Live location sharing: geolocation utilities (#8126)

* geolocation utilities

Signed-off-by: Kerry Archibald <kerrya@element.io>

* remove debug

Signed-off-by: Kerry Archibald <kerrya@element.io>

* comments for ts-ignores

Signed-off-by: Kerry Archibald <kerrya@element.io>

src/utils/beacon/geolocation.ts

@@ -0,0 +1,126 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { logger } from "matrix-js-sdk/src/logger";
+
+// map GeolocationPositionError codes
+// https://developer.mozilla.org/en-US/docs/Web/API/GeolocationPositionError
+export enum GeolocationError {
+    // no navigator.geolocation
+    Unavailable = 'Unavailable',
+    // The acquisition of the geolocation information failed because the page didn't have the permission to do it.
+    PermissionDenied = 'PermissionDenied',
+    // The acquisition of the geolocation failed because at least one internal source of position returned an internal error.
+    PositionUnavailable = 'PositionUnavailable',
+    // The time allowed to acquire the geolocation was reached before the information was obtained.
+    Timeout = 'Timeout',
+    // other unexpected failure
+    Default = 'Default'
+}
+
+const GeolocationOptions = {
+    timeout: 5000,
+    maximumAge: 1000,
+};
+
+const isGeolocationPositionError = (error: unknown): error is GeolocationPositionError =>
+    typeof error === 'object' && !!error['PERMISSION_DENIED'];
+/**
+ * Maps GeolocationPositionError to our GeolocationError enum
+ */
+export const mapGeolocationError = (error: GeolocationPositionError | Error): GeolocationError => {
+    logger.error('Geolocation failed', error?.message ?? error);
+
+    if (isGeolocationPositionError(error)) {
+        switch (error?.code) {
+            case error.PERMISSION_DENIED:
+                return GeolocationError.PermissionDenied;
+            case error.POSITION_UNAVAILABLE:
+                return GeolocationError.PositionUnavailable;
+            case error.TIMEOUT:
+                return GeolocationError.Timeout;
+            default:
+                return GeolocationError.Default;
+        }
+    } else if (error.message === GeolocationError.Unavailable) {
+        return GeolocationError.Unavailable;
+    } else {
+        return GeolocationError.Default;
+    }
+};
+
+const getGeolocation = (): Geolocation => {
+    if (!navigator.geolocation) {
+        throw new Error(GeolocationError.Unavailable);
+    }
+    return navigator.geolocation;
+};
+
+export type GenericPosition = {
+    latitude: number;
+    longitude: number;
+    altitude?: number;
+    accuracy?: number;
+    timestamp: number;
+};
+
+export type TimedGeoUri = {
+    geoUri: string;
+    timestamp: number;
+};
+
+export const genericPositionFromGeolocation = (geoPosition: GeolocationPosition): GenericPosition => {
+    const {
+        latitude, longitude, altitude, accuracy,
+    } = geoPosition.coords;
+    return {
+        timestamp: geoPosition.timestamp,
+        latitude, longitude, altitude, accuracy,
+    };
+};
+
+export const getGeoUri = (position: GenericPosition): string => {
+    const lat = position.latitude;
+    const lon = position.longitude;
+    const alt = (
+        Number.isFinite(position.altitude)
+            ? `,${position.altitude}`
+            : ""
+    );
+    const acc = (
+        Number.isFinite(position.accuracy)
+            ? `;u=${position.accuracy}`
+            : ""
+    );
+    return `geo:${lat},${lon}${alt}${acc}`;
+};
+
+export const mapGeolocationPositionToTimedGeo = (position: GeolocationPosition): TimedGeoUri => {
+    return { timestamp: position.timestamp, geoUri: getGeoUri(genericPositionFromGeolocation(position)) };
+};
+
+export const watchPosition = (
+    onWatchPosition: PositionCallback,
+    onWatchPositionError: (error: GeolocationError) => void): () => void => {
+    try {
+        const onError = (error) => onWatchPositionError(mapGeolocationError(error));
+        const watchId = getGeolocation().watchPosition(onWatchPosition, onError, GeolocationOptions);
+        const clearWatch = () => getGeolocation().clearWatch(watchId);
+        return clearWatch;
+    } catch (error) {
+        throw new Error(mapGeolocationError(error));
+    }
+};

src/utils/beacon/index.ts

@@ -15,3 +15,4 @@ limitations under the License.
 */
 
 export * from './duration';
+export * from './geolocation';