feat(proxy): warn on unsupported encoding, fixes #692

a-h · Apr 22, 2024 · 9ee8751 · 9ee8751
1 parent 3c47c10
commit 9ee8751
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Showing 4 changed files with 103 additions and 15 deletions.
diff --git a/.version b/.version
@@ -1 +1 @@
-0.2.650
+0.2.667
diff --git a/cmd/templ/generatecmd/cmd.go b/cmd/templ/generatecmd/cmd.go
@@ -343,7 +343,7 @@ func (cmd *Generate) StartProxy(ctx context.Context) (p *proxy.Handler, err erro
 	if cmd.Args.ProxyBind == "" {
 		cmd.Args.ProxyBind = "127.0.0.1"
 	}
-	p = proxy.New(cmd.Args.ProxyBind, cmd.Args.ProxyPort, target)
+	p = proxy.New(cmd.Log, cmd.Args.ProxyBind, cmd.Args.ProxyPort, target)
 	go func() {
 		cmd.Log.Info("Proxying", slog.String("from", p.URL), slog.String("to", p.Target.String()))
 		if err := http.ListenAndServe(fmt.Sprintf("%s:%d", cmd.Args.ProxyBind, cmd.Args.ProxyPort), p); err != nil {

diff --git a/cmd/templ/generatecmd/proxy/proxy.go b/cmd/templ/generatecmd/proxy/proxy.go
@@ -5,7 +5,8 @@ import (
 	"compress/gzip"
 	"fmt"
 	"io"
-	"log"
+	stdlog "log"
+	"log/slog"
 	"math"
 	"net/http"
 	"net/http/httputil"
@@ -27,6 +28,7 @@ var script string
 const scriptTag = `<script src="/_templ/reload/script.js"></script>`
 
 type Handler struct {
+	log    *slog.Logger
 	URL    string
 	Target *url.URL
 	p      *httputil.ReverseProxy
@@ -45,7 +47,9 @@ func (pwc passthroughWriteCloser) Close() error {
 	return nil
 }
 
-func modifyResponse(r *http.Response) error {
+const unsupportedContentEncoding = "Unsupported content encoding, hot reload script not inserted."
+
+func (h *Handler) modifyResponse(r *http.Response) error {
 	if r.Header.Get("templ-skip-modify") == "true" {
 		return nil
 	}
@@ -75,6 +79,10 @@ func modifyResponse(r *http.Response) error {
 		newWriter = func(out io.Writer) io.WriteCloser {
 			return brotli.NewWriter(out)
 		}
+	case "":
+		// No content encoding.
+	default:
+		h.log.Warn(unsupportedContentEncoding, slog.String("encoding", r.Header.Get("Content-Encoding")))
 	}
 
 	// Read the encoded body.
@@ -110,21 +118,23 @@ func modifyResponse(r *http.Response) error {
 	return nil
 }
 
-func New(bind string, port int, target *url.URL) *Handler {
+func New(log *slog.Logger, bind string, port int, target *url.URL) (h *Handler) {
 	p := httputil.NewSingleHostReverseProxy(target)
-	p.ErrorLog = log.New(os.Stderr, "Proxy to target error: ", 0)
+	p.ErrorLog = stdlog.New(os.Stderr, "Proxy to target error: ", 0)
 	p.Transport = &roundTripper{
 		maxRetries:      10,
 		initialDelay:    100 * time.Millisecond,
 		backoffExponent: 1.5,
 	}
-	p.ModifyResponse = modifyResponse
-	return &Handler{
+	h = &Handler{
+		log:    log,
 		URL:    fmt.Sprintf("http://%s:%d", bind, port),
 		Target: target,
 		p:      p,
 		sse:    sse.New(),
 	}
+	p.ModifyResponse = h.modifyResponse
+	return h
 }
 
 func (p *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {

diff --git a/cmd/templ/generatecmd/proxy/proxy_test.go b/cmd/templ/generatecmd/proxy/proxy_test.go
@@ -7,11 +7,13 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"strconv"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -58,7 +60,9 @@ func TestProxy(t *testing.T) {
 		r.Header.Set("Content-Length", "16")
 
 		// Act
-		err := modifyResponse(r)
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err := h.modifyResponse(r)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -86,7 +90,9 @@ func TestProxy(t *testing.T) {
 		r.Header.Set("templ-skip-modify", "true")
 
 		// Act
-		err := modifyResponse(r)
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err := h.modifyResponse(r)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -118,7 +124,9 @@ func TestProxy(t *testing.T) {
 		}
 
 		// Act
-		err := modifyResponse(r)
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err := h.modifyResponse(r)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -148,7 +156,9 @@ func TestProxy(t *testing.T) {
 		r.Header.Set("Content-Length", "16")
 
 		// Act
-		err := modifyResponse(r)
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err := h.modifyResponse(r)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -196,7 +206,10 @@ func TestProxy(t *testing.T) {
 		r.Header.Set("Content-Length", fmt.Sprintf("%d", expectedLength))
 
 		// Act
-		if err = modifyResponse(r); err != nil {
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err = h.modifyResponse(r)
+		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
 
@@ -248,7 +261,10 @@ func TestProxy(t *testing.T) {
 		r.Header.Set("Content-Length", fmt.Sprintf("%d", expectedLength))
 
 		// Act
-		if err = modifyResponse(r); err != nil {
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err = h.modifyResponse(r)
+		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
 
@@ -275,7 +291,8 @@ func TestProxy(t *testing.T) {
 		if err != nil {
 			t.Fatalf("unexpected error parsing URL: %v", err)
 		}
-		handler := New("0.0.0.0", 0, u)
+		log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+		handler := New(log, "0.0.0.0", 0, u)
 		proxyServer := httptest.NewServer(handler)
 		defer proxyServer.Close()
 
@@ -353,4 +370,65 @@ func TestProxy(t *testing.T) {
 			t.Fatalf("timeout waiting for sse response")
 		}
 	})
+	t.Run("unsupported encodings result in a warning", func(t *testing.T) {
+		// Arrange
+		r := &http.Response{
+			Body:   io.NopCloser(bytes.NewReader([]byte("<p>Data</p>"))),
+			Header: make(http.Header),
+		}
+		r.Header.Set("Content-Type", "text/html, charset=utf-8")
+		r.Header.Set("Content-Encoding", "weird-encoding")
+
+		// Act
+		lh := newTestLogHandler()
+		log := slog.New(lh)
+		h := New(log, "127.0.0.1", 7474, &url.URL{Scheme: "http", Host: "example.com"})
+		err := h.modifyResponse(r)
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		// Assert
+		if len(lh.records) != 1 {
+			t.Fatalf("expected 1 log entry, but got %d", len(lh.records))
+		}
+		record := lh.records[0]
+		if record.Message != unsupportedContentEncoding {
+			t.Errorf("expected warning message %q, got %q", unsupportedContentEncoding, record.Message)
+		}
+		if record.Level != slog.LevelWarn {
+			t.Errorf("expected warning, got level %v", record.Level)
+		}
+	})
+}
+
+func newTestLogHandler() *testLogHandler {
+	return &testLogHandler{
+		m:       new(sync.Mutex),
+		records: nil,
+	}
+}
+
+type testLogHandler struct {
+	m       *sync.Mutex
+	records []slog.Record
+}
+
+func (h *testLogHandler) Enabled(context.Context, slog.Level) bool {
+	return true
+}
+
+func (h *testLogHandler) Handle(ctx context.Context, r slog.Record) error {
+	h.m.Lock()
+	defer h.m.Unlock()
+	h.records = append(h.records, r)
+	return nil
+}
+
+func (h *testLogHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return h
+}
+
+func (h *testLogHandler) WithGroup(name string) slog.Handler {
+	return h
 }