I'm trying to validate a model and it's contents. However, because of the structure of loopbacks custom validation functions it's quite difficult to program more advanced logic than simple string validation.
Job.validate('job_definition, function(err){
//err();
//this will succeed in throwing error
Job.app.models.anotherModel.findOne({where:{name:this.job_definition.toolName}}, function(error, tool){
if(tool.aProperty === this.job_definition.aProperty){
//err();
//this will not succeed, validation script will exit before err() is thrown
}
});
}, {message: 'this is malformed'});
How can I get this validation function to 'wait' before exiting?
Here is an example using validateAsync (https://apidocs.strongloop.com/loopback-datasource-juggler/#validatable-validateasync). Note that you have to run err() when you want to fail validation.
module.exports = function(Person) {
function myCustom(err, done) {
console.log('async validate');
var name = this.name;
setTimeout(function() {
if(name == 'Ray') {
err();
done();
} else {
done();
}
}, 1000);
}
Person.validateAsync('name', myCustom, {message:'Dont like'});
};
Does this make sense? FYI, I could rewrite that if a bit nicer.
Related
I am pretty new to Node.js or Javascript in general when it comes to serverside stuff. Currently I am tring to validate some of the user input and set default values if something is wrong. Now if I run my validation the json object appears in the database befor my validation is completed.
The way I am doing the validation isnt maybe the best right now but if someone can explain me the behavior, I am pretty sure i can understand Javascript alot better in the future.
Is there a better way of doing validation (without mongoose or other ODM modules) with callbacks, middleware or should I use some async module?
Here is my code:
module.exports = function(app, express, todoDB, listDB, statusDB) {
var moment = require('moment');
var todoRouter = express.Router();
todoRouter.post('/', function(req, res, next) {
console.log('1');
if (!(moment(req.body.createDate).isValid())) {
req.body.createDate = moment().format("DD-MM-YYYY HH:mm:ss");
}
else {
req.body.createDate = moment(req.body.createDate).format("DD-MM-YYYY HH:mm:ss");
}
console.log('2');
if (req.body.list_id == '') {
listDB.findOne({list: 'Neu'}, function(reqdb, docs) {
if (docs == null) {
listDB.insert({list: 'Neu', index: 1});
listDB.findOne({list: 'Neu'}, function(reqdb, docs) {
console.log('AnlageListID');
console.log(docs._id);
req.body.list_id = docs._id;
});
}
else {
console.log('BestehendeListID');
console.log(docs._id);
req.body.list_id = docs._id;
}
});
}
console.log('3');
if (req.body.status_id == '') {
statusDB.findOne({status: 'offen'}, function(reqdb, docs) {
if (docs == null) {
statusDB.insert({status: 'offen', index: 1});
statusDB.findOne({status: 'offen'}, function(reqdb, docs) {
console.log('AnlageStatusID');
console.log(docs._id);
req.body.status_id = docs._id;
});
}
else {
console.log('BestehendeStatusID');
console.log(docs._id)
req.body.status_id = docs._id;
}
});
}
console.log('4');
console.log('StatusID');
console.log(req.body.status_id);
console.log('ListID');
console.log(req.body.list_id);
todoDB.insert({
todo: req.body.todo,
createDate: req.body.createDate,
endDate: req.body.endDate,
discription: req.body.discription,
comment: req.body.comment,
list_id: req.body.list_id,
priority_id: req.body.priority_id,
section_id: req.body.section_id,
user_id: req.body.user_id,
status_id: req.body.status_id,
company_id: req.body.company_id
});
res.json({message: 'TODO erfolgreich hinzugefügt!'});
});
return todoRouter;
};
... and this is the ouput:
1
2
3
4
StatusID
ListID
POST /api/todos 200 76.136 ms - 44
BestehendeListID
M3Xh46VjVjaTFoCM
BestehendeStatusID
48v80B4fbO87c8um
PS: Its a small "project" just for me learing the MEAN Stack so I am using neDB.
If I understand correctly you try to sequentially execute a number of asynchronous calls and introduce checks in the code to validate if previous asynchronous calls have completed. This is not going to work in a general case because your checks may be processed before the asynchronous call goes through. It might work now and then just by chance, but I would not expect even that.
There are standard mechanisms for that. One of them is using promises, another one using async and yet another one if stacking up all callbacks one into another. Below I will demonstrate how to address the problem using async, but the same general idea applies to using promises. Check the async project on Github then the following part-solution will become clear:
var async = require("async")
async.waterfall([
function(next) {
listDB.findOne({list: 'Neu'}, next); // quits on error
},
function(doc, next) {
if (doc) {
return next(null, doc._id);
}
statusDB.insert({status: 'offen', index: 1}, function(err) {
if (err) return next(err); // quit on error
statusDB.findOne({status: 'offen'}, function(err, doc) {
next(err, doc._id); // quits on error
});
});
},
function(id, next) {
// do next step and so on
next();
}
],
// this is the exit function: it will get called whenever an error
// is passed to any of the `next` callbacks or when the last
// function in the waterfall series calls its `next` callback (with
// or without an error)
function(err) {
console.error("Error processing:", err)
});
Before inserting a new record in the database I need to perform some checks and then decide if the record can be insterted or not.
I thought to use the beforeCreate hook doing something like this:
Data.beforeCreate(function(object, options) {
Data.scope('complexQuery').findAll().then(function (result) {
if (result.length >= 1) {
// do not insert the record
}
else {
// go ahead and insert
}
});
});
Any idea on how to stop the creation of the record?
Is this the right way to do it?
You can either throw an error, or reject the promise:
Data.beforeCreate(function(object, options) {
Data.scope('complexQuery').findAll().then(function (result) {
if (result.length >= 1) {
throw new Error('Already exists')
return sequelize.Promise.reject('Already exists')
}
else {
// go ahead and insert
}
});
});
Since you are actually doing validation, it would maybe fit better as a validation function :)
sequelize.define('model', attributes, {
validate: {
complexQuery: function () {
// Do the validation here instead
}
}
});
The validation is run both for creates and updates
Ok, lets say I have two Models. Contract and CommLog. Both work find independently but I need many CommLog to relate to each Contract.
In the ContractSchema trying async
ContractSchema.methods.getCommLog = function getCommLog(){
var log = false;
async.parallel([
function(){
CommLog.find({commType:'contract',parent:this._id},function(err,comms){
log = comms;
});
}],
function(){return log;});
};
Where I am trying to use it
router.get('/:code', function(req, res, next) {
Contract.findOne({accessCode:req.params.code},function(err,contract){
if(err)
res.send(err);
var data;
if(contract != null){
var comms = contract.getCommLog();
data = {error:false,data:contract,commlog:comms}
}else{
data = {error:true,message:"No Contract"}
}
res.json(data);
});
});
Where it shows var comms = contract.getCommLog(); It is never returning anything because the getCommLog() is not executing async...
I think its my misunderstanding of mongoose querying, so if you understand what I am trying to accomplish, please let me know what I am doing wrong. I have tried without async which would always return false.
The find call can return all matching results with one query, so I don't think you need async here. The reason it is not populating correctly when you call res.json(data) is because you are not waiting for the method call to finish before you fire off your server response. You would be better off nesting an additional CommLogs.find call within the Contract.find call, and only sending your response once that finishes.
//pseudo code:
Contract.find({}, function(err, contract) {
if(err || !contract) {
//return error response
}
else {
CommLogs.find({contract: contract._id}, function(err, commlogs) {
if(err || !commlogs) {
//return error response 2
}
else {
res.json({errors: false, contract: contract, commlogs: commlogs});
}
});
}
}
This is my code:
var thisValue = new models.Value({
id:id,
title:title //this is a unique value
});
console.log(thisValue);
thisValue.save(function(err, product, numberAffected) {
if (err) {
if (err.code === 11000) { //error for dupes
console.error('Duplicate blocked!');
models.Value.find({title:title}, function(err, docs)
{
callback(docs) //this is ugly
});
}
return;
}
console.log('Value saved:', product);
if (callback) {
callback(product);
}
});
If I detect that a duplicate is trying to be inserted, i block it. However, when that happens, i want to return the existing document. As you can see I have implemented a string of callbacks, but this is ugly and its unpredictable (ie. how do i know which callback will be called? How do i pass in the right one?). Does anyone know how to solve this problem? Any help appreciated.
While your code doesn't handle a few error cases, and uses the wrong find function, the general flow is typical giving the work you want to do.
If there are errors other than the duplicate, the callback isn't called, which likely will cause downstream issues in your NodeJs application
use findOne rather than find as there will be only one result given the key is unique. Otherwise, it will return an array.
If your callback expected the traditional error as the first argument, you could directly pass the callback to the findOne function rather than introducing an anonymous function.
You also might want to look at findOneAndUpdate eventually, depending on what your final schema and logic will be.
As mentioned, you might be able to use findOneAndUpdate, but with additional cost.
function save(id, title, callback) {
Value.findOneAndUpdate(
{id: id, title: title}, /* query */
{id: id, title: title}, /* update */
{ upsert: true}, /* create if it doesn't exist */
callback);
}
There's still a callback of course, but it will write the data again if the duplicate is found. Whether that's an issue is really dependent on use cases.
I've done a little clean-up of your code... but it's really quite simple and the callback should be clear. The callback to the function always receives either the newly saved document or the one that was matched as a duplicate. It's the responsibility of the function calling saveNewValue to check for an error and properly handle it. You'll see how I've also made certain that the callback is called regardless of type of error and is always called with the result in a consistent way.
function saveNewValue(id, title, callback) {
if (!callback) { throw new Error("callback required"); }
var thisValue = new models.Value({
id:id,
title:title //this is a unique value
});
thisValue.save(function(err, product) {
if (err) {
if (err.code === 11000) { //error for dupes
return models.Value.findOne({title:title}, callback);
}
}
callback(err, product);
});
}
Alternatively, you could use the promise pattern. This example is using when.js.
var when = require('when');
function saveNewValue(id, title) {
var deferred = when.defer();
var thisValue = new models.Value({
id:id,
title:title //this is a unique value
});
thisValue.save(function(err, product) {
if (err) {
if (err.code === 11000) { //error for dupes
return models.Value.findOne({title:title}, function(err, val) {
if (err) {
return deferred.reject(err);
}
return deferred.resolve(val);
});
}
return deferred.reject(err);
}
return deferred.resolve(product);
});
return deferred.promise;
}
saveNewValue('123', 'my title').then(function(doc) {
// success
}, function(err) {
// failure
});
I really like WiredPrairie's answer, but his promise implementation is way too complicated.
So, I decided to add my own promise implementation.
Mongoose 3.8.x
If you're using latest Mongoose 3.8.x then there is no need to use any other promise module, because since 3.8.0 model .create() method returns a promise:
function saveNewValue(id, title) {
return models.Value.create({
id:id,
title:title //this is a unique value
}).then(null, function(err) {
if (err.code === 11000) {
return models.Value.findOne({title:title}).exec()
} else {
throw err;
}
});
}
saveNewValue('123', 'my title').then(function(doc) {
// success
console.log('success', doc);
}, function(err) {
// failure
console.log('failure', err);
});
models.Value.findOne({title:title}).exec() also returns a promise, so there is no need for callbacks or any additional casting here.
And if you don't normally use promises in your code, here is callback version of it:
function saveNewValue(id, title, callback) {
models.Value.create({
id:id,
title:title //this is a unique value
}).then(null, function(err) {
if (err.code === 11000) {
return models.Value.findOne({title:title}).exec()
} else {
throw err;
}
}).onResolve(callback);
}
Previous versions of Mongoose
If you're using any Mongoose version prior to 3.8.0, then you may need some help from when module:
var when = require('when'),
nodefn = require('when/node/function');
function saveNewValue(id, title) {
var thisValue = new models.Value({
id:id,
title:title //this is a unique value
});
var promise = nodefn.call(thisValue.save.bind(thisValue));
return promise.spread(function(product, numAffected) {
return product;
}).otherwise(function(err) {
if (err.code === 11000) {
return models.Value.findOne({title:title}).exec()
} else {
throw err;
}
});
}
I'm using nodefn.call helper function to turn callback-styled .save() method into a promise. Mongoose team promised to add promises support to it in Mongoose 4.x.
Then I'm using .spread helper method to extract the first argument from .save() callback.
It should be very awesome to use non-blocking code but I'm running out of ideas how to acomplish this task. I have to validate a value by making few db queries like so:
validate = function() {
var valid = true;
db.collection('posts').findOne({date: ....}, function(err, post){
if (..) valid = false
}
db.collection('posts').findOne({author: .....}, function(err, post){
if (..) valid = false
}
return valid;
}
It is very good that validations can run in concurent manner, but the problem is how to return the final state. Obviously my example will not work. The function will return before db queries execution.
Welcome to the async world.
You should use something like async or fnqueue for your control flow,
then you can setup a chain of validations.
function isValid (mainCallback) {
new FnQueue({
date: function (callback) {
if (...) {
callback();
} else {
callback(new Error('what\'s happened here');
}
},
author: function (callback) {
db.collection('posts').findOne({ author: ..... }, callback);
}
},
function (err, data) {
mainCallback(Boolean(err)); //you should more than this :)
},
1 // concurrency level for serial execution
);
If you are using mongoose, then you can use the validations that are supported in the models. Take a look the validation docs for details and examples.
If you are not using mongoose, then you will need to pass a callback to your validate function, and the callback will receive the boolean. Also, you will need to handle the flow of your function so that they are run in series or parallel, depending on your needs. So if it is in in series, the following would work:
validate = function(callback) {
var valid = true;
db.collection('posts').findOne({date: ....}, function(err, post){
if (..) {
return callback(true);
}
db.collection('posts').findOne({author: .....}, function(err, post){
if (..) callback(false);
});
});
}