feat(api): add cell geolocation cache

Author: coderbyheart

package-lock.json

@@ -87,7 +87,9 @@
   ],
   "prettier": "@bifravst/prettier-config",
   "peerDependencies": {
+    "@aws-sdk/client-dynamodb": "^3.552.0",
     "@aws-sdk/client-ssm": "^3.552.0",
+    "@aws-sdk/util-dynamodb": "^3.552.0",
     "@bifravst/aws-ssm-settings-helpers": "^1.0.3",
     "@hello.nrfcloud.com/proto": "^6.5.0",
     "@sinclair/typebox": "^0.32.20"

package.json

@@ -0,0 +1,123 @@
+import { describe, it, mock } from 'node:test'
+import assert from 'node:assert/strict'
+import { ResourceNotFoundException } from '@aws-sdk/client-dynamodb'
+import { get, store } from './cache.js'
+import { arrayContaining, check, objectMatching } from 'tsmatchers'
+
+export const assertCall = (
+	mockFn: ReturnType<(typeof mock)['fn']>,
+	args: Record<string, unknown>,
+	callNumber: number = 0,
+): void => {
+	check(mockFn.mock.calls[callNumber]?.arguments).is(
+		arrayContaining(objectMatching(args)),
+	)
+}
+
+void describe('cellGeoLocation/cache', () => {
+	void describe('get()', () => {
+		void it('should return null if cell is not cached', async () => {
+			const send = mock.fn(async () =>
+				Promise.reject(
+					new ResourceNotFoundException({
+						message: ` Requested resource not found`,
+						$metadata: {},
+					}),
+				),
+			)
+			assert.equal(
+				await get({
+					db: { send } as any,
+					TableName: 'cacheTable',
+				})({
+					area: 42,
+					mccmnc: 53005,
+					cell: 666,
+				}),
+				null,
+			)
+			assertCall(send, {
+				input: {
+					Key: {
+						cellId: {
+							S: '53005-42-666',
+						},
+					},
+					TableName: 'cacheTable',
+				},
+			})
+		})
+
+		void it('should return the location if the cell is cached', async () => {
+			const send = mock.fn(async () =>
+				Promise.resolve({
+					$metadata: {
+						httpStatusCode: 200,
+						requestId: 'SHTTK1LO0ELJ5LI2U0LUJOUBOJVV4KQNSO5AEMVJF66Q9ASUAAJG',
+						extendedRequestId: undefined,
+						cfId: undefined,
+						attempts: 1,
+						totalRetryDelay: 0,
+					},
+					Item: {
+						cellId: { S: '53005-42-666' },
+						lat: { N: '-36.87313199' },
+						lng: { N: '174.7577405' },
+						accuracy: { N: '510' },
+					},
+				}),
+			)
+			assert.deepEqual(
+				await get({
+					db: { send } as any,
+					TableName: 'cacheTable',
+				})({
+					area: 42,
+					mccmnc: 53005,
+					cell: 666,
+				}),
+				{ accuracy: 510, lat: -36.87313199, lng: 174.7577405 },
+			)
+			assertCall(send, {
+				input: {
+					Key: {
+						cellId: {
+							S: '53005-42-666',
+						},
+					},
+					TableName: 'cacheTable',
+				},
+			})
+		})
+	})
+	void describe('store()', () => {
+		void it('should store the cell', async () => {
+			const send = mock.fn(async () => Promise.resolve({}))
+			await store({
+				db: { send } as any,
+				TableName: 'cacheTable',
+			})(
+				{
+					area: 42,
+					mccmnc: 53005,
+					cell: 666,
+				},
+				{ accuracy: 510, lat: -36.87313199, lng: 174.7577405 },
+			)
+			assertCall(send, {
+				input: {
+					Item: {
+						accuracy: { N: '510' },
+						cellId: { S: '53005-42-666' },
+						lat: { N: '-36.87313199' },
+						lng: { N: '174.7577405' },
+						ttl: {
+							N: `${Math.floor(Date.now() / 1000) + 30 * 24 * 60 * 60}`,
+						},
+					},
+					TableName: 'cacheTable',
+				},
+			})
+		})
+	})
+})

src/cellGeoLocation/cache.spec.ts

@@ -0,0 +1,54 @@
+import {
+	DynamoDBClient,
+	GetItemCommand,
+	PutItemCommand,
+} from '@aws-sdk/client-dynamodb'
+import { cellId } from './cellId.js'
+import { marshall, unmarshall } from '@aws-sdk/util-dynamodb'
+
+export const get =
+	({ db, TableName }: { db: DynamoDBClient; TableName: string }) =>
+	async (
+		cell: Parameters<typeof cellId>[0],
+	): Promise<{ lat: number; lng: number; accuracy: number } | null> => {
+		try {
+			const { Item } = await db.send(
+				new GetItemCommand({
+					TableName,
+					Key: {
+						cellId: {
+							S: cellId(cell),
+						},
+					},
+				}),
+			)
+			const { lat, lng, accuracy } = unmarshall(
+				Item as Record<string, never>,
+			) as {
+				lat: number
+				lng: number
+				accuracy: number
+			}
+			return { lat, lng, accuracy }
+		} catch {
+			return null
+		}
+	}
+
+export const store =
+	({ db, TableName }: { db: DynamoDBClient; TableName: string }) =>
+	async (
+		cell: Parameters<typeof cellId>[0],
+		location: { lat: number; lng: number; accuracy: number },
+	): Promise<void> => {
+		await db.send(
+			new PutItemCommand({
+				TableName,
+				Item: marshall({
+					cellId: cellId(cell),
+					...location,
+					ttl: Math.floor(Date.now() / 1000) + 30 * 24 * 60 * 60,
+				}),
+			}),
+		)
+	}

src/cellGeoLocation/cache.ts

@@ -0,0 +1,15 @@
+import { describe, it } from 'node:test'
+import assert from 'node:assert/strict'
+import { cellId } from './cellId.js'
+
+void describe('cellId', () => {
+	void it('should generate a cellId', () =>
+		assert.equal(
+			cellId({
+				area: 42,
+				mccmnc: 53005,
+				cell: 666,
+			}),
+			'53005-42-666',
+		))
+})

src/cellGeoLocation/cellId.spec.ts

@@ -0,0 +1,9 @@
+export const cellId = ({
+	area,
+	mccmnc,
+	cell,
+}: {
+	area: number
+	mccmnc: number
+	cell: number
+}): string => `${mccmnc}-${area}-${cell}`