feat: support pdf assignment detail

Author: riflowth

domain/assignment.go

@@ -60,7 +60,7 @@ type CreateAssignment struct {
 	Level         AssignmentLevel
 	PublishDate   time.Time
 	DueDate       *time.Time
-	DetailFile    io.Reader
+	DetailFile    *File
 	TestcaseFiles []TestcaseFile
 }
 
@@ -72,7 +72,7 @@ type UpdateAssignment struct {
 	Level         *AssignmentLevel
 	PublishDate   *time.Time
 	DueDate       *time.Time
-	DetailFile    io.Reader
+	DetailFile    *File
 	TestcaseFiles *[]TestcaseFile
 }
 

domain/domain.go

@@ -1,6 +1,8 @@
 package domain
 
 import (
+	"io"
+
 	"github.com/codern-org/codern/platform"
 )
 
@@ -34,3 +36,8 @@ type Usecase struct {
 type Publisher struct {
 	Grading GradingPublisher
 }
+
+type File struct {
+	Reader   io.Reader
+	MimeType string
+}

internal/validator/payload.go

@@ -3,8 +3,11 @@ package validator
 import (
 	"errors"
 	"fmt"
+	"io"
 	"mime/multipart"
+	"net/http"
 	"reflect"
+	"strings"
 
 	"github.com/codern-org/codern/domain"
 	errs "github.com/codern-org/codern/domain/error"
@@ -123,3 +126,35 @@ func fileParser(payload interface{}, ctx *fiber.Ctx) error {
 
 	return nil
 }
+
+func GetMimeType(seeker io.ReadSeeker) (string, error) {
+	if seeker == nil {
+		return "", nil
+	}
+
+	// https://golang.org/src/net/http/sniff.go?s=646:688#L11
+	buf := make([]byte, 512)
+
+	_, err := seeker.Seek(0, io.SeekStart)
+	if err != nil {
+		return "", err
+	}
+
+	bytesRead, err := seeker.Read(buf)
+	if err != nil && err != io.EOF {
+		return "", err
+	}
+
+	_, err = seeker.Seek(0, 0)
+	if err != nil {
+		return "", err
+	}
+
+	// Slice buf to remove fill-up zero values which cause a wrong content type detection
+	mimeType := http.DetectContentType(buf[:bytesRead])
+
+	mimeType, _, _ = strings.Cut(mimeType, ";")
+	mimeType = strings.TrimSpace(mimeType)
+
+	return mimeType, nil
+}

platform/server/controller/assignment.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/codern-org/codern/domain"
 	errs "github.com/codern-org/codern/domain/error"
+	"github.com/codern-org/codern/internal/validator"
 	"github.com/codern-org/codern/platform/server/middleware"
 	"github.com/codern-org/codern/platform/server/payload"
 	"github.com/codern-org/codern/platform/server/response"
@@ -39,18 +40,29 @@ func (c *AssignmentController) Create(ctx *fiber.Ctx) error {
 	user := middleware.GetUserFromCtx(ctx)
 	testcaseFiles := domain.CreateTestcaseFiles(pl.TestcaseInputFiles, pl.TestcaseOutputFiles)
 
+	fileMimeType, err := validator.GetMimeType(pl.DetailFile)
+	if err != nil {
+		return err
+	}
+	if fileMimeType != "text/plain" && fileMimeType != "application/pdf" {
+		return errs.New(errs.ErrBodyParser, "unsupported file type")
+	}
+
 	if err := c.assignmentUsecase.Create(
 		user.Id,
 		pl.WorkspaceId,
 		&domain.CreateAssignment{
-			Name:          pl.Name,
-			Description:   pl.Description,
-			MemoryLimit:   pl.MemoryLimit,
-			TimeLimit:     pl.TimeLimit,
-			Level:         pl.Level,
-			PublishDate:   pl.PublishDate,
-			DueDate:       pl.DueDate,
-			DetailFile:    pl.DetailFile,
+			Name:        pl.Name,
+			Description: pl.Description,
+			MemoryLimit: pl.MemoryLimit,
+			TimeLimit:   pl.TimeLimit,
+			Level:       pl.Level,
+			PublishDate: pl.PublishDate,
+			DueDate:     pl.DueDate,
+			DetailFile: &domain.File{
+				Reader:   pl.DetailFile,
+				MimeType: fileMimeType,
+			},
 			TestcaseFiles: testcaseFiles,
 		},
 	); err != nil {
@@ -202,18 +214,29 @@ func (c *AssignmentController) Update(ctx *fiber.Ctx) error {
 	user := middleware.GetUserFromCtx(ctx)
 	testcaseFiles := domain.CreateTestcaseFiles(pl.TestcaseInputFiles, pl.TestcaseOutputFiles)
 
+	fileMimeType, err := validator.GetMimeType(pl.DetailFile)
+	if err != nil {
+		return err
+	}
+	if fileMimeType != "text/plain" && fileMimeType != "application/pdf" {
+		return errs.New(errs.ErrBodyParser, "unsupported file type")
+	}
+
 	if err := c.assignmentUsecase.Update(
 		user.Id,
 		pl.AssignmentId,
 		&domain.UpdateAssignment{
-			Name:          pl.Name,
-			Description:   pl.Description,
-			MemoryLimit:   pl.MemoryLimit,
-			TimeLimit:     pl.TimeLimit,
-			Level:         pl.Level,
-			PublishDate:   pl.PublishDate,
-			DueDate:       pl.DueDate,
-			DetailFile:    pl.DetailFile,
+			Name:        pl.Name,
+			Description: pl.Description,
+			MemoryLimit: pl.MemoryLimit,
+			TimeLimit:   pl.TimeLimit,
+			Level:       pl.Level,
+			PublishDate: pl.PublishDate,
+			DueDate:     pl.DueDate,
+			DetailFile: &domain.File{
+				Reader:   pl.DetailFile,
+				MimeType: fileMimeType,
+			},
 			TestcaseFiles: &testcaseFiles,
 		},
 	); err != nil {

usecase/assignment.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"math"
+	"strings"
 	"time"
 
 	"github.com/codern-org/codern/domain"
@@ -46,10 +47,15 @@ func (u *assignmentUsecase) Create(
 		return errs.New(errs.ErrWorkspaceNoPerm, "permission denied")
 	}
 
+	fileExt := "md"
+	if ca.DetailFile.MimeType == "application/pdf" {
+		fileExt = "pdf"
+	}
+
 	id := generator.GetId()
 	filePath := fmt.Sprintf(
-		"/workspaces/%d/assignments/%d/detail/problem.md",
-		workspaceId, id,
+		"/workspaces/%d/assignments/%d/detail/problem.%s",
+		workspaceId, id, fileExt,
 	)
 
 	assignment := &domain.Assignment{
@@ -70,7 +76,7 @@ func (u *assignmentUsecase) Create(
 	}
 
 	// TODO: retry strategy, error
-	if err := u.seaweedfs.Upload(ca.DetailFile, 0, filePath); err != nil {
+	if err := u.seaweedfs.Upload(ca.DetailFile.Reader, 0, filePath); err != nil {
 		return errs.New(errs.ErrFileSystem, "cannot upload file", err)
 	}
 
@@ -123,12 +129,21 @@ func (u *assignmentUsecase) Update(
 
 	assignment.DueDate = ua.DueDate
 
+	fileExt := "md"
+	if ua.DetailFile.MimeType == "application/pdf" {
+		fileExt = "pdf"
+	}
+	fileNameTokens := strings.Split(assignment.DetailUrl, "/")
+	fileName := fileNameTokens[len(fileNameTokens)-1]
+	fileName, _, _ = strings.Cut(fileName, ".")
+	assignment.DetailUrl = strings.Join(fileNameTokens[:len(fileNameTokens)-1], "/") + fmt.Sprintf("/%s.%s", fileName, fileExt)
+
 	if err := u.assignmentRepository.Update(assignment); err != nil {
 		return errs.New(errs.ErrUpdateAssignment, "cannot update assignment id %d", assignmentId, err)
 	}
 
 	// TODO: retry strategy, error
-	if err := u.seaweedfs.Upload(ua.DetailFile, 0, assignment.DetailUrl); err != nil {
+	if err := u.seaweedfs.Upload(ua.DetailFile.Reader, 0, assignment.DetailUrl); err != nil {
 		return errs.New(errs.ErrFileSystem, "cannot upload detail file while updating assignment id %d", assignmentId, err)
 	}