initial commit

httpdebug.go

@@ -0,0 +1,82 @@
+package httpdebug
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"unicode"
+)
+
+// Wrap returns an http handler that serves h while logging requests and responses to stderr.
+func Wrap(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		log.Println(r.Method, r.URL.Path, r.Proto)
+
+		hBuf := &bytes.Buffer{}
+		r.Header.Write(hBuf)
+		log.Println(hBuf.String())
+
+		requestBuf := &bytes.Buffer{}
+		responseBuf := &bytes.Buffer{}
+
+		defer r.Body.Close()
+
+		r.Body = ioutil.NopCloser(io.TeeReader(r.Body, requestBuf))
+
+		h.ServeHTTP(rw{
+			ResponseWriter: w,
+			w:              responseBuf,
+		}, r)
+
+		if requestBuf.Len() > 1024 {
+			trimmed := &bytes.Buffer{}
+			io.CopyN(trimmed, requestBuf, 128)
+			requestBuf = trimmed
+		}
+
+		log.Println()
+		log.Println(logsafe(requestBuf.String()))
+
+		hBuf.Reset()
+		w.Header().Write(hBuf)
+		log.Println(hBuf.String())
+
+		responseBuf = trim(responseBuf, 128)
+
+		log.Println()
+		log.Println(logsafe(responseBuf.String()))
+	})
+}
+
+type rw struct {
+	http.ResponseWriter
+	w io.Writer
+}
+
+func (rw rw) Write(b []byte) (int, error) {
+	rw.w.Write(b)
+	return rw.ResponseWriter.Write(b)
+}
+
+func logsafe(str string) string {
+	buf := &bytes.Buffer{}
+
+	for _, r := range str {
+		if unicode.IsPrint(r) || unicode.IsSpace(r) {
+			fmt.Fprintf(buf, "%c", r)
+		} else {
+			fmt.Fprintf(buf, "%x", r)
+		}
+	}
+
+	return buf.String()
+}
+
+func trim(b *bytes.Buffer, n int) *bytes.Buffer {
+	trimmed := &bytes.Buffer{}
+	io.CopyN(trimmed, b, int64(n))
+	return trimmed
+}