reactive counts test

lib/exposure/exposure.js

@@ -1,3 +1,4 @@
+import genCountEndpoint from '../query/counts/genEndpoint.server.js';
 import createGraph from '../query/lib/createGraph.js';
 import recursiveCompose from '../query/lib/recursiveCompose.js';
 import hypernova from '../query/hypernova/hypernova.js';
@@ -52,6 +53,7 @@ export default class Exposure {
         }
 
         this.initCountMethod();
+        this.initCountPublication();
     }
 
     _validateAndClean() {
@@ -171,7 +173,7 @@ export default class Exposure {
     }
 
     /**
-     * Initializez the method to retrieve the count of the data via Meteor.call
+     * Initializes the method to retrieve the count of the data via Meteor.call
      * @returns {*}
      */
     initCountMethod() {
@@ -186,6 +188,25 @@ export default class Exposure {
         })
     }
 
+    /**
+     * Initializes the reactive endpoint to retrieve the count of the data.
+     */
+    initCountPublication() {
+        const collection = this.collection;
+
+        genCountEndpoint(this.name, {
+            getCursor(session) {
+                return collection.find(session.filters, {
+                    fields: {_id: 1},
+                }, this.userId);
+            },
+
+            getSession(body) {
+                return { filters: body.$filters || {} };
+            },
+        });
+    }
+
     /**
      * Initializes security enforcement
      * THINK: Maybe instead of overriding .find, I could store this data of security inside the collection object.

lib/namedQuery/constants.js

@@ -0,0 +1,2 @@
+export const COUNTS_COLLECTION_CLIENT = '$grapher.counts';
+export const COUNTS_COLLECTION_SERVER = '$grapher.counts_requests';

lib/namedQuery/expose/extension.js

@@ -1,3 +1,5 @@
+import { check } from 'meteor/check';
+
 import NamedQuery from '../namedQuery.js';
 import ExposeSchema from './schema.js';
 import mergeDeep from './lib/mergeDeep.js';
@@ -5,6 +7,7 @@ import createGraph from '../../query/lib/createGraph.js';
 import recursiveCompose from '../../query/lib/recursiveCompose.js';
 import prepareForProcess from '../../query/lib/prepareForProcess.js';
 import deepClone from 'lodash.cloneDeep';
+import genCountEndpoint from '../../query/counts/genEndpoint.server';
 
 _.extend(NamedQuery.prototype, {
     expose(config = {}) {
@@ -19,6 +22,8 @@ _.extend(NamedQuery.prototype, {
         ExposeSchema.clean(config);
         this.exposeConfig = config;
 
+        this._paramSchema = new SimpleSchema(this.exposeConfig.schema);
+
         if (config.method) {
             this._initMethod();
         }
@@ -32,6 +37,7 @@ _.extend(NamedQuery.prototype, {
         }
 
         this._initCountMethod();
+        this._initCountPublication();
 
         if (config.embody) {
             this.body = mergeDeep(
@@ -74,7 +80,27 @@ _.extend(NamedQuery.prototype, {
 
                 return self.clone(newParams).getCount();
             }
-        })
+        });
+    },
+
+    _initCountPublication() {
+        const self = this;
+
+        genCountEndpoint(self.name, {
+            getCursor(session) {
+                const query = self.clone(session.params);
+                return query.getCursorForCounting();
+            },
+
+            getSession(newParams) {
+                self._validateParams(newParams);
+                if (self.exposeConfig.firewall) {
+                    self.exposeConfig.firewall.call(this, this.userId, newParams);
+                }
+
+                return { params: newParams };
+            },
+        });
     },
 
     _initPublication() {
@@ -100,13 +126,13 @@ _.extend(NamedQuery.prototype, {
         if (params && this.exposeConfig.schema) {
             if (process.env.NODE_ENV !== 'production') {
                 try {
-                    (new SimpleSchema(this.exposeConfig.schema)).validate(params);
+                    this._paramSchema.validate(params);
                 } catch (validationError) {
                     console.error(`Invalid parameters supplied to query ${this.queryName}`, validationError);
                     throw validationError; // rethrow
                 }
             } else {
-                (new SimpleSchema(this.exposeConfig.schema)).validate(params);
+                this._paramSchema.validate(params);
             }
         }
     }

lib/namedQuery/namedQuery.client.js

@@ -1,3 +1,4 @@
+import CountSubscription from '../query/counts/countSubscription';
 import createGraph from '../query/lib/createGraph.js';
 import recursiveFetch from '../query/lib/recursiveFetch.js';
 import prepareForProcess from '../query/lib/prepareForProcess.js';
@@ -22,6 +23,20 @@ export default class extends Base {
         return this.subscriptionHandle;
     }
 
+    /**
+     * Subscribe to the counts for this query
+     *
+     * @param callback
+     * @returns {Object}
+     */
+    subscribeCount(callback) {
+        if (!this._counter) {
+            this._counter = new CountSubscription(this);
+        }
+
+        return this._counter.subscribe(this.params, callback);
+    }
+
     /**
      * Unsubscribe if an existing subscription exists
      */
@@ -33,6 +48,16 @@ export default class extends Base {
         this.subscriptionHandle = null;
     }
 
+    /**
+     * Unsubscribe to the counts if a subscription exists.
+     */
+    unsubscribeCount() {
+        if (this._counter) {
+            this._counter.unsubscribe();
+            this._counter = null;
+        }
+    }
+
     /**
      * Fetches elements in sync using promises
      * @return {*}
@@ -90,6 +115,10 @@ export default class extends Base {
      * @returns {any}
      */
     async getCountSync() {
+        if (this._counter) {
+            throw new Meteor.Error('This query is reactive, meaning you cannot use promises to fetch the data.');
+        }
+
         return await callWithPromise(this.name + '.count', prepareForProcess(this.body, this.params));
     }
 
@@ -99,11 +128,15 @@ export default class extends Base {
      * @returns {any}
      */
     getCount(callback) {
-        if (!callback) {
-            throw new Meteor.Error('not-allowed', 'You are on client so you must either provide a callback to get the count.');
+        if (this._counter) {
+            return this._counter.getCount();
+        } else {
+            if (!callback) {
+                throw new Meteor.Error('not-allowed', 'You are on client so you must either provide a callback to get the count or subscribe first.');
+            } else {
+                return Meteor.call(this.name + '.count', this.params, callback);
+            }
         }
-
-        return Meteor.call(this.name + '.count', this.params, callback);
     }
 
     /**

lib/namedQuery/namedQuery.server.js

@@ -30,7 +30,16 @@ export default class extends Base {
      * @returns {any}
      */
     getCount() {
+        return this.getCursorForCounting().count();
+    }
+
+    /**
+     * Returns the cursor for counting
+     * This is most likely used for counts cursor
+     */
+    getCursorForCounting() {
         let body = prepareForProcess(this.body, this.params);
-        return this.collection.find(body.$filters || {}, {}).count();
+
+        return this.collection.find(body.$filters || {}, {fields: {_id: 1}});
     }
 }

lib/namedQuery/testing/client.test.js

@@ -49,6 +49,22 @@ describe('Named Query', function () {
         })
     });
 
+    it('Should work with reactive counts', function (done) {
+        const query = postListExposure.clone({title: 'User Post - 3'});
+
+        const handle = query.subscribeCount();
+        Tracker.autorun(c => {
+            if (handle.ready()) {
+                c.stop();
+                const count = query.getCount();
+                handle.stop();
+
+                assert.equal(count, 6);
+                done();
+            }
+        });
+    });
+
     it('Should work with reactive queries', function (done) {
         const query = createQuery({
             postListExposure: {

lib/query/counts/collection.js

@@ -0,0 +1,7 @@
+import { Mongo } from 'meteor/mongo';
+import { COUNTS_COLLECTION_CLIENT } from './constants';
+
+/**
+ * Internal collection used to store counts on the client.
+ */
+export default new Mongo.Collection(COUNTS_COLLECTION_CLIENT);

lib/query/counts/constants.js

@@ -0,0 +1 @@
+export const COUNTS_COLLECTION_CLIENT = '$grapher.counts';

lib/query/counts/countSubscription.js

@@ -0,0 +1,109 @@
+import { EJSON } from 'meteor/ejson';
+import { Meteor } from 'meteor/meteor';
+import { ReactiveVar } from 'meteor/reactive-var';
+import { Tracker } from 'meteor/tracker';
+
+import Counts from './collection';
+import createFauxSubscription from './createFauxSubscription';
+import prepareForProcess from '../lib/prepareForProcess.js';
+import NamedQueryBase from '../../namedQuery/namedQuery.base';
+
+export default class CountSubscription {
+    /**
+     * @param {*} query - The query to use when fetching counts
+     */
+    constructor(query) {
+        this.accessToken = new ReactiveVar(null);
+        this.fauxHandle = null;
+        this.query = query;
+    }
+
+    /**
+     * Starts a subscription request for reactive counts.
+     *
+     * @param {*} arg - The argument to pass to {name}.count.subscribe
+     * @param {*} callback
+     */
+    subscribe(arg, callback) {
+        // Don't try to resubscribe if arg hasn't changed
+        if (EJSON.equals(this.lastArgs, arg) && this.fauxHandle) {
+            return this.fauxHandle;
+        }
+
+        this.accessToken.set(null);
+        this.lastArgs = arg;
+
+        Meteor.call(this.query.name + '.count.subscribe', arg, (error, token) => {
+            if (!this._markedForUnsubscribe) {
+                this.subscriptionHandle = Meteor.subscribe(this.query.name + '.count', token, callback);
+                this.accessToken.set(token);
+
+                this.disconnectComputation = Tracker.autorun(() => this.handleDisconnect());
+            }
+
+            this._markedForUnsubscribe = false;
+        });
+
+        this.fauxHandle = createFauxSubscription(this);
+        return this.fauxHandle;
+    }
+
+    /**
+     * Unsubscribes from the count endpoint, if there is such a subscription.
+     */
+    unsubscribe() {
+        if (this.subscriptionHandle) {
+            this.disconnectComputation.stop();
+            this.subscriptionHandle.stop();
+        } else {
+            // If we hit this branch, then Meteor.call in subscribe hasn't finished yet
+            // so set a flag to stop the subscription from being created
+            this._markedForUnsubscribe = true;
+        }
+
+        this.accessToken.set(null);
+        this.fauxHandle = null;
+        this.subscriptionHandle = null;
+    }
+
+    /**
+     * Reactively fetch current document count. Returns null if the subscription is not ready yet.
+     *
+     * @returns {Number|null} - Current document count
+     */
+    getCount() {
+        const id = this.accessToken.get();
+        if (id === null) return null;
+
+        const doc = Counts.findOne(id);
+        return doc.count;
+    }
+
+    /**
+     * All session info gets deleted when the server goes down, so when the client attempts to
+     * optimistically resume the '.count' publication, the server will throw a 'no-request' error.
+     *
+     * This function prevents that by manually stopping and restarting the subscription when the
+     * connection to the server is lost.
+     */
+    handleDisconnect() {
+        const status = Meteor.status();
+        if (!status.connected) {
+            this._markedForResume = true;
+            this.fauxHandle = null;
+            this.subscriptionHandle.stop();
+        }
+
+        if (status.connected && this._markedForResume) {
+            this._markedForResume = false;
+            this.subscribe(this.lastArgs);
+        }
+    }
+
+    /**
+     * Returns whether or not a subscription request has been made.
+     */
+    isSubscribed() {
+        return this.accessToken.get() !== null;
+    }
+}

lib/query/counts/createFauxSubscription.js

@@ -0,0 +1,10 @@
+/**
+ * This method creates a "fake" subscription handle so that users of CountSubscription#subscribe
+ * have an interface consistent with normal subscriptions.
+ *
+ * @param {CountSubscription} countManager
+ */
+export default (countManager) => ({
+    ready: () => countManager.accessToken.get() !== null && countManager.subscriptionHandle.ready(),
+    stop: () => countManager.unsubscribe(),
+});

lib/query/counts/genEndpoint.server.js

@@ -0,0 +1,70 @@
+import { check } from 'meteor/check';
+import { Meteor } from 'meteor/meteor';
+import { Mongo } from 'meteor/mongo';
+
+import { COUNTS_COLLECTION_CLIENT } from './constants';
+
+// XXX: Should this persist between server restarts?
+const collection = new Mongo.Collection(null);
+
+/**
+ * This method generates a reactive count endpoint (a method and publication) for a collection or named query.
+ *
+ * @param {String} name - Name of the query or collection
+ * @param {Function} getCursor - Takes in the user's session document as an argument, and turns that into a Mongo cursor.
+ * @param {Function} getSession - Takes the subscribe method's argument as its parameter. Should enforce any necessary security constraints. The return value of this function is stored in the session document.
+ */
+export default (name, { getCursor, getSession }) => {
+    Meteor.methods({
+        [name + '.count.subscribe'](paramsOrBody) {
+            const session = getSession.call(this, paramsOrBody);
+            const existingSession = collection.findOne({ ...session, userId: this.userId });
+
+            // Try to reuse sessions if the user subscribes multiple times with the same data
+            if (existingSession) {
+                return existingSession._id;
+            }
+
+            const token = collection.insert({
+                ...session,
+                query: name,
+                userId: this.userId,
+            });
+
+            return token;
+        },
+    });
+
+    Meteor.publish(name + '.count', function(token) {
+        check(token, String);
+        const self = this;
+        const request = collection.findOne({ _id: token, userId: self.userId });
+
+        if (!request) {
+            throw new Error('no-request', `You must acquire a request token via the "${name}.count.subscribe" method first.`);
+        }
+
+        const cursor = getCursor.call(this, request);
+
+        // Start counting
+        let count = 0;
+        self.added(COUNTS_COLLECTION_CLIENT, token, { count });
+        const handle = cursor.observeChanges({
+            added(id) {
+                count++;
+                self.changed(COUNTS_COLLECTION_CLIENT, token, { count });
+            },
+
+            removed(id) {
+                count--;
+                self.changed(COUNTS_COLLECTION_CLIENT, token, { count });
+            },
+        });
+
+        self.onStop(() => {
+            handle.stop();
+            collection.remove(token);
+        });
+        self.ready();
+    });
+};

lib/query/counts/testing/bootstrap/collection.test.js

@@ -0,0 +1,6 @@
+import { Mongo } from 'meteor/mongo';
+import { SimpleSchema } from 'meteor/aldeed:simple-schema';
+
+const PostsCollection = new Mongo.Collection('counts_posts');
+
+export default PostsCollection;

lib/query/counts/testing/bootstrap/namedQuery.test.js

@@ -0,0 +1,10 @@
+import { createQuery } from 'meteor/cultofcoders:grapher';
+
+const query = createQuery('counts_posts_query', {
+    counts_posts: {
+        _id: 1,
+        text: 1,
+    },
+});
+
+export default query;

lib/query/counts/testing/client.test.js

@@ -0,0 +1,65 @@
+import { Tracker } from 'meteor/tracker';
+import PostsCollection from './bootstrap/collection.test';
+import NamedQuery from './bootstrap/namedQuery.test';
+
+describe('Reactive count tests', function () {
+    it('Should fetch the initial count', function (done) {
+        const query = NamedQuery.clone();
+        const handle = query.subscribeCount();
+
+        Tracker.autorun(c => {
+            if (handle.ready()) {
+                c.stop();
+                const count = query.getCount();
+                handle.stop();
+
+                assert.equal(count, 3);
+                done();
+            }
+        });
+    });
+
+    // TODO: Can these tests fail if assert gets called too quickly?
+    it('Should update when a document is added', function (done) {
+        const query = NamedQuery.clone();
+        const handle = query.subscribeCount();
+
+        Tracker.autorun(c => {
+            if (handle.ready()) {
+                c.stop();
+                const count = query.getCount();
+                assert.equal(count, 3);
+
+                Meteor.call('addPost', 'text4', (error, newId) => {
+                    const newCount = query.getCount();
+                    assert.equal(newCount, 4);
+
+                    Meteor.call('removePost', newId);
+                    handle.stop();
+                    done();
+                });
+            }
+        });
+    });
+
+    it('Should update when a document is removed', function (done) {
+        const query = NamedQuery.clone();
+        const handle = query.subscribeCount();
+
+        Tracker.autorun(c => {
+            if (handle.ready()) {
+                c.stop();
+                const count = query.getCount();
+                assert.equal(count, 3);
+
+                Meteor.call('removePost', 'removeid', (error) => {
+                    const newCount = query.getCount();
+                    assert.equal(newCount, 2);
+
+                    handle.stop();
+                    done();
+                });
+            }
+        });
+    });
+});

lib/query/counts/testing/server.test.js

@@ -0,0 +1,19 @@
+import { Meteor } from 'meteor/meteor';
+import PostsCollection from './bootstrap/collection.test';
+import query from './bootstrap/namedQuery.test';
+
+query.expose();
+PostsCollection.remove({});
+PostsCollection.insert({ text: 'text 1' });
+PostsCollection.insert({ text: 'text 2' });
+PostsCollection.insert({ _id: 'removeid', text: 'text 3' });
+
+Meteor.methods({
+    addPost(text) {
+        return PostsCollection.insert({ text });
+    },
+
+    removePost(id) {
+        PostsCollection.remove({ _id: id });
+    },
+});

lib/query/query.client.js

@@ -1,4 +1,5 @@
 import { _ } from 'meteor/underscore';
+import CountSubscription from './counts/countSubscription';
 import createGraph from './lib/createGraph.js';
 import recursiveFetch from './lib/recursiveFetch.js';
 import prepareForProcess from './lib/prepareForProcess.js';
@@ -22,6 +23,23 @@ export default class Query extends Base {
         return this.subscriptionHandle;
     }
 
+    /**
+     * Subscribe to the counts for this query
+     *
+     * @param callback
+     * @returns {Object}
+     */
+    subscribeCount(callback) {
+        if (!this._counter) {
+            this._counter = new CountSubscription(this);
+        }
+
+        return this._counter.subscribe(
+            prepareForProcess(this.body, this.params),
+            callback
+        );
+    }
+
     /**
      * Unsubscribe if an existing subscription exists
      */
@@ -33,6 +51,16 @@ export default class Query extends Base {
         this.subscriptionHandle = null;
     }
 
+    /**
+     * Unsubscribe to the counts if a subscription exists.
+     */
+    unsubscribeCount() {
+        if (this._counter) {
+            this._counter.unsubscribe();
+            this._counter = null;
+        }
+    }
+
     /**
      * Fetches elements in sync using promises
      * @return {*}
@@ -90,6 +118,10 @@ export default class Query extends Base {
      * @returns {any}
      */
     async getCountSync() {
+        if (this._counter) {
+            throw new Meteor.Error('This query is reactive, meaning you cannot use promises to fetch the data.');
+        }
+
         return await callWithPromise(this.name + '.count', prepareForProcess(this.body, this.params));
     }
 
@@ -99,11 +131,19 @@ export default class Query extends Base {
      * @returns {any}
      */
     getCount(callback) {
-        if (!callback) {
-            throw new Meteor.Error('not-allowed', 'You are on client so you must either provide a callback to get the count.');
+        if (this._counter) {
+            return this._counter.getCount();
+        } else {
+            if (!callback) {
+                throw new Meteor.Error('not-allowed', 'You are on client so you must either provide a callback to get the count or subscribe first.');
+            } else {
+                return Meteor.call(
+                    this.name + '.count',
+                    prepareForProcess(this.body, this.params),
+                    callback
+                );
+            }
         }
-
-        return Meteor.call(this.name + '.count', prepareForProcess(this.body, this.params), callback);
     }
 
     /**

package.js

@@ -23,13 +23,14 @@ Package.onUse(function (api) {
         'ecmascript',
         'underscore',
         'promise',
+        'reactive-var',
+        'mongo',
         'aldeed:simple-schema@1.5.3',
         'matb33:collection-hooks@0.8.4',
         'reywood:publish-composite@1.4.2',
         'dburles:mongo-collection-instances@0.3.5',
         'tmeasday:check-npm-versions@0.3.1',
         'meteorhacks:aggregate@1.3.0',
-        'mongo'
     ];
 
     api.use(packages);
@@ -82,6 +83,10 @@ Package.onTest(function (api) {
     api.addFiles('lib/namedQuery/testing/bootstrap/client.js', 'client');
     api.addFiles('lib/namedQuery/testing/bootstrap/server.js', 'server');
 
+    // REACTIVE COUNTS
+    api.addFiles('lib/query/counts/testing/server.test.js', 'server');
+    api.addFiles('lib/query/counts/testing/client.test.js', 'client');
+
     api.addFiles('lib/namedQuery/testing/server.test.js', 'server');
     api.addFiles('lib/namedQuery/testing/client.test.js', 'client');
 });