From 854839daf8b6f4b694f803fc2828fb35d856d2e3 Mon Sep 17 00:00:00 2001 From: David Stotijn Date: Sun, 27 Sep 2020 14:59:22 +0200 Subject: [PATCH] Remove stray file --- pkg/proxy/reverseproxy.go | 611 -------------------------------------- 1 file changed, 611 deletions(-) delete mode 100644 pkg/proxy/reverseproxy.go diff --git a/pkg/proxy/reverseproxy.go b/pkg/proxy/reverseproxy.go deleted file mode 100644 index a53b023..0000000 --- a/pkg/proxy/reverseproxy.go +++ /dev/null @@ -1,611 +0,0 @@ -// Copyright 2011 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// HTTP reverse proxy handler - -package proxy - -import ( - "context" - "fmt" - "io" - "log" - "net" - "net/http" - "net/textproto" - "net/url" - "strings" - "sync" - "time" - - "golang.org/x/net/http/httpguts" -) - -// ReverseProxy is an HTTP Handler that takes an incoming request and -// sends it to another server, proxying the response back to the -// client. -// -// ReverseProxy by default sets the client IP as the value of the -// X-Forwarded-For header. -// -// If an X-Forwarded-For header already exists, the client IP is -// appended to the existing values. As a special case, if the header -// exists in the Request.Header map but has a nil value (such as when -// set by the Director func), the X-Forwarded-For header is -// not modified. -// -// To prevent IP spoofing, be sure to delete any pre-existing -// X-Forwarded-For header coming from the client or -// an untrusted proxy. -type ReverseProxy struct { - // Director 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. - // Director must not access the provided Request - // after returning. - Director func(*http.Request) - - // The transport used to perform proxy requests. - // If nil, http.DefaultTransport is used. - Transport http.RoundTripper - - // FlushInterval specifies the flush interval - // to flush to the client while copying the - // response body. - // If zero, no periodic flushing is done. - // A negative value means to flush immediately - // after each write to the client. - // The FlushInterval is ignored when ReverseProxy - // recognizes a response as a streaming response; - // for such responses, writes are flushed to the client - // immediately. - FlushInterval time.Duration - - // ErrorLog specifies an optional logger for errors - // that occur when attempting to proxy the request. - // If nil, logging is done via the log package's standard logger. - ErrorLog *log.Logger - - // BufferPool optionally specifies a buffer pool to - // get byte slices for use by io.CopyBuffer when - // copying HTTP response bodies. - BufferPool BufferPool - - // 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 without any call to 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 - - // ErrorHandler is an optional function that handles errors - // reaching the backend or errors from ModifyResponse. - // - // If nil, the default is to log the provided error and return - // a 502 Status Bad Gateway response. - ErrorHandler func(http.ResponseWriter, *http.Request, error) -} - -// 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 -} - -// NewSingleHostReverseProxy 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. -// NewSingleHostReverseProxy does not rewrite the Host header. -// To rewrite Host headers, use ReverseProxy directly with a custom -// Director policy. -func NewSingleHostReverseProxy(target *url.URL) *ReverseProxy { - targetQuery := target.RawQuery - director := func(req *http.Request) { - 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 - } - if _, ok := req.Header["User-Agent"]; !ok { - // explicitly disable User-Agent so it's not set to default value - req.Header.Set("User-Agent", "") - } - } - return &ReverseProxy{Director: director} -} - -func copyHeader(dst, src http.Header) { - for k, vv := range src { - for _, v := range vv { - dst.Add(k, v) - } - } -} - -// 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 (p *ReverseProxy) defaultErrorHandler(rw http.ResponseWriter, req *http.Request, err error) { - p.logf("http: proxy error: %v", err) - rw.WriteHeader(http.StatusBadGateway) -} - -func (p *ReverseProxy) getErrorHandler() func(http.ResponseWriter, *http.Request, error) { - if p.ErrorHandler != nil { - return p.ErrorHandler - } - return p.defaultErrorHandler -} - -// 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.getErrorHandler()(rw, req, err) - return false - } - return true -} - -func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) { - transport := p.Transport - if transport == nil { - transport = http.DefaultTransport - } - - ctx := req.Context() - 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.Header == nil { - outreq.Header = make(http.Header) // Issue 33142: historical behavior was to always allocate - } - - p.Director(outreq) - outreq.Close = false - - reqUpType := upgradeType(outreq.Header) - removeConnectionHeaders(outreq.Header) - - // Remove hop-by-hop headers to the backend. Especially - // important is "Connection" because we want a persistent - // connection, regardless of what the client sent to us. - for _, h := range hopHeaders { - hv := outreq.Header.Get(h) - if hv == "" { - continue - } - if h == "Te" && hv == "trailers" { - // 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) - continue - } - outreq.Header.Del(h) - } - - // 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) - } - - if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil { - // If we aren't the first proxy retain prior - // X-Forwarded-For information as a comma+space - // separated list and fold multiple headers into one. - prior, ok := outreq.Header["X-Forwarded-For"] - omit := ok && prior == nil // Issue 38079: nil now means don't populate the header - if len(prior) > 0 { - clientIP = strings.Join(prior, ", ") + ", " + clientIP - } - if !omit { - outreq.Header.Set("X-Forwarded-For", clientIP) - } - } - - res, err := transport.RoundTrip(outreq) - if err != nil { - p.getErrorHandler()(rw, outreq, err) - return - } - - // 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 - } - - removeConnectionHeaders(res.Header) - - for _, h := range hopHeaders { - res.Header.Del(h) - } - - 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 = p.copyResponse(rw, res.Body, p.flushInterval(req, res)) - if err != nil { - defer res.Body.Close() - // Since we're streaming the response, if we run into an error all we can do - // is abort the request. Issue 23643: ReverseProxy should use ErrAbortHandler - // on read error while copying body. - if !shouldPanicOnCopyError(req) { - p.logf("suppressing panic for copyResponse error in test; copy error: %v", err) - return - } - panic(http.ErrAbortHandler) - } - 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. - if fl, ok := rw.(http.Flusher); ok { - fl.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) - } - } -} - -var inOurTests bool // whether we're in our own tests - -// shouldPanicOnCopyError reports whether the reverse proxy should -// panic with http.ErrAbortHandler. This is the right thing to do by -// default, but Go 1.10 and earlier did not, so existing unit tests -// weren't expecting panics. Only panic in our own tests, or when -// running under the HTTP server. -func shouldPanicOnCopyError(req *http.Request) bool { - if inOurTests { - // Our tests know to handle this panic. - return true - } - if req.Context().Value(http.ServerContextKey) != nil { - // We seem to be running under an HTTP server, so - // it'll recover the panic. - return true - } - // Otherwise act like Go 1.10 and earlier to not break - // existing tests. - return false -} - -// removeConnectionHeaders removes hop-by-hop headers listed in the "Connection" header of h. -// See RFC 7230, section 6.1 -func removeConnectionHeaders(h http.Header) { - for _, f := range h["Connection"] { - for _, sf := range strings.Split(f, ",") { - if sf = textproto.TrimString(sf); sf != "" { - h.Del(sf) - } - } - } -} - -// flushInterval returns the p.FlushInterval value, conditionally -// overriding its value for a specific request/response. -func (p *ReverseProxy) flushInterval(req *http.Request, res *http.Response) time.Duration { - resCT := res.Header.Get("Content-Type") - - // For Server-Sent Events responses, flush immediately. - // The MIME type is defined in https://www.w3.org/TR/eventsource/#text-event-stream - if resCT == "text/event-stream" { - return -1 // negative means immediately - } - - // TODO: more specific cases? e.g. res.ContentLength == -1? - return p.FlushInterval -} - -func (p *ReverseProxy) copyResponse(dst io.Writer, src io.Reader, flushInterval time.Duration) error { - if flushInterval != 0 { - if wf, ok := dst.(writeFlusher); ok { - mlw := &maxLatencyWriter{ - dst: wf, - latency: flushInterval, - } - defer mlw.stop() - - // set up initial timer so headers get flushed even if body writes are delayed - mlw.flushPending = true - mlw.t = time.AfterFunc(flushInterval, mlw.delayedFlush) - - dst = mlw - } - } - - var buf []byte - if p.BufferPool != nil { - buf = p.BufferPool.Get() - defer p.BufferPool.Put(buf) - } - _, err := p.copyBuffer(dst, src, buf) - return err -} - -// copyBuffer returns any write errors or non-EOF read errors, and the amount -// of bytes written. -func (p *ReverseProxy) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (int64, error) { - if len(buf) == 0 { - buf = make([]byte, 32*1024) - } - var written int64 - for { - nr, rerr := src.Read(buf) - if rerr != nil && rerr != io.EOF && rerr != context.Canceled { - p.logf("httputil: ReverseProxy read error during body copy: %v", rerr) - } - if nr > 0 { - nw, werr := dst.Write(buf[:nr]) - if nw > 0 { - written += int64(nw) - } - if werr != nil { - return written, werr - } - if nr != nw { - return written, io.ErrShortWrite - } - } - if rerr != nil { - if rerr == io.EOF { - rerr = nil - } - return written, rerr - } - } -} - -func (p *ReverseProxy) logf(format string, args ...interface{}) { - if p.ErrorLog != nil { - p.ErrorLog.Printf(format, args...) - } else { - log.Printf(format, args...) - } -} - -type writeFlusher interface { - io.Writer - http.Flusher -} - -type maxLatencyWriter struct { - dst writeFlusher - latency time.Duration // non-zero; negative means to flush immediately - - mu sync.Mutex // protects t, flushPending, and dst.Flush - t *time.Timer - flushPending bool -} - -func (m *maxLatencyWriter) Write(p []byte) (n int, err error) { - m.mu.Lock() - defer m.mu.Unlock() - n, err = m.dst.Write(p) - if m.latency < 0 { - m.dst.Flush() - return - } - if m.flushPending { - return - } - if m.t == nil { - m.t = time.AfterFunc(m.latency, m.delayedFlush) - } else { - m.t.Reset(m.latency) - } - m.flushPending = true - return -} - -func (m *maxLatencyWriter) delayedFlush() { - m.mu.Lock() - defer m.mu.Unlock() - if !m.flushPending { // if stop was called but AfterFunc already started this goroutine - return - } - m.dst.Flush() - m.flushPending = false -} - -func (m *maxLatencyWriter) stop() { - m.mu.Lock() - defer m.mu.Unlock() - m.flushPending = false - if m.t != nil { - m.t.Stop() - } -} - -func upgradeType(h http.Header) string { - if !httpguts.HeaderValuesContainsToken(h["Connection"], "Upgrade") { - return "" - } - return strings.ToLower(h.Get("Upgrade")) -} - -func (p *ReverseProxy) handleUpgradeResponse(rw http.ResponseWriter, req *http.Request, res *http.Response) { - reqUpType := upgradeType(req.Header) - resUpType := upgradeType(res.Header) - if reqUpType != resUpType { - p.getErrorHandler()(rw, req, fmt.Errorf("backend tried to switch protocol %q when %q was requested", resUpType, reqUpType)) - return - } - - copyHeader(res.Header, rw.Header()) - - hj, ok := rw.(http.Hijacker) - if !ok { - p.getErrorHandler()(rw, req, fmt.Errorf("can't switch protocols using non-Hijacker ResponseWriter type %T", rw)) - return - } - backConn, ok := res.Body.(io.ReadWriteCloser) - if !ok { - p.getErrorHandler()(rw, req, fmt.Errorf("internal error: 101 switching protocols response with non-writable body")) - return - } - - backConnCloseCh := make(chan bool) - go func() { - // Ensure that the cancelation 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) - - conn, brw, err := hj.Hijack() - if err != nil { - p.getErrorHandler()(rw, req, fmt.Errorf("Hijack failed on protocol switch: %v", err)) - return - } - defer conn.Close() - 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.getErrorHandler()(rw, req, fmt.Errorf("response write: %v", err)) - return - } - if err := brw.Flush(); err != nil { - p.getErrorHandler()(rw, req, fmt.Errorf("response flush: %v", err)) - return - } - errc := make(chan error, 1) - spc := switchProtocolCopier{user: conn, backend: backConn} - go spc.copyToBackend(errc) - go spc.copyFromBackend(errc) - <-errc - return -} - -// switchProtocolCopier exists so goroutines proxying data back and -// forth have nice names in stacks. -type switchProtocolCopier struct { - user, backend io.ReadWriter -} - -func (c switchProtocolCopier) copyFromBackend(errc chan<- error) { - _, err := io.Copy(c.user, c.backend) - errc <- err -} - -func (c switchProtocolCopier) copyToBackend(errc chan<- error) { - _, err := io.Copy(c.backend, c.user) - errc <- err -}