mirror of https://github.com/coder/coder.git
92 lines
1.9 KiB
Go
92 lines
1.9 KiB
Go
package tracing
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import (
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"bufio"
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"net"
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"net/http"
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"golang.org/x/xerrors"
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)
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var (
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_ http.ResponseWriter = (*StatusWriter)(nil)
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_ http.Hijacker = (*StatusWriter)(nil)
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)
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// StatusWriter intercepts the status of the request and the response body up
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// to maxBodySize if Status >= 400. It is guaranteed to be the ResponseWriter
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// directly downstream from Middleware.
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type StatusWriter struct {
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http.ResponseWriter
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Status int
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Hijacked bool
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responseBody []byte
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wroteHeader bool
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}
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func StatusWriterMiddleware(next http.Handler) http.Handler {
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return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
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sw := &StatusWriter{ResponseWriter: rw}
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next.ServeHTTP(sw, r)
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})
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}
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func (w *StatusWriter) WriteHeader(status int) {
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if !w.wroteHeader {
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w.Status = status
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w.wroteHeader = true
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}
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w.ResponseWriter.WriteHeader(status)
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}
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func (w *StatusWriter) Write(b []byte) (int, error) {
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const maxBodySize = 4096
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if !w.wroteHeader {
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w.Status = http.StatusOK
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w.wroteHeader = true
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}
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if w.Status >= http.StatusBadRequest {
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// This is technically wrong as multiple calls to write
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// will simply overwrite w.ResponseBody but given that
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// we typically only write to the response body once
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// and this field is only used for logging I'm leaving
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// this as-is.
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w.responseBody = make([]byte, minInt(len(b), maxBodySize))
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copy(w.responseBody, b)
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}
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return w.ResponseWriter.Write(b)
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}
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func minInt(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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func (w *StatusWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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hijacker, ok := w.ResponseWriter.(http.Hijacker)
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if !ok {
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return nil, nil, xerrors.Errorf("%T is not a http.Hijacker", w.ResponseWriter)
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}
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w.Hijacked = true
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return hijacker.Hijack()
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}
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func (w *StatusWriter) ResponseBody() []byte {
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return w.responseBody
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}
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func (w *StatusWriter) Flush() {
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f, ok := w.ResponseWriter.(http.Flusher)
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if !ok {
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panic("http.ResponseWriter is not http.Flusher")
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}
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f.Flush()
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}
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