Feature/fileinfo create copy (#9198)

* Initial implementation of a CopyFileInfos function that creates new FileInfo objects copied from provided FileIds with the provided user as the creator and not linked to a post yet. This can subsequently be used to copy existing attachments from another post to attach to a new post without having to re-upload the actual files

* added a unit test for the CopyFileInfos function

* resolving pull request suggestions

6 files changed, 127 insertions, 0 deletions

diff --git a/app/file.go b/app/file.go
index 7dbcdd394..7a642a956 100644
--- a/app/file.go
+++ b/app/file.go
@@ -604,3 +604,33 @@ func (a *App) GetFileInfo(fileId string) (*model.FileInfo, *model.AppError) {
 		return result.Data.(*model.FileInfo), nil
 	}
 }
+
+func (a *App) CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError) {
+	newFileIds := []string{}
+
+	now := model.GetMillis()
+
+	for _, fileId := range fileIds {
+		fileInfo := &model.FileInfo{}
+
+		if result := <-a.Srv.Store.FileInfo().Get(fileId); result.Err != nil {
+			return nil, result.Err
+		} else {
+			fileInfo = result.Data.(*model.FileInfo)
+		}
+
+		fileInfo.Id = model.NewId()
+		fileInfo.CreatorId = userId
+		fileInfo.CreateAt = now
+		fileInfo.UpdateAt = now
+		fileInfo.PostId = ""
+
+		if result := <-a.Srv.Store.FileInfo().Save(fileInfo); result.Err != nil {
+			return newFileIds, result.Err
+		}
+
+		newFileIds = append(newFileIds, fileInfo.Id)
+	}
+
+	return newFileIds, nil
+}
diff --git a/app/file_test.go b/app/file_test.go
index 23750ad6e..c736328cf 100644
--- a/app/file_test.go
+++ b/app/file_test.go
@@ -161,3 +161,34 @@ func TestMigrateFilenamesToFileInfos(t *testing.T) {
 	infos = th.App.MigrateFilenamesToFileInfos(rpost)
 	assert.Equal(t, 1, len(infos))
 }
+
+func TestCopyFileInfos(t *testing.T) {
+	th := Setup().InitBasic()
+	defer th.TearDown()
+
+	teamId := model.NewId()
+	channelId := model.NewId()
+	userId := model.NewId()
+	filename := "test"
+	data := []byte("abcd")
+
+	info1, err := th.App.DoUploadFile(time.Date(2007, 2, 4, 1, 2, 3, 4, time.Local), teamId, channelId, userId, filename, data)
+	require.Nil(t, err)
+	defer func() {
+		<-th.App.Srv.Store.FileInfo().PermanentDelete(info1.Id)
+		th.App.RemoveFile(info1.Path)
+	}()
+
+	infoIds, err := th.App.CopyFileInfos(userId, []string{info1.Id})
+	require.Nil(t, err)
+
+	info2, err := th.App.GetFileInfo(infoIds[0])
+	require.Nil(t, err)
+	defer func() {
+		<-th.App.Srv.Store.FileInfo().PermanentDelete(info2.Id)
+		th.App.RemoveFile(info2.Path)
+	}()
+
+	assert.NotEqual(t, info1.Id, info2.Id, "should not be equal")
+	assert.Equal(t, info2.PostId, "", "should be empty string")
+}
diff --git a/app/plugin_api.go b/app/plugin_api.go
index 31bfd401d..c3ab8fab2 100644
--- a/app/plugin_api.go
+++ b/app/plugin_api.go
@@ -275,6 +275,10 @@ func (api *PluginAPI) UpdatePost(post *model.Post) (*model.Post, *model.AppError
 	return api.app.UpdatePost(post, false)
 }
 
+func (api *PluginAPI) CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError) {
+	return api.app.CopyFileInfos(userId, fileIds)
+}
+
 func (api *PluginAPI) KVSet(key string, value []byte) *model.AppError {
 	return api.app.SetPluginKey(api.id, key, value)
 }
diff --git a/plugin/api.go b/plugin/api.go
index d0ad178ca..927fd3c6a 100644
--- a/plugin/api.go
+++ b/plugin/api.go
@@ -155,6 +155,13 @@ type API interface {
 	// UpdatePost updates a post.
 	UpdatePost(post *model.Post) (*model.Post, *model.AppError)
 
+	// CopyFileInfos creates a copy of FileInfo objects provided in the list of FileIds
+	// these new FileInfo objects will not be linked to any post and will
+	// be ready to provide to a new CreatePost call
+	// this should be used when you want to create a copy of a post including
+	// file attachments without duplicating the file uploads
+	CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError)
+
 	// KVSet will store a key-value pair, unique per plugin.
 	KVSet(key string, value []byte) *model.AppError
 
diff --git a/plugin/client_rpc_generated.go b/plugin/client_rpc_generated.go
index b43b93c5b..9106f2fad 100644
--- a/plugin/client_rpc_generated.go
+++ b/plugin/client_rpc_generated.go
@@ -1820,6 +1820,36 @@ func (s *apiRPCServer) UpdatePost(args *Z_UpdatePostArgs, returns *Z_UpdatePostR
 	return nil
 }
 
+type Z_CopyFileInfosArgs struct {
+	A string
+	B []string
+}
+
+type Z_CopyFileInfosReturns struct {
+	A []string
+	B *model.AppError
+}
+
+func (g *apiRPCClient) CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError) {
+	_args := &Z_CopyFileInfosArgs{userId, fileIds}
+	_returns := &Z_CopyFileInfosReturns{}
+	if err := g.client.Call("Plugin.CopyFileInfos", _args, _returns); err != nil {
+		log.Printf("RPC call to CopyFileInfos API failed: %s", err.Error())
+	}
+	return _returns.A, _returns.B
+}
+
+func (s *apiRPCServer) CopyFileInfos(args *Z_CopyFileInfosArgs, returns *Z_CopyFileInfosReturns) error {
+	if hook, ok := s.impl.(interface {
+		CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError)
+	}); ok {
+		returns.A, returns.B = hook.CopyFileInfos(args.A, args.B)
+	} else {
+		return fmt.Errorf("API CopyFileInfos called but not implemented.")
+	}
+	return nil
+}
+
 type Z_KVSetArgs struct {
 	A string
 	B []byte
diff --git a/plugin/plugintest/api.go b/plugin/plugintest/api.go
index 35a83ca9c..cf9ffa6a8 100644
--- a/plugin/plugintest/api.go
+++ b/plugin/plugintest/api.go
@@ -37,6 +37,31 @@ func (_m *API) AddChannelMember(channelId string, userId string) (*model.Channel
 	return r0, r1
 }
 
+// CopyFileInfos provides a mock function with given fields: userId, fileIds
+func (_m *API) CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError) {
+	ret := _m.Called(userId, fileIds)
+
+	var r0 []string
+	if rf, ok := ret.Get(0).(func(string, []string) []string); ok {
+		r0 = rf(userId, fileIds)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]string)
+		}
+	}
+
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func(string, []string) *model.AppError); ok {
+		r1 = rf(userId, fileIds)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
+}
+
 // CreateChannel provides a mock function with given fields: channel
 func (_m *API) CreateChannel(channel *model.Channel) (*model.Channel, *model.AppError) {
 	ret := _m.Called(channel)