Work towards handling linked record field updates, like the column being deleted from the model.

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

@@ -19,12 +19,18 @@ exports.find = async function(ctx) {
 exports.save = async function(ctx) {
   const instanceId = ctx.user.instanceId
   const db = new CouchDB(instanceId)
+  const oldModelId = ctx.request.body._id
   const modelToSave = {
     type: "model",
     _id: newid(),
     views: {},
     ...ctx.request.body,
   }
+  // get the model in its previous state for differencing
+  let oldModel = null
+  if (oldModelId) {
+    oldModel = await db.get(oldModelId)
+  }
 
   // rename record fields when table column is renamed
   const { _rename } = modelToSave
@@ -70,8 +76,11 @@ exports.save = async function(ctx) {
   // update linked records
   await linkRecords.updateLinks({
     instanceId,
-    eventType: linkRecords.EventType.MODEL_SAVE,
+    eventType: oldModel
+      ? linkRecords.EventType.MODEL_UPDATED
+      : linkRecords.EventType.MODEL_SAVE,
     model: modelToSave,
+    oldModel: oldModel,
   })
   await db.put(designDoc)
 

packages/server/src/db/linkedRecords/LinkController.js

@@ -1,5 +1,5 @@
 const CouchDB = require("../index")
-const linkedRecords = require("./index")
+const { IncludeDocs, getLinkDocuments } = require("./linkUtils")
 
 /**
  * Creates a new link document structure which can be put to the database. It is important to
@@ -62,11 +62,14 @@ class LinkController {
   /**
    * Checks if the model this was constructed with has any linking columns currently.
    * If the model has not been retrieved this will retrieve it based on the eventData.
+   * @params {object|null} model If a model that is not known to the link controller is to be tested.
    * @returns {Promise<boolean>} True if there are any linked fields, otherwise it will return
    * false.
    */
-  async doesModelHaveLinkedFields() {
+  async doesModelHaveLinkedFields(model = null) {
-    const model = await this.model()
+    if (model == null) {
+      model = await this.model()
+    }
     for (let fieldName of Object.keys(model.schema)) {
       const { type } = model.schema[fieldName]
       if (type === "link") {
@@ -79,12 +82,23 @@ class LinkController {
   /**
    * Utility function for main getLinkDocuments function - refer to it for functionality.
    */
-  getLinkDocs(recordId = null) {
+  getRecordLinkDocs(recordId, includeDocs = IncludeDocs.EXCLUDE) {
-    return linkedRecords.getLinkDocuments({
+    return getLinkDocuments({
       instanceId: this._instanceId,
       modelId: this._modelId,
       recordId,
-      includeDocs: false,
+      includeDocs,
+    })
+  }
+
+  /**
+   * Utility function for main getLinkDocuments function - refer to it for functionality.
+   */
+  getModelLinkDocs(includeDocs = IncludeDocs.EXCLUDE) {
+    return getLinkDocuments({
+      instanceId: this._instanceId,
+      modelId: this._modelId,
+      includeDocs,
     })
   }
 
@@ -101,7 +115,7 @@ class LinkController {
     const record = this._record
     const operations = []
     // get link docs to compare against
-    const linkVals = await this.getLinkDocs(record._id)
+    const linkVals = await this.getRecordLinkDocs(record._id)
     for (let fieldName of Object.keys(model.schema)) {
       // get the links this record wants to make
       const recordField = record[fieldName]
@@ -155,15 +169,16 @@ class LinkController {
   async recordDeleted() {
     const record = this._record
     // need to get the full link docs to be be able to delete it
-    const linkDocIds = await this.getLinkDocs(record._id).map(
+    const linkDocs = await this.getRecordLinkDocs(
-      linkVal => linkVal.id
+      record._id,
+      IncludeDocs.INCLUDE
     )
-    if (linkDocIds.length === 0) {
+    if (linkDocs.length === 0) {
       return null
     }
-    const toDelete = linkDocIds.map(id => {
+    const toDelete = linkDocs.map(doc => {
       return {
-        _id: id,
+        ...doc,
         _deleted: true,
       }
     })
@@ -198,6 +213,33 @@ class LinkController {
     return model
   }
 
+  async modelUpdated(oldModel) {
+    // first start by checking if any link columns have been deleted
+    // TODO: need to delete link column deletion
+    const newModel = await this.model()
+    const modelId = newModel._id
+    const linkDocs = await this.getModelLinkDocs(IncludeDocs.INCLUDE)
+    for (let fieldName of Object.keys(oldModel.schema)) {
+      const field = oldModel.schema[fieldName]
+      // this field has been removed from the model schema
+      if (field.type === "link" && newModel.schema[fieldName] == null) {
+        let toDelete = linkDocs.filter(linkDoc => {
+          let correctDoc =
+            linkDoc.doc1.modelId === modelId ? linkDoc.doc1 : linkDoc.doc2
+          return correctDoc.fieldName === fieldName
+        })
+        await this._db.bulkDocs(
+          toDelete.map(doc => {
+            return {
+              ...doc,
+              _deleted: true,
+            }
+          })
+        )
+      }
+    }
+  }
+
   /**
    * When a model is deleted this will carry out the necessary operations to make sure
    * any linked models have the joining column correctly removed as well as removing any
@@ -217,14 +259,14 @@ class LinkController {
       }
     }
     // need to get the full link docs to delete them
-    const linkDocIds = await this.getLinkDocs().map(linkVal => linkVal.id)
+    const linkDocs = await this.getModelLinkDocs(IncludeDocs.INCLUDE)
-    if (linkDocIds.length === 0) {
+    if (linkDocs.length === 0) {
       return null
     }
     // get link docs for this model and configure for deletion
-    const toDelete = linkDocIds.map(id => {
+    const toDelete = linkDocs.map(doc => {
       return {
-        _id: id,
+        ...doc,
         _deleted: true,
       }
     })

packages/server/src/db/linkedRecords/index.js

@@ -1,6 +1,5 @@
 const LinkController = require("./LinkController")
-const CouchDB = require("../index")
+const { IncludeDocs, getLinkDocuments, createLinkView } = require("./linkUtils")
-const Sentry = require("@sentry/node")
 
 /**
  * This functionality makes sure that when records with links are created, updated or deleted they are processed
@@ -12,43 +11,15 @@ const EventType = {
   RECORD_UPDATE: "record:update",
   RECORD_DELETE: "record:delete",
   MODEL_SAVE: "model:save",
+  MODEL_UPDATED: "model:updated",
   MODEL_DELETE: "model:delete",
 }
 
 exports.EventType = EventType
-
+// re-export utils here for ease of use
-/**
+exports.IncludeDocs = IncludeDocs
- * Creates the link view for the instance, this will overwrite the existing one, but this should only
+exports.getLinkDocuments = getLinkDocuments
- * be called if it is found that the view does not exist.
+exports.createLinkView = createLinkView
- * @param {string} instanceId The instance to which the view should be added.
- * @returns {Promise<void>} The view now exists, please note that the next view of this query will actually build it,
- * so it may be slow.
- */
-exports.createLinkView = async instanceId => {
-  const db = new CouchDB(instanceId)
-  const designDoc = await db.get("_design/database")
-  const view = {
-    map: function(doc) {
-      if (doc.type === "link") {
-        let doc1 = doc.doc1
-        let doc2 = doc.doc2
-        emit([doc1.modelId, doc1.recordId], {
-          id: doc2.recordId,
-          fieldName: doc1.fieldName,
-        })
-        emit([doc2.modelId, doc2.recordId], {
-          id: doc1.recordId,
-          fieldName: doc2.fieldName,
-        })
-      }
-    }.toString(),
-  }
-  designDoc.views = {
-    ...designDoc.views,
-    by_link: view,
-  }
-  await db.put(designDoc)
-}
 
 /**
  * Update link documents for a record or model - this is to be called by the API controller when a change is occurring.
@@ -56,8 +27,9 @@ exports.createLinkView = async instanceId => {
  * future quite easily (all updates go through one function).
  * @param {string} instanceId The ID of the instance in which the change is occurring.
  * @param {string} modelId The ID of the of the model which is being changed.
- * * @param {object|null} record The record which is changing, e.g. created, updated or deleted.
+ * @param {object|null} record The record which is changing, e.g. created, updated or deleted.
  * @param {object|null} model If the model has already been retrieved this can be used to reduce database gets.
+ * @param {object|null} oldModel If the model is being updated then the old model can be provided for differencing.
  * @returns {Promise<object>} When the update is complete this will respond successfully. Returns the record for
  * record operations and the model for model operations.
  */
@@ -67,6 +39,7 @@ exports.updateLinks = async ({
   record,
   modelId,
   model,
+  oldModel,
 }) => {
   // make sure model ID is set
   if (model != null) {
@@ -78,7 +51,11 @@ exports.updateLinks = async ({
     model,
     record,
   })
-  if (!(await linkController.doesModelHaveLinkedFields())) {
+  if (
+    !(await linkController.doesModelHaveLinkedFields()) &&
+    (oldModel == null ||
+      !(await linkController.doesModelHaveLinkedFields(oldModel)))
+  ) {
     return record
   }
   switch (eventType) {
@@ -89,6 +66,8 @@ exports.updateLinks = async ({
       return await linkController.recordDeleted()
     case EventType.MODEL_SAVE:
       return await linkController.modelSaved()
+    case EventType.MODEL_UPDATED:
+      return await linkController.modelUpdated(oldModel)
     case EventType.MODEL_DELETE:
       return await linkController.modelDeleted()
     default:
@@ -114,11 +93,11 @@ exports.attachLinkInfo = async (instanceId, records) => {
   // start by getting all the link values for performance reasons
   let responses = await Promise.all(
     records.map(record =>
-      exports.getLinkDocuments({
+      getLinkDocuments({
         instanceId,
         modelId: record.modelId,
         recordId: record._id,
-        includeDocs: false,
+        includeDocs: IncludeDocs.EXCLUDE,
       })
     )
   )
@@ -141,50 +120,3 @@ exports.attachLinkInfo = async (instanceId, records) => {
   // otherwise return the first element as there was only one input
   return wasArray ? records : records[0]
 }
-
-/**
- * Gets the linking documents, not the linked documents themselves.
- * @param {string} instanceId The instance in which we are searching for linked records.
- * @param {string} modelId The model which we are searching for linked records against.
- * @param {string|null} fieldName The name of column/field which is being altered, only looking for
- * linking documents that are related to it. If this is not specified then the table level will be assumed.
- * @param {string|null} recordId The ID of the record which we want to find linking documents for -
- * if this is not specified then it will assume model or field level depending on whether the
- * field name has been specified.
- * @param {boolean|null} includeDocs whether to include docs in the response call, this is considerably slower so only
- * use this if actually interested in the docs themselves.
- * @returns {Promise<object[]>} This will return an array of the linking documents that were found
- * (if any).
- */
-exports.getLinkDocuments = async ({
-  instanceId,
-  modelId,
-  recordId,
-  includeDocs,
-}) => {
-  const db = new CouchDB(instanceId)
-  let params
-  if (recordId != null) {
-    params = { key: [modelId, recordId] }
-  }
-  // only model is known
-  else {
-    params = { startKey: [modelId], endKey: [modelId, {}] }
-  }
-  params.include_docs = !!includeDocs
-  try {
-    const response = await db.query("database/by_link", params)
-    if (includeDocs) {
-      return response.rows.map(row => row.doc)
-    } else {
-      return response.rows.map(row => row.value)
-    }
-  } catch (err) {
-    // check if the view doesn't exist, it should for all new instances
-    if (err != null && err.name === "not_found") {
-      await exports.createLinkView(instanceId)
-    } else {
-      Sentry.captureException(err)
-    }
-  }
-}

packages/server/src/db/linkedRecords/linkUtils.js

@@ -0,0 +1,91 @@
+const CouchDB = require("../index")
+const Sentry = require("@sentry/node")
+
+/**
+ * Only needed so that boolean parameters are being used for includeDocs
+ * @type {{EXCLUDE: boolean, INCLUDE: boolean}}
+ */
+exports.IncludeDocs = {
+  INCLUDE: true,
+  EXCLUDE: false,
+}
+
+/**
+ * Creates the link view for the instance, this will overwrite the existing one, but this should only
+ * be called if it is found that the view does not exist.
+ * @param {string} instanceId The instance to which the view should be added.
+ * @returns {Promise<void>} The view now exists, please note that the next view of this query will actually build it,
+ * so it may be slow.
+ */
+exports.createLinkView = async instanceId => {
+  const db = new CouchDB(instanceId)
+  const designDoc = await db.get("_design/database")
+  const view = {
+    map: function(doc) {
+      if (doc.type === "link") {
+        let doc1 = doc.doc1
+        let doc2 = doc.doc2
+        emit([doc1.modelId, doc1.recordId], {
+          id: doc2.recordId,
+          fieldName: doc1.fieldName,
+        })
+        emit([doc2.modelId, doc2.recordId], {
+          id: doc1.recordId,
+          fieldName: doc2.fieldName,
+        })
+      }
+    }.toString(),
+  }
+  designDoc.views = {
+    ...designDoc.views,
+    by_link: view,
+  }
+  await db.put(designDoc)
+}
+
+/**
+ * Gets the linking documents, not the linked documents themselves.
+ * @param {string} instanceId The instance in which we are searching for linked records.
+ * @param {string} modelId The model which we are searching for linked records against.
+ * @param {string|null} fieldName The name of column/field which is being altered, only looking for
+ * linking documents that are related to it. If this is not specified then the table level will be assumed.
+ * @param {string|null} recordId The ID of the record which we want to find linking documents for -
+ * if this is not specified then it will assume model or field level depending on whether the
+ * field name has been specified.
+ * @param {boolean|null} includeDocs whether to include docs in the response call, this is considerably slower so only
+ * use this if actually interested in the docs themselves.
+ * @returns {Promise<object[]>} This will return an array of the linking documents that were found
+ * (if any).
+ */
+exports.getLinkDocuments = async ({
+  instanceId,
+  modelId,
+  recordId,
+  includeDocs,
+}) => {
+  const db = new CouchDB(instanceId)
+  let params
+  if (recordId != null) {
+    params = { key: [modelId, recordId] }
+  }
+  // only model is known
+  else {
+    params = { startKey: [modelId], endKey: [modelId, {}] }
+  }
+  params.include_docs = !!includeDocs
+  try {
+    const response = await db.query("database/by_link", params)
+    if (includeDocs) {
+      return response.rows.map(row => row.doc)
+    } else {
+      return response.rows.map(row => row.value)
+    }
+  } catch (err) {
+    // check if the view doesn't exist, it should for all new instances
+    if (err != null && err.name === "not_found") {
+      await exports.createLinkView(instanceId)
+    } else {
+      Sentry.captureException(err)
+    }
+  }
+}