feat: file upload and download

models/app_file.go

@@ -0,0 +1,28 @@
+package models
+
+import "gorm.io/gorm"
+
+type AppFileType string
+
+const (
+	AppFileTypeLessonPlan AppFileType = "lesson_plan"
+)
+
+type AppFile struct {
+	gorm.Model
+	FileType         AppFileType `gorm:"type:varchar(64);not null;index" json:"fileType"`
+	OriginalFilename string      `gorm:"size:255;not null" json:"originalFilename"`
+	StoredFilename   string      `gorm:"size:255;not null;uniqueIndex" json:"storedFilename"`
+	FilePath         string      `gorm:"size:1024;not null" json:"filePath"`
+	ContentType      string      `gorm:"size:255;not null" json:"contentType"`
+	FileSize         int64       `gorm:"not null" json:"fileSize"`
+	MD5              string      `gorm:"size:32;not null;uniqueIndex" json:"md5"`
+	UploaderID       uint        `gorm:"not null;index" json:"uploaderId"`
+	UploaderName     string      `gorm:"size:255;not null;index" json:"uploaderName"`
+	DownloadCount    int64       `gorm:"not null;default:0" json:"downloadCount"`
+	LastDownloadAt   *int64      `gorm:"type:bigint;index" json:"lastDownloadAt"`
+}
+
+func (AppFile) TableName() string {
+	return "app_files"
+}