Support body rewrite

config/config.go

@@ -87,16 +87,21 @@ func GetTimeout() int {
 	return timeout
 }
 
-func GetRewrites() map[string]string {
+func GetRewrites(hostMatch string) map[string]string {
 	v := packable.NewString()
 	conf.Get(nsConf, flagRewrites, v)
 	m := make(map[string]string)
 	for _, v := range strings.Split(v.String(), ",") {
-		if len(v) == 0 {
-			return m
+		vs := strings.Split(v, ":")
+		if len(v) < 3 {
+			continue
 		}
-		from := v[:strings.Index(v, ":")]
-		to := v[strings.Index(v, ":")+1:]
+		host := vs[0]
+		if host != hostMatch {
+			continue
+		}
+		from := vs[1]
+		to := strings.Join(vs[2:], ":")
 		m[from] = to
 	}
 	return m

config/new.go

@@ -47,6 +47,7 @@ type fileConf struct {
 
 func Init() error {
 	log.SetFlags(log.Ldate | log.Ltime | log.Llongfile)
+	log.SetFlags(log.Ltime | log.Lshortfile)
 	if err := fromFile(); err != nil {
 		return err
 	}
@@ -120,7 +121,7 @@ func fromFlags() error {
 	binds = append(binds, addFlag(flagRate, "100", "rate limit per second"))
 	binds = append(binds, addFlag(flagBurst, "100", "rate limit burst"))
 	binds = append(binds, addFlag(flagTimeout, "30", "seconds to wait for limiter"))
-	binds = append(binds, addFlag(flagRewrites, "", "comma-separated regex:v to rewrite in response bodies"))
+	binds = append(binds, addFlag(flagRewrites, "", "comma-separated from:replace:replacement to rewrite in response bodies"))
 	flag.Parse()
 
 	for _, bind := range binds {

server/proxy.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"bytes"
 	"io"
 	"local/rproxy3/config"
 	"local/rproxy3/storage/packable"
@@ -23,7 +24,7 @@ type rewrite struct {
 }
 
 func (s *Server) Proxy(w http.ResponseWriter, r *http.Request) {
-	newURL, err := s.lookup(r.Host)
+	newURL, err := s.lookup(mapKey(r.Host))
 	var transport http.RoundTripper
 	transport = &redirPurge{
 		proxyHost:     r.Host,
@@ -31,7 +32,7 @@ func (s *Server) Proxy(w http.ResponseWriter, r *http.Request) {
 		baseTransport: http.DefaultTransport,
 	}
 	transport = &rewrite{
-		rewrites:      config.GetRewrites(),
+		rewrites:      config.GetRewrites(mapKey(r.Host)),
 		baseTransport: transport,
 	}
 	if err != nil {
@@ -46,13 +47,17 @@ func (s *Server) Proxy(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *Server) lookup(host string) (*url.URL, error) {
-	host = strings.Split(host, ".")[0]
-	host = strings.Split(host, ":")[0]
 	v := packable.NewURL()
 	err := s.db.Get(nsRouting, host, v)
 	return v.URL(), err
 }
 
+func mapKey(host string) string {
+	host = strings.Split(host, ".")[0]
+	host = strings.Split(host, ":")[0]
+	return host
+}
+
 func (rp *redirPurge) RoundTrip(r *http.Request) (*http.Response, error) {
 	resp, err := rp.baseTransport.RoundTrip(r)
 	if err != nil {
@@ -69,13 +74,22 @@ func (rw *rewrite) RoundTrip(r *http.Request) (*http.Response, error) {
 	if err != nil {
 		return resp, err
 	}
+	if len(rw.rewrites) == 0 {
+		return resp, err
+	}
+	resp.Header.Del("Content-Length")
 	pr, pw := io.Pipe()
 	body := resp.Body
 	resp.Body = pr
 	go func() {
 		buff := make([]byte, 1024)
-		for n, err := body.Read(buff); err == nil || n > 0; n, err = body.Read(buff) {
+		n, err := body.Read(buff)
+		for err == nil || n > 0 {
 			chunk := buff[:n]
+			for k, v := range rw.rewrites {
+				chunk = bytes.Replace(chunk, []byte(k), []byte(v), -1)
+			}
+			n = len(chunk)
 			m := 0
 			for m < n {
 				l, err := pw.Write(chunk[m:])
@@ -85,6 +99,7 @@ func (rw *rewrite) RoundTrip(r *http.Request) (*http.Response, error) {
 				}
 				m += l
 			}
+			n, err = body.Read(buff)
 		}
 		pw.CloseWithError(err)
 	}()

server/proxy_test.go

@@ -1,3 +1,42 @@
 package server
 
+import (
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+type fakeTransport struct{}
+
+func (ft fakeTransport) RoundTrip(r *http.Request) (*http.Response, error) {
+	return &http.Response{
+		Body: r.Body,
+	}, nil
+}
+
 // empty url -> OK   //TODO
+func TestRewrite(t *testing.T) {
+	transport := &rewrite{
+		rewrites: map[string]string{
+			"a": "b",
+		},
+		baseTransport: fakeTransport{},
+	}
+
+	r, err := http.NewRequest("GET", "asdf", strings.NewReader("mary had a little lamb"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	resp, err := transport.RoundTrip(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(b) != "mbry hbd b little lbmb" {
+		t.Errorf("failed to replace: got %q, want \"b\"", b)
+	}
+}