {
		res[i] = toLowerTable[b[i]]
	}

	return getString(res)
}

func toUpper(b string) string {
	var res = make([]byte, len(b))
	copy(res, b)
	for i := range b {
		res[i] = toUpperTable[b[i]]
	}

	return getString(res)
}

func trimRight(s string, cutset byte) string {
	lenStr := len(s)
	for lenStr > 0 && s[lenStr-1] == cutset {
		lenStr--
	}
	return s[:lenStr]
}

// AssertEqual checks if values are equal
func assertEqual(t testing.TB, a interface{}, b interface{}, information ...string) {
	if reflect.DeepEqual(a, b) {
		return
	}
	info := ""
	if len(information) > 0 {
		info = information[0]
	}
	_, file, line, _ := runtime.Caller(1)
	t.Fatalf(`
		Test: 	 	%s
		Trace: 	 	%s:%d
		Error: 	 	Not equal
		Expect: 	%v [%s]
		Result: 	%v [%s]
		Message:  	%s`, t.Name(), filepath.Base(file), line, a, reflect.TypeOf(a).Name(), b, reflect.TypeOf(b).Name(), info)
}

// Generate and set ETag header to response
func setETag(ctx *Ctx, weak bool) {
	body := ctx.Fasthttp.Response.Body()
	// Skips ETag if no response body is present
	if len(body) <= 0 {
		return
	}
	// Get ETag header from request
	clientEtag := ctx.Get(HeaderIfNoneMatch)

	// Generate ETag for response
	crc32q := crc32.MakeTable(0xD5828281)
	etag := fmt.Sprintf("\"%d-%v\"", len(body), crc32.Checksum(body, crc32q))

	// Enable weak tag
	if weak {
		etag = "W/" + "\"" + etag + "\""
	}

	// Check if client's ETag is weak
	if strings.HasPrefix(clientEtag, "W/") {
		// Check if server's ETag is weak
		if clientEtag[2:] == etag || clientEtag[2:] == etag[2:] {
			// W/1 == 1 || W/1 == W/1
			ctx.SendStatus(304)
			ctx.Fasthttp.ResetBody()
			return
		}
		// W/1 != W/2 || W/1 != 2
		ctx.Set(HeaderETag, etag)
		return
	}
	if strings.Contains(clientEtag, etag) {
		// 1 == 1
		ctx.SendStatus(304)
		ctx.Fasthttp.ResetBody()
		return
	}
	// 1 != 2
	ctx.Set(HeaderETag, etag)
}

func getGroupPath(prefix, path string) string {
	if path == "/" {
		path = ""
	}
	path = prefix + path
	path = strings.Replace(path, "//", "/", -1)
	return path
}

func getMIME(extension string) (mime string) {
	if len(extension) == 0 {
		return mime
	}
	if extension[0] == '.' {
		mime = extMIME[extension[1:]]
	} else {
		mime = extMIME[extension]
	}
	if len(mime) == 0 {
		return MIMEOctetStream
	}
	return mime
}

// Check if key is in arguments
func getArgument(arg string) bool {
	for i := range os.Args[1:] {
		if os.Args[1:][i] == arg {
			return true
		}
	}
	return false
}

// return valid offer for header negotiation
func getOffer(header string, offers ...string) string {
	if len(offers) == 0 {
		return ""
	}
	if header == "" {
		return offers[0]
	}

	specs := strings.Split(header, ",")
	for i := range offers {
		for k := range specs {
			spec := strings.TrimSpace(specs[k])
			if strings.HasPrefix(spec, "*") {
				return offers[i]
			}
			if strings.HasPrefix(spec, offers[i]) {
				return offers[i]
			}
		}
	}
	return ""
}

// Adapted from:
// https://github.com/jshttp/fresh/blob/10e0471669dbbfbfd8de65bc6efac2ddd0bfa057/index.js#L110
func parseTokenList(noneMatchBytes []byte) []string {
	var (
		start int
		end   int
		list  []string
	)
	for i := range noneMatchBytes {
		switch noneMatchBytes[i] {
		case 0x20:
			if start == end {
				start = i + 1
				end = i + 1
			}
		case 0x2c:
			list = append(list, getString(noneMatchBytes[start:end]))
			start = i + 1
			end = i + 1
		default:
			end = i + 1
		}
	}

	list = append(list, getString(noneMatchBytes[start:end]))
	return list
}

// https://golang.org/src/net/net.go#L113
// Helper methods for application#test
type testConn struct {
	net.Conn
	r bytes.Buffer
	w bytes.Buffer
}

func (c *testConn) RemoteAddr() net.Addr {
	return &net.TCPAddr{
		IP: net.IPv4(0, 0, 0, 0),
	}
}
func (c *testConn) LocalAddr() net.Addr                { return c.RemoteAddr() }
func (c *testConn) Read(b []byte) (int, error)         { return c.r.Read(b) }
func (c *testConn) Write(b []byte) (int, error)        { return c.w.Write(b) }
func (c *testConn) Close() error                       { return nil }
func (c *testConn) SetDeadline(t time.Time) error      { return nil }
func (c *testConn) SetReadDeadline(t time.Time) error  { return nil }
func (c *testConn) SetWriteDeadline(t time.Time) error { return nil }

// #nosec G103
// getString converts byte slice to a string without memory allocation.
// See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .
var getString = func(b []byte) string {
	return *(*string)(unsafe.Pointer(&b))
}
var getStringImmutable = func(b []byte) string {
	return string(b)
}

// #nosec G103
// getBytes converts string to a byte slice without memory allocation.
// See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .
var getBytes = func(s string) (b []byte) {
	return *(*[]byte)(unsafe.Pointer(&s))
}
var getBytesImmutable = func(s string) (b []byte) {
	return []byte(s)
}

// ⚠️ This path parser was based on urlpath by @ucarion (MIT License).
// 💖 Modified for the Fiber router by @renanbastos93 & @renewerner87
// 🤖 ucarion/urlpath - renanbastos93/fastpath - renewerner87/fastpath

// paramsParser holds the path segments and param names
type parsedParams struct {
	segs   []paramSeg
	params []string
}

// paramsSeg holds the segment metadata
type paramSeg struct {
	Param      string
	Const      string
	IsParam    bool
	IsOptional bool
	IsLast     bool
}

var paramsDummy = make([]string, 100)

const wildcardParam string = "*"

// New ...
func getParams(pattern string) (p parsedParams) {
	var patternCount int
	aPattern := []string{""}
	if pattern != "" {
		aPattern = strings.Split(pattern, "/")[1:] // every route starts with an "/"
	}
	patternCount = len(aPattern)

	var out = make([]paramSeg, patternCount)
	var params []string
	var segIndex int
	for i := 0; i < patternCount; i++ {
		partLen := len(aPattern[i])
		if partLen == 0 { // skip empty parts
			continue
		}
		// is parameter ?
		if aPattern[i][0] == '*' || aPattern[i][0] == ':' {
			out[segIndex] = paramSeg{
				Param:      getTrimmedParam(aPattern[i]),
				IsParam:    true,
				IsOptional: aPattern[i] == wildcardParam || aPattern[i][partLen-1] == '?',
			}
			params = append(params, out[segIndex].Param)
		} else {
			// combine const segments
			if segIndex > 0 && !out[segIndex-1].IsParam {
				segIndex--
				out[segIndex].Const += "/" + aPattern[i]
				// create new const segment
			} else {
				out[segIndex] = paramSeg{
					Const: aPattern[i],
				}
			}
		}
		segIndex++
	}
	if segIndex == 0 {
		segIndex++
	}
	out[segIndex-1].IsLast = true

	p = parsedParams{segs: out[:segIndex:segIndex], params: params}
	//fmt.Printf("%+v\n", p)
	return
}

// Match ...
func (p *parsedParams) getMatch(s string, partialCheck bool) ([]string, bool) {
	lenKeys := len(p.params)
	params := paramsDummy[0:lenKeys:lenKeys]
	var i, j, paramsIterator, partLen int
	if len(s) > 0 {
		s = s[1:]
	}
	for index, segment := range p.segs {
		partLen = len(s)
		// check parameter
		if segment.IsParam {
			// determine parameter length
			if segment.Param == wildcardParam {
				if segment.IsLast {
					i = partLen
				} else {
					// for the expressjs behavior -> "/api/*/:param" - "/api/joker/batman/robin/1" -> "joker/batman/robin", "1"
					i = getCharPos(s, '/', strings.Count(s, "/")-(len(p.segs)-(index+1))+1)
				}
			} else {
				i = strings.IndexByte(s, '/')
			}
			if i == -1 {
				i = partLen
			}

			if !segment.IsOptional && i == 0 {
				return nil, false
			}

			params[paramsIterator] = s[:i]
			paramsIterator++
		} else {
			// check const segment
			i = len(segment.Const)
			if partLen < i || (i == 0 && partLen > 0) || s[:i] != segment.Const || (partLen > i && s[i] != '/') {
				return nil, false
			}
		}

		// reduce founded part from the string
		if partLen > 0 {
			j = i + 1
			if segment.IsLast || partLen < j {
				j = i
			}

			s = s[j:]
		}
	}
	if len(s) != 0 && !partialCheck {
		return nil, false
	}

	return params, true
}
func getTrimmedParam(param string) string {
	start := 0
	end := len(param)

	if param[start] != ':' { // is not a param
		return param
	}
	start++
	if param[end-1] == '?' { // is ?
		end--
	}

	return param[start:end]
}
func getCharPos(s string, char byte, matchCount int) int {
	if matchCount == 0 {
		matchCount = 1
	}
	endPos, pos := 0, 0
	for matchCount > 0 && pos != -1 {
		if pos > 0 {
			s = s[pos+1:]
			endPos++
		}
		pos = strings.IndexByte(s, char)
		endPos += pos
		matchCount--
	}
	return endPos
}

// HTTP methods and their unique INTs
var methodINT = map[string]int{
	MethodGet:     0,
	MethodHead:    1,
	MethodPost:    2,
	MethodPut:     3,
	MethodDelete:  4,
	MethodConnect: 5,
	MethodOptions: 6,
	MethodTrace:   7,
	MethodPatch:   8,
}

// HTTP methods were copied from net/http.
const (
	MethodGet     = "GET"     // RFC 7231, 4.3.1
	MethodHead    = "HEAD"    // RFC 7231, 4.3.2
	MethodPost    = "POST"    // RFC 7231, 4.3.3
	MethodPut     = "PUT"     // RFC 7231, 4.3.4
	MethodPatch   = "PATCH"   // RFC 5789
	MethodDelete  = "DELETE"  // RFC 7231, 4.3.5
	MethodConnect = "CONNECT" // RFC 7231, 4.3.6
	MethodOptions = "OPTIONS" // RFC 7231, 4.3.7
	MethodTrace   = "TRACE"   // RFC 7231, 4.3.8
)

// MIME types that are commonly  used
const (
	MIMETextXML               = "text/xml"
	MIMETextHTML              = "text/html"
	MIMETextPlain             = "text/plain"
	MIMEApplicationJSON       = "application/json"
	MIMEApplicationJavaScript = "application/javascript"
	MIMEApplicationXML        = "application/xml"
	MIMEApplicationForm       = "application/x-www-form-urlencoded"
	MIMEMultipartForm         = "multipart/form-data"
	MIMEOctetStream           = "application/octet-stream"
)

// HTTP status codes were copied from net/http.
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
	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
)

// HTTP Headers were copied from net/http.
const (
	HeaderAuthorization                   = "Authorization"
	HeaderProxyAuthenticate               = "Proxy-Authenticate"
	HeaderProxyAuthorization              = "Proxy-Authorization"
	HeaderWWWAuthenticate                 = "WWW-Authenticate"
	HeaderAge                             = "Age"
	HeaderCacheControl                    = "Cache-Control"
	HeaderClearSiteData                   = "Clear-Site-Data"
	HeaderExpires                         = "Expires"
	HeaderPragma                          = "Pragma"
	HeaderWarning                         = "Warning"
	HeaderAcceptCH                        = "Accept-CH"
	HeaderAcceptCHLifetime                = "Accept-CH-Lifetime"
	HeaderContentDPR                      = "Content-DPR"
	HeaderDPR                             = "DPR"
	HeaderEarlyData                       = "Early-Data"
	HeaderSaveData                        = "Save-Data"
	HeaderViewportWidth                   = "Viewport-Width"
	HeaderWidth                           = "Width"
	HeaderETag                            = "ETag"
	HeaderIfMatch                         = "If-Match"
	HeaderIfModifiedSince                 = "If-Modified-Since"
	HeaderIfNoneMatch                     = "If-None-Match"
	HeaderIfUnmodifiedSince               = "If-Unmodified-Since"
	HeaderLastModified                    = "Last-Modified"
	HeaderVary                            = "Vary"
	HeaderConnection                      = "Connection"
	HeaderKeepAlive                       = "Keep-Alive"
	HeaderAccept                          = "Accept"
	HeaderAcceptCharset                   = "Accept-Charset"
	HeaderAcceptEncoding                  = "Accept-Encoding"
	HeaderAcceptLanguage                  = "Accept-Language"
	HeaderCookie                          = "Cookie"
	HeaderExpect                          = "Expect"
	HeaderMaxForwards                     = "Max-Forwards"
	HeaderSetCookie                       = "Set-Cookie"
	HeaderAccessControlAllowCredentials   = "Access-Control-Allow-Credentials"
	HeaderAccessControlAllowHeaders       = "Access-Control-Allow-Headers"
	HeaderAccessControlAllowMethods       = "Access-Control-Allow-Methods"
	HeaderAccessControlAllowOrigin        = "Access-Control-Allow-Origin"
	HeaderAccessControlExposeHeaders      = "Access-Control-Expose-Headers"
	HeaderAccessControlMaxAge             = "Access-Control-Max-Age"
	HeaderAccessControlRequestHeaders     = "Access-Control-Request-Headers"
	HeaderAccessControlRequestMethod      = "Access-Control-Request-Method"
	HeaderOrigin                          = "Origin"
	HeaderTimingAllowOrigin               = "Timing-Allow-Origin"
	HeaderXPermittedCrossDomainPolicies   = "X-Permitted-Cross-Domain-Policies"
	HeaderDNT                             = "DNT"
	HeaderTk                              = "Tk"
	HeaderContentDisposition              = "Content-Disposition"
	HeaderContentEncoding                 = "Content-Encoding"
	HeaderContentLanguage                 = "Content-Language"
	HeaderContentLength                   = "Content-Length"
	HeaderContentLocation                 = "Content-Location"
	HeaderContentType                     = "Content-Type"
	HeaderForwarded                       = "Forwarded"
	HeaderVia                             = "Via"
	HeaderXForwardedFor                   = "X-Forwarded-For"
	HeaderXForwardedHost                  = "X-Forwarded-Host"
	HeaderXForwardedProto                 = "X-Forwarded-Proto"
	HeaderLocation                        = "Location"
	HeaderFrom                            = "From"
	HeaderHost                            = "Host"
	HeaderReferer                         = "Referer"
	HeaderReferrerPolicy                  = "Referrer-Policy"
	HeaderUserAgent                       = "User-Agent"
	HeaderAllow                           = "Allow"
	HeaderServer                          = "Server"
	HeaderAcceptRanges                    = "Accept-Ranges"
	HeaderContentRange                    = "Content-Range"
	HeaderIfRange                         = "If-Range"
	HeaderRange                           = "Range"
	HeaderContentSecurityPolicy           = "Content-Security-Policy"
	HeaderContentSecurityPolicyReportOnly = "Content-Security-Policy-Report-Only"
	HeaderCrossOriginResourcePolicy       = "Cross-Origin-Resource-Policy"
	HeaderExpectCT                        = "Expect-CT"
	HeaderFeaturePolicy                   = "Feature-Policy"
	HeaderPublicKeyPins                   = "Public-Key-Pins"
	HeaderPublicKeyPinsReportOnly         = "Public-Key-Pins-Report-Only"
	HeaderStrictTransportSecurity         = "Strict-Transport-Security"
	HeaderUpgradeInsecureRequests         = "Upgrade-Insecure-Requests"
	HeaderXContentTypeOptions             = "X-Content-Type-Options"
	HeaderXDownloadOptions                = "X-Download-Options"
	HeaderXFrameOptions                   = "X-Frame-Options"
	HeaderXPoweredBy                      = "X-Powered-By"
	HeaderXXSSProtection                  = "X-XSS-Protection"
	HeaderLastEventID                     = "Last-Event-ID"
	HeaderNEL                             = "NEL"
	HeaderPingFrom                        = "Ping-From"
	HeaderPingTo                          = "Ping-To"
	HeaderReportTo                        = "Report-To"
	HeaderTE                              = "TE"
	HeaderTrailer                         = "Trailer"
	HeaderTransferEncoding                = "Transfer-Encoding"
	HeaderSecWebSocketAccept              = "Sec-WebSocket-Accept"
	HeaderSecWebSocketExtensions          = "Sec-WebSocket-Extensions"
	HeaderSecWebSocketKey                 = "Sec-WebSocket-Key"
	HeaderSecWebSocketProtocol            = "Sec-WebSocket-Protocol"
	HeaderSecWebSocketVersion             = "Sec-WebSocket-Version"
	HeaderAcceptPatch                     = "Accept-Patch"
	HeaderAcceptPushPolicy                = "Accept-Push-Policy"
	HeaderAcceptSignature                 = "Accept-Signature"
	HeaderAltSvc                          = "Alt-Svc"
	HeaderDate                            = "Date"
	HeaderIndex                           = "Index"
	HeaderLargeAllocation                 = "Large-Allocation"
	HeaderLink                            = "Link"
	HeaderPushPolicy                      = "Push-Policy"
	HeaderRetryAfter                      = "Retry-After"
	HeaderServerTiming                    = "Server-Timing"
	HeaderSignature                       = "Signature"
	HeaderSignedHeaders                   = "Signed-Headers"
	HeaderSourceMap                       = "SourceMap"
	HeaderUpgrade                         = "Upgrade"
	HeaderXDNSPrefetchControl             = "X-DNS-Prefetch-Control"
	HeaderXPingback                       = "X-Pingback"
	HeaderXRequestID                      = "X-Request-ID"
	HeaderXRequestedWith                  = "X-Requested-With"
	HeaderXRobotsTag                      = "X-Robots-Tag"
	HeaderXUACompatible                   = "X-UA-Compatible"
)

// HTTP status codes were copied from net/http.
var statusMessage = map[int]string{
	100: "Continue",
	101: "Switching Protocols",
	102: "Processing",
	103: "Early Hints",
	200: "OK",
	201: "Created",
	202: "Accepted",
	203: "Non-Authoritative Information",
	204: "No Content",
	205: "Reset Content",
	206: "Partial Content",
	207: "Multi-Status",
	208: "Already Reported",
	226: "IM Used",
	300: "Multiple Choices",
	301: "Moved Permanently",
	302: "Found",
	303: "See Other",
	304: "Not Modified",
	305: "Use Proxy",
	306: "Switch Proxy",
	307: "Temporary Redirect",
	308: "Permanent Redirect",
	400: "Bad Request",
	401: "Unauthorized",
	402: "Payment Required",
	403: "Forbidden",
	404: "Not Found",
	405: "Method Not Allowed",
	406: "Not Acceptable",
	407: "Proxy Authentication Required",
	408: "Request Timeout",
	409: "Conflict",
	410: "Gone",
	411: "Length Required",
	412: "Precondition Failed",
	413: "Request Entity Too Large",
	414: "Request URI Too Long",
	415: "Unsupported Media Type",
	416: "Requested Range Not Satisfiable",
	417: "Expectation Failed",
	418: "I'm a teapot",
	421: "Misdirected Request",
	422: "Unprocessable Entity",
	423: "Locked",
	424: "Failed Dependency",
	426: "Upgrade Required",
	428: "Precondition Required",
	429: "Too Many Requests",
	431: "Request Header Fields Too Large",
	451: "Unavailable For Legal Reasons",
	500: "Internal Server Error",
	501: "Not Implemented",
	502: "Bad Gateway",
	503: "Service Unavailable",
	504: "Gateway Timeout",
	505: "HTTP Version Not Supported",
	506: "Variant Also Negotiates",
	507: "Insufficient Storage",
	508: "Loop Detected",
	510: "Not Extended",
	511: "Network Authentication Required",
}

// MIME types were copied from https://github.com/nginx/nginx/blob/master/conf/mime.types
var extMIME = map[string]string{
	"html":    "text/html",
	"htm":     "text/html",
	"shtml":   "text/html",
	"css":     "text/css",
	"gif":     "image/gif",
	"jpeg":    "image/jpeg",
	"jpg":     "image/jpeg",
	"xml":     "application/xml",
	"js":      "application/javascript",
	"atom":    "application/atom+xml",
	"rss":     "application/rss+xml",
	"mml":     "text/mathml",
	"txt":     "text/plain",
	"jad":     "text/vnd.sun.j2me.app-descriptor",
	"wml":     "text/vnd.wap.wml",
	"htc":     "text/x-component",
	"png":     "image/png",
	"svg":     "image/svg+xml",
	"svgz":    "image/svg+xml",
	"tif":     "image/tiff",
	"tiff":    "image/tiff",
	"wbmp":    "image/vnd.wap.wbmp",
	"webp":    "image/webp",
	"ico":     "image/x-icon",
	"jng":     "image/x-jng",
	"bmp":     "image/x-ms-bmp",
	"woff":    "font/woff",
	"woff2":   "font/woff2",
	"jar":     "application/java-archive",
	"war":     "application/java-archive",
	"ear":     "application/java-archive",
	"json":    "application/json",
	"hqx":     "application/mac-binhex40",
	"doc":     "application/msword",
	"pdf":     "application/pdf",
	"ps":      "application/postscript",
	"eps":     "application/postscript",
	"ai":      "application/postscript",
	"rtf":     "application/rtf",
	"m3u8":    "application/vnd.apple.mpegurl",
	"kml":     "application/vnd.google-earth.kml+xml",
	"kmz":     "application/vnd.google-earth.kmz",
	"xls":     "application/vnd.ms-excel",
	"eot":     "application/vnd.ms-fontobject",
	"ppt":     "application/vnd.ms-powerpoint",
	"odg":     "application/vnd.oasis.opendocument.graphics",
	"odp":     "application/vnd.oasis.opendocument.presentation",
	"ods":     "application/vnd.oasis.opendocument.spreadsheet",
	"odt":     "application/vnd.oasis.opendocument.text",
	"wmlc":    "application/vnd.wap.wmlc",
	"7z":      "application/x-7z-compressed",
	"cco":     "application/x-cocoa",
	"jardiff": "application/x-java-archive-diff",
	"jnlp":    "application/x-java-jnlp-file",
	"run":     "application/x-makeself",
	"pl":      "application/x-perl",
	"pm":      "application/x-perl",
	"prc":     "application/x-pilot",
	"pdb":     "application/x-pilot",
	"rar":     "application/x-rar-compressed",
	"rpm":     "application/x-redhat-package-manager",
	"sea":     "application/x-sea",
	"swf":     "application/x-shockwave-flash",
	"sit":     "application/x-stuffit",
	"tcl":     "application/x-tcl",
	"tk":      "application/x-tcl",
	"der":     "application/x-x509-ca-cert",
	"pem":     "application/x-x509-ca-cert",
	"crt":     "application/x-x509-ca-cert",
	"xpi":     "application/x-xpinstall",
	"xhtml":   "application/xhtml+xml",
	"xspf":    "application/xspf+xml",
	"zip":     "application/zip",
	"bin":     "application/octet-stream",
	"exe":     "application/octet-stream",
	"dll":     "application/octet-stream",
	"deb":     "application/octet-stream",
	"dmg":     "application/octet-stream",
	"iso":     "application/octet-stream",
	"img":     "application/octet-stream",
	"msi":     "application/octet-stream",
	"msp":     "application/octet-stream",
	"msm":     "application/octet-stream",
	"mid":     "audio/midi",
	"midi":    "audio/midi",
	"kar":     "audio/midi",
	"mp3":     "audio/mpeg",
	"ogg":     "audio/ogg",
	"m4a":     "audio/x-m4a",
	"ra":      "audio/x-realaudio",
	"3gpp":    "video/3gpp",
	"3gp":     "video/3gpp",
	"ts":      "video/mp2t",
	"mp4":     "video/mp4",
	"mpeg":    "video/mpeg",
	"mpg":     "video/mpeg",
	"mov":     "video/quicktime",
	"webm":    "video/webm",
	"flv":     "video/x-flv",
	"m4v":     "video/x-m4v",
	"mng":     "video/x-mng",
	"asx":     "video/x-ms-asf",
	"asf":     "video/x-ms-asf",
	"wmv":     "video/x-ms-wmv",
	"avi":     "video/x-msvideo",
}