I'm trying to get Web NFC to work through the Web NFC API, but I can't get it past an error message of NotAllowedError: NFC permission request denied.
I'm using this on Chrome 89 Dev on a Windows 10 computer, and the source code is being run locally.
I have tried the examples posted on the Internet also, including the Google sample but it returns the same error. I'm not concerned with it being experimental at this point as referring to this does show it has successfully passed the necessary tests, including permissions.
The HTML/JS code I'm using is below, and I've read the specification point 9.3, but I can't make sense of it to write it as code, so is there a guideline algorithm that would be helpful here to resolve this?
async function readTag() {
if ("NDEFReader" in window) {
const reader = new NDEFReader();
try {
await reader.scan();
reader.onreading = event => {
const decoder = new TextDecoder();
for (const record of event.message.records) {
consoleLog("Record type: " + record.recordType);
consoleLog("MIME type: " + record.mediaType);
consoleLog("=== data ===\n" + decoder.decode(record.data));
}
}
} catch(error) {
consoleLog(error);
}
} else {
consoleLog("Web NFC is not supported.");
}
}
async function writeTag() {
if ("NDEFWriter" in window) {
const writer = new NDEFWriter();
try {
await writer.write("helloworld");
consoleLog("NDEF message written!");
} catch(error) {
consoleLog(error);
}
} else {
consoleLog("Web NFC is not supported.");
}
}
function consoleLog(data) {
var logElement = document.getElementById('log');
logElement.innerHTML += data + '\n';
};<!DOCTYPE html>
<html>
<head>
<script src="webnfc.js"></script>
</head>
<body>
<p>
<button onclick="readTag()">Test NFC Read</button>
<button onclick="writeTag()">Test NFC Write</button>
</p>
<pre id="log"></pre>
</body>
</html>
From https://web.dev/nfc/#security-and-permissions
I guess you are running from a
file://URL as you said "locally" which is not supported.You need to host it from a local web server using a
https://URLOnce in the right scope trying to scan or write should trigger a user prompt.
You can also check permissions see https://web.dev/nfc/#check-for-permission
Update:
So I tried the sample page https://googlechrome.github.io/samples/web-nfc/
And this works for me on Android Chrome 87 with "Experimental Web Platform features" enabled
When you hit the scan button A dialog asking for permission pops up.
Comparing the code in this sample to yours I notice that does:-
Where as yours does:-
I don't know if it is the style setting what happens on the Event or something else (Hey this is all experimental)
Update2 To answer the question from the comments of Desktop support.
So you should be some of the desktop/browser combinations at the moment and may be in the future there will be wider support as this is no longer experimental standards. Obviously as your test link suggest Chrome on a Linux Desktop should work as this is really similar to Android Support, with all the NFC device handling done by
libnfcand the browser just has to know about this library instead of every type usb or other device than can do NFC.From what seen of NFC support on Windows, most of this is focussed on direct controlling the NFC reader via USB as just another USB device, while there is a libnfc equivalent in
Windows.Networking.ProximityAPI's I've not come across any NFC reader saying they support this or anybody using it.For Mac Deskstop, given that Apple are behind the curve with NFC support in iOS, I feel their desktop support will be even further behind even though it could be similar to Linux.