Parsing Multipart Form Data

The Parse Data middleware supports parsing multipart form data, including handling file uploads. Non-file fields are converted into their appropriate types, while files are processed as in-memory objects.

File Object Typing

Files processed by the middleware are stored in request.files as an array of objects with the following structure:

interface RouterMemoryFile {
  fieldName: string  // Name of the form field, e.g., "file"
  filename: string   // Original file name, e.g., "photo.jpg"
  extension: string  // File extension, e.g., "jpg"
  mimetype: string   // MIME type, e.g., "image/jpeg"
  buffer: Buffer     // File data as a buffer in memory
  size: number       // File size in bytes
}

Example

Request:

const formData = new FormData()
formData.append("username", "john_doe")
formData.append("file", imageInput.files) // Assuming imageInput is a file input element
 
fetch("/upload", {
  method: "POST",
  body: formData
})

Server-side:

import v from "vkrun"
 
const vkrun = v.App()
 
vkrun.post("/upload", (request: v.Request, response: v.Response) => {
  console.log(request.body)
  // Output: { username: "john_doe" }
  // Non-file fields remain in `body`.
 
  console.log(request.files)
  // Output: [
  //  {
  //    "fieldName": "file",
  //    "filename": "example.txt",
  //    "extension": "txt",
  //    "mimetype": "text/plain",
  //    "buffer": "<Buffer 54 68 69 73 20 69 73 20 61 6e 20 65 78 ...>",
  //    "size": 12345
  //  },
  //  {
  //    "fieldName": "file",
  //    "filename": "photo.jpg",
  //    "extension": "jpg",
  //    "mimetype": "image/jpeg",
  //    "buffer": "<Buffer ff d8 ff e0 00 10 4a 46 49 46 00 01 02 ...>",
  //    "size": 54321
  //  }
  // ]
 
  response.status(200).end()
})

URl Encoded Form Data SQL Injection