feat: implement legacy config auth storage and core api

chfs-ng/internal/auth/auth.go

@@ -1,5 +1,12 @@
 package auth
 
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"strings"
+)
+
 type PermMask uint8
 
 const (
@@ -12,8 +19,116 @@ const (
 func (p PermMask) HasRead() bool   { return p&Read != 0 }
 func (p PermMask) HasWrite() bool  { return p&Write != 0 }
 func (p PermMask) HasDelete() bool { return p&Delete != 0 }
+func ParseMask(s string) PermMask {
+	var p PermMask
+	for _, r := range strings.ToLower(s) {
+		switch r {
+		case 'r':
+			p |= Read
+		case 'w':
+			p |= Read | Write
+		case 'd':
+			p |= Read | Write | Delete
+		}
+	}
+	return p
+}
 
+type PathRule struct {
+	Dir  string
+	Mask PermMask
+}
 type Account struct {
 	Username, Password string
 	Mask               PermMask
+	Rules              []PathRule
+}
+type Manager struct {
+	Accounts map[string]*Account
+	Guest    *Account
+}
+
+func ParseRules(values []string) (*Manager, error) {
+	m := &Manager{Accounts: map[string]*Account{}}
+	for _, value := range values {
+		for _, item := range strings.Split(value, "|") {
+			if item == "" {
+				continue
+			}
+			fields := strings.Split(item, ":")
+			if len(fields) < 3 || len(fields)%2 == 0 {
+				continue
+			}
+			a := &Account{Username: fields[0], Password: fields[1], Mask: ParseMask(fields[2])}
+			for i := 3; i+1 < len(fields); i += 2 {
+				a.Rules = append(a.Rules, PathRule{Dir: strings.Trim(fields[i], "/"), Mask: ParseMask(fields[i+1])})
+			}
+			if a.Username == "" {
+				m.Guest = a
+			} else {
+				m.Accounts[a.Username] = a
+			}
+		}
+	}
+	if m.Guest == nil {
+		m.Guest = &Account{Mask: Read | Write}
+	}
+	return m, nil
+}
+
+func (m *Manager) Authenticate(user, pwd string) *Account {
+	if a, ok := m.Accounts[user]; ok && a.Password == pwd {
+		return a
+	}
+	if user == "" && pwd == "" {
+		return m.Guest
+	}
+	return nil
+}
+func (a *Account) MaskFor(path string) PermMask {
+	path = strings.Trim(path, "/")
+	best := -1
+	mask := a.Mask
+	for _, r := range a.Rules {
+		d := strings.Trim(r.Dir, "/")
+		if matchPath(d, path) && len(d) > best {
+			best = len(d)
+			mask = r.Mask
+		}
+	}
+	return mask
+}
+func matchPath(pattern, path string) bool {
+	if pattern == "" {
+		return path == ""
+	}
+	pp := strings.Split(pattern, "/")
+	ps := strings.Split(path, "/")
+	if len(ps) < len(pp) {
+		return false
+	}
+	for i, p := range pp {
+		if p == "*" {
+			return true
+		}
+		if p == "?" {
+			if ps[i] == "" {
+				return false
+			}
+			continue
+		}
+		if p != ps[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func NewToken() string {
+	b := make([]byte, 32)
+	if _, e := rand.Read(b); e != nil {
+		h := sha256.Sum256([]byte("fallback"))
+		return hex.EncodeToString(h[:])
+	}
+	return hex.EncodeToString(b)
 }