logging: query filter for array of strings (#5779)

Co-authored-by: Matt Holt <[email protected]>
Co-authored-by: Francis Lavoie <[email protected]>

modules/logging/filters.go

@@ -373,9 +373,23 @@ func (m *QueryFilter) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 
 // Filter filters the input field.
 func (m QueryFilter) Filter(in zapcore.Field) zapcore.Field {
-	u, err := url.Parse(in.String)
+	if array, ok := in.Interface.(caddyhttp.LoggableStringArray); ok {
+		newArray := make(caddyhttp.LoggableStringArray, len(array))
+		for i, s := range array {
+			newArray[i] = m.processQueryString(s)
+		}
+		in.Interface = newArray
+	} else {
+		in.String = m.processQueryString(in.String)
+	}
+
+	return in
+}
+
+func (m QueryFilter) processQueryString(s string) string {
+	u, err := url.Parse(s)
 	if err != nil {
-		return in
+		return s
 	}
 
 	q := u.Query()
@@ -397,9 +411,7 @@ func (m QueryFilter) Filter(in zapcore.Field) zapcore.Field {
 	}
 
 	u.RawQuery = q.Encode()
-	in.String = u.String()
-
-	return in
+	return u.String()
 }
 
 type cookieFilterAction struct {

modules/logging/filters_test.go

@@ -83,7 +83,7 @@ func TestIPMaskMultiValue(t *testing.T) {
 	}
 }
 
-func TestQueryFilter(t *testing.T) {
+func TestQueryFilterSingleValue(t *testing.T) {
 	f := QueryFilter{[]queryFilterAction{
 		{replaceAction, "foo", "REDACTED"},
 		{replaceAction, "notexist", "REDACTED"},
@@ -102,6 +102,40 @@ func TestQueryFilter(t *testing.T) {
 	}
 }
 
+func TestQueryFilterMultiValue(t *testing.T) {
+	f := QueryFilter{
+		Actions: []queryFilterAction{
+			{Type: replaceAction, Parameter: "foo", Value: "REDACTED"},
+			{Type: replaceAction, Parameter: "notexist", Value: "REDACTED"},
+			{Type: deleteAction, Parameter: "bar"},
+			{Type: deleteAction, Parameter: "notexist"},
+			{Type: hashAction, Parameter: "hash"},
+		},
+	}
+
+	if f.Validate() != nil {
+		t.Fatalf("the filter must be valid")
+	}
+
+	out := f.Filter(zapcore.Field{Interface: caddyhttp.LoggableStringArray{
+		"/path1?foo=a&foo=b&bar=c&bar=d&baz=e&hash=hashed",
+		"/path2?foo=c&foo=d&bar=e&bar=f&baz=g&hash=hashed",
+	}})
+	arr, ok := out.Interface.(caddyhttp.LoggableStringArray)
+	if !ok {
+		t.Fatalf("field is wrong type: %T", out.Interface)
+	}
+
+	expected1 := "/path1?baz=e&foo=REDACTED&foo=REDACTED&hash=e3b0c442"
+	expected2 := "/path2?baz=g&foo=REDACTED&foo=REDACTED&hash=e3b0c442"
+	if arr[0] != expected1 {
+		t.Fatalf("query parameters in entry 0 have not been filtered correctly: got %s, expected %s", arr[0], expected1)
+	}
+	if arr[1] != expected2 {
+		t.Fatalf("query parameters in entry 1 have not been filtered correctly: got %s, expected %s", arr[1], expected2)
+	}
+}
+
 func TestValidateQueryFilter(t *testing.T) {
 	f := QueryFilter{[]queryFilterAction{
 		{},