Implement casbin adapter for go-pg/pg

README.md

@@ -1,2 +1,65 @@
-# casbin-pg-adapter
-A go-pg adapter for casbin
+Go-pg Adapter
+====
+
+Go-pg Adapter is the [Go-pg](https://github.com/go-pg/pg) adapter for [Casbin](https://github.com/casbin/casbin). With this library, Casbin can load policy from PostgreSQL or save policy to it.
+
+## Installation
+
+    go get github.com/MonedaCacao/casbin-pg-adapter
+
+## Env Variables
+
+Populate .env with necessary environment variable values:
+
+    $ nano .env
+
+```
+DATABASE_ADDRESSES=
+DATABASE_USER_NAME=
+DATABSE_USER_PASSORD=
+```
+
+## Simple Postgres Example
+
+```go
+package main
+
+import (
+	pgadapter "github.com/MonedaCacao/casbin-pg-adapter"
+	"github.com/casbin/casbin"
+)
+
+func main() {
+	// Initialize a Go-pg adapter and use it in a Casbin enforcer:
+	// The adapter will use the Postgres database named "casbin".
+	// If it doesn't exist, the adapter will create it automatically.
+	a, _ := pgadapter.NewAdapter() // Your driver and data source.
+
+	// Or you can use an existing DB "abc" like this:
+	// The adapter will use the table named "casbin_rule".
+	// If it doesn't exist, the adapter will create it automatically.
+
+	e := casbin.NewEnforcer("examples/rbac_model.conf", a)
+
+	// Load the policy from DB.
+	e.LoadPolicy()
+
+	// Check the permission.
+	e.Enforce("alice", "data1", "read")
+
+	// Modify the policy.
+	// e.AddPolicy(...)
+	// e.RemovePolicy(...)
+
+	// Save the policy back to DB.
+	e.SavePolicy()
+}
+```
+
+## Getting Help
+
+- [Casbin](https://github.com/casbin/casbin)
+
+## License
+
+This project is under Apache 2.0 License. See the [LICENSE](LICENSE) file for the full license text.

adapter.go

@@ -0,0 +1,276 @@
+package pgadapter
+
+import (
+	"github.com/MonedaCacao/casbin-pg-adapter/config"
+	"github.com/casbin/casbin/model"
+	"github.com/casbin/casbin/persist"
+	"github.com/go-pg/pg"
+	"github.com/go-pg/pg/orm"
+	"log"
+	"strings"
+)
+
+const (
+	tableExistsErrorCode = "ERROR #42P07"
+)
+
+// CasbinRule represents a rule in Casbin.
+type CasbinRule struct {
+	Id    int
+	PType string
+	V0    string
+	V1    string
+	V2    string
+	V3    string
+	V4    string
+	V5    string
+}
+
+// Adapter represents the github.com/go-pg/pg adapter for policy storage.
+type Adapter struct {
+	db *pg.DB
+}
+
+// finalizer is the destructor for Adapter.
+func finalizer(a *Adapter) {}
+
+// NewAdapter is the constructor for Adapter.
+// The adapter will automatically create a DB named "casbin"
+func NewAdapter() (*Adapter, error) {
+	a := Adapter{}
+
+	// Open the DB, create it if not existed.
+	err := a.open()
+	if err != nil {
+		return nil, err
+	}
+
+	return &a, nil
+}
+
+func (a *Adapter) createDatabase() error {
+	var err error
+	var db *pg.DB
+
+	env := config.GetEnvVariables()
+	cfg := config.GetConfig(*env)
+
+	db = pg.Connect(&pg.Options{
+		Addr:     cfg.DatabaseAddresses,
+		User:     cfg.DatabaseUsername,
+		Password: cfg.DatabseUserPassord,
+	})
+
+	defer db.Close()
+
+	_, err = db.Exec("CREATE DATABASE casbin")
+	if err != nil {
+		log.Println("can't create database", err)
+		return err
+	}
+
+	return nil
+}
+
+func (a *Adapter) open() error {
+	var err error
+	var db *pg.DB
+
+	env := config.GetEnvVariables()
+	cfg := config.GetConfig(*env)
+
+	err = a.createDatabase()
+	if err != nil {
+		panic(err)
+	}
+
+	db = pg.Connect(&pg.Options{
+		Addr:     cfg.DatabaseAddresses,
+		User:     cfg.DatabaseUsername,
+		Password: cfg.DatabseUserPassord,
+		Database: "casbin",
+	})
+
+	a.db = db
+
+	return a.createTable()
+}
+
+func (a *Adapter) close() error {
+	err := a.db.Close()
+	if err != nil {
+		return err
+	}
+
+	a.db = nil
+	return nil
+}
+
+func (a *Adapter) createTable() error {
+	err := a.db.CreateTable(&CasbinRule{}, &orm.CreateTableOptions{
+		Temp: false,
+	})
+	if err != nil {
+		errorCode := err.Error()[0:12]
+		if errorCode != tableExistsErrorCode {
+			return err
+		}
+	}
+	return nil
+}
+
+func (a *Adapter) dropTable() error {
+	err := a.db.DropTable(&CasbinRule{}, &orm.DropTableOptions{})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func loadPolicyLine(line *CasbinRule, model model.Model) {
+	const prefixLine = ", "
+	var sb strings.Builder
+
+	sb.WriteString(line.PType)
+	if len(line.V0) > 0 {
+		sb.WriteString(prefixLine)
+		sb.WriteString(line.V0)
+	}
+	if len(line.V1) > 0 {
+		sb.WriteString(prefixLine)
+		sb.WriteString(line.V1)
+	}
+	if len(line.V2) > 0 {
+		sb.WriteString(prefixLine)
+		sb.WriteString(line.V2)
+	}
+	if len(line.V3) > 0 {
+		sb.WriteString(prefixLine)
+		sb.WriteString(line.V3)
+	}
+	if len(line.V4) > 0 {
+		sb.WriteString(prefixLine)
+		sb.WriteString(line.V4)
+	}
+	if len(line.V5) > 0 {
+		sb.WriteString(prefixLine)
+		sb.WriteString(line.V5)
+	}
+
+	persist.LoadPolicyLine(sb.String(), model)
+}
+
+// LoadPolicy loads policy from database.
+func (a *Adapter) LoadPolicy(model model.Model) error {
+	var lines []*CasbinRule
+
+	if _, err := a.db.Query(&lines, `SELECT * FROM casbin_rules`); err != nil {
+		return err
+	}
+
+	for _, line := range lines {
+		loadPolicyLine(line, model)
+	}
+
+	return nil
+}
+
+func savePolicyLine(ptype string, rule []string) *CasbinRule {
+	line := &CasbinRule{PType: ptype}
+
+	l := len(rule)
+	if l > 0 {
+		line.V0 = rule[0]
+	}
+	if l > 1 {
+		line.V1 = rule[1]
+	}
+	if l > 2 {
+		line.V2 = rule[2]
+	}
+	if l > 3 {
+		line.V3 = rule[3]
+	}
+	if l > 4 {
+		line.V4 = rule[4]
+	}
+	if l > 5 {
+		line.V5 = rule[5]
+	}
+
+	return line
+}
+
+// SavePolicy saves policy to database.
+func (a *Adapter) SavePolicy(model model.Model) error {
+	err := a.dropTable()
+	if err != nil {
+		return err
+	}
+	err = a.createTable()
+	if err != nil {
+		return err
+	}
+
+	var lines []*CasbinRule
+
+	for ptype, ast := range model["p"] {
+		for _, rule := range ast.Policy {
+			line := savePolicyLine(ptype, rule)
+			lines = append(lines, line)
+		}
+	}
+
+	for ptype, ast := range model["g"] {
+		for _, rule := range ast.Policy {
+			line := savePolicyLine(ptype, rule)
+			lines = append(lines, line)
+		}
+	}
+
+	err = a.db.Insert(&lines)
+	return err
+}
+
+// AddPolicy adds a policy rule to the storage.
+func (a *Adapter) AddPolicy(sec string, ptype string, rule []string) error {
+	line := savePolicyLine(ptype, rule)
+	err := a.db.Insert(line)
+	return err
+}
+
+// RemovePolicy removes a policy rule from the storage.
+func (a *Adapter) RemovePolicy(sec string, ptype string, rule []string) error {
+	line := savePolicyLine(ptype, rule)
+	err := a.db.Delete(line)
+	return err
+}
+
+// RemoveFilteredPolicy removes policy rules that match the filter from the storage.
+func (a *Adapter) RemoveFilteredPolicy(sec string, ptype string, fieldIndex int, fieldValues ...string) error {
+	line := &CasbinRule{PType: ptype}
+
+	idx := fieldIndex + len(fieldValues)
+	if fieldIndex <= 0 && idx > 0 {
+		line.V0 = fieldValues[0-fieldIndex]
+	}
+	if fieldIndex <= 1 && idx > 1 {
+		line.V1 = fieldValues[1-fieldIndex]
+	}
+	if fieldIndex <= 2 && idx > 2 {
+		line.V2 = fieldValues[2-fieldIndex]
+	}
+	if fieldIndex <= 3 && idx > 3 {
+		line.V3 = fieldValues[3-fieldIndex]
+	}
+	if fieldIndex <= 4 && idx > 4 {
+		line.V4 = fieldValues[4-fieldIndex]
+	}
+	if fieldIndex <= 5 && idx > 5 {
+		line.V5 = fieldValues[5-fieldIndex]
+	}
+
+	err := a.db.Delete(line)
+	return err
+}