Load plugin after another fastify - node.js

I'm currently working on an api where I autoload my plugins but I would like to add global hooks on all routes.
What I'm currently doing is I load all my plugins and after I load my middlewares but I have a problem
I'm trying to use mongoClient created by fastify-mongo but I always end up with the error mongo is not defined.
When I'm using it on my controller everything works i thinks I get this error because the plugin is not fully loaded, I did find .ready but it doesn't work
plugin/mongo.js
import fp from 'fastify-plugin';
import mongoPl from '#fastify/mongodb';
async function mongo(fastify, opts) {
fastify.register(mongoPl, {
forceClose: true,
url: 'mongodb://mongo:27017'
});
}
export default fp(mongo, {
name: 'mongo'
});
libs/middleware
import fp from "fastify-plugin";
async function hooks(fastify, opts) {
fastify.addHook('onRequest', (req, res, done) => {
// Inject mongo client
mongoClient(req);
done();
});
}
async function mongoClient(req){
try {
req.db = this.mongo.client.db('db-name');
}catch (e) {
console.error(e);
}
}
export default fp(hooks, {
name: 'hooksMiddleware'
});
app.js
app.register(AutoLoad, {
dir: join(import.meta.url, 'plugins'),
options: Object.assign({})
}).after(() => {
app.register(hooksMiddleware, {});
});

Your setup looks good, but the this context in mongoClient function is undefined.
Here some fixes:
async function hooks(fastify, opts) {
fastify.addHook('onRequest', (req, res, done) => {
// Inject mongo client
mongoClient.call(fastify, req);
done();
});
}
Or:
async function hooks(fastify, opts) {
// NOTE: I changed from arrow to an anonymous function
fastify.addHook('onRequest', function (req, res, done) {
// Inject mongo client
mongoClient.call(this, req);
done();
});
}
You need to know:
the this context is set only on those named function that you provide to Fastify. The mongoClient function is just a function outside the Fastify's control
the this context cannot be set for arrow function. (opinion) I will never stop to say: use arrow function only for 1-line function, otherwise named function are always the best choice (better stack tracing, more readable)

Related

How to implement fastify hook for specific prefix?

I needed a separate validation logic per version (prefix)
const routes = require('./routes/v1/users')
fastify.register(route, { prefix: `/v1` }) // currently using fastify#4.5.2
Might be good if there's something similar to below:
fastify.register(route, {
prefix: `/v1`,
preValidation: (req, reply) => { /* logic here */ }
})
Tried looking fastify docs, other channels and I can't find any similar implementation.
There is not such option to the fastify.register method, but you can do it playing with encapsulation.
You can create a dedicated context that includes your routes + the hook.
This context will be isolated by other context you will create with register.
This example show you how:
const fastify = require('fastify')({ logger: false, exposeHeadRoutes: false })
async function run() {
const route = function routesPlugin(fastify, options, next) {
fastify.get('/hello', async (request, reply) => {
console.log('request')
return { hello: 'world' }
})
next()
}
fastify.register(function intermediatePlugin(instance, opts, next) {
instance.addHook('preValidation', function hook(request, reply, done) {
console.log('only for v1')
done()
})
instance.register(route, { prefix: `/v1` })
next()
})
fastify.register(route, { prefix: `/v2` })
await fastify.inject('/v1/hello')
await fastify.inject('/v2/hello')
}
run()
You can visualize this structure by using fastify-overview (and the fastify-overview-ui plugin together:
Note that the hook is child of the intermediatePlugin that is not shared by the v2's routesPlugin sibling.

Why does it return undefined?

So I have two files, server.js and db.js
Now Here is the code that I am having issue with :
server.js :
var DB = require('./db')
app.get("/test", (req, res) => {
console.log(DB.getPostAll())
})
db.js :
MongoClient.connect(uri, { useNewUrlParser: true })
.then(function (db) {
console.log("Connected")
var dbo = db.db('test')
module.exports.getPostAll = function getPostAll() {
return (
dbo.collection('posts').find({}).toArray(function (err, res) {
if (err) throw err;
else return res
})
)
}
})
.catch(function (err) {
})
Sorry for the silly question. But can anyone say what am I doing wrong here ?
I am trying to use two returns. Before this I tried to use a variable in place of the returns in db.js's getPostAll. But it also returns undefined.
There are plenty of bad practices in the code, I'll try to cover some.
Your db.js file triggers an asynchronous action the moment it is required.
You are not returning the Promise from the db.js file, hence your server.js file starts executing code without knowing if the connection to the DB was fulfilled/pending or rejected
You are exporting a method after a function is executed, this leads to many odd and unexpected side effects. It is best to define all your exports at the top level of the file.
The simplest way to solve your issue is:
server.js :
const connectDB = require('./db')
connectDB().then((db) => {
app.get("/test", (req, res) => {
console.log(db.getPostAll())
})
app.listen(...); // lift the server ONLY when the db is connected
});
db.js :
module.exports = function connectDB() {
return MongoClient.connect(uri, { useNewUrlParser: true })
.then(function (db) {
console.log("Connected")
var dbo = db.db('test')
return {
getPostAll() {
return dbo.collection('posts').find({}).toArray()
}
}
})
}
In the db.js file, I am exporting a function that returns a promise, this way I can tell when the connection is complete (by having the promise resolved), it returns an object with all the db methods you need (getPostAll).
In the server.js file, I am waiting for the async connection to be established before I lift the app, this way I know i have my application in a ready state when it is served, and I have the db methods readily available for my app.
You are getting undefined as your promise has not resolved. Try using an async function and await your db operation to finish. See working with async funtions . you can also try mongoose object modeling as your mongodb client.

Node.js trouble with callback in loop

Being new to Node, I am still having some troubles with callbacks.
In the mapBpiIfindex function I am trying to loop through all of the VLANs found by the vlans function. Once it has looped through all VLANs, creating the map, I want to output the map to the browser. But, the only output I am getting is {}. How can I send the mapping to the browser? I am not even sure if I am using my callbacks correctly.
var express = require('express');
var router = express.Router();
var snmp = require('snmp-native');
// Create a Session with explicit default host, port, and community.
let session = new snmp.Session({ host: 'AASW0120', port: 161, community: 'community' })
let Mibs = {
hostname: [1,3,6,1,2,1,1,5,0],
vlans: [1,3,6,1,4,1,9,9,46,1,3,1,1,2],
dot1dBasePortIfIndex: [1,3,6,1,2,1,17,1,4,1,2]
}
/* Get all VLANs on switch */
function vlans(snmpSession, cb) {
let vlans = []
session.getSubtree({ oid: Mibs.vlans }, function (error, varbinds) {
if (error) {
console.log('Fail :(');
} else {
varbinds.forEach(function (varbind) {
vlans.push(varbind.oid[varbind.oid.length -1])
})
}
cb(vlans)
})
}
/* Map BPIs to Ifindices */
function mapBpiIfindex(session, cb) {
let map = {}
vlans(session, function (vlans) {
vlans.forEach(function (vlan) {
session.getSubtree({oid: Mibs.dot1dBasePortIfIndex, community: 'community#' + vlan}, function (error, varbinds) {
if (error) {
console.log('Fail :(')
} else {
varbinds.forEach(function (varbind) {
map[varbind.oid[varbind.oid.length -1]] = {ifindex: varbind.value, vlan: vlan}
})
}
})
})
cb(map)
})
}
router.get('/vlans', function (req, res, next) {
vlans(session, function (vlans) {
res.send(vlans)
})
})
router.get('/bpi-ifindex', function (req, res, next) {
mapBpiIfindex(session, function (mapping) {
res.send(mapping)
})
})
The answer is no, youre not using it correctly ;)
A few things here:
You should be clear that only the code within the callback is executed after the operation has finished, so cb(map)does not wait until all youre looped callbacks have finished. Thats why nothing is returned (because when cb is called, the async functions have not finished yet and map values are undefined. Have a look at this How do I return the response from an asynchronous call?, its the same principle.
Have a look at async module. Specifically, the do* or whilst methods. It'll help you process loops with async function calls.
Apart from that, you should not use forEach if you mind about performance.

Unit testing validation with express-validator

How can I unit test my validations that are done using express-validator?
I have tried creating a dummy request object, but I get the error: TypeError: Object #<Object> has no method 'checkBody'. I am able to manually test that the validation works in the application.
Here is what I have tried:
describe('couponModel', function () {
it('returns errors when necessary fields are empty', function(done){
var testBody = {
merchant : '',
startDate : '',
endDate : ''
};
var request = {
body : testBody
};
var errors = Model.validateCouponForm(request);
errors.should.not.be.empty;
done();
});
});
My understanding is that the checkBody method is added to the request object when I have app.use(expressValidator()) in my express application, but as I am only testing that the validation is working in this unit test I do not have an instance of the express application available, and the validation method that I am testing is not called directly from it anyway as it is only called through a post route, which I do not want to call for a unit test as it involves a database operation.
Here's a solution for the new express-validator api (v4):
tl;dr: You can use this function:
exports.testExpressValidatorMiddleware = async (req, res, middlewares) => {
await Promise.all(middlewares.map(async (middleware) => {
await middleware(req, res, () => undefined);
}));
};
It can be called like this:
const { validationResult } = require('express-validator/check');
await testExpressValidatorMiddleware(req, res, expressValidatorMiddlewareArray);
const result = validationResult(req);
expect(result....
These solutions assume you have the async/await syntax available. You can use the node-mocks-http library to create the req and res objects.
Explanation:
Each element in an express-validator array is applied to the route as middleware. Say this is your array:
[
check('addresses.*.street').exists(),
check('addresses.*.postalCode').isPostalCode(),
]
Each check will be loaded as middleware.
In order to test middleware, we need to implement a function which acts similarly to how express implements middleware.
Express middleware always accepts three params, the request and response objects, and the next function it should call (next by convention). Why do we need next? For scenarios where we want our middleware to do something before and after the proceeding function, e.g.
const loggerMiddleware = (req, res, next) => {
console.log('req body is ' + req.body);
next();
console.log('res status is ' + res.status);
};
But express-validator doesn't do this, it just calls next() once each of its validators is finished. For that reason, our implementation doesn't really need to bother with next().
Instead, we can just run each of our middlewares in turn and pass an empty function as next to avoid a TypeError:
middlewares.map((middleware) => {
middleware(req, res, () => undefined);
});
But this won't work, because express-validator middleware returns promises and we need to wait for them to resolve...
middlewares.map(async (middleware) => {
await middleware(req, res, () => undefined);
});
And we don't want to move on until all promises in our iteration are resolved (Mozilla docs on Promise.all are here):
await Promise.all(middlewares.map(async (middleware) => {
await middleware(req, res, () => undefined);
}));
And we should extract this as a reusable function:
exports.testExpressValidatorMiddleware = async (req, res, middlewares) => {
await Promise.all(middlewares.map(async (middleware) => {
await middleware(req, res, () => undefined);
}));
};
And now we've arrived at my solution. If someone can improve on this implementation, I'm very happy to make edits.
I faced the same issue and I had to create the methods using this:
var validRequest = {
// Default validations used
checkBody: function () { return this; },
checkQuery: function () { return this; },
notEmpty: function () { return this; },
// Custom validations used
isArray: function () { return this; },
gte: function () { return this; },
// Validation errors
validationErrors: function () { return false; }
};
function getValidInputRequest(request) {
Object.assign(request, validRequest);
return request;
}
So, in your code you have to call the getValidInputRequest helper:
describe('couponModel', function () {
it('returns errors when necessary fields are empty', function(done){
var testBody = {
merchant : '',
startDate : '',
endDate : ''
};
var request = {
body : testBody
};
request = getValidInputRequest(request); // <-- Update the request
var errors = Model.validateCouponForm(request);
errors.should.not.be.empty;
done();
});
});
Now, the request object has the body property and all the methods needed by express-validator.
If you want to test the cases that the validator fails, you should use something like this:
function getInvalidInputRequest(request, errorParams) {
// Get de default valid request
Object.assign(request, validRequest);
// Override the validationErrors function with desired errors
request.validationErrors = function () {
var errors = [];
errorParams.forEach(function(error){
errors.push({msg: 'the parameter "'+ error +'" is mandatory'})
});
return errors;
};
return request;
}
And to update the request you should do:
request = getInvalidInputRequest(request, ['mandatory_param_1', 'mandatory_param_2']);

How to test stubbed database queries

I have a Sails.Js controller that looks like this
module.exports = {
confirmID: function(req,res) {
var uid = req.params.id;
User.findOne({id:uid}).exec(function(err,user) {
// ...
});
}
}
where User is a sails-postgres model. I have tried testing it with mocha, sinon and supertest with a test like this
describe('Controller', function() {
var sandbox;
before(function() {
sandbox = sinon.sandbox.create();
sandbox.stub(User, 'findOne');
});
after(function() {
sandbox.restore();
});
describe('GET /confirmid/:id', function() {
it('should do something', function(done) {
request(sails.hooks.http.app)
.get('/confirmid/123')
.expect(200)
.end(function(err,res) {
sandbox.fakes[0].called.should.be.true;
done();
});
});
});
If I leave it at that it errors out because exec is called on undefined, but I can't seem to stub the nested exec method without either errors or the test hanging. Is there a way to stub a series of method calls such as .find().exec()? Or am I best to just leave this to integration tests where I can test it with an actual database?
Assuming that you really want to stub (not just spy) - you want to control what the query resolves to as opposed to simply knowing whether the query was executed. Here's what I'm using to stub sails/waterline query methods. Something like...
var stubQueryMethod = require('stubQueryMethod');
describe('Controller', function() {
before(function() {
stubQueryMethod(User, 'findOne', {
id: 123,
name: 'Fred Fakes'
});
});
after(function() {
User.findOne.restore();
});
describe('GET /confirmid/:id', function() {
it('should do something', function(done) {
request(sails.hooks.http.app)
.get('/confirmid/123')
.expect(200)
.end(function(err,user) {
user.should.have.property('name', 'Fred Fakes');
done();
});
});
});
});
Source: https://gist.github.com/wxactly/f2258078d802923a1a0d
For people looking for other options to stub or mock waterline models, I've found the following four options:
stubQueryMethod.js gist - https://gist.github.com/wxactly/f2258078d802923a1a0d
model mock gist - https://gist.github.com/campbellwmorgan/e305cc36365fa2d052a7
weaselpecker - https://github.com/ottogiron/weaselpecker
sails-mock-models - https://github.com/ryanwilliamquinn/sails-mock-models
After evaluating each one, I've decided on sails-mock-models because it is easy to understand and seems the most used sails mocking library according to npm: https://www.npmjs.com/package/sails-mock-models
Hope this helps someone!
Update: I'm still using sails-mock-models, and it is quite easy, but there are a few drawbacks such as it fails to return promises that are taken into a q.all(promiseArray).then() call. If I get around to investigating the other options or find a workaround, I will post it here.
This will only work for queries that use exec and it overloads all exec calls so if you try to return an error and you have, say, a controller with a policy out front, and the policy does a database lookup, you'll likely go into error there prior to hitting the controller code you intended to test.... that can be fixed with stub.onCall(x), but it is still a bit precarious.
Warnings aside, here's how I've done this in the past:
var path = require('path');
var sinon = require('sinon');
var Deferred = require(path.join(
process.cwd(),
'node_modules/sails',
'node_modules/waterline',
'lib/waterline/query/deferred'
));
module.exports = function () {
return sinon.stub(Deferred.prototype, 'exec');
};
Assuming you have the following service, MyService:
module.exports.dbCall = function (id, cb) {
Model.findOne(id).exec(function (err, result) {
if (err) {
sails.log.error('db calls suck, man');
return cb(err, null);
}
cb(null, result);
});
};
You can test the error case like so:
before(function () {
stub = databaseStub();
});
afterEach(function () {
stub.reset();
});
after(function () {
stub.restore();
});
it('should return errors', function (done) {
stub.onCall(0).callsArgWith(0, 'error');
MyService.dbCall(1, function (err, results) {
assert.equal(err, 'error');
assert.equal(results, null);
done();
});
});

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