Replacer supports case-insensitive header placeholders (fixes #476)

middleware/replacer.go

@@ -86,9 +86,9 @@ func NewReplacer(r *http.Request, rr *responseRecorder, emptyValue string) Repla
 		rep.replacements["{latency}"] = time.Since(rr.start).String()
 	}
 
-	// Header placeholders
-	for header, val := range r.Header {
-		rep.replacements[headerReplacer+header+"}"] = strings.Join(val, ",")
+	// Header placeholders (case-insensitive)
+	for header, values := range r.Header {
+		rep.replacements[headerReplacer+strings.ToLower(header)+"}"] = strings.Join(values, ",")
 	}
 
 	return rep
@@ -97,24 +97,39 @@ func NewReplacer(r *http.Request, rr *responseRecorder, emptyValue string) Repla
 // Replace performs a replacement of values on s and returns
 // the string with the replaced values.
 func (r replacer) Replace(s string) string {
-	for placeholder, replacement := range r.replacements {
+	// Header replacements - these are case-insensitive, so we can't just use strings.Replace()
+	startPos := strings.Index(s, headerReplacer)
+	for startPos > -1 {
+		// carefully find end of placeholder
+		endOffset := strings.Index(s[startPos+1:], "}")
+		if endOffset == -1 {
+			startPos = strings.Index(s[startPos+len(headerReplacer):], headerReplacer)
+			continue
+		}
+		endPos := startPos + len(headerReplacer) + endOffset
+
+		// look for replacement, case-insensitive
+		placeholder := strings.ToLower(s[startPos:endPos])
+		replacement := r.replacements[placeholder]
 		if replacement == "" {
 			replacement = r.emptyValue
 		}
-		s = strings.Replace(s, placeholder, replacement, -1)
+
+		// do the replacement manually
+		s = s[:startPos] + replacement + s[endPos:]
+
+		// move to next one
+		startPos = strings.Index(s[endOffset:], headerReplacer)
 	}
 
-	// Replace any header placeholders that weren't found
-	for strings.Contains(s, headerReplacer) {
-		idxStart := strings.Index(s, headerReplacer)
-		endOffset := idxStart + len(headerReplacer)
-		idxEnd := strings.Index(s[endOffset:], "}")
-		if idxEnd > -1 {
-			s = s[:idxStart] + r.emptyValue + s[endOffset+idxEnd+1:]
-		} else {
-			break
+	// Regular replacements - these are easier because they're case-sensitive
+	for placeholder, replacement := range r.replacements {
+		if replacement == "" {
+			replacement = r.emptyValue
 		}
+		s = strings.Replace(s, placeholder, replacement, -1)
 	}
+
 	return s
 }
 

middleware/replacer_test.go

@@ -10,102 +10,104 @@ import (
 func TestNewReplacer(t *testing.T) {
 	w := httptest.NewRecorder()
 	recordRequest := NewResponseRecorder(w)
-	userJSON := `{"username": "dennis"}`
+	reader := strings.NewReader(`{"username": "dennis"}`)
 
-	reader := strings.NewReader(userJSON) //Convert string to reader
-
-	request, err := http.NewRequest("POST", "http://caddyserver.com", reader) //Create request with JSON body
+	request, err := http.NewRequest("POST", "http://localhost", reader)
 	if err != nil {
-		t.Fatalf("Request Formation Failed \n")
+		t.Fatal("Request Formation Failed\n")
 	}
 	replaceValues := NewReplacer(request, recordRequest, "")
 
 	switch v := replaceValues.(type) {
 	case replacer:
 
-		if v.replacements["{host}"] != "caddyserver.com" {
-			t.Errorf("Expected host to be caddyserver.com")
+		if v.replacements["{host}"] != "localhost" {
+			t.Error("Expected host to be localhost")
 		}
 		if v.replacements["{method}"] != "POST" {
-			t.Errorf("Expected request method  to be POST")
+			t.Error("Expected request method  to be POST")
 		}
 		if v.replacements["{status}"] != "200" {
-			t.Errorf("Expected status to be 200")
+			t.Error("Expected status to be 200")
 		}
 
 	default:
-		t.Fatalf("Return Value from New Replacer expected pass type assertion into a replacer type   \n")
+		t.Fatal("Return Value from New Replacer expected pass type assertion into a replacer type\n")
 	}
 }
 
 func TestReplace(t *testing.T) {
 	w := httptest.NewRecorder()
 	recordRequest := NewResponseRecorder(w)
-	userJSON := `{"username": "dennis"}`
-
-	reader := strings.NewReader(userJSON) //Convert string to reader
+	reader := strings.NewReader(`{"username": "dennis"}`)
 
-	request, err := http.NewRequest("POST", "http://caddyserver.com", reader) //Create request with JSON body
+	request, err := http.NewRequest("POST", "http://localhost", reader)
 	if err != nil {
-		t.Fatalf("Request Formation Failed \n")
+		t.Fatal("Request Formation Failed\n")
 	}
-	replaceValues := NewReplacer(request, recordRequest, "")
-
-	switch v := replaceValues.(type) {
-	case replacer:
+	request.Header.Set("Custom", "fooBar")
+	repl := NewReplacer(request, recordRequest, "-")
 
-		if v.Replace("This host is {host}") != "This host is caddyserver.com" {
-			t.Errorf("Expected host replacement failed")
+	if expected, actual := "This host is localhost.", repl.Replace("This host is {host}."); expected != actual {
+		t.Errorf("{host} replacement: expected '%s', got '%s'", expected, actual)
+	}
+	if expected, actual := "This request method is POST.", repl.Replace("This request method is {method}."); expected != actual {
+		t.Errorf("{method} replacement: expected '%s', got '%s'", expected, actual)
 	}
-		if v.Replace("This request method is {method}") != "This request method is POST" {
-			t.Errorf("Expected method  replacement failed")
+	if expected, actual := "The response status is 200.", repl.Replace("The response status is {status}."); expected != actual {
+		t.Errorf("{status} replacement: expected '%s', got '%s'", expected, actual)
 	}
-		if v.Replace("The response status is {status}") != "The response status is 200" {
-			t.Errorf("Expected status replacement failed")
+	if expected, actual := "The Custom header is fooBar.", repl.Replace("The Custom header is {>Custom}."); expected != actual {
+		t.Errorf("{>Custom} replacement: expected '%s', got '%s'", expected, actual)
 	}
 
-	default:
-		t.Fatalf("Return Value from New Replacer expected pass type assertion into a replacer type   \n")
+	// Test header case-insensitivity
+	if expected, actual := "The cUsToM header is fooBar...", repl.Replace("The cUsToM header is {>cUsToM}..."); expected != actual {
+		t.Errorf("{>cUsToM} replacement: expected '%s', got '%s'", expected, actual)
+	}
+
+	// Test non-existent header/value
+	if expected, actual := "The Non-Existent header is -.", repl.Replace("The Non-Existent header is {>Non-Existent}."); expected != actual {
+		t.Errorf("{>Non-Existent} replacement: expected '%s', got '%s'", expected, actual)
 	}
 
+	// Test bad placeholder
+	if expected, actual := "Bad {host placeholder...", repl.Replace("Bad {host placeholder..."); expected != actual {
+		t.Errorf("bad placeholder: expected '%s', got '%s'", expected, actual)
+	}
+
+	// Test bad header placeholder
+	if expected, actual := "Bad {>Custom placeholder", repl.Replace("Bad {>Custom placeholder"); expected != actual {
+		t.Errorf("bad header placeholder: expected '%s', got '%s'", expected, actual)
+	}
 }
 
 func TestSet(t *testing.T) {
 	w := httptest.NewRecorder()
 	recordRequest := NewResponseRecorder(w)
-	userJSON := `{"username": "dennis"}`
+	reader := strings.NewReader(`{"username": "dennis"}`)
 
-	reader := strings.NewReader(userJSON) //Convert string to reader
-
-	request, err := http.NewRequest("POST", "http://caddyserver.com", reader) //Create request with JSON body
+	request, err := http.NewRequest("POST", "http://localhost", reader)
 	if err != nil {
 		t.Fatalf("Request Formation Failed \n")
 	}
-	replaceValues := NewReplacer(request, recordRequest, "")
-
-	replaceValues.Set("host", "getcaddy.com")
-	replaceValues.Set("method", "GET")
-	replaceValues.Set("status", "201")
-	replaceValues.Set("variable", "value")
+	repl := NewReplacer(request, recordRequest, "")
 
-	switch v := replaceValues.(type) {
-	case replacer:
+	repl.Set("host", "getcaddy.com")
+	repl.Set("method", "GET")
+	repl.Set("status", "201")
+	repl.Set("variable", "value")
 
-		if v.Replace("This host is {host}") != "This host is getcaddy.com" {
-			t.Errorf("Expected host replacement failed")
-		}
-		if v.Replace("This request method is {method}") != "This request method is GET" {
-			t.Errorf("Expected method  replacement failed")
+	if repl.Replace("This host is {host}") != "This host is getcaddy.com" {
+		t.Error("Expected host replacement failed")
 	}
-		if v.Replace("The response status is {status}") != "The response status is 201" {
-			t.Errorf("Expected status replacement failed")
+	if repl.Replace("This request method is {method}") != "This request method is GET" {
+		t.Error("Expected method replacement failed")
 	}
-		if v.Replace("The value of variable is {variable}") != "The value of variable is value" {
-			t.Errorf("Expected status replacement failed")
+	if repl.Replace("The response status is {status}") != "The response status is 201" {
+		t.Error("Expected status replacement failed")
 	}
-
-	default:
-		t.Fatalf("Return Value from New Replacer expected pass type assertion into a replacer type   \n")
+	if repl.Replace("The value of variable is {variable}") != "The value of variable is value" {
+		t.Error("Expected variable replacement failed")
 	}
-
 }