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authoranonymous2022-09-21 12:46:08 -0400
committeranonymous2022-09-21 12:46:08 -0400
commit33a84bb2acf9626fa86c2c165b91b66a718e1526 (patch)
tree4d97e686103ff688a558553ee507927c2e88ab50 /graffiti.js
parent8ca207d31ef3eb9c3102f7fdb23f85b53d16924f (diff)
log in is now just a toggle function, no loggedIn bool
Diffstat (limited to 'graffiti.js')
-rw-r--r--graffiti.js222
1 files changed, 222 insertions, 0 deletions
diff --git a/graffiti.js b/graffiti.js
new file mode 100644
index 0000000..7a9c168
--- /dev/null
+++ b/graffiti.js
@@ -0,0 +1,222 @@
+import Auth from './auth.js'
+import { randomString } from './utils.js'
+
+export default class {
+
+ constructor(graffitiURL="https://graffiti.csail.mit.edu") {
+ this.graffitiURL = graffitiURL
+ this.open = false
+ this.subscriptionData = {}
+ this.eventTarget = new EventTarget()
+ }
+
+ // CALL THIS BEFORE DOING ANYTHING ELSE
+ async initialize() {
+ // Perform authorization
+ this.authParams = await Auth.connect(this.graffitiURL)
+
+ // Rewrite the URL
+ this.wsURL = new URL(this.graffitiURL)
+ this.wsURL.host = "app." + this.wsURL.host
+ if (this.wsURL.protocol == 'https:') {
+ this.wsURL.protocol = 'wss:'
+ } else {
+ this.wsURL.protocol = 'ws:'
+ }
+ if (this.authParams.token) {
+ this.wsURL.searchParams.set("token", this.authParams.token)
+ }
+
+ // And commence connection
+ this.connect()
+ }
+
+ connect() {
+ this.ws = new WebSocket(this.wsURL)
+ this.ws.onmessage = this.onMessage.bind(this)
+ this.ws.onclose = this.onClose.bind(this)
+ this.ws.onopen = this.onOpen.bind(this)
+ }
+
+ // authorization functions
+ get myID() { return this.authParams.myID }
+ toggleLogIn() {
+ this.myID? Auth.logOut() : Auth.logIn(this.graffitiURL)
+ }
+
+ async onClose() {
+ this.open = false
+ console.error("lost connection to graffiti server, attemping reconnect soon...")
+ await new Promise(resolve => setTimeout(resolve, 2000))
+ this.connect()
+ }
+
+ async request(msg) {
+ // Create a random message ID
+ const messageID = randomString()
+
+ // Create a listener for the reply
+ const dataPromise = new Promise(resolve => {
+ this.eventTarget.addEventListener(messageID, (e) => {
+ resolve(e.data)
+ })
+ })
+
+ // Wait for the socket to open
+ if (!this.open) {
+ await new Promise(resolve => {
+ this.eventTarget.addEventListener("graffitiOpen", () => resolve() )
+ })
+ }
+
+ // Send the request
+ msg.messageID = messageID
+ this.ws.send(JSON.stringify(msg))
+
+ // Await the reply
+ const data = await dataPromise
+ delete data.messageID
+
+ if (data.type == 'error') {
+ throw data
+ } else {
+ return data
+ }
+ }
+
+ onMessage(event) {
+ const data = JSON.parse(event.data)
+
+ if ('messageID' in data) {
+ // It's a reply
+ // Forward it back to the sender
+ const messageEvent = new Event(data.messageID)
+ messageEvent.data = data
+ this.eventTarget.dispatchEvent(messageEvent)
+
+ } else if (['updates', 'removes'].includes(data.type)) {
+ // Subscription data
+ if (data.queryID in this.subscriptionData) {
+ const sd = this.subscriptionData[data.queryID]
+
+ // For each data point, either add or remove it
+ for (const r of data.results) {
+ if (data.type == 'updates') {
+ sd.updateCallback(r)
+ } else {
+ sd.removeCallback(r)
+ }
+ }
+
+ // And update this query's notion of "now"
+ if (data.complete) {
+ if (data.historical) {
+ sd.historyComplete = true
+ }
+ if (sd.historyComplete) {
+ sd.since = data.now
+ }
+ }
+ }
+ } else if (data.type == 'error') {
+ if (data.reason == 'authorization') {
+ this.logOut()
+ }
+ throw data
+ }
+ }
+
+ async update(object, query) {
+ const data = await this.request({
+ type: "update",
+ object, query
+ })
+ return data.objectID
+ }
+
+ async remove(objectID) {
+ await this.request({
+ type: "remove",
+ objectID
+ })
+ }
+
+ async subscribe(
+ query,
+ updateCallback,
+ removeCallback,
+ since=null,
+ queryID=null) {
+
+ // Create a random query ID
+ if (!queryID) queryID = randomString()
+
+ // Send the request
+ await this.request({
+ type: "subscribe",
+ queryID, query, since
+ })
+
+ // Store the subscription in case of disconnections
+ this.subscriptionData[queryID] = {
+ query, since, updateCallback, removeCallback,
+ historyComplete: false
+ }
+
+ return queryID
+ }
+
+ async unsubscribe(queryID) {
+ // Remove allocated space
+ delete this.subscriptionData[queryID]
+
+ // And unsubscribe
+ const data = await this.request({
+ type: "unsubscribe",
+ queryID
+ })
+ }
+
+ async onOpen() {
+ console.log("connected to the graffiti socket")
+ this.open = true
+ this.eventTarget.dispatchEvent(new Event("graffitiOpen"))
+ // Resubscribe to hanging queries
+ for (const queryID in this.subscriptionData) {
+ const sd = this.subscriptionData[queryID]
+ await this.subscribe(
+ sd.query,
+ sd.updateCallback,
+ sd.removeCallback,
+ sd.since,
+ queryID)
+ }
+ }
+
+ // Adds required fields to an object.
+ // You should probably call this before 'update'
+ completeObject(object) {
+ // Add by/to fields
+ object._by = this.myID
+ if ('_to' in object && !Array.isArray(object._to)) {
+ throw new Error("_to must be an array")
+ }
+
+ // Pre-generate the object's ID if it does not already exist
+ if (!object._id) object._id = randomString()
+ }
+
+ // Utility function to get a universally unique string
+ // that represents a particular object
+ objectUUID(object) {
+ if (!object._id || !object._by) {
+ throw {
+ type: 'error',
+ content: 'the object you are trying to identify does not have an ID or owner',
+ object
+ }
+ }
+ return object._id + object._by
+ }
+
+}