Add plugin API for UploadFile method (#9684)

* Add plugin API for UploadFile method

* Add minimum server version documentation to plugin API UploadFile function

* Reorganize some imports

app/file.go

@@ -397,6 +397,25 @@ func (a *App) UploadFiles(teamId string, channelId string, userId string, files
 	return resStruct, nil
 }
 
+// UploadFile uploads a single file in form of a completely constructed byte array for a channel.
+func (a *App) UploadFile(data []byte, channelId string, filename string) (*model.FileInfo, *model.AppError) {
+	info, _, appError := a.DoUploadFileExpectModification(time.Now(), "noteam", channelId, "nouser", filename, data)
+
+	if appError != nil {
+		return nil, appError
+	}
+
+	if info.PreviewPath != "" || info.ThumbnailPath != "" {
+		previewPathList := []string{info.PreviewPath}
+		thumbnailPathList := []string{info.ThumbnailPath}
+		imageDataList := [][]byte{data}
+
+		a.HandleImages(previewPathList, thumbnailPathList, imageDataList)
+	}
+
+	return info, nil
+}
+
 func (a *App) DoUploadFile(now time.Time, rawTeamId string, rawChannelId string, rawUserId string, rawFilename string, data []byte) (*model.FileInfo, *model.AppError) {
 	info, _, err := a.DoUploadFileExpectModification(now, rawTeamId, rawChannelId, rawUserId, rawFilename, data)
 	return info, err

app/file_test.go

@@ -107,6 +107,30 @@ func TestDoUploadFile(t *testing.T) {
 	}
 }
 
+func TestUploadFile(t *testing.T) {
+	th := Setup()
+	defer th.TearDown()
+
+	channelId := model.NewId()
+	filename := "test"
+	data := []byte("abcd")
+
+	info1, err := th.App.UploadFile(data, channelId, filename)
+	if err != nil {
+		t.Fatal(err)
+	} else {
+		defer func() {
+			<-th.App.Srv.Store.FileInfo().PermanentDelete(info1.Id)
+			th.App.RemoveFile(info1.Path)
+		}()
+	}
+
+	if info1.Path != fmt.Sprintf("%v/teams/noteam/channels/%v/users/nouser/%v/%v",
+		time.Now().Format("20060102"), channelId, info1.Id, filename) {
+		t.Fatal("stored file at incorrect path", info1.Path)
+	}
+}
+
 func TestGetInfoForFilename(t *testing.T) {
 	th := Setup().InitBasic()
 	defer th.TearDown()

app/plugin_api.go

@@ -430,6 +430,10 @@ func (api *PluginAPI) ReadFile(path string) ([]byte, *model.AppError) {
 	return api.app.ReadFile(path)
 }
 
+func (api *PluginAPI) UploadFile(data []byte, channelId string, filename string) (*model.FileInfo, *model.AppError) {
+	return api.app.UploadFile(data, channelId, filename)
+}
+
 func (api *PluginAPI) GetEmojiImage(emojiId string) ([]byte, string, *model.AppError) {
 	return api.app.GetEmojiImage(emojiId)
 }