moved out of vue plugin

4 files changed, 395 insertions, 0 deletions

diff --git a/README.md b/README.md
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+# The Basic Graffiti Javascript Library
+
+This is the base Javascript library that interfaces with the [Graffiti server](https://github.com/csail-graffiti/server).
+We recommend not using the vanilla library itself but instead using framework plugins built on top of this library like the [Graffiti plugin for Vue.JS](https://github.com/csail-graffiti/graffiti-js-vue).
+
+With this library:
+
+```javascript
+import GraffitiSocket from "https://csail-graffiti.github.io/graffiti-js-vanilla/socket.js"
+
+// You can initialize a connection to the graffiti server
+const gs = GraffitiSocket()
+await gs.initialize()
+
+// You can subscribe to queries
+const queryID = await gs.subscribe({
+    type: 'post',
+    content: { $type: 'string' }
+  }
+  // With an arbitrary update callback
+  (obj) => console.log(`An object has been created: {obj}`)
+  // and delete callback
+  (obj) => console.log(`An object with id {obj._id} by user {obj._by} has been deleted`.
+)
+
+// And then unsubscribe to those queries
+await gs.unsubscribe(queryID)
+
+// You can log in and out and check your logged-in status
+gs.logIn()
+gs.logOut()
+if (gs.loggedIn) {
+  ...
+}
+
+// When you are logged in you reference your user ID
+console.log(gs.myID)
+
+// And when you are logged in you can
+// create objects,
+const myCoolPost = {
+  type: 'post',
+  content: 'hello world'
+}
+gs.complete(myCoolPost)
+await gs.update(myCoolPost)
+
+// replace objects,
+myCoolPost.content += '!!!'
+await gs.update(myCoolPost)
+
+// and delete objects.
+await gs.delete(myCoolPost)
+```
diff --git a/src/auth.js b/src/auth.js
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+++ b/src/auth.js
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+import { randomString, sha256 } from './utils.js'
+
+export default {
+
+  async logIn(origin) {
+    // Generate a random client secret and state
+    const clientSecret = randomString()
+    const state = randomString()
+
+    // The client ID is the secret's hex hash
+    const clientID = await sha256(clientSecret)
+
+    // Store the client secret as a local variable
+    window.localStorage.setItem('graffitiClientSecret', clientSecret)
+    window.localStorage.setItem('graffitiClientID', clientID)
+    window.localStorage.setItem('graffitiAuthState', state)
+
+    // Redirect to the login window
+    const authURL = new URL(origin)
+    authURL.searchParams.set('client_id', clientID)
+    authURL.searchParams.set('redirect_uri', window.location.href)
+    authURL.searchParams.set('state', state)
+    window.location.href = authURL
+  },
+
+  async connect(origin) {
+    origin = new URL(origin)
+    origin.host = "auth." + origin.host
+
+    // Check to see if we are already logged in
+    let token = window.localStorage.getItem('graffitiToken')
+    let myID  = window.localStorage.getItem('graffitiID')
+
+    if (!token || !myID) {
+
+      // Check to see if we are redirecting back
+      const url = new URL(window.location)
+      if (url.searchParams.has('code')) {
+
+        // Extract the code and state from the URL and strip it from the history
+        const code = url.searchParams.get('code')
+        const state = url.searchParams.get('state')
+        url.searchParams.delete('code')
+        url.searchParams.delete('state')
+        window.history.replaceState({}, '', url)
+
+        // Get stored variables and remove them
+        const clientSecret = window.localStorage.getItem('graffitiClientSecret')
+        const clientID     = window.localStorage.getItem('graffitiClientID')
+        const storedState  = window.localStorage.getItem('graffitiAuthState')
+        window.localStorage.removeItem('graffitiClientSecret')
+        window.localStorage.removeItem('graffitiClientID')
+        window.localStorage.removeItem('graffitiAuthState')
+
+        // Make sure state has been preserved
+        if (state != storedState) {
+          throw new Error("The state in local storage does not match the state sent by the server")
+        }
+
+        // Construct the body of the POST
+        let form = new FormData()
+        form.append('client_id', clientID)
+        form.append('client_secret', clientSecret)
+        form.append('code', code)
+
+        // Ask to exchange the code for a token
+        const tokenURL = new URL('token', origin)
+        const response = await fetch(tokenURL, {
+            method: 'post',
+            body: form
+        })
+
+        // Make sure the response is OK
+        if (!response.ok) {
+          let reason = response.status + ": "
+          try {
+            reason += (await response.json()).detail
+          } catch (e) {
+            reason += response.statusText
+          }
+
+          throw new Error(`The authorization code could not be exchanged for a token.\n\n${reason}`)
+        }
+
+        // Parse out the token
+        const data = await response.json()
+        token = data.access_token
+        myID = data.owner_id
+
+        // And make sure that the token is valid
+        if (!token) {
+          throw new Error(`The authorization token could not be parsed from the response.\n\n${data}`)
+        }
+
+        // Store the token and ID
+        window.localStorage.setItem('graffitiToken', token)
+        window.localStorage.setItem('graffitiID', myID)
+      }
+    }
+
+    const loggedIn = (token != null) && (myID != null),
+
+    return { loggedIn, myID, token }
+
+  },
+
+  logOut() {
+    window.localStorage.removeItem('graffitiToken')
+    window.localStorage.removeItem('graffitiID')
+    window.location.reload()
+  },
+
+}
diff --git a/src/socket.js b/src/socket.js
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index 0000000..d324b78
--- /dev/null
+++ b/src/socket.js
@@ -0,0 +1,217 @@
+import Auth from './auth.js'
+import { randomString } from './utils.js'
+
+export default class {
+
+  constructor(origin="https://graffiti.csail.mit.edu") {
+    this.origin = origin
+    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.origin)
+
+    // Rewrite the URL
+    this.wsURL = new URL(origin)
+    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
+  logIn() { Auth.logIn(this.origin) }
+  logOut() { Auth.logOut() }
+  get myID() { return this.authParams.myID }
+  get loggedIn() { return this.authParams.loggedIn }
+
+  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', 'deletes'].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.deleteCallback(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
+          }
+        }
+      }
+    }
+  }
+
+  async update(object) {
+    const data = await this.request({
+      type: "update",
+      object
+    })
+    return data.objectID
+  }
+
+  async delete(objectID) {
+    await this.request({
+      type: "delete",
+      objectID
+    })
+  }
+
+  async subscribe(
+    query,
+    updateCallback,
+    deleteCallback,
+    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, deleteCallback,
+      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.deleteCallback,
+        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
+  }
+
+}
diff --git a/src/utils.js b/src/utils.js
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--- /dev/null
+++ b/src/utils.js
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+export function randomString() {
+  return Math.random().toString(36).substr(2)
+}
+
+export async function sha256(input) {
+  const encoder = new TextEncoder()
+  const inputBytes = encoder.encode(input)
+  const outputBuffer = await crypto.subtle.digest('SHA-256', inputBytes)
+  const outputArray = Array.from(new Uint8Array(outputBuffer))
+  return outputArray.map(b => b.toString(16).padStart(2, '0')).join('')
+}