feat: implement ListFiles and DownloadFile RPCs with documentation updates in GRPC.md

examples/grpcentity/server.go

@@ -7,16 +7,30 @@ import (
 	"io"
 	"math/rand"
 	"net"
+	"sync"
 	"time"
 
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/reflection"
+	"google.golang.org/grpc/status"
 )
 
 var min = 0
 var max = 100
 var port = ":8080"
 
+type UploadedFile struct {
+	FileName   string
+	Content    []byte
+	UploadedAt int64
+}
+
+var (
+	fileStore = make(map[string]*UploadedFile)
+	storeMu   sync.RWMutex
+)
+
 func random(min, max int, src rand.Source) int {
 	return rand.New(src).Intn(max-min) + min
 }
@@ -89,11 +103,23 @@ func (IoTServer) GetRandomPass(ctx context.Context, r *protoapi.RequestPass) (*p
 func (IoTServer) UploadFile(stream protoapi.IoTService_UploadFileServer) error {
 	var totalBytes int64
 	var fileName string
+	var buffer []byte
 
 	for {
 		chunk, err := stream.Recv()
 		if err == io.EOF {
 			fmt.Printf("File upload completed. Received %d bytes for file '%s'\n", totalBytes, fileName)
+
+			if fileName != "" {
+				storeMu.Lock()
+				fileStore[fileName] = &UploadedFile{
+					FileName:   fileName,
+					Content:    buffer,
+					UploadedAt: time.Now().Unix(),
+				}
+				storeMu.Unlock()
+			}
+
 			return stream.SendAndClose(&protoapi.UploadStatus{
 				Success:       true,
 				Message:       fmt.Sprintf("File '%s' uploaded successfully.", fileName),
@@ -108,10 +134,57 @@ func (IoTServer) UploadFile(stream protoapi.IoTService_UploadFileServer) error {
 		if fileName == "" {
 			fileName = chunk.GetFileName()
 		}
+		buffer = append(buffer, chunk.GetContent()...)
 		totalBytes += int64(len(chunk.GetContent()))
 	}
 }
 
+func (IoTServer) ListFiles(ctx context.Context, r *protoapi.EmptyRequest) (*protoapi.FileList, error) {
+	storeMu.RLock()
+	defer storeMu.RUnlock()
+
+	var files []*protoapi.FileMetadata
+	for _, f := range fileStore {
+		files = append(files, &protoapi.FileMetadata{
+			FileName:   f.FileName,
+			FileSize:   int64(len(f.Content)),
+			UploadedAt: f.UploadedAt,
+		})
+	}
+
+	return &protoapi.FileList{Files: files}, nil
+}
+
+func (IoTServer) DownloadFile(r *protoapi.DownloadRequest, stream protoapi.IoTService_DownloadFileServer) error {
+	storeMu.RLock()
+	f, exists := fileStore[r.GetFileName()]
+	storeMu.RUnlock()
+
+	if !exists {
+		return status.Errorf(codes.NotFound, "file %s not found", r.GetFileName())
+	}
+
+	chunkSize := 1024 // 1KB 청크 단위
+	totalBytes := len(f.Content)
+
+	for i := 0; i < totalBytes; i += chunkSize {
+		end := i + chunkSize
+		if end > totalBytes {
+			end = totalBytes
+		}
+
+		err := stream.Send(&protoapi.FileChunk{
+			FileName: f.FileName,
+			Content:  f.Content[i:end],
+		})
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func ServerRun(addr string) {
 	server := grpc.NewServer()
 	var iotServer IoTServer