Version: 0.9.73.dev.260505

后端：
1.阶段 5 course 服务边界落地
- 新增 cmd/course 独立进程入口，落地 services/course dao/rpc/sv
- 新增 gateway/client/course、shared/contracts/course 和 shared/ports course port
- 将 /api/v1/course/* HTTP 门面切到 course zrpc，gateway 只保留鉴权、限流、幂等、文件读取和响应透传
- 保留 course 迁移期直写 schedule_events / schedules 权限，维持课程导入两个表同事务写入语义
- 为 course parse-image 补 bytes RPC 契约和 gRPC 消息大小配置，兼容课表图片上传
- 补充 course.rpc 示例配置与阶段 5 文档基线、切流点、残留依赖和 smoke 记录

backend/gateway/client/course/client.go

@@ -0,0 +1,162 @@
+package course
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"strings"
+	"time"
+
+	coursepb "github.com/LoveLosita/smartflow/backend/services/course/rpc/pb"
+	coursecontracts "github.com/LoveLosita/smartflow/backend/shared/contracts/course"
+	"github.com/zeromicro/go-zero/zrpc"
+	"google.golang.org/grpc"
+)
+
+const (
+	defaultEndpoint          = "127.0.0.1:9087"
+	defaultTimeout           = 10 * time.Second
+	defaultMaxRPCMessageSize = 8 * 1024 * 1024
+	rpcMessageSizePadding    = 1024 * 1024
+)
+
+type ClientConfig struct {
+	Endpoints     []string
+	Target        string
+	Timeout       time.Duration
+	MaxImageBytes int64
+}
+
+// Client 是 gateway 访问 course zrpc 的最小适配层。
+//
+// 职责边界：
+// 1. 只负责跨进程 gRPC 调用和 JSON/bytes 透传，不触碰 DAO；
+// 2. HTTP 入参仍由 gateway/api 做基础绑定，业务校验交给 course 服务；
+// 3. import 冲突通过 CourseImportConflictError 返回，让 HTTP 层保留 409 + conflicts 数据。
+type Client struct {
+	rpc coursepb.CourseClient
+}
+
+func NewClient(cfg ClientConfig) (*Client, error) {
+	timeout := cfg.Timeout
+	if timeout <= 0 {
+		timeout = defaultTimeout
+	}
+	endpoints := normalizeEndpoints(cfg.Endpoints)
+	target := strings.TrimSpace(cfg.Target)
+	if len(endpoints) == 0 && target == "" {
+		endpoints = []string{defaultEndpoint}
+	}
+
+	maxMessageSize := normalizeMaxRPCMessageSize(cfg.MaxImageBytes)
+	zclient, err := zrpc.NewClient(zrpc.RpcClientConf{
+		Endpoints: endpoints,
+		Target:    target,
+		NonBlock:  true,
+		Timeout:   int64(timeout / time.Millisecond),
+	}, zrpc.WithDialOption(grpc.WithDefaultCallOptions(
+		grpc.MaxCallRecvMsgSize(maxMessageSize),
+		grpc.MaxCallSendMsgSize(maxMessageSize),
+	)))
+	if err != nil {
+		return nil, err
+	}
+	client := &Client{rpc: coursepb.NewCourseClient(zclient.Conn())}
+	if err := client.ping(timeout); err != nil {
+		return nil, err
+	}
+	return client, nil
+}
+
+func (c *Client) ValidateCourse(ctx context.Context, req coursecontracts.UserCheckCourseRequest) error {
+	_, err := c.callJSON(ctx, c.rpc.ValidateCourse, req)
+	return responseFromRPCError(err)
+}
+
+func (c *Client) ImportCourses(ctx context.Context, req coursecontracts.UserImportCoursesRequest) (json.RawMessage, error) {
+	resp, err := c.callJSON(ctx, c.rpc.ImportCourses, req)
+	raw, err := jsonFromResponse(resp, err)
+	if err != nil {
+		return nil, err
+	}
+	var result coursecontracts.ImportCoursesResult
+	if err := json.Unmarshal(raw, &result); err != nil {
+		return nil, err
+	}
+	if result.Conflict {
+		return nil, CourseImportConflictError{conflicts: result.Conflicts}
+	}
+	return raw, nil
+}
+
+func (c *Client) ParseCourseTableImage(ctx context.Context, req coursecontracts.CourseImageParseRequest) (json.RawMessage, error) {
+	resp, err := c.rpc.ParseCourseImage(ctx, &coursepb.CourseImageRequest{
+		Filename:   req.Filename,
+		MimeType:   req.MIMEType,
+		ImageBytes: req.ImageBytes,
+	})
+	return jsonFromResponse(resp, err)
+}
+
+func (c *Client) ensureReady() error {
+	if c == nil || c.rpc == nil {
+		return errors.New("course zrpc client is not initialized")
+	}
+	return nil
+}
+
+func (c *Client) ping(timeout time.Duration) error {
+	if err := c.ensureReady(); err != nil {
+		return err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	_, err := c.rpc.Ping(ctx, &coursepb.StatusResponse{})
+	return responseFromRPCError(err)
+}
+
+func (c *Client) callJSON(ctx context.Context, fn func(context.Context, *coursepb.JSONRequest, ...grpc.CallOption) (*coursepb.JSONResponse, error), payload any) (*coursepb.JSONResponse, error) {
+	if err := c.ensureReady(); err != nil {
+		return nil, err
+	}
+	raw, err := json.Marshal(payload)
+	if err != nil {
+		return nil, err
+	}
+	return fn(ctx, &coursepb.JSONRequest{PayloadJson: raw})
+}
+
+func jsonFromResponse(resp *coursepb.JSONResponse, rpcErr error) (json.RawMessage, error) {
+	if rpcErr != nil {
+		return nil, responseFromRPCError(rpcErr)
+	}
+	if resp == nil {
+		return nil, errors.New("course zrpc service returned empty JSON response")
+	}
+	if len(resp.DataJson) == 0 {
+		return json.RawMessage("null"), nil
+	}
+	return json.RawMessage(resp.DataJson), nil
+}
+
+func normalizeEndpoints(values []string) []string {
+	endpoints := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed != "" {
+			endpoints = append(endpoints, trimmed)
+		}
+	}
+	return endpoints
+}
+
+func normalizeMaxRPCMessageSize(maxImageBytes int64) int {
+	if maxImageBytes <= 0 {
+		return defaultMaxRPCMessageSize
+	}
+	size := maxImageBytes + rpcMessageSizePadding
+	if size < defaultMaxRPCMessageSize {
+		return defaultMaxRPCMessageSize
+	}
+	return int(size)
+}