readFileAsBlob

Reads a file from an IDBDevice and returns it as a Javascript Blob object.

namespace CheerpX {
  class IDBDevice {
    async readFileAsBlob(filename: string): Promise<Blob>;
  }
}

Parameters

filename (string) - The path to the file within the IDBDevice, starting with a / (e.g., /filename). Do not include the mount point.

Returns

CheerpX.IDBDevice.readFileAsBlob returns a Promise that resolves to a Javascript Blob object. This object represents the file’s data, which can be further manipulated or converted as needed.

Example

// Create a read-only block device for a disk image stored on the HTTP server
const blockDevice = await CheerpX.HttpBytesDevice.create("/cheerpXImage.ext2");
// Make the block device read-write using a persistent IndexedDB overlay
const idbDevice = await CheerpX.IDBDevice.create("block_idbDevice");
const overlayDevice = await CheerpX.OverlayDevice.create(
  blockDevice,
  idbDevice
);
// Initialize the CheerpX environment
const mountPoints = [
  // Use the disk image as the filesystem root
  { type: "ext2", path: "/", dev: overlayDevice },
];
const cx = await CheerpX.Linux.create({
  mounts: mountPoints,
});

const outputBlob = await idbDevice.readFileAsBlob("/fileName");
console.log(outputBlob);

View stored files in DevTools

To see your stored files, open Developer Tools, go to the Application tab, and check Storage > IndexedDB. Here, you can browse and inspect your files easily!
Want to learn more? Check out these related guides:

Files and filesystems

Input and output