101 lines
2.1 KiB
Go
101 lines
2.1 KiB
Go
// Copyright (c) 2013, Prometheus Team
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license that can be found in
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// the LICENSE file.
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package exp
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import (
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"fmt"
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"net/http"
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"reflect"
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"strconv"
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)
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const (
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unknownStatusCode = "unknown"
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statusFieldName = "status"
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)
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type status string
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func (s status) unknown() bool {
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return len(s) == 0
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}
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func (s status) String() string {
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if s.unknown() {
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return unknownStatusCode
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}
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return string(s)
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}
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func computeApproximateRequestSize(r http.Request) (s int) {
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s += len(r.Method)
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if r.URL != nil {
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s += len(r.URL.String())
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}
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s += len(r.Proto)
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for name, values := range r.Header {
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s += len(name)
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for _, value := range values {
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s += len(value)
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}
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}
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s += len(r.Host)
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// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
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if r.ContentLength != -1 {
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s += int(r.ContentLength)
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}
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return
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}
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// ResponseWriterDelegator is a means of wrapping http.ResponseWriter to divine
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// the response code from a given answer, especially in systems where the
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// response is treated as a blackbox.
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type ResponseWriterDelegator struct {
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http.ResponseWriter
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status status
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BytesWritten int
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}
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func (r ResponseWriterDelegator) String() string {
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return fmt.Sprintf("ResponseWriterDelegator decorating %s with status %s and %d bytes written.", r.ResponseWriter, r.status, r.BytesWritten)
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}
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func (r *ResponseWriterDelegator) WriteHeader(code int) {
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r.status = status(strconv.Itoa(code))
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r.ResponseWriter.WriteHeader(code)
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}
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func (r *ResponseWriterDelegator) Status() string {
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if r.status.unknown() {
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delegate := reflect.ValueOf(r.ResponseWriter).Elem()
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statusField := delegate.FieldByName(statusFieldName)
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if statusField.IsValid() {
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r.status = status(strconv.Itoa(int(statusField.Int())))
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}
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}
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return r.status.String()
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}
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func (r *ResponseWriterDelegator) Write(b []byte) (n int, err error) {
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n, err = r.ResponseWriter.Write(b)
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r.BytesWritten += n
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return
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}
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func NewResponseWriterDelegator(delegate http.ResponseWriter) *ResponseWriterDelegator {
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return &ResponseWriterDelegator{
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ResponseWriter: delegate,
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}
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}
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