btcpayserver/BTCPayServer/Views/Shared/CameraScanner.cshtml

<template id="camera-qr-scanner-wrap">
	<div v-if="modalId" :id="modalId" class="modal fade" data-backdrop="static">
		<div class="modal-dialog" role="document">
			<div class="modal-content">
				<div class="modal-header">
					<h5 class="modal-title">
						{{title}}
                        <span v-if="workload.length > 0">Animated QR detected: {{workload.length}} / {{workload[0].total}} scanned</span>
					</h5>
					<button type="button" class="close" aria-label="Close" v-on:click="close">
						<span aria-hidden="true">&times;</span>
					</button>
				</div>
				<div class="modal-body">
					<slot/>
				</div>
			</div>
		</div>
	</div>
	<div v-else>
		<slot></slot>
		<div v-if="workload.length > 0">Animated QR detected: {{workload.length}} / {{workload[0].total}} scanned</div>
	</div>
</template>

<div id="camera-qr-scanner-modal-app" v-cloak class="only-for-js">
	<scanner-wrap v-bind="$data" v-on:close="close">
		<div v-if="isLoaded && requestInput" class="d-flex justify-content-center align-items-center" :class="{'border border-secondary': !isModal}">
			<div class="spinner-border text-secondary position-absolute" role="status"></div>
			<qrcode-drop-zone v-on:decode="onDecode" v-on:init="logErrors">
				<qrcode-stream v-on:decode="onDecode" v-on:init="onInit" :camera="camera" :track="paint"/>
			</qrcode-drop-zone>
			<qrcode-capture v-if="noStreamApiSupport" v-on:decode="onDecode" :camera="camera"/>
		</div>
		<div v-else-if="qrData || errorMessage">
			<div v-if="errorMessage" class="alert alert-danger" role="alert">
				{{errorMessage}}
			</div>
			<div class="text-break text-monospace">
				{{qrData}}
			</div>
			<div class="mt-4">
				<button type="button" class="btn btn-primary mr-1" v-if="qrData" v-on:click="submitData">Submit</button>
				<button type="button" class="btn btn-secondary mr-1" v-on:click="retry">Retry</button>
				<button type="button" class="btn btn-outline-secondary" v-if="isModal" v-on:click="close">Cancel</button>
			</div>
		</div>
	</scanner-wrap>
</div>

<script>
function initCameraScanningApp(title, onDataSubmit, modalId) {
	const isModal = !!modalId;

	Vue.component('scanner-wrap', {
		props: ["modalId", "title", "workload"],
		template: "#camera-qr-scanner-wrap",
		methods: {
			close() {
				this.$emit('close');
			}
		}
  	});

	new Vue({
		el: '#camera-qr-scanner-modal-app',
		data() {
			return {
				isModal,
				isLoaded: !isModal,
				title: title,
				modalId: modalId,
				noStreamApiSupport: false,
				qrData: null,
				errorMessage: null,
				workload: [],
				camera: "auto"
			}
		},
		mounted() {
			if (this.isModal) {
				const $modal = $("#" + this.modalId);
				$modal.on("shown.bs.modal", () => { this.isLoaded = true; });
				$modal.on("hide.bs.modal", () => { this.isLoaded = false; });
			} else {
				this.isLoaded = true;
			}
		},
		computed: {
			requestInput() {
				return this.camera === 'auto' && this.errorMessage === null;
			}
		},
		methods: {
			setQrData (qrData) {
				this.qrData = qrData;
				this.camera = qrData ? "off" : "auto";
			},
			retry() {
				this.camera = "off";
				this.$nextTick(this.reset);
			},
			reset() {
				this.setQrData(null);
				this.errorMessage = null;
				this.workload = [];
			},
			close() {
				if (this.modalId) {
					$("#" + this.modalId).modal('hide');
				}
				this.reset();
			},
			onDecode(content) {
				if (this.qrData) return;

				if (!content.toLowerCase().startsWith("ur:")) {
					this.setQrData(content);
					this.workload = [];
				} else {
					const [index, total] = window.bcur.extractSingleWorkload(content);
					if (this.workload.length > 0) {
						const currentTotal = this.workload[0].total;
						if (total !== currentTotal) {
							this.workload = [];
						}
					}
					if (!this.workload.find(i => i.index === index)) {
						this.workload.push({
							index,
							total,
							data: content,
						});
						if (this.workload.length === total) {
							const decoded = window.bcur.decodeUR(this.workload.map(i => i.data));
							this.setQrData(decoded);
						}
					}
				}
			},
			submitData() {
				if (onDataSubmit) {
					onDataSubmit(this.qrData);
				}
				this.close();
			},
			logErrors(promise) {
				promise.catch(console.error)
			},
			paint(location, ctx) {
				ctx.fillStyle = '#137547';
				[
					location.topLeftFinderPattern,
					location.topRightFinderPattern,
					location.bottomLeftFinderPattern
				].forEach(({ x, y }) => {
					ctx.fillRect(x - 5, y - 5, 10, 10);
				})
			},
			onInit(promise) {
				promise.then(() => {
					this.errorMessage = null;
				}).catch(error => {
					if (error.name === 'StreamApiNotSupportedError') {
						this.noStreamApiSupport = true;
					} else if (error.name === 'NotAllowedError') {
						this.errorMessage = 'A permission to the camera is needed to scan the QR code. Please grant the browser access and then retry.'
					} else if (error.name === 'NotFoundError') {
						this.errorMessage = 'A camera was not detected on your device.'
					} else if (error.name === 'NotSupportedError') {
						this.errorMessage = 'This page is served in non-secure context (HTTPS, localhost or file://)'
					} else if (error.name === 'NotReadableError') {
						this.errorMessage = 'Couldn\'t access your camera. Is it already in use?'
					} else if (error.name === 'OverconstrainedError') {
						this.errorMessage = 'Constraints don\'t match any installed camera.'
					} else {
						this.errorMessage = 'UNKNOWN ERROR: ' + error.message
					}
				})
			}
		}
	});
}
</script>