Implement debugging feature (#43)

Author: sunshineplan

debug.go

@@ -0,0 +1,43 @@
+package gohttp
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httputil"
+	"regexp"
+)
+
+type debugger struct {
+	rt       http.RoundTripper
+	w        io.Writer
+	reqBody  bool
+	respBody bool
+}
+
+func (t *debugger) RoundTrip(req *http.Request) (*http.Response, error) {
+	if t.rt == nil {
+		t.rt = http.DefaultTransport
+	}
+	reqBody, err := httputil.DumpRequestOut(req, t.reqBody)
+	if err != nil {
+		return nil, err
+	}
+	res, err := t.rt.RoundTrip(req)
+	if err != nil {
+		return nil, err
+	}
+	respBody, err := httputil.DumpResponse(res, t.respBody)
+	if err != nil {
+		return nil, err
+	}
+	t.Write("-> ", reqBody)
+	t.Write("<- ", respBody)
+	return res, nil
+}
+
+var lineStart = regexp.MustCompile(`(?m)^`)
+
+func (w *debugger) Write(prefix string, buf []byte) {
+	w.w.Write(append(lineStart.ReplaceAll(bytes.TrimSpace(buf), []byte(prefix)), '\n', '\n'))
+}

gohttp.go

@@ -2,6 +2,7 @@ package gohttp
 
 import (
 	"context"
+	"io"
 	"net/http"
 	"time"
 )
@@ -30,6 +31,10 @@ func SetAgent(agent string) {
 	}
 }
 
+func SetDebug(w io.Writer, reqBody, respBody bool) {
+	defaultSession.SetDebug(w, reqBody, respBody)
+}
+
 // SetProxy sets default client transport proxy.
 func SetProxy(proxy string) error {
 	return defaultSession.SetProxy(proxy)

session.go

@@ -1,6 +1,7 @@
 package gohttp
 
 import (
+	"io"
 	"net/http"
 	"net/http/cookiejar"
 	"net/url"
@@ -28,21 +29,32 @@ func NewSession() *Session {
 	return newSession(c)
 }
 
+func (s *Session) SetDebug(w io.Writer, reqBody, respBody bool) {
+	if w != nil {
+		s.client.Transport = &debugger{s.client.Transport, w, reqBody, respBody}
+	} else if t, ok := s.client.Transport.(*debugger); ok {
+		s.client.Transport = t.rt
+	}
+}
+
 func (s *Session) setProxy(fn func(*http.Request) (*url.URL, error)) {
-	var tr *http.Transport
-	var ok bool
 	if s.client.Transport == nil {
-		if tr, ok = http.DefaultTransport.(*http.Transport); ok {
-			tr.Proxy = fn
+		if t, ok := http.DefaultTransport.(*http.Transport); ok {
+			t.Proxy = fn
+			return
 		}
 	} else {
-		if tr, ok = s.client.Transport.(*http.Transport); ok {
-			tr.Proxy = fn
+		if t, ok := s.client.Transport.(*http.Transport); ok {
+			t.Proxy = fn
+			return
+		} else if t, ok := s.client.Transport.(*debugger); ok {
+			if t, ok := t.rt.(*http.Transport); ok {
+				t.Proxy = fn
+				return
+			}
 		}
 	}
-	if !ok {
-		panic("Transport is not *http.Transport type")
-	}
+	panic("Transport is not *http.Transport type")
 }
 
 // SetProxy sets Session client transport proxy.

session_test.go

@@ -25,6 +25,7 @@ func TestSession(t *testing.T) {
 	tsURL, _ := url.Parse(ts.URL)
 
 	s := NewSession()
+	s.SetDebug(os.Stdout, true, true)
 	s.Header.Set("hello", "world")
 	s.SetCookie(tsURL, "one", "first")
 	s.SetCookie(tsURL, "two", "second")