#1447 - back-end usage scenario

Add `FilesService` impl.

Author: 4ntoine

cli/daemon/daemon.go

@@ -35,6 +35,7 @@ import (
 	srv_debug "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/debug/v1"
 	srv_monitor "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/monitor/v1"
 	srv_settings "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/settings/v1"
+	srv_files "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/files/v1"
 	"github.com/segmentio/stats/v4"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -98,6 +99,9 @@ func runDaemonCommand(cmd *cobra.Command, args []string) {
 	// Register the debug session service
 	srv_debug.RegisterDebugServiceServer(s, &daemon.DebugService{})
 
+	// Register the files service
+	srv_files.RegisterFilesServiceServer(s, &daemon.FilesService{})
+
 	if !daemonize {
 		// When parent process ends terminate also the daemon
 		go func() {

commands/daemon/files.go

@@ -0,0 +1,41 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to [email protected].
+
+package daemon
+
+import (
+	"context"
+	"os"
+
+	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/files/v1"
+)
+
+// FilesService implements the `Files` service
+type FilesService struct {
+	rpc.UnimplementedFilesServiceServer
+}
+
+// LoadFile returns a requested file content or an error.
+func (s *FilesService) LoadFile(ctx context.Context, req *rpc.LoadFileRequest) (*rpc.LoadFileResponse, error) {
+	content, err := os.ReadFile(req.Path)
+	if err == nil {
+		return &rpc.LoadFileResponse{
+			Content: content,
+			Type: rpc.ContentType_CONTENT_TYPE_RAW_UNSPECIFIED,
+		}, nil
+	}
+
+	return nil, err
+}