Fixes the captured response writer miscounting the body size (#61)

Author: ufukty

backend/internal/web/captured/rw_test.go

@@ -2,6 +2,8 @@ package captured
 
 import (
 	"cmp"
+	"fmt"
+	"math"
 	"net/http"
 	"strconv"
 )
@@ -10,6 +12,7 @@ type ResponseWriter struct {
 	wrapped    http.ResponseWriter
 	statusCode int
 	written    bool
+	size       uint
 }
 
 func New(w http.ResponseWriter) *ResponseWriter {
@@ -22,6 +25,7 @@ func (rw *ResponseWriter) Header() http.Header {
 
 func (rw *ResponseWriter) Write(n []byte) (int, error) {
 	rw.written = true
+	rw.size += uint(len(n))
 	return rw.wrapped.Write(n)
 }
 
@@ -45,3 +49,20 @@ func (rw ResponseWriter) StatusRepresentation() string {
 	}
 	return strconv.Itoa(rw.statusCode)
 }
+
+func bytes(i uint) string {
+	units := []string{"B", "KB", "MB", "GB", "TB", "PB", "EB"}
+	j := 0
+	for k := i; k >= 1024 && j+1 < len(units); k /= 1024 {
+		j++
+	}
+	d := float64(i) / math.Pow(1024, float64(j))
+	if d != float64(int(d)) {
+		return fmt.Sprintf("%.1f%s", d, units[j])
+	}
+	return fmt.Sprintf("%d%s", int(d), units[j])
+}
+
+func (rw ResponseWriter) SizeRepresentation() string {
+	return bytes(rw.size)
+}

backend/internal/web/captured/rw.go …nd/internal/web/reception/captured/rw.gobackend/internal/web/captured/rw.go renamed to backend/internal/web/reception/captured/rw.go backend/internal/web/captured/rw.go renamed to backend/internal/web/reception/captured/rw.go

@@ -0,0 +1,66 @@
+package captured
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+// fake
+type hijacker struct {
+	http.ResponseWriter
+}
+
+func (h hijacker) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	panic("not to call")
+}
+
+var _ http.Hijacker = (*hijacker)(nil)
+
+func ExampleResponseWriter_additionalMethods() {
+	var rw http.ResponseWriter = New(hijacker{})
+	if _, ok := rw.(http.Hijacker); !ok {
+		fmt.Println("the non-ResponseWriter methods are not available directly")
+	}
+	if _, ok := rw.(interface{ Unwrap() http.ResponseWriter }).Unwrap().(http.Hijacker); ok {
+		fmt.Println("become so, after unwrapping")
+	}
+	// Output:
+	// the non-ResponseWriter methods are not available directly
+	// become so, after unwrapping
+}
+
+func TestBytes(t *testing.T) {
+	tcs := map[uint]string{
+		0:                 "0B",
+		10:                "10B",
+		20:                "20B",
+		1000:              "1000B",
+		1024:              "1KB",
+		1024 + 102:        "1.1KB",
+		1000 * 1024:       "1000KB",
+		1024 * 1024:       "1MB",
+		1.5 * 1024 * 1024: "1.5MB",
+		1<<63 - 1:         "8EB",
+	}
+	for input, expected := range tcs {
+		t.Run(fmt.Sprintf("%d", input), func(t *testing.T) {
+			got := bytes(input)
+			if got != expected {
+				t.Errorf("expected %q got %q", expected, got)
+			}
+		})
+	}
+}
+
+func TestResponseWriter_SizeRepresentation(t *testing.T) {
+	crw := New(httptest.NewRecorder())
+	crw.Write([]byte("lorem ipsum dolor sit amet consectetur adipscing elit"))
+	expected, got := "53B", crw.SizeRepresentation()
+	if expected != got {
+		t.Errorf("expected %q got %q", expected, got)
+	}
+}

backend/internal/web/reception/captured/rw_test.go

@@ -18,7 +18,7 @@ import (
 
 	"logbook/config/deployment"
 	"logbook/internal/logger"
-	"logbook/internal/web/captured"
+	"logbook/internal/web/reception/captured"
 	"logbook/internal/web/reception/summarizer"
 	"logbook/models/columns"
 )

backend/internal/web/reception/receptionist.go

@@ -5,7 +5,7 @@ import (
 	"net/http"
 	"time"
 
-	"logbook/internal/web/captured"
+	"logbook/internal/web/reception/captured"
 )
 
 type colorizer interface {