snapshot of https://github.com/casbin/casbin.git (master, 2026-09-15; blobs > 131072B omitted)

persist/file-adapter/adapter.go

@@ -0,0 +1,157 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 fileadapter
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"os"
+	"strings"
+
+	"github.com/casbin/casbin/v3/model"
+	"github.com/casbin/casbin/v3/persist"
+)
+
+// Adapter is the file adapter for Casbin.
+// It can load policy from file or save policy to file.
+type Adapter struct {
+	filePath string
+}
+
+func (a *Adapter) UpdatePolicy(sec string, ptype string, oldRule, newRule []string) error {
+	return errors.New("not implemented")
+}
+
+func (a *Adapter) UpdatePolicies(sec string, ptype string, oldRules, newRules [][]string) error {
+	return errors.New("not implemented")
+}
+
+func (a *Adapter) UpdateFilteredPolicies(sec string, ptype string, newRules [][]string, fieldIndex int, fieldValues ...string) ([][]string, error) {
+	return nil, errors.New("not implemented")
+}
+
+// NewAdapter is the constructor for Adapter.
+func NewAdapter(filePath string) *Adapter {
+	return &Adapter{filePath: filePath}
+}
+
+// LoadPolicy loads all policy rules from the storage.
+func (a *Adapter) LoadPolicy(model model.Model) error {
+	if a.filePath == "" {
+		return errors.New("invalid file path, file path cannot be empty")
+	}
+
+	return a.loadPolicyFile(model, persist.LoadPolicyLine)
+}
+
+// SavePolicy saves all policy rules to the storage.
+func (a *Adapter) SavePolicy(model model.Model) error {
+	if a.filePath == "" {
+		return errors.New("invalid file path, file path cannot be empty")
+	}
+
+	var tmp bytes.Buffer
+
+	for ptype, ast := range model["p"] {
+		for _, rule := range ast.Policy {
+			line, err := persist.PolicyLineToCsv(ptype, rule)
+			if err != nil {
+				return err
+			}
+			tmp.WriteString(line)
+			tmp.WriteString("\n")
+		}
+	}
+
+	for ptype, ast := range model["g"] {
+		for _, rule := range ast.Policy {
+			line, err := persist.PolicyLineToCsv(ptype, rule)
+			if err != nil {
+				return err
+			}
+			tmp.WriteString(line)
+			tmp.WriteString("\n")
+		}
+	}
+
+	return a.savePolicyFile(strings.TrimRight(tmp.String(), "\n"))
+}
+
+func (a *Adapter) loadPolicyFile(model model.Model, handler func(string, model.Model) error) error {
+	f, err := os.Open(a.filePath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		err = handler(line, model)
+		if err != nil {
+			return err
+		}
+	}
+	return scanner.Err()
+}
+
+func (a *Adapter) savePolicyFile(text string) error {
+	f, err := os.Create(a.filePath)
+	if err != nil {
+		return err
+	}
+	w := bufio.NewWriter(f)
+
+	_, err = w.WriteString(text)
+	if err != nil {
+		return err
+	}
+
+	err = w.Flush()
+	if err != nil {
+		return err
+	}
+
+	return f.Close()
+}
+
+// AddPolicy adds a policy rule to the storage.
+func (a *Adapter) AddPolicy(sec string, ptype string, rule []string) error {
+	return errors.New("not implemented")
+}
+
+// AddPolicies adds policy rules to the storage.
+func (a *Adapter) AddPolicies(sec string, ptype string, rules [][]string) error {
+	return errors.New("not implemented")
+}
+
+// RemovePolicy removes a policy rule from the storage.
+func (a *Adapter) RemovePolicy(sec string, ptype string, rule []string) error {
+	return errors.New("not implemented")
+}
+
+// RemovePolicies removes policy rules from the storage.
+func (a *Adapter) RemovePolicies(sec string, ptype string, rules [][]string) error {
+	return errors.New("not implemented")
+}
+
+// RemoveFilteredPolicy removes policy rules that match the filter from the storage.
+func (a *Adapter) RemoveFilteredPolicy(sec string, ptype string, fieldIndex int, fieldValues ...string) error {
+	return errors.New("not implemented")
+}