William/v2 prototype

package.json

@@ -34,6 +34,7 @@
     "firebase-admin": "^8.12.1",
     "nano": "^9.0.5",
     "node-fetch": "^2.6.7",
+    "rfc4648": "^1.5.2",
     "serverlet": "^0.1.1"
   },
   "devDependencies": {

src/db/couchDevices.ts

@@ -0,0 +1,173 @@
+import {
+  asArray,
+  asDate,
+  asObject,
+  asOptional,
+  asString,
+  uncleaner
+} from 'cleaners'
+import {
+  asCouchDoc,
+  asMaybeConflictError,
+  asMaybeNotFoundError,
+  DatabaseSetup,
+  makeJsDesign
+} from 'edge-server-tools'
+import { ServerScope } from 'nano'
+import { base64 } from 'rfc4648'
+
+import { asBase64 } from '../types/pushCleaners'
+import { Device } from '../types/pushTypes'
+
+/**
+ * A device returned from the database.
+ * Mutate the `device` object, then call `save` to commit the changes.
+ */
+export interface DeviceRow {
+  device: Device
+  save: () => Promise<void>
+}
+
+/**
+ * An API key, as stored in Couch.
+ */
+export const asCouchDevice = asCouchDoc<Omit<Device, 'deviceId'>>(
+  asObject({
+    created: asDate,
+
+    // Status:
+    apiKey: asOptional(asString),
+    deviceToken: asOptional(asString),
+    loginIds: asArray(asBase64),
+    visited: asDate
+  })
+)
+const wasCouchDevice = uncleaner(asCouchDevice)
+type CouchDevice = ReturnType<typeof asCouchDevice>
+
+/**
+ * Looks up devices that contain a particular login.
+ */
+const loginIdDesign = makeJsDesign('loginId', ({ emit }) => ({
+  map: function (doc) {
+    for (let i = 0; i < doc.loginIds.length; ++i) {
+      emit(doc.loginIds[i], null)
+    }
+  }
+}))
+
+export const couchDevicesSetup: DatabaseSetup = {
+  name: 'push-devices',
+  documents: {
+    '_design/loginId': loginIdDesign
+  }
+}
+
+/**
+ * Looks up a device by its id.
+ * If the device does not exist in the database, creates a fresh row.
+ */
+export async function getDeviceById(
+  connection: ServerScope,
+  deviceId: string,
+  date: Date
+): Promise<DeviceRow> {
+  const db = connection.use(couchDevicesSetup.name)
+  const raw = await db.get(deviceId).catch(error => {
+    if (asMaybeNotFoundError(error) != null) return
+    throw error
+  })
+
+  if (raw == null) {
+    return makeDeviceRow(connection, {
+      created: date,
+      deviceId,
+      apiKey: undefined,
+      deviceToken: undefined,
+      loginIds: [],
+      visited: date
+    })
+  }
+  const clean = asCouchDevice(raw)
+  return makeDeviceRow(
+    connection,
+    { ...clean.doc, deviceId: clean.id },
+    clean.rev
+  )
+}
+
+/**
+ * Finds all the devices that have logged into this account.
+ */
+export async function getDevicesByLoginId(
+  connection: ServerScope,
+  loginId: Uint8Array
+): Promise<DeviceRow[]> {
+  const db = connection.use(couchDevicesSetup.name)
+  const response = await db.view('loginId', 'loginId', {
+    include_docs: true,
+    key: base64.stringify(loginId)
+  })
+  return response.rows.map(row => {
+    const clean = asCouchDevice(row.doc)
+    return makeDeviceRow(
+      connection,
+      { ...clean.doc, deviceId: clean.id },
+      clean.rev
+    )
+  })
+}
+
+function makeDeviceRow(
+  connection: ServerScope,
+  device: Device,
+  rev?: string
+): DeviceRow {
+  const db = connection.db.use(couchDevicesSetup.name)
+  let base = { ...device }
+
+  return {
+    device,
+
+    async save(): Promise<void> {
+      while (true) {
+        // Write to the database:
+        const doc: CouchDevice = {
+          doc: device,
+          id: device.deviceId,
+          rev
+        }
+        const response = await db.insert(wasCouchDevice(doc)).catch(error => {
+          if (asMaybeConflictError(error) == null) throw error
+        })
+
+        // If that worked, the merged document is now the latest:
+        if (response?.ok === true) {
+          base = { ...device }
+          rev = doc.rev
+          return
+        }
+
+        // Something went wrong, so grab the latest remote document:
+        const raw = await db.get(device.deviceId)
+        const clean = asCouchDevice(raw)
+        rev = clean.rev
+        const remote = clean.doc
+
+        // If we don't have local edits, take the remote field:
+        if (device.apiKey === base.apiKey) {
+          device.apiKey = remote.apiKey
+        }
+        if (device.deviceToken === base.deviceToken) {
+          device.deviceToken = remote.deviceToken
+        }
+        if (device.loginIds === base.loginIds) {
+          device.loginIds = remote.loginIds
+        }
+        if (remote.visited > device.visited) {
+          device.visited = remote.visited
+        }
+      }
+    }
+  }
+}