Some groundwork for the linked records, building up a much more in-depth emitter for models and records to drive the record cleanup.

packages/server/src/api/controllers/model.js

@@ -12,12 +12,12 @@ exports.fetch = async function(ctx) {
 
 exports.find = async function(ctx) {
   const db = new CouchDB(ctx.user.instanceId)
-  const model = await db.get(ctx.params.id)
-  ctx.body = model
+  ctx.body = await db.get(ctx.params.id)
 }
 
 exports.save = async function(ctx) {
-  const db = new CouchDB(ctx.user.instanceId)
+  const instanceId = ctx.user.instanceId
+  const db = new CouchDB(instanceId)
   const modelToSave = {
     type: "model",
     _id: newid(),
@@ -54,7 +54,7 @@ exports.save = async function(ctx) {
   modelToSave._rev = result.rev
 
   const { schema } = ctx.request.body
-  for (let key in schema) {
+  for (let key of Object.keys(schema)) {
     // model has a linked record
     if (schema[key].type === "link") {
       // create the link field in the other model
@@ -84,13 +84,18 @@ exports.save = async function(ctx) {
   }
   await db.put(designDoc)
 
+  // syntactic sugar for event emission
+  modelToSave.modelId = modelToSave._id
+  ctx.eventEmitter &&
+    ctx.eventEmitter.emitModel(`model:save`, instanceId, modelToSave)
   ctx.status = 200
   ctx.message = `Model ${ctx.request.body.name} saved successfully.`
   ctx.body = modelToSave
 }
 
 exports.destroy = async function(ctx) {
-  const db = new CouchDB(ctx.user.instanceId)
+  const instanceId = ctx.user.instanceId
+  const db = new CouchDB(instanceId)
 
   const modelToDelete = await db.get(ctx.params.modelId)
 
@@ -105,7 +110,7 @@ exports.destroy = async function(ctx) {
   )
 
   // Delete linked record fields in dependent models
-  for (let key in modelToDelete.schema) {
+  for (let key of Object.keys(modelToDelete.schema)) {
     const { type, modelId } = modelToDelete.schema[key]
     if (type === "link") {
       const linkedModel = await db.get(modelId)
@@ -119,6 +124,10 @@ exports.destroy = async function(ctx) {
   delete designDoc.views[modelViewId]
   await db.put(designDoc)
 
+  // syntactic sugar for event emission
+  modelToDelete.modelId = modelToDelete._id
+  ctx.eventEmitter &&
+    ctx.eventEmitter.emitModel(`model:delete`, instanceId, modelToDelete)
   ctx.status = 200
   ctx.message = `Model ${ctx.params.modelId} deleted.`
 }

packages/server/src/api/controllers/record.js

@@ -2,21 +2,6 @@ const CouchDB = require("../../db")
 const validateJs = require("validate.js")
 const newid = require("../../db/newid")
 
-function emitEvent(eventType, ctx, record) {
-  let event = {
-    record,
-    instanceId: ctx.user.instanceId,
-  }
-  // add syntactic sugar for mustache later
-  if (record._id) {
-    event.id = record._id
-  }
-  if (record._rev) {
-    event.revision = record._rev
-  }
-  ctx.eventEmitter && ctx.eventEmitter.emit(eventType, event)
-}
-
 validateJs.extend(validateJs.validators.datetime, {
   parse: function(value) {
     return new Date(value).getTime()
@@ -28,7 +13,8 @@ validateJs.extend(validateJs.validators.datetime, {
 })
 
 exports.patch = async function(ctx) {
-  const db = new CouchDB(ctx.user.instanceId)
+  const instanceId = ctx.user.instanceId
+  const db = new CouchDB(instanceId)
   const record = await db.get(ctx.params.id)
   const model = await db.get(record.modelId)
   const patchfields = ctx.request.body
@@ -55,13 +41,16 @@ exports.patch = async function(ctx) {
   const response = await db.put(record)
   record._rev = response.rev
   record.type = "record"
+  ctx.eventEmitter &&
+    ctx.eventEmitter.emitRecord(`record:update`, instanceId, record, model)
   ctx.body = record
   ctx.status = 200
   ctx.message = `${model.name} updated successfully.`
 }
 
 exports.save = async function(ctx) {
-  const db = new CouchDB(ctx.user.instanceId)
+  const instanceId = ctx.user.instanceId
+  const db = new CouchDB(instanceId)
   const record = ctx.request.body
   record.modelId = ctx.params.modelId
 
@@ -124,7 +113,8 @@ exports.save = async function(ctx) {
     }
   }
 
-  emitEvent(`record:save`, ctx, record)
+  ctx.eventEmitter &&
+    ctx.eventEmitter.emitRecord(`record:save`, instanceId, record, model)
   ctx.body = record
   ctx.status = 200
   ctx.message = `${model.name} created successfully`
@@ -180,7 +170,8 @@ exports.find = async function(ctx) {
 }
 
 exports.destroy = async function(ctx) {
-  const db = new CouchDB(ctx.user.instanceId)
+  const instanceId = ctx.user.instanceId
+  const db = new CouchDB()
   const record = await db.get(ctx.params.recordId)
   if (record.modelId !== ctx.params.modelId) {
     ctx.throw(400, "Supplied modelId doesn't match the record's modelId")
@@ -188,9 +179,10 @@ exports.destroy = async function(ctx) {
   }
   ctx.body = await db.remove(ctx.params.recordId, ctx.params.revId)
   ctx.status = 200
-  // for automations
+  // for automations include the record that was deleted
   ctx.record = record
-  emitEvent(`record:delete`, ctx, record)
+  ctx.eventEmitter &&
+    ctx.eventEmitter.emitRecord(`record:delete`, instanceId, record)
 }
 
 exports.validate = async function(ctx) {

packages/server/src/automations/queue/inMemoryQueue.js

@@ -1,44 +0,0 @@
-let events = require("events")
-
-// Bull works with a Job wrapper around all messages that contains a lot more information about
-// the state of the message, implement this for the sake of maintaining API consistency
-function newJob(queue, message) {
-  return {
-    timestamp: Date.now(),
-    queue: queue,
-    data: message,
-  }
-}
-
-// designed to replicate Bull (https://github.com/OptimalBits/bull) in memory as a sort of mock
-class InMemoryQueue {
-  // opts is not used by this as there is no real use case when in memory, but is the same API as Bull
-  constructor(name, opts) {
-    this._name = name
-    this._opts = opts
-    this._messages = []
-    this._emitter = new events.EventEmitter()
-  }
-
-  // same API as bull, provide a callback and it will respond when messages are available
-  process(func) {
-    this._emitter.on("message", async () => {
-      if (this._messages.length <= 0) {
-        return
-      }
-      let msg = this._messages.shift()
-      let resp = func(msg)
-      if (resp.then != null) {
-        await resp
-      }
-    })
-  }
-
-  // simply puts a message to the queue and emits to the queue for processing
-  add(msg) {
-    this._messages.push(newJob(this._name, msg))
-    this._emitter.emit("message")
-  }
-}
-
-module.exports = InMemoryQueue

packages/server/src/automations/triggers.js

@@ -1,8 +1,8 @@
 const CouchDB = require("../db")
 const emitter = require("../events/index")
-const InMemoryQueue = require("./queue/inMemoryQueue")
+const InMemoryQueue = require("../utilities/queue/inMemoryQueue")
 
-let automationQueue = new InMemoryQueue()
+let automationQueue = new InMemoryQueue("automationQueue")
 
 const FAKE_STRING = "TEST"
 const FAKE_BOOL = false

packages/server/src/db/linkedRecords.js

@@ -0,0 +1,73 @@
+const CouchDB = require("./index")
+const emitter = require("../events/index")
+const InMemoryQueue = require("../utilities/queue/inMemoryQueue")
+
+/**
+ * This functionality makes sure that when records with links are created, updated or deleted they are processed
+ * correctly - making sure that no stale links are left around and that all links have been made successfully.
+ */
+
+const EventType = {
+  RECORD_SAVE: "record:save",
+  RECORD_UPDATE: "record:update",
+  RECORD_DELETE: "record:delete",
+  MODEL_SAVE: "model:save",
+  MODEL_DELETE: "model:delete",
+}
+const linkedRecordQueue = new InMemoryQueue("linkedRecordQueue")
+
+function createEmitterCallback(eventName) {
+  emitter.on(eventName, function(event) {
+    if (!event || !event.record || !event.record.modelId) {
+      return
+    }
+    linkedRecordQueue.add({
+      type: eventName,
+      event,
+    })
+  })
+}
+
+for (let typeKey of Object.keys(EventType)) {
+  createEmitterCallback(EventType[typeKey])
+}
+
+function doesModelHaveLinkedRecords(model) {
+  for (let key of Object.keys(model.schema)) {
+    const { type } = model.schema[key]
+    if (type === "link") {
+      return true
+    }
+  }
+  return false
+}
+
+linkedRecordQueue.process(async job => {
+  let event = job.data
+  // can't operate without these properties
+  if (event.instanceId == null || event.modelId == null) {
+    return
+  }
+  const db = new CouchDB(event.instanceId)
+  let model = event.model == null ? await db.get(event.modelId) : event.model
+  // model doesn't have links, can stop here
+  if (!doesModelHaveLinkedRecords(model)) {
+    return
+  }
+  // no linked records to operate on
+  if (model == null) {
+    return
+  }
+  switch (event.type) {
+    case EventType.RECORD_SAVE:
+      break
+    case EventType.RECORD_UPDATE:
+      break
+    case EventType.RECORD_DELETE:
+      break
+    case EventType.MODEL_SAVE:
+      break
+    case EventType.MODEL_DELETE:
+      break
+  }
+})

packages/server/src/events/index.js

@@ -6,6 +6,45 @@ const EventEmitter = require("events").EventEmitter
  * future.
  */
 
-const emitter = new EventEmitter()
+/**
+ * Extending the standard emitter to some syntactic sugar and standardisation to the emitted event.
+ * This is specifically quite important for mustache used in automations.
+ */
+class BudibaseEmitter extends EventEmitter {
+  emitRecord(eventName, instanceId, record, model = null) {
+    let event = {
+      record,
+      instanceId,
+      modelId: record.modelId,
+    }
+    if (model) {
+      event.model = model
+    }
+    if (record._id) {
+      event.id = record._id
+    }
+    if (record._rev) {
+      event.revision = record._rev
+    }
+    this.emit(eventName, event)
+  }
+
+  emitModel(eventName, instanceId, model = null) {
+    let event = {
+      model,
+      instanceId,
+      modelId: model._id,
+    }
+    if (model._id) {
+      event.id = model._id
+    }
+    if (model._rev) {
+      event.revision = model._rev
+    }
+    this.emit(eventName, event)
+  }
+}
+
+const emitter = new BudibaseEmitter()
 
 module.exports = emitter

packages/server/src/utilities/queue/inMemoryQueue.js

@@ -0,0 +1,78 @@
+let events = require("events")
+
+/**
+ * Bull works with a Job wrapper around all messages that contains a lot more information about
+ * the state of the message, this object constructor implements the same schema of Bull jobs
+ * for the sake of maintaining API consistency.
+ * @param {string} queue The name of the queue which the message will be carried on.
+ * @param {object} message The JSON message which will be passed back to the consumer.
+ * @returns {Object} A new job which can now be put onto the queue, this is mostly an
+ * internal structure so that an in memory queue can be easily swapped for a Bull queue.
+ */
+function newJob(queue, message) {
+  return {
+    timestamp: Date.now(),
+    queue: queue,
+    data: message,
+  }
+}
+
+/**
+ * This is designed to replicate Bull (https://github.com/OptimalBits/bull) in memory as a sort of mock.
+ * It is relatively simple, using an event emitter internally to register when messages are available
+ * to the consumers - in can support many inputs and many consumers.
+ */
+class InMemoryQueue {
+  /**
+   * The constructor the queue, exactly the same as that of Bulls.
+   * @param {string} name The name of the queue which is being configured.
+   * @param {object|null} opts This is not used by the in memory queue as there is no real use
+   * case when in memory, but is the same API as Bull
+   */
+  constructor(name, opts = null) {
+    this._name = name
+    this._opts = opts
+    this._messages = []
+    this._emitter = new events.EventEmitter()
+  }
+
+  /**
+   * Same callback API as Bull, each callback passed to this will consume messages as they are
+   * available. Please note this is a queue service, not a notification service, so each
+   * consumer will receive different messages.
+   * @param {function<object>} func The callback function which will return a "Job", the same
+   * as the Bull API, within this job the property "data" contains the JSON message. Please
+   * note this is incredibly limited compared to Bull as in reality the Job would contain
+   * a lot more information about the queue and current status of Bull cluster.
+   */
+  process(func) {
+    this._emitter.on("message", async () => {
+      if (this._messages.length <= 0) {
+        return
+      }
+      let msg = this._messages.shift()
+      let resp = func(msg)
+      if (resp.then != null) {
+        await resp
+      }
+    })
+  }
+
+  // simply puts a message to the queue and emits to the queue for processing
+  /**
+   * Simple function to replicate the add message functionality of Bull, putting
+   * a new message on the queue. This then emits an event which will be used to
+   * return the message to a consumer (if one is attached).
+   * @param {object} msg A message to be transported over the queue, this should be
+   * a JSON message as this is required by Bull.
+   */
+  add(msg) {
+    if (typeof msg !== "object") {
+      throw "Queue only supports carrying JSON."
+    }
+    this._messages.push(newJob(this._name, msg))
+    this._emitter.emit("message")
+  }
+}
+
+module.exports = InMemoryQueue