Upload Middleware Configuration in Vkrun

Configuration

The Upload middleware provides multiple configuration options for both disk and memory storage.

Disk Storage

Use diskStorage to save files to the local filesystem.

Configuration Options

destination: The directory where files will be stored.
filename: A function to customize the stored file name.

Example: Disk Storage with Custom Validation

const upload = v.upload.diskStorage({
  destination: "./uploads",
  filename: (file) => `${file.fieldName}-${Date.now()}.${file.extension}`
}).singleFile({
  fieldName: "avatar",
  size: {
    value: 1000000,
    onError: (res) => res.status(413).json({ error: "File too large!" })
  },
  extensions: {
    value: ["jpg", "png"],
    onError: (res) => res.status(415).json({ error: "Invalid file type!" })
  }
})

Memory Storage

Use memoryStorage to temporarily store files in memory.

Configuration Options

filename: A function to customize the in-memory file name.

Example: Memory Storage for Single File

const upload = v.upload.memoryStorage().singleFile({
  fieldName: "profile",
  required: {
    enable: true,
    onError: (res) => res.status(400).json({ error: "File is required!" })
  }
})
 
app.post("/upload-memory", upload, (req, res) => {
  res.status(200).json({ message: "File uploaded to memory!", file: req.files })
})

Multiple Files

Handle multiple files by specifying an array of field configurations.

Example: Multiple Files with Validation

const upload = v.upload.diskStorage({ destination: "./uploads" }).multipleFiles([
  {
    fieldName: "images",
    min: {
      value: 2,
      onError: (res) => res.status(400).json({ error: "At least 2 images required!" })
    },
    max: { value: 5 },
    extensions: {
      value: ["png", "jpg"],
      onError: (res) => res.status(415).json({ error: "Invalid image format!" })
    }
  },
  {
    fieldName: "documents",
    max: { value: 3 },
    extensions: {
      value: ["pdf"],
      onError: (res) => res.status(415).json({ error: "Invalid document format!" })
    }
  }
])

Accessing File Data

Uploaded files are available in req.files. Each file object contains:

fieldName: The name of the form field.
filename: The stored file name.
originalName: The original file name.
size: File size in bytes.
mimetype: The MIME type of the file.
path: The full path to the file (for disk storage).

Example: File Data Structure

app.post("/upload", upload, (req, res) => {
  console.log(req.files)
  res.status(200).json({ files: req.files })
})

Error Handling

Custom error handling can be implemented for validation constraints such as required files, size limits, or invalid extensions. Use the onError callback to define your response.

Example: Custom Error Messages

const upload = v.upload.diskStorage({ destination: "./uploads" }).singleFile({
  fieldName: "file",
  size: {
    value: 2000000,
    onError: (res) => res.status(413).json({ error: "File exceeds maximum size of 2MB" })
  },
  extensions: {
    value: ["png", "jpg"],
    onError: (res) => res.status(415).json({ error: "Only PNG and JPG files are allowed" })
  }
})

This ensures a consistent and user-friendly error response for file upload validations.

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