feature: saving files as blob in database

+ files (e.g. branding pictues, attachments) can be saved as a blob in a database. The feature can be turned
  on and off (feature toggle) with the env var FILE_STORAGE_MODE

+ a new controller with the endpoints /file/branding etc. had to be
  created since the files are statically linked when fs is used.

+ the files plus metadata are stored in the table 'file'

Author: broccoli

cmd/wire_gen.go

@@ -53,4 +53,5 @@ var ProviderSetController = wire.NewSet(
 	NewEmbedController,
 	NewBadgeController,
 	NewRenderController,
+	NewFileController,
 )

internal/controller/controller.go

@@ -0,0 +1,36 @@
+package controller
+
+import (
+	"strconv"
+
+	"github.com/apache/answer/internal/base/handler"
+	"github.com/apache/answer/internal/repo/file"
+	"github.com/gin-gonic/gin"
+)
+
+type FileController struct {
+	FileRepo file.FileRepo
+}
+
+func NewFileController(repo file.FileRepo) *FileController {
+	return &FileController{FileRepo: repo}
+}
+
+func (bc *FileController) GetFile(ctx *gin.Context) {
+	id := ctx.Param("id")
+	download := ctx.DefaultQuery("download", "")
+
+	blob, err := bc.FileRepo.GetByID(ctx.Request.Context(), id)
+	if err != nil || blob == nil {
+		handler.HandleResponse(ctx, err, "file not found")
+		return
+	}
+
+	ctx.Header("Content-Type", blob.MimeType)
+	ctx.Header("Content-Length", strconv.FormatInt(blob.Size, 10))
+	if download != "" {
+		ctx.Header("Content-Disposition", "attachment; filename=\""+download+"\"")
+	}
+
+	ctx.Data(200, blob.MimeType, blob.Content)
+}

internal/controller/file_controller.go

@@ -0,0 +1,18 @@
+package entity
+
+import (
+	"time"
+)
+
+type File struct {
+	ID        string    `xorm:"pk varchar(36)"`
+	FileName  string    `xorm:"varchar(255) not null"`
+	MimeType  string    `xorm:"varchar(100)"`
+	Size      int64     `xorm:"bigint"`
+	Content   []byte    `xorm:"blob"`
+	CreatedAt time.Time `xorm:"created"`
+}
+
+func (File) TableName() string {
+	return "file"
+}

internal/entity/file_entity.go

@@ -76,6 +76,7 @@ var (
 		&entity.BadgeAward{},
 		&entity.FileRecord{},
 		&entity.PluginKVStorage{},
+		&entity.File{},
 	}
 
 	roles = []*entity.Role{

internal/migrations/init_data.go

@@ -0,0 +1,44 @@
+package file
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/apache/answer/internal/base/data"
+	"github.com/apache/answer/internal/base/reason"
+	"github.com/apache/answer/internal/entity"
+	"github.com/segmentfault/pacman/errors"
+)
+
+type FileRepo interface {
+	Save(ctx context.Context, file *entity.File) error
+	GetByID(ctx context.Context, id string) (*entity.File, error)
+}
+
+type fileRepo struct {
+	data *data.Data
+}
+
+func NewFileRepo(data *data.Data) FileRepo {
+	return &fileRepo{data: data}
+}
+
+func (r *fileRepo) Save(ctx context.Context, file *entity.File) error {
+	_, err := r.data.DB.Context(ctx).Insert(file)
+	if err != nil {
+		return errors.InternalServer(reason.DatabaseError).WithError(err).WithStack()
+	}
+	return nil
+}
+
+func (r *fileRepo) GetByID(ctx context.Context, id string) (*entity.File, error) {
+	var blob entity.File
+	ok, err := r.data.DB.Context(ctx).ID(id).Get(&blob)
+	if err != nil {
+		return nil, errors.InternalServer(reason.DatabaseError).WithError(err).WithStack()
+	}
+	if !ok {
+		return nil, sql.ErrNoRows
+	}
+	return &blob, nil
+}

internal/repo/file/file_repo.go

@@ -57,6 +57,7 @@ type AnswerAPIRouter struct {
 	metaController          *controller.MetaController
 	badgeController         *controller.BadgeController
 	adminBadgeController    *controller_admin.BadgeController
+	fileController          *controller.FileController
 }
 
 func NewAnswerAPIRouter(
@@ -90,6 +91,7 @@ func NewAnswerAPIRouter(
 	metaController *controller.MetaController,
 	badgeController *controller.BadgeController,
 	adminBadgeController *controller_admin.BadgeController,
+	fileController *controller.FileController,
 ) *AnswerAPIRouter {
 	return &AnswerAPIRouter{
 		langController:          langController,
@@ -122,6 +124,7 @@ func NewAnswerAPIRouter(
 		metaController:          metaController,
 		badgeController:         badgeController,
 		adminBadgeController:    adminBadgeController,
+		fileController:          fileController,
 	}
 }
 
@@ -148,6 +151,9 @@ func (a *AnswerAPIRouter) RegisterMustUnAuthAnswerAPIRouter(authUserMiddleware *
 
 	// plugins
 	r.GET("/plugin/status", a.pluginController.GetAllPluginStatus)
+
+	// file branding
+	r.GET("/file/branding/:id", a.fileController.GetFile)
 }
 
 func (a *AnswerAPIRouter) RegisterUnAuthAnswerAPIRouter(r *gin.RouterGroup) {
@@ -171,6 +177,10 @@ func (a *AnswerAPIRouter) RegisterUnAuthAnswerAPIRouter(r *gin.RouterGroup) {
 	r.GET("/personal/question/page", a.questionController.PersonalQuestionPage)
 	r.GET("/question/link", a.questionController.GetQuestionLink)
 
+	//file
+	r.GET("/file/post/:id", a.fileController.GetFile)
+	r.GET("/file/avatar/:id", a.fileController.GetFile)
+
 	// comment
 	r.GET("/comment/page", a.commentController.GetCommentWithPage)
 	r.GET("/personal/comment/page", a.commentController.GetCommentPersonalWithPage)
@@ -310,6 +320,7 @@ func (a *AnswerAPIRouter) RegisterAnswerAPIRouter(r *gin.RouterGroup) {
 
 	// meta
 	r.PUT("/meta/reaction", a.metaController.AddOrUpdateReaction)
+
 }
 
 func (a *AnswerAPIRouter) RegisterAnswerAdminAPIRouter(r *gin.RouterGroup) {

internal/router/answer_api_router.go

@@ -20,6 +20,7 @@
 package service
 
 import (
+	"github.com/apache/answer/internal/repo/file"
 	"github.com/apache/answer/internal/service/action"
 	"github.com/apache/answer/internal/service/activity"
 	"github.com/apache/answer/internal/service/activity_common"
@@ -40,7 +41,7 @@ import (
 	"github.com/apache/answer/internal/service/follow"
 	"github.com/apache/answer/internal/service/importer"
 	"github.com/apache/answer/internal/service/meta"
-	"github.com/apache/answer/internal/service/meta_common"
+	metacommon "github.com/apache/answer/internal/service/meta_common"
 	"github.com/apache/answer/internal/service/notice_queue"
 	"github.com/apache/answer/internal/service/notification"
 	notficationcommon "github.com/apache/answer/internal/service/notification_common"
@@ -128,4 +129,5 @@ var ProviderSetService = wire.NewSet(
 	badge.NewBadgeGroupService,
 	importer.NewImporterService,
 	file_record.NewFileRecordService,
+	file.NewFileRepo,
 )