validate-image-type/README.md

Check the image file of a Buffer/Uint8Array that matched expected image MIME-type.

# validate-image-type [![Actions Status](https://github.com/azu/validate-image-type/workflows/test/badge.svg)](https://github.com/azu/validate-image-type/actions?query=workflow%3A"test")

Check the image file of a Buffer/Uint8Array that matched expected image MIME-type.

This library check the **file contents** instead of **file extensions** using following:

- [sindresorhus/file-type: Detect the file type of a Buffer/Uint8Array/ArrayBuffer](https://github.com/sindresorhus/file-type)
- [sindresorhus/is-svg: Check if a string or buffer is SVG](https://github.com/sindresorhus/is-svg)

## Features

- Support various image types: [popular images types](https://github.com/sindresorhus/image-type#supported-file-types) + SVG
- Reject File Camouflage by checking actual content buffer

## Install

Install with [npm](https://www.npmjs.com/):

    npm install validate-image-type

## Usage

```ts
import { validateMIMEType } from "validate-image-type";
const result = await validateMIMEType("./image.png", {
    allowMimeTypes: ['image/jpeg', 'image/gif', 'image/png', 'image/svg+xml']
});
if (!result.ok) {
    console.error(result.error);
    return;
}
console.log("This image is supported!");
```

See following document about MimeType.

- https://developer.mozilla.org/docs/Web/HTTP/Basics_of_HTTP/MIME_types

## Supported file types 

Basic images file types and SVG(`image/svg+xml`).

    "jpg",
    "png",
    "gif",
    "webp",
    "flif",
    "cr2",
    "tif",
    "bmp",
    "jxr",
    "psd",
    "ico",
    "bpg",
    "jp2",
    "jpm",
    "jpx",
    "heic",
    "cur",
    "dcm",
    "svg"


## Examples

Integration with [Multer](https://github.com/expressjs/multer) middleware.

```js
const multer = require('multer');
const temp_local_img_dir = path.join(__dirname, `/.temp_local_img_dir`);
const upload = multer({ dest: temp_local_img_dir });
const asyncWrapper = fn => {
    return (req, res, next) => {
        return fn(req, res, next).catch(next);
    }
};

app.post(
  '/upload',
  upload.single('image'), 
  asyncWrapper(async (req, res, next) => {
    const validationResult = await validateMIMEType(req.file.path, {
      originalFilename: req.file.originalname,
      allowMimeTypes: ['image/jpeg', 'image/gif', 'image/png', 'image/svg+xml'],
    });
    console.log('validationResult', validationResult);
    if (!validationResult.ok) {
      return res.send(400);
    }
    // uploading task
    // ...
  })
);
```

## Changelog

See [Releases page](https://github.com/azu/validate-image-type/releases).

## Running tests

Install devDependencies and Run `npm test`:

    npm test

## Contributing

Pull requests and stars are always welcome.

For bugs and feature requests, [please create an issue](https://github.com/azu/validate-image-type/issues).

1. Fork it!
2. Create your feature branch: `git checkout -b my-new-feature`
3. Commit your changes: `git commit -am 'Add some feature'`
4. Push to the branch: `git push origin my-new-feature`
5. Submit a pull request :D

## Author

- [github/azu](https://github.com/azu)
- [twitter/azu_re](https://twitter.com/azu_re)

## License

MIT © azu