chore: initial commit of ai site platform

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/internal/agentcap/capsule.go

@@ -0,0 +1,121 @@
+package agentcap
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+
+	"golang.org/x/crypto/hkdf"
+)
+
+const Prefix = "AJZ1"
+
+// Descriptor 智能体解密后才能看到的请求契约（前端不展示明文）。
+type Descriptor struct {
+	Version    string           `json:"v"`
+	BaseURL    string           `json:"base_url"`
+	AppSlug    string           `json:"app_slug"`
+	TenantHint string           `json:"tenant_hint,omitempty"`
+	Auth       AuthSpec         `json:"auth"`
+	Resources  []ResourceSpec   `json:"resources"`
+	Notes      string           `json:"notes,omitempty"`
+}
+
+type AuthSpec struct {
+	Type   string `json:"type"` // bearer_jwt
+	Header string `json:"header"`
+}
+
+type ResourceSpec struct {
+	Name       string   `json:"name"`
+	Path       string   `json:"path"`
+	Methods    []string `json:"methods"`
+	Filters    []string `json:"filters,omitempty"`
+	Sorts      []string `json:"sorts,omitempty"`
+	Fields     []FieldSpec `json:"fields,omitempty"`
+	PrimaryKey string   `json:"primary_key"`
+}
+
+type FieldSpec struct {
+	Name string `json:"name"`
+	Type string `json:"type"`
+}
+
+func DeriveKey(masterSecret string, tenantID int64, userID int64) []byte {
+	h := hkdf.New(sha256.New, []byte(masterSecret), []byte("aijianzhan-agent-v1"), []byte(fmt.Sprintf("%d:%d", tenantID, userID)))
+	key := make([]byte, 32)
+	_, _ = io.ReadFull(h, key)
+	return key
+}
+
+func Encrypt(key []byte, desc *Descriptor) (string, error) {
+	raw, err := json.Marshal(desc)
+	if err != nil {
+		return "", err
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", err
+	}
+	ciphertext := gcm.Seal(nil, nonce, raw, nil)
+	return fmt.Sprintf("%s.%s.%s",
+		Prefix,
+		base64.RawURLEncoding.EncodeToString(nonce),
+		base64.RawURLEncoding.EncodeToString(ciphertext),
+	), nil
+}
+
+func Decrypt(key []byte, capsule string) (*Descriptor, error) {
+	parts := strings.Split(capsule, ".")
+	if len(parts) != 3 || parts[0] != Prefix {
+		return nil, fmt.Errorf("invalid capsule format")
+	}
+	nonce, err := base64.RawURLEncoding.DecodeString(parts[1])
+	if err != nil {
+		return nil, err
+	}
+	ciphertext, err := base64.RawURLEncoding.DecodeString(parts[2])
+	if err != nil {
+		return nil, err
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+	plain, err := gcm.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return nil, fmt.Errorf("decrypt failed")
+	}
+	var desc Descriptor
+	if err := json.Unmarshal(plain, &desc); err != nil {
+		return nil, err
+	}
+	return &desc, nil
+}
+
+func PublicAgentKey(masterSecret string, tenantID, userID int64) string {
+	key := DeriveKey(masterSecret, tenantID, userID)
+	return base64.RawURLEncoding.EncodeToString(key)
+}
+
+func ParseAgentKey(b64 string) ([]byte, error) {
+	return base64.RawURLEncoding.DecodeString(b64)
+}