feat: support simple LDAP server (#1155)

* feat:Support simple ldap server

* fix:fix review problems

* fix:fix review problems

object/ldapserver.go

@@ -0,0 +1,74 @@
+// Copyright 2022 The Casdoor Authors. All Rights Reserved.
+//
+// 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 object
+
+import (
+	"fmt"
+	"log"
+	"strings"
+
+	"github.com/forestmgy/ldapserver"
+)
+
+func GetNameAndOrgFromDN(DN string) (string, string, string) {
+	DNValue := strings.Split(DN, ",")
+	if len(DNValue) == 1 || strings.ToLower(DNValue[0])[0] != 'c' || strings.ToLower(DNValue[1])[0] != 'o' {
+		return "", "", "please use correct Admin Name format like cn=xxx,ou=xxx,dc=example,dc=com"
+	}
+	return DNValue[0][3:], DNValue[1][3:], ""
+}
+
+func GetUserNameAndOrgFromBaseDnAndFilter(baseDN, filter string) (string, string, int) {
+	if !strings.Contains(baseDN, "ou=") || !strings.Contains(filter, "cn=") {
+		return "", "", ldapserver.LDAPResultInvalidDNSyntax
+	}
+	name := getUserNameFromFilter(filter)
+	_, org, _ := GetNameAndOrgFromDN(fmt.Sprintf("cn=%s,", name) + baseDN)
+	errCode := ldapserver.LDAPResultSuccess
+	return name, org, errCode
+}
+
+func getUserNameFromFilter(filter string) string {
+	nameIndex := strings.Index(filter, "cn=")
+	var name string
+	for i := nameIndex + 3; filter[i] != ')'; i++ {
+		name = name + string(filter[i])
+	}
+	return name
+}
+
+func GetFilteredUsers(m *ldapserver.Message, name, org string) ([]*User, int) {
+	var filteredUsers []*User
+	if name == "*" && m.Client.IsOrgAdmin { // get all users from organization 'org'
+		if m.Client.OrgName == "built-in" && org == "*" {
+			filteredUsers = GetGlobalUsers()
+			return filteredUsers, ldapserver.LDAPResultSuccess
+		} else if m.Client.OrgName == "built-in" || org == m.Client.OrgName {
+			filteredUsers = GetUsers(org)
+			return filteredUsers, ldapserver.LDAPResultSuccess
+		} else {
+			return nil, ldapserver.LDAPResultInsufficientAccessRights
+		}
+	} else {
+		hasPermission, err := CheckUserPermission(fmt.Sprintf("%s/%s", m.Client.OrgName, m.Client.UserName), fmt.Sprintf("%s/%s", org, name), org, true)
+		if !hasPermission {
+			log.Printf("ErrMsg = %v", err.Error())
+			return nil, ldapserver.LDAPResultInsufficientAccessRights
+		}
+		user := getUser(org, name)
+		filteredUsers = append(filteredUsers, user)
+		return filteredUsers, ldapserver.LDAPResultSuccess
+	}
+}