Move common function into existing file

middleware/header.go

-package middleware
-
-import (
-	"net/http"
-	"time"
-)
-
-// currentTime returns time.Now() everytime it's called. It's used for mocking in tests.
-var currentTime = func() time.Time {
-	return time.Now()
-}
-
-// SetLastModifiedHeader checks if the provided modTime is valid and if it is sets it
-// as a Last-Modified header to the ResponseWriter. If the modTime is in the future
-// the current time is used instead.
-func SetLastModifiedHeader(w http.ResponseWriter, modTime time.Time) {
-	if modTime.IsZero() || modTime.Equal(time.Unix(0, 0)) {
-		// the time does not appear to be valid. Don't put it in the response
-		return
-	}
-
-	// RFC 2616 - Section 14.29 - Last-Modified:
-	// An origin server MUST NOT send a Last-Modified date which is later than the
-	// server's time of message origination. In such cases, where the resource's last
-	// modification would indicate some time in the future, the server MUST replace
-	// that date with the message origination date.
-	now := currentTime()
-	if modTime.After(now) {
-		modTime = now
-	}
-
-	w.Header().Set("Last-Modified", modTime.UTC().Format(http.TimeFormat))
-}

middleware/header_test.go

-package middleware
-
-import (
-	"fmt"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-	"time"
-)
-
-func TestSetLastModified(t *testing.T) {
-	nowTime := time.Now()
-
-	// ovewrite the function to return reliable time
-	originalGetCurrentTimeFunc := currentTime
-	currentTime = func() time.Time {
-		return nowTime
-	}
-	defer func() {
-		currentTime = originalGetCurrentTimeFunc
-	}()
-
-	pastTime := nowTime.Truncate(1 * time.Hour)
-	futureTime := nowTime.Add(1 * time.Hour)
-
-	tests := []struct {
-		inputModTime         time.Time
-		expectedIsHeaderSet  bool
-		expectedLastModified string
-	}{
-		{
-			inputModTime:         pastTime,
-			expectedIsHeaderSet:  true,
-			expectedLastModified: pastTime.UTC().Format(http.TimeFormat),
-		},
-		{
-			inputModTime:         nowTime,
-			expectedIsHeaderSet:  true,
-			expectedLastModified: nowTime.UTC().Format(http.TimeFormat),
-		},
-		{
-			inputModTime:         futureTime,
-			expectedIsHeaderSet:  true,
-			expectedLastModified: nowTime.UTC().Format(http.TimeFormat),
-		},
-		{
-			inputModTime:        time.Time{},
-			expectedIsHeaderSet: false,
-		},
-	}
-
-	for i, test := range tests {
-		responseRecorder := httptest.NewRecorder()
-		errorPrefix := fmt.Sprintf("Test [%d]: ", i)
-		SetLastModifiedHeader(responseRecorder, test.inputModTime)
-		actualLastModifiedHeader := responseRecorder.Header().Get("Last-Modified")
-
-		if test.expectedIsHeaderSet && actualLastModifiedHeader == "" {
-			t.Fatalf(errorPrefix + "Expected to find Last-Modified header, but found nothing")
-		}
-
-		if !test.expectedIsHeaderSet && actualLastModifiedHeader != "" {
-			t.Fatalf(errorPrefix+"Did not expect to find Last-Modified header, but found one [%s].", actualLastModifiedHeader)
-		}
-
-		if test.expectedLastModified != actualLastModifiedHeader {
-			t.Errorf(errorPrefix+"Expected Last-Modified content [%s], found [%s}", test.expectedLastModified, actualLastModifiedHeader)
-		}
-	}
-}

middleware/middleware.go

@@ -4,6 +4,7 @@ package middleware
 import (
 	"net/http"
 	"path"
+	"time"
 )
 
 type (
@@ -78,3 +79,30 @@ func IndexFile(root http.FileSystem, fpath string, indexFiles []string) (string,
 	}
 	return "", false
 }
+
+// SetLastModifiedHeader checks if the provided modTime is valid and if it is sets it
+// as a Last-Modified header to the ResponseWriter. If the modTime is in the future
+// the current time is used instead.
+func SetLastModifiedHeader(w http.ResponseWriter, modTime time.Time) {
+	if modTime.IsZero() || modTime.Equal(time.Unix(0, 0)) {
+		// the time does not appear to be valid. Don't put it in the response
+		return
+	}
+
+	// RFC 2616 - Section 14.29 - Last-Modified:
+	// An origin server MUST NOT send a Last-Modified date which is later than the
+	// server's time of message origination. In such cases, where the resource's last
+	// modification would indicate some time in the future, the server MUST replace
+	// that date with the message origination date.
+	now := currentTime()
+	if modTime.After(now) {
+		modTime = now
+	}
+
+	w.Header().Set("Last-Modified", modTime.UTC().Format(http.TimeFormat))
+}
+
+// currentTime returns time.Now() everytime it's called. It's used for mocking in tests.
+var currentTime = func() time.Time {
+	return time.Now()
+}

middleware/middleware_test.go

 package middleware
 
 import (
+	"fmt"
 	"net/http"
+	"net/http/httptest"
 	"testing"
+	"time"
 )
 
 func TestIndexfile(t *testing.T) {
@@ -42,3 +45,64 @@ func TestIndexfile(t *testing.T) {
 		}
 	}
 }
+
+func TestSetLastModified(t *testing.T) {
+	nowTime := time.Now()
+
+	// ovewrite the function to return reliable time
+	originalGetCurrentTimeFunc := currentTime
+	currentTime = func() time.Time {
+		return nowTime
+	}
+	defer func() {
+		currentTime = originalGetCurrentTimeFunc
+	}()
+
+	pastTime := nowTime.Truncate(1 * time.Hour)
+	futureTime := nowTime.Add(1 * time.Hour)
+
+	tests := []struct {
+		inputModTime         time.Time
+		expectedIsHeaderSet  bool
+		expectedLastModified string
+	}{
+		{
+			inputModTime:         pastTime,
+			expectedIsHeaderSet:  true,
+			expectedLastModified: pastTime.UTC().Format(http.TimeFormat),
+		},
+		{
+			inputModTime:         nowTime,
+			expectedIsHeaderSet:  true,
+			expectedLastModified: nowTime.UTC().Format(http.TimeFormat),
+		},
+		{
+			inputModTime:         futureTime,
+			expectedIsHeaderSet:  true,
+			expectedLastModified: nowTime.UTC().Format(http.TimeFormat),
+		},
+		{
+			inputModTime:        time.Time{},
+			expectedIsHeaderSet: false,
+		},
+	}
+
+	for i, test := range tests {
+		responseRecorder := httptest.NewRecorder()
+		errorPrefix := fmt.Sprintf("Test [%d]: ", i)
+		SetLastModifiedHeader(responseRecorder, test.inputModTime)
+		actualLastModifiedHeader := responseRecorder.Header().Get("Last-Modified")
+
+		if test.expectedIsHeaderSet && actualLastModifiedHeader == "" {
+			t.Fatalf(errorPrefix + "Expected to find Last-Modified header, but found nothing")
+		}
+
+		if !test.expectedIsHeaderSet && actualLastModifiedHeader != "" {
+			t.Fatalf(errorPrefix+"Did not expect to find Last-Modified header, but found one [%s].", actualLastModifiedHeader)
+		}
+
+		if test.expectedLastModified != actualLastModifiedHeader {
+			t.Errorf(errorPrefix+"Expected Last-Modified content [%s], found [%s}", test.expectedLastModified, actualLastModifiedHeader)
+		}
+	}
+}