file-upload

File Upload Example

This example demonstrates file upload and download in DotWeb.

Features

• Single file upload
• Multiple file upload
• File download
• List uploaded files
• Delete files
• File size limits

Running

cd example/file-upload
go run main.go

Testing

Upload Single File

# Create a test file
echo "Hello, DotWeb!" > test.txt

# Upload file
curl -F '[email protected]' http://localhost:8080/upload
# Output:
# ✅ File uploaded!
# 📁 Name: test.txt
# 📊 Size: 14 bytes
# 📍 Path: ./uploads/test.txt

Upload Multiple Files

curl -F '[email protected]' -F '[email protected]' http://localhost:8080/upload/multiple
# Output:
# Uploaded 2 files:
# [✅ file1.txt ✅ file2.txt]

List Files

curl http://localhost:8080/files
# Output:
# 📂 Uploaded files:
# 📁 test.txt (14 bytes)

Download File

curl http://localhost:8080/download/test.txt -o downloaded.txt

Delete File

curl -X DELETE http://localhost:8080/files/test.txt
# Output: ✅ File deleted: test.txt

API Reference

Upload File

// Get single file
file, header, err := ctx.Request().FormFile("file")

// Get file content
data, err := io.ReadAll(file)

// Get file name
filename := header.Filename

Upload Multiple Files

// Parse multipart form
err := ctx.Request().ParseMultipartForm(32 << 20) // 32MB

// Get all files
files := ctx.Request().MultipartForm.File["files"]

Download File

// Set headers for download
ctx.Response().Header().Set("Content-Disposition", "attachment; filename="+filename)
ctx.Response().Header().Set("Content-Type", "application/octet-stream")

// Send file data
data, _ := os.ReadFile(filePath)
ctx.Write(200, data)

Configuration

Set Max Body Size

// 10MB limit
app.HttpServer.SetMaxBodySize(10 * 1024 * 1024)

// Unlimited
app.HttpServer.SetMaxBodySize(-1)

File Upload Helper

DotWeb provides a built-in upload file helper:

// Using UploadFile helper
uploadFile := ctx.Request().UploadFile("file")
if uploadFile != nil {
    filename := uploadFile.Filename
    data := uploadFile.Data  // []byte
    size := len(data)
}

Common Patterns

Validate File Type

func isValidFileType(filename string) bool {
    ext := strings.ToLower(filepath.Ext(filename))
    allowed := []string{".jpg", ".jpeg", ".png", ".gif", ".pdf"}
    for _, a := range allowed {
        if ext == a {
            return true
        }
    }
    return false
}

Generate Unique Filename

import "github.com/google/uuid"

func uniqueFilename(filename string) string {
    ext := filepath.Ext(filename)
    return uuid.New().String() + ext
}

Check File Size

func checkFileSize(size int64, maxSize int64) bool {
    return size <= maxSize
}

Notes

• Always validate uploaded files
• Set appropriate max body size
• Use unique filenames to avoid conflicts
• Check file types for security
• Clean up old files periodically