使用Chrome API将文件保存到USB

Question

I have a Chrome app with "usb" permission and I want to create a file "notes.txt" in USB mass storage. When he finished and press "save to USB" button.

I tried to use chrome.usb.bulkTransfer, but it just ends with

Unchecked runtime.lastError while running usb.bulkTransfer: Transfer failed.

Is possible to save a file to a USB mass storage with Chrome API, without the direct input from user?

Answer 1

Regarding saving a file to a USB mass storage without the direct input from user, try using chrome.usb.controlTransfer(connectionHandle, transferInfo, transferCallback) which is generally used to send or receive configurations or command parameters to a USB device. The controlTransfer method always sends to/reads from endpoint 0, and no claimInterface is required.

And since requestAccess is now deprecated, operation is now implicitly performed as part of openDevice and this function will return true on all platforms.