Cara menangani file yang dibuka dari file explorer

Palances Liao
Palances Liao

Cara modern

Menggunakan File Handling API

Pertama, deklarasikan atribut file_handlers dalam manifes aplikasi web Anda. File Handling API mengharuskan Anda menentukan properti action (URL penanganan) dan properti accept, yang merupakan objek dengan jenis MIME sebagai kunci dan array ekstensi file yang sesuai.

{
  "file_handlers": [
    {
      "action": "./",
      "accept": {
        "image/*": [".jpg", ".jpeg", ".png", ".webp", ".svg"]
      }
    }
  ]
}

Selanjutnya, Anda harus menggunakan File Handling API untuk menangani file yang dibuka secara imperatif melalui launchQueue.

if ('launchQueue' in window && 'files' in LaunchParams.prototype) {
  launchQueue.setConsumer((launchParams) => {
    if (!launchParams.files.length) {
      return;
    }
    for (const fileHandle of launchParams.files) {
      // Handle the file.
    }
  });
}

Browser Support

  • Chrome: 102.
  • Edge: 102.
  • Firefox: not supported.
  • Safari: not supported.

Source

Cara klasik

Menggunakan metode DataTransferItem.getAsFile() klasik

Jika File Handling API tidak didukung, Anda masih dapat melakukan drag and drop file dari file explorer ke aplikasi. Metode DataTransferItem.getAsFile() menampilkan objek File item data drag. Jika item bukan file, metode ini akan menampilkan null. Meskipun Anda dapat membaca file, tidak ada cara untuk menulis kembali ke file tersebut. Metode ini memiliki kelemahan karena tidak mendukung direktori.

Browser Support

  • Chrome: 11.
  • Edge: 12.
  • Firefox: 50.
  • Safari: 5.1.

Source

Progressive enhancement

Cuplikan di bawah menggunakan File Handling API jika tersedia, dan juga mendaftarkan pengendali drag and drop sehingga file yang di-drag dapat ditangani.

Deklarasikan jenis file yang dapat ditangani dalam manifes aplikasi web. Browser yang tidak mendukung File Handling API akan mengabaikannya.

{
  "file_handlers": [
    {
      "action": "./",
      "accept": {
        "image/*": [".jpg", ".jpeg", ".png", ".webp", ".svg"]
      }
    }
  ]
}

// File Handling API
const handleLaunchFiles = () => {
  window.launchQueue.setConsumer((launchParams) => {
    if (!launchParams.files.length) {
      return;
    }
    launchParams.files.forEach(async (handle) => {
      const file = await handle.getFile();
      console.log(`File: ${file.name}`);
      // Do something with the file.
    });
  });
};

if ('launchQueue' in window && 'files' in LaunchParams.prototype) {
  handleLaunchFiles();
}

// This is the drag and drop zone.
const elem = document.querySelector('main');
// Prevent navigation.
elem.addEventListener('dragover', (e) => {
  e.preventDefault();
});
// Visually highlight the drop zone.
elem.addEventListener('dragenter', (e) => {
  elem.style.outline = 'solid red 1px';
});
// Visually unhighlight the drop zone.
elem.addEventListener('dragleave', (e) => {
  elem.style.outline = '';
});
// This is where the drop is handled.
elem.addEventListener('drop', async (e) => {
  // Prevent navigation.
  e.preventDefault();
  // Unhighlight the drop zone.
  elem.style.outline = '';
  // Prepare an array of promises…
  const fileHandlesPromises = [...e.dataTransfer.items]
    // …by including only files (where file misleadingly means actual file _or_
    // directory)…
    .filter((item) => item.kind === 'file')
    // …and, depending on previous feature detection…
    .map((item) => item.getAsFile());
  // Loop over the array of promises.
  for await (const handle of fileHandlesPromises) {
    // This is where we can actually exclusively act on the files.
    if (handle.isFile) {
      console.log(`File: ${handle.name}`);
      // Do something with the file.
    }
  }
});

Bacaan lebih lanjut

Demo

HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link rel="manifest" href="manifest.json" />
    <title>How to handle files opened from the file explorer</title>
    <link rel="stylesheet" href="style.css" />
    <!-- TODO: Devsite - Removed inline handlers -->
    <!-- <script>
      if ('serviceWorker' in navigator) {
        window.addEventListener('load', async () => {
          const registration = await navigator.serviceWorker.register(
            'sw.js',
          );
          console.log(
            'Service worker registered for scope',
            registration.scope,
          );
        });
      }
    </script>
    <script src="script.js" type="module"></script> -->
  </head>
  <body>
    <h1>How to handle files opened from the file explorer</h1>
    <p>Install the app. After the installation, try opening an image file from the file explorer with the app.
  </body>
</html>

CSS


        html {
  box-sizing: border-box;
  font-family: system-ui, sans-serif;
  color-scheme: dark light;
}

*, *:before, *:after {
  box-sizing: inherit;
}

body {
  margin: 1rem;
}

img {
  height: auto;
  max-width: 100%;
  display: block;
}

JS


        if ('launchQueue' in window && 'files' in LaunchParams.prototype) {
  launchQueue.setConsumer((launchParams) => {
    if (!launchParams.files.length) {
      return;
    }
    for (const fileHandle of launchParams.files) {
      document.body.innerHTML += `
${fileHandle.name}
`;
    }
  });
}