restructured the project to comply community guideline, for others check release note

internal/http/content_type.go

@@ -0,0 +1,32 @@
+package http
+
+import (
+	"mime"
+	"net/http"
+)
+
+type ContentType string
+
+func GetContentType(h http.Header) ContentType {
+	ct := h.Get("Content-Type")
+	if ct == "" {
+		return ""
+	}
+	ct, _, err := mime.ParseMediaType(ct)
+	if err != nil {
+		return ""
+	}
+	return ContentType(ct)
+}
+
+func (ct ContentType) IsHTML() bool {
+	return ct == "text/html" || ct == "application/xhtml+xml"
+}
+
+func (ct ContentType) IsJSON() bool {
+	return ct == "application/json"
+}
+
+func (ct ContentType) IsPlainText() bool {
+	return ct == "text/plain"
+}

internal/http/header_utils.go

@@ -0,0 +1,42 @@
+package http
+
+import (
+	"net/http"
+	"slices"
+)
+
+func RemoveHop(h http.Header) {
+	reqUpType := UpgradeType(h)
+	RemoveHopByHopHeaders(h)
+
+	if reqUpType != "" {
+		h.Set("Connection", "Upgrade")
+		h.Set("Upgrade", reqUpType)
+	} else {
+		h.Del("Connection")
+	}
+}
+
+func CopyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
+func FilterHeaders(h http.Header, allowed []string) {
+	if allowed == nil {
+		return
+	}
+
+	for i := range allowed {
+		allowed[i] = http.CanonicalHeaderKey(allowed[i])
+	}
+
+	for key := range h {
+		if !slices.Contains(allowed, key) {
+			h.Del(key)
+		}
+	}
+}

internal/http/modify_response_writer.go

@@ -0,0 +1,96 @@
+// Modified from Traefik Labs's MIT-licensed code (https://github.com/traefik/traefik/blob/master/pkg/middlewares/response_modifier.go)
+// Copyright (c) 2020-2024 Traefik Labs
+
+package http
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"net/http"
+)
+
+type ModifyResponseFunc func(*http.Response) error
+type ModifyResponseWriter struct {
+	w http.ResponseWriter
+	r *http.Request
+
+	headerSent bool
+	code       int
+
+	modifier    ModifyResponseFunc
+	modified    bool
+	modifierErr error
+}
+
+func NewModifyResponseWriter(w http.ResponseWriter, r *http.Request, f ModifyResponseFunc) *ModifyResponseWriter {
+	return &ModifyResponseWriter{
+		w:        w,
+		r:        r,
+		modifier: f,
+		code:     http.StatusOK,
+	}
+}
+
+func (w *ModifyResponseWriter) WriteHeader(code int) {
+	if w.headerSent {
+		return
+	}
+
+	if code >= http.StatusContinue && code < http.StatusOK {
+		w.w.WriteHeader(code)
+	}
+
+	defer func() {
+		w.headerSent = true
+		w.code = code
+	}()
+
+	if w.modifier == nil || w.modified {
+		w.w.WriteHeader(code)
+		return
+	}
+
+	resp := http.Response{
+		Header:  w.w.Header(),
+		Request: w.r,
+	}
+
+	if err := w.modifier(&resp); err != nil {
+		w.modifierErr = err
+		logger.Errorf("error modifying response: %s", err)
+		w.w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.modified = true
+	w.w.WriteHeader(code)
+}
+
+func (w *ModifyResponseWriter) Header() http.Header {
+	return w.w.Header()
+}
+
+func (w *ModifyResponseWriter) Write(b []byte) (int, error) {
+	w.WriteHeader(w.code)
+	if w.modifierErr != nil {
+		return 0, w.modifierErr
+	}
+	return w.w.Write(b)
+}
+
+// Hijack hijacks the connection.
+func (w *ModifyResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	if h, ok := w.w.(http.Hijacker); ok {
+		return h.Hijack()
+	}
+
+	return nil, nil, fmt.Errorf("not a hijacker: %T", w.w)
+}
+
+// Flush sends any buffered data to the client.
+func (w *ModifyResponseWriter) Flush() {
+	if flusher, ok := w.w.(http.Flusher); ok {
+		flusher.Flush()
+	}
+}

internal/http/reverse_proxy_mod.go

@@ -0,0 +1,556 @@
+// Copyright 2011 The Go Authors.
+// Modified from the Go project under the a BSD-style License (https://cs.opensource.google/go/go/+/refs/tags/go1.23.1:src/net/http/httputil/reverseproxy.go)
+// https://cs.opensource.google/go/go/+/master:LICENSE
+
+package http
+
+// This is a small mod on net/http/httputil/reverseproxy.go
+// that boosts performance in some cases
+// and compatible to other modules of this project
+// Copyright (c) 2024 yusing
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptrace"
+	"net/textproto"
+	"net/url"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+	"golang.org/x/net/http/httpguts"
+)
+
+// A ProxyRequest contains a request to be rewritten by a [ReverseProxy].
+type ProxyRequest struct {
+	// In is the request received by the proxy.
+	// The Rewrite function must not modify In.
+	In *http.Request
+
+	// Out is the request which will be sent by the proxy.
+	// The Rewrite function may modify or replace this request.
+	// Hop-by-hop headers are removed from this request
+	// before Rewrite is called.
+	Out *http.Request
+}
+
+// SetXForwarded sets the X-Forwarded-For, X-Forwarded-Host, and
+// X-Forwarded-Proto headers of the outbound request.
+//
+//   - The X-Forwarded-For header is set to the client IP address.
+//   - The X-Forwarded-Host header is set to the host name requested
+//     by the client.
+//   - The X-Forwarded-Proto header is set to "http" or "https", depending
+//     on whether the inbound request was made on a TLS-enabled connection.
+//
+// If the outbound request contains an existing X-Forwarded-For header,
+// SetXForwarded appends the client IP address to it. To append to the
+// inbound request's X-Forwarded-For header (the default behavior of
+// [ReverseProxy] when using a Director function), copy the header
+// from the inbound request before calling SetXForwarded:
+//
+//	rewriteFunc := func(r *httputil.ProxyRequest) {
+//		r.Out.Header["X-Forwarded-For"] = r.In.Header["X-Forwarded-For"]
+//		r.SetXForwarded()
+//	}
+func (r *ProxyRequest) SetXForwarded() {
+	clientIP, _, err := net.SplitHostPort(r.In.RemoteAddr)
+	if err == nil {
+		r.Out.Header.Set("X-Forwarded-For", clientIP)
+	} else {
+		r.Out.Header.Del("X-Forwarded-For")
+	}
+	r.Out.Header.Set("X-Forwarded-Host", r.In.Host)
+	if r.In.TLS == nil {
+		r.Out.Header.Set("X-Forwarded-Proto", "http")
+	} else {
+		r.Out.Header.Set("X-Forwarded-Proto", "https")
+	}
+}
+
+func (r *ProxyRequest) AddXForwarded() {
+	clientIP, _, err := net.SplitHostPort(r.In.RemoteAddr)
+	if err == nil {
+		prior := r.Out.Header["X-Forwarded-For"]
+		if len(prior) > 0 {
+			clientIP = strings.Join(prior, ", ") + ", " + clientIP
+		}
+		r.Out.Header.Set("X-Forwarded-For", clientIP)
+	} else {
+		r.Out.Header.Del("X-Forwarded-For")
+	}
+	r.Out.Header.Set("X-Forwarded-Host", r.In.Host)
+	if r.In.TLS == nil {
+		r.Out.Header.Set("X-Forwarded-Proto", "http")
+	} else {
+		r.Out.Header.Set("X-Forwarded-Proto", "https")
+	}
+}
+
+// ReverseProxy is an HTTP Handler that takes an incoming request and
+// sends it to another server, proxying the response back to the
+// client.
+//
+// 1xx responses are forwarded to the client if the underlying
+// transport supports ClientTrace.Got1xxResponse.
+type ReverseProxy struct {
+	// Rewrite must be a function which modifies
+	// the request into a new request to be sent
+	// using Transport. Its response is then copied
+	// back to the original client unmodified.
+	// Rewrite must not access the provided ProxyRequest
+	// or its contents after returning.
+	//
+	// The Forwarded, X-Forwarded, X-Forwarded-Host,
+	// and X-Forwarded-Proto headers are removed from the
+	// outbound request before Rewrite is called. See also
+	// the ProxyRequest.SetXForwarded method.
+	//
+	// Unparsable query parameters are removed from the
+	// outbound request before Rewrite is called.
+	// The Rewrite function may copy the inbound URL's
+	// RawQuery to the outbound URL to preserve the original
+	// parameter string. Note that this can lead to security
+	// issues if the proxy's interpretation of query parameters
+	// does not match that of the downstream server.
+	//
+	// At most one of Rewrite or Director may be set.
+	Rewrite func(*ProxyRequest)
+
+	// The transport used to perform proxy requests.
+	// If nil, http.DefaultTransport is used.
+	Transport http.RoundTripper
+
+	// ModifyResponse is an optional function that modifies the
+	// Response from the backend. It is called if the backend
+	// returns a response at all, with any HTTP status code.
+	// If the backend is unreachable, the optional ErrorHandler is
+	// called before ModifyResponse.
+	//
+	// If ModifyResponse returns an error, ErrorHandler is called
+	// with its error value. If ErrorHandler is nil, its default
+	// implementation is used.
+	ModifyResponse func(*http.Response) error
+
+	ServeHTTP http.HandlerFunc
+}
+
+// A BufferPool is an interface for getting and returning temporary
+// byte slices for use by [io.CopyBuffer].
+type BufferPool interface {
+	Get() []byte
+	Put([]byte)
+}
+
+func singleJoiningSlash(a, b string) string {
+	aslash := strings.HasSuffix(a, "/")
+	bslash := strings.HasPrefix(b, "/")
+	switch {
+	case aslash && bslash:
+		return a + b[1:]
+	case !aslash && !bslash:
+		return a + "/" + b
+	}
+	return a + b
+}
+
+func joinURLPath(a, b *url.URL) (path, rawpath string) {
+	if a.RawPath == "" && b.RawPath == "" {
+		return singleJoiningSlash(a.Path, b.Path), ""
+	}
+	// Same as singleJoiningSlash, but uses EscapedPath to determine
+	// whether a slash should be added
+	apath := a.EscapedPath()
+	bpath := b.EscapedPath()
+
+	aslash := strings.HasSuffix(apath, "/")
+	bslash := strings.HasPrefix(bpath, "/")
+
+	switch {
+	case aslash && bslash:
+		return a.Path + b.Path[1:], apath + bpath[1:]
+	case !aslash && !bslash:
+		return a.Path + "/" + b.Path, apath + "/" + bpath
+	}
+	return a.Path + b.Path, apath + bpath
+}
+
+// NewReverseProxy returns a new [ReverseProxy] that routes
+// URLs to the scheme, host, and base path provided in target. If the
+// target's path is "/base" and the incoming request was for "/dir",
+// the target request will be for /base/dir.
+//
+// NewReverseProxy does not rewrite the Host header.
+//
+// To customize the ReverseProxy behavior beyond what
+// NewReverseProxy provides, use ReverseProxy directly
+// with a Rewrite function. The ProxyRequest SetURL method
+// may be used to route the outbound request. (Note that SetURL,
+// unlike NewReverseProxy, rewrites the Host header
+// of the outbound request by default.)
+//
+//	proxy := &ReverseProxy{
+//		Rewrite: func(r *ProxyRequest) {
+//			r.SetURL(target)
+//			r.Out.Host = r.In.Host // if desired
+//		},
+//	}
+//
+
+func NewReverseProxy(target *url.URL, transport http.RoundTripper) *ReverseProxy {
+	rp := &ReverseProxy{
+		Rewrite: func(pr *ProxyRequest) {
+			rewriteRequestURL(pr.Out, target)
+		}, Transport: transport,
+	}
+	rp.ServeHTTP = rp.serveHTTP
+	return rp
+}
+
+func rewriteRequestURL(req *http.Request, target *url.URL) {
+	targetQuery := target.RawQuery
+	req.URL.Scheme = target.Scheme
+	req.URL.Host = target.Host
+	req.URL.Path, req.URL.RawPath = joinURLPath(target, req.URL)
+	if targetQuery == "" || req.URL.RawQuery == "" {
+		req.URL.RawQuery = targetQuery + req.URL.RawQuery
+	} else {
+		req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
+	}
+}
+
+// Hop-by-hop headers. These are removed when sent to the backend.
+// As of RFC 7230, hop-by-hop headers are required to appear in the
+// Connection header field. These are the headers defined by the
+// obsoleted RFC 2616 (section 13.5.1) and are used for backward
+// compatibility.
+var hopHeaders = []string{
+	"Connection",
+	"Proxy-Connection", // non-standard but still sent by libcurl and rejected by e.g. google
+	"Keep-Alive",
+	"Proxy-Authenticate",
+	"Proxy-Authorization",
+	"Te",      // canonicalized version of "TE"
+	"Trailer", // not Trailers per URL above; https://www.rfc-editor.org/errata_search.php?eid=4522
+	"Transfer-Encoding",
+	"Upgrade",
+}
+
+func copyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
+func (p *ReverseProxy) errorHandler(rw http.ResponseWriter, r *http.Request, err error, writeHeader bool) {
+	logger.Errorf("http proxy to %s failed: %s", r.URL.String(), err)
+	if writeHeader {
+		rw.WriteHeader(http.StatusBadGateway)
+	}
+}
+
+// modifyResponse conditionally runs the optional ModifyResponse hook
+// and reports whether the request should proceed.
+func (p *ReverseProxy) modifyResponse(rw http.ResponseWriter, res *http.Response, req *http.Request) bool {
+	if p.ModifyResponse == nil {
+		return true
+	}
+	if err := p.ModifyResponse(res); err != nil {
+		res.Body.Close()
+		p.errorHandler(rw, req, err, true)
+		return false
+	}
+	return true
+}
+
+func (p *ReverseProxy) serveHTTP(rw http.ResponseWriter, req *http.Request) {
+	transport := p.Transport
+
+	ctx := req.Context()
+	if ctx.Done() != nil {
+		// CloseNotifier predates context.Context, and has been
+		// entirely superseded by it. If the request contains
+		// a Context that carries a cancellation signal, don't
+		// bother spinning up a goroutine to watch the CloseNotify
+		// channel (if any).
+		//
+		// If the request Context has a nil Done channel (which
+		// means it is either context.Background, or a custom
+		// Context implementation with no cancellation signal),
+		// then consult the CloseNotifier if available.
+	} else if cn, ok := rw.(http.CloseNotifier); ok {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithCancel(ctx)
+		defer cancel()
+		notifyChan := cn.CloseNotify()
+		go func() {
+			select {
+			case <-notifyChan:
+				cancel()
+			case <-ctx.Done():
+			}
+		}()
+	}
+
+	outreq := req.Clone(ctx)
+	if req.ContentLength == 0 {
+		outreq.Body = nil // Issue 16036: nil Body for http.Transport retries
+	}
+	if outreq.Body != nil {
+		// Reading from the request body after returning from a handler is not
+		// allowed, and the RoundTrip goroutine that reads the Body can outlive
+		// this handler. This can lead to a crash if the handler panics (see
+		// Issue 46866). Although calling Close doesn't guarantee there isn't
+		// any Read in flight after the handle returns, in practice it's safe to
+		// read after closing it.
+		defer outreq.Body.Close()
+	}
+	if outreq.Header == nil {
+		outreq.Header = make(http.Header) // Issue 33142: historical behavior was to always allocate
+	}
+
+	outreq.Close = false
+
+	reqUpType := UpgradeType(outreq.Header)
+	if !IsPrint(reqUpType) {
+		p.errorHandler(rw, req, fmt.Errorf("client tried to switch to invalid protocol %q", reqUpType), true)
+		return
+	}
+
+	RemoveHopByHopHeaders(outreq.Header)
+
+	// Issue 21096: tell backend applications that care about trailer support
+	// that we support trailers. (We do, but we don't go out of our way to
+	// advertise that unless the incoming client request thought it was worth
+	// mentioning.) Note that we look at req.Header, not outreq.Header, since
+	// the latter has passed through removeHopByHopHeaders.
+	if httpguts.HeaderValuesContainsToken(req.Header["Te"], "trailers") {
+		outreq.Header.Set("Te", "trailers")
+	}
+
+	// After stripping all the hop-by-hop connection headers above, add back any
+	// necessary for protocol upgrades, such as for websockets.
+	if reqUpType != "" {
+		outreq.Header.Set("Connection", "Upgrade")
+		outreq.Header.Set("Upgrade", reqUpType)
+	}
+
+	outreq.Header.Del("Forwarded")
+	// outreq.Header.Del("X-Forwarded-For")
+	// outreq.Header.Del("X-Forwarded-Host")
+	// outreq.Header.Del("X-Forwarded-Proto")
+
+	pr := &ProxyRequest{
+		In:  req,
+		Out: outreq,
+	}
+	p.Rewrite(pr)
+	outreq = pr.Out
+
+	if _, ok := outreq.Header["User-Agent"]; !ok {
+		// If the outbound request doesn't have a User-Agent header set,
+		// don't send the default Go HTTP client User-Agent.
+		outreq.Header.Set("User-Agent", "")
+	}
+
+	trace := &httptrace.ClientTrace{
+		Got1xxResponse: func(code int, header textproto.MIMEHeader) error {
+			h := rw.Header()
+			// copyHeader(h, http.Header(header))
+			for k, vv := range header {
+				for _, v := range vv {
+					h.Add(k, v)
+				}
+			}
+			rw.WriteHeader(code)
+
+			// Clear headers, it's not automatically done by ResponseWriter.WriteHeader() for 1xx responses
+			clear(h)
+			return nil
+		},
+	}
+	outreq = outreq.WithContext(httptrace.WithClientTrace(outreq.Context(), trace))
+
+	res, err := transport.RoundTrip(outreq)
+	if err != nil {
+		p.errorHandler(rw, outreq, err, false)
+		errMsg := err.Error()
+		res = &http.Response{
+			Status:        http.StatusText(http.StatusBadGateway),
+			StatusCode:    http.StatusBadGateway,
+			Proto:         outreq.Proto,
+			ProtoMajor:    outreq.ProtoMajor,
+			ProtoMinor:    outreq.ProtoMinor,
+			Header:        make(http.Header),
+			Body:          io.NopCloser(bytes.NewReader([]byte(errMsg))),
+			Request:       outreq,
+			ContentLength: int64(len(errMsg)),
+			TLS:           outreq.TLS,
+		}
+	}
+
+	// Deal with 101 Switching Protocols responses: (WebSocket, h2c, etc)
+	if res.StatusCode == http.StatusSwitchingProtocols {
+		if !p.modifyResponse(rw, res, outreq) {
+			return
+		}
+		p.handleUpgradeResponse(rw, outreq, res)
+		return
+	}
+
+	if !p.modifyResponse(rw, res, outreq) {
+		return
+	}
+
+	copyHeader(rw.Header(), res.Header)
+
+	// The "Trailer" header isn't included in the Transport's response,
+	// at least for *http.Transport. Build it up from Trailer.
+	announcedTrailers := len(res.Trailer)
+	if announcedTrailers > 0 {
+		trailerKeys := make([]string, 0, len(res.Trailer))
+		for k := range res.Trailer {
+			trailerKeys = append(trailerKeys, k)
+		}
+		rw.Header().Add("Trailer", strings.Join(trailerKeys, ", "))
+	}
+
+	rw.WriteHeader(res.StatusCode)
+
+	_, err = io.Copy(rw, res.Body)
+	if err != nil {
+		p.errorHandler(rw, req, err, true)
+		res.Body.Close()
+		return
+	}
+	res.Body.Close() // close now, instead of defer, to populate res.Trailer
+
+	if len(res.Trailer) > 0 {
+		// Force chunking if we saw a response trailer.
+		// This prevents net/http from calculating the length for short
+		// bodies and adding a Content-Length.
+		http.NewResponseController(rw).Flush()
+	}
+
+	if len(res.Trailer) == announcedTrailers {
+		copyHeader(rw.Header(), res.Trailer)
+		return
+	}
+
+	for k, vv := range res.Trailer {
+		k = http.TrailerPrefix + k
+		for _, v := range vv {
+			rw.Header().Add(k, v)
+		}
+	}
+}
+
+func UpgradeType(h http.Header) string {
+	if !httpguts.HeaderValuesContainsToken(h["Connection"], "Upgrade") {
+		return ""
+	}
+	return h.Get("Upgrade")
+}
+
+// RemoveHopByHopHeaders removes hop-by-hop headers.
+func RemoveHopByHopHeaders(h http.Header) {
+	// RFC 7230, section 6.1: Remove headers listed in the "Connection" header.
+	for _, f := range h["Connection"] {
+		for _, sf := range strings.Split(f, ",") {
+			if sf = textproto.TrimString(sf); sf != "" {
+				h.Del(sf)
+			}
+		}
+	}
+	// RFC 2616, section 13.5.1: Remove a set of known hop-by-hop headers.
+	// This behavior is superseded by the RFC 7230 Connection header, but
+	// preserve it for backwards compatibility.
+	for _, f := range hopHeaders {
+		h.Del(f)
+	}
+}
+
+func (p *ReverseProxy) handleUpgradeResponse(rw http.ResponseWriter, req *http.Request, res *http.Response) {
+	reqUpType := UpgradeType(req.Header)
+	resUpType := UpgradeType(res.Header)
+	if !IsPrint(resUpType) { // We know reqUpType is ASCII, it's checked by the caller.
+		p.errorHandler(rw, req, fmt.Errorf("backend tried to switch to invalid protocol %q", resUpType), true)
+	}
+	if !strings.EqualFold(reqUpType, resUpType) {
+		p.errorHandler(rw, req, fmt.Errorf("backend tried to switch protocol %q when %q was requested", resUpType, reqUpType), true)
+		return
+	}
+
+	backConn, ok := res.Body.(io.ReadWriteCloser)
+	if !ok {
+		p.errorHandler(rw, req, fmt.Errorf("internal error: 101 switching protocols response with non-writable body"), true)
+		return
+	}
+
+	rc := http.NewResponseController(rw)
+	conn, brw, hijackErr := rc.Hijack()
+	if errors.Is(hijackErr, http.ErrNotSupported) {
+		p.errorHandler(rw, req, fmt.Errorf("can't switch protocols using non-Hijacker ResponseWriter type %T", rw), true)
+		return
+	}
+
+	backConnCloseCh := make(chan bool)
+	go func() {
+		// Ensure that the cancellation of a request closes the backend.
+		// See issue https://golang.org/issue/35559.
+		select {
+		case <-req.Context().Done():
+		case <-backConnCloseCh:
+		}
+		backConn.Close()
+	}()
+	defer close(backConnCloseCh)
+
+	if hijackErr != nil {
+		p.errorHandler(rw, req, fmt.Errorf("hijack failed on protocol switch: %w", hijackErr), true)
+		return
+	}
+	defer conn.Close()
+
+	copyHeader(rw.Header(), res.Header)
+
+	res.Header = rw.Header()
+	res.Body = nil // so res.Write only writes the headers; we have res.Body in backConn above
+	if err := res.Write(brw); err != nil {
+		p.errorHandler(rw, req, fmt.Errorf("response write: %s", err), true)
+		return
+	}
+	if err := brw.Flush(); err != nil {
+		p.errorHandler(rw, req, fmt.Errorf("response flush: %s", err), true)
+		return
+	}
+	errc := make(chan error, 1)
+
+	go func() {
+		_, err := io.Copy(conn, backConn)
+		errc <- err
+	}()
+	go func() {
+		_, err := io.Copy(backConn, conn)
+		errc <- err
+	}()
+	<-errc
+}
+
+func IsPrint(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] < ' ' || s[i] > '~' {
+			return false
+		}
+	}
+	return true
+}
+
+var logger = logrus.WithField("module", "http")

internal/http/status_code.go

@@ -0,0 +1,7 @@
+package http
+
+import "net/http"
+
+func IsSuccess(status int) bool {
+	return status >= http.StatusOK && status < http.StatusMultipleChoices
+}