Initial QSfera import

Server/vendor/github.com/libregraph/lico/identifier/utils.go

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2017-2019 Kopano and its licensors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package identifier
+
+import (
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/gabriel-vasile/mimetype"
+)
+
+var (
+	farPastExpiryTime                 = time.Unix(0, 0)
+	farPastExpiryTimeHTTPHeaderString = farPastExpiryTime.UTC().Format(http.TimeFormat)
+)
+
+func addCommonResponseHeaders(header http.Header) {
+	header.Set("X-Frame-Options", "DENY")
+	header.Set("X-XSS-Protection", "1; mode=block")
+	header.Set("X-Content-Type-Options", "nosniff")
+	header.Set("Referrer-Policy", "origin")
+}
+
+func addNoCacheResponseHeaders(header http.Header) {
+	header.Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	header.Set("Pragma", "no-cache")
+	header.Set("Expires", farPastExpiryTimeHTTPHeaderString)
+}
+
+func encodeImageAsDataURL(b []byte) (string, error) {
+	mt := mimetype.Detect(b)
+	if !strings.HasPrefix(mt.String(), "image/") {
+		return "", fmt.Errorf("not an image: %s", mt)
+	}
+
+	return "data:" + mt.String() + ";base64," + base64.StdEncoding.EncodeToString(b), nil
+}