feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

backend/infra/impl/document/parser/builtin/util.go

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * 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 builtin
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"math/rand"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/coze-dev/coze-studio/backend/infra/contract/document"
+)
+
+const baseWord = "1Aa2Bb3Cc4Dd5Ee6Ff7Gg8Hh9Ii0JjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz"
+const knowledgePrefix = "BIZ_KNOWLEDGE"
+const imgSrcFormat = `<img src="" data-tos-key="%s">`
+
+func createSecret(uid int64, fileType string) string {
+	num := 10
+	input := fmt.Sprintf("upload_%d_Ma*9)fhi_%d_gou_%s_rand_%d", uid, time.Now().Unix(), fileType, rand.Intn(100000))
+	// 做md5，取前20个,// mapIntToBase62 把数字映射到 Base62
+	hash := sha256.Sum256([]byte(fmt.Sprintf("%s", input)))
+	hashString := base64.StdEncoding.EncodeToString(hash[:])
+	if len(hashString) > num {
+		hashString = hashString[:num]
+	}
+
+	result := ""
+	for _, char := range hashString {
+		index := int(char) % 62
+		result += string(baseWord[index])
+	}
+	return result
+}
+func getExtension(uri string) string {
+	if uri == "" {
+		return ""
+	}
+	fileExtension := path.Base(uri)
+	ext := path.Ext(fileExtension)
+	if ext != "" {
+		return strings.TrimPrefix(ext, ".")
+	}
+	return ""
+}
+
+func getCreatorIDFromExtraMeta(extraMeta map[string]any) int64 {
+	if extraMeta == nil {
+		return 0
+	}
+	if uid, ok := extraMeta[document.MetaDataKeyCreatorID]; ok {
+		if uidInt, ok := uid.(int64); ok {
+			return uidInt
+		}
+	}
+	return 0
+}