Ember & RSVP: How to resolve nested relations in route's model function? - javascript

Having problems to understand how to resolve nested models in ember. Damn.
I don't know if it's a common approach but I don't want my controllers or components care about asynchronicity at all. Therefore it's necessary to resolve everything needed in my routes.
My current approach does not work for nested relations (I'm describing it in the comments).
First some model definitions:
var Project = DS.Model.extend({
name: DS.attr("string"),
tasks: DS.hasMany("task", {async: true}),
// ...
});
var Task = DS.Model.extend({
name: DS.attr("string"),
documentation: DS.belongsTo("task_documentation", {async: true}),
// ...
});
var TaskDocumentation = DS.Model.extend({
lastEditor: DS.attr("string")
// ...
});
ProjectRoute:
ProjectRoute = Em.Route.extend({
model: function () {
var project;
return this.store.find("project", {name: "foo"}).then(function (resolvedProject) {
project = resolvedProject.objectAt(0);
return resolvedProject.get("tasks");
}).then(function (resolvedTasks) {
console.log("For some reason nothing left to do to resolve tasks: "
+ project.get("tasks").objectAt(0).get("name"));
// Collect documentation
var docu = []
project.get("tasks").forEach(function (task, index) {
docus[i] = task.get("documentation");
});
return Em.RSVP.all(docus);
}).then(function (resolvedDocus) {
// docus are resolved but not attached to project.
console.log(project.get("tasks")
.objectAt(0)
.get("documentation")
.get("lastEditor")); // "undefined"
// Setting documentation for each task manually does not help:
project.get("tasks").forEach(function(task, index) {
task.set("documentation", resolvedDocus.objectAt(index));
});
console.log(project.get("tasks")
.objectAt(0)
.get("documentation")
.get("lastEditor")); // still undefined
return project;
});
}
});
I'm currently using Ember 1.7.0 with Ember Data 1.0.0-beta.10
I guess there's a much easier way. Hope you guys can give me a hint. Thanks in advance!
UPDATE:
Thank you for input KingPin!
An important detail I totally forgot to mention is that I'm using FixturesAdaptor right now. That's why everything had to be declared async.
You said the collection returned by find did not define tasks. That's not the case. Everything is resolved correctly. The tasks are available. Even the documentation for each task can be accessed.
// ...
}).then(function (resolvedDocus) {
// resolvedDocus have been resolved. I simply cant't attach them to project's tasks
console.log(resolvedDocus.firstObject.lastEditor); // "Mr. Foo"
});
What I want to accomplish is to return a single project whose properties are directly accessible. At the moment I could create something like model.project, model.tasks, model.taskDocs but when I set project.someTask's documentation, nothing happens.
Another Update (cause I'm stupid)
There's a typo.
var project;
return this.store.find("project", {name: "foo"}).then(function (resolvedProject) {
project = resolvedProject.objectAt(0);
// This of course returns a collection.
return resolvedProject.get("tasks");
// I meant...
return resolvedProject.objectAt(0).get("tasks");
The problem still is the same. Sorry if that caused confusion.
SOLVED
It turned out to be a bug in Ember-Data 1.0 beta 10. I tried to identify the actual issue but there are multiple things listed that could have caused the problem.
Once again. Thanks!

Most of your issues here resolve around the fact that your find returns a collection, which won't have tasks defined on it (I'm specifically referring to resolvedProject.get('tasks')) so you never resolve tasks.
ProjectRoute = Em.Route.extend({
model: function () {
var project;
return this.store.find("project", {name: "foo"}).then(function (resolvedProjects) {
// resolvedProjects is a collection,
// but let's assume your api only returns a single project
project = resolvedProject.objectAt(0);
return project.get("tasks");
}).then(function (resolvedTasks) {
// this was empty because you didn't grab the tasks off a project
console.log(project.get("tasks.firstObject.name"));
var documents = resolvedTasks.getEach('documentation');
return Em.RSVP.all(documents);
});
}
});
Example: http://emberjs.jsbin.com/sonane/1/edit

Related

Sequelize restrict update if many-to-many relation established

In general I have a goal to restrict any update of an entity if it's binded to anything.
To be specific I have two models: Order and Good. They have many-to-many relation.
const Good = sequelize.define('good' , { name:Sequelize.STRING });
const Order = sequelize.define('order' , { });
//M:N relation
Good.belongsToMany(Order, { through: 'GoodsInOrders' });
Order.belongsToMany(Good, { through: 'GoodsInOrders' });
I have tried to set onUpdate: 'NO ACTION' and onUpdate: 'RESTRICT' inside belongsToMany association defining but it has no effect.
Here is the code to reproduce my manipulations with goods and order
//creating few goods
const good1 = await Good.create({ name:'Coca-Cola' });
const good2 = await Good.create({ name:'Hamburger' });
const good3 = await Good.create({ name:'Fanta' });
//creating an order
const order = await Order.create();
//adding good1 and good2 to the order
await order.addGoods([good1,good2]);
//It's ok to update good3 since no orders contains It
await good3.update( { name:'Pepsi' });
//But I need to fire an exeption if I try to update any goods belonged to order
//There should be an error because we previously added good1 to order
await good1.update( { name:'Sandwich' });
I have no clue how to restrict it in a simple way.
Surely we always can add beforeUpdate hook on Good model but I would like to avoid this kind of complications.
I will be glad to any ideas.
As I said I was looking for simpler alternative to hooks but many researches after all led me to nowhere.
My solution was to declare the beforeUpdate hook inside Good model so inital definition
const Good = sequelize.define('good' , { name : Sequelize.STRING } );
was transformed into this
const Good = sequelize.define('good', {
name: Sequelize.STRING
}, {
hooks: {
beforeUpdate: async (instance, options) => {
if ((await instance.getOrders()).length)
return Promise.reject('error');
return Promise.resolve();
}
}
});
So here we add the hook that fires every time before update particular good.
It makes inner request of list of orders that contains current good.
(await instance.getOrders()).length
And depends on the result it either fire an exception if the list isn't empty or just return resolved promise that means that everything ok and current good can be updated.

Sequelize: can you use hooks to add a comment to a query?

Heroku recently posted a list of some good tips for postgres. I was most intreged by the Track the Source of Your Queries section. I was curious if this was something that's possible to use with Sequelize. I know that sequelize has hooks, but wasn't sure if hooks could be used to make actual query string adjustments.
I'm curious if it's possible to use a hook or another Sequelize method to append a comment to Sequelize query (without using .raw) to keep track of where the query was called from.
(Appending and prepending to queries would also be helpful for implementing row-level security, specifically set role / reset role)
Edit: Would it be possible to use sequelize.fn() for this?
If you want to just insert a "tag" into the SQL query you could use Sequelize.literal() to pass a literal string to the query generator. Adding this to options.attributes.include will add it, however it will also need an alias so you would have to pass some kind of value as well.
Model.findById(id, {
attributes: {
include: [
[Sequelize.literal('/* your comment */ 1'), 'an_alias'],
],
},
});
This would produce SQL along the lines of
SELECT `model`.`id`, /* your comment */ 1 as `an_alias`
FROM `model` as `model`
WHERE `model`.`id` = ???
I played around with automating this a bit and it probably goes beyond the scope of this answer, but you could modify the Sequelize.Model.prototype before you create a connection using new Sequelize() to tweak the handling of the methods. You would need to do this for all the methods you want to "tag".
// alias findById() so we can call it once we fiddle with the input
Sequelize.Model.prototype.findById_untagged = Sequelize.Model.prototype.findById;
// override the findbyId() method so we can intercept the options.
Sequelize.Model.prototype.findById = function findById(id, options) {
// get the caller somehow (I was having trouble accessing the call stack properly)
const caller = ???;
// you need to make sure it's defined and you aren't overriding settings, etc
options.attributes.include.push([Sequelize.literal('/* your comment */ 1'), 'an_alias']);
// pass it off to the aliased method to continue as normal
return this.findById_untagged(id, options);
}
// create the connection
const connection = new Sequelize(...);
Note: it may not be possible to do this automagically as Sequelize has use strict so the arguments.caller and arguments.callee properties are not accessible.
2nd Note: if you don't care about modifying the Sequelize.Model prototypes you can also abstract your calls to the Sequelize methods and tweak the options there.
function Wrapper(model) {
return {
findById(id, options) {
// do your stuff
return model.findById(id, options);
},
};
}
Wrapper(Model).findById(id, options);
3rd Note: You can also submit a pull request to add this functionality to Sequelize under a new option value, like options.comment, which is added at the end of the query.
This overrides the sequelize.query() method that's internally used by Sequelize for all queries to add a comment showing the location of the query in the code. It also adds the stack trace to errors thrown.
const excludeLineTexts = ['node_modules', 'internal/process', ' anonymous ', 'runMicrotasks', 'Promise.'];
// overwrite the query() method that Sequelize uses internally for all queries so the error shows where in the code the query is from
sequelize.query = function () {
let stack;
const getStack = () => {
if (!stack) {
const o = {};
Error.captureStackTrace(o, sequelize.query);
stack = o.stack;
}
return stack;
};
const lines = getStack().split(/\n/g).slice(1);
const line = lines.find((l) => !excludeLineTexts.some((t) => l.includes(t)));
if (line) {
const methodAndPath = line.replace(/(\s+at (async )?|[^a-z0-9.:/\\\-_ ]|:\d+\)?$)/gi, '');
if (methodAndPath) {
const comment = `/* ${methodAndPath} */`;
if (arguments[0]?.query) {
arguments[0].query = `${comment} ${arguments[0].query}`;
} else {
arguments[0] = `${comment} ${arguments[0]}`;
}
}
}
return Sequelize.prototype.query.apply(this, arguments).catch((err) => {
err.fullStack = getStack();
throw err;
});
};

Knockout mapping data from server, lost subscriptions

I'm trying to represent multiple selects with its selected values from backend JSON to knockout view model.
And it's needed to retrieve this JSON when each select is changed, first time - all is ok, but if I apply mapping again (ko.mapping.fromJS(test_data, ViewModel)), all subscriptions are lost does anyone know how to avoid this situation?
jsfiddle (I don't know why selects don't have its values, without jsfiddle - all is ok):
http://jsfiddle.net/0bww2apv/2/
$(ViewModel.attributes()).each(function(index, attribute) {
attribute.attribute_value.subscribe(function(name) {
console.log('SUBSCRIBE', name);
var send_data = {};
$(ViewModel.attributes()).each(function (index, attribute) {
send_data[attribute.attribute_name.peek()] = attribute.attribute_value.peek();
if (attribute.attribute_value() === null) {
send_data = null;
return false;
}
});
if (send_data) {
console.log('REQUEST TO BACKEND: ', ko.toJSON(send_data));
ko.mapping.fromJS(test_data, ViewModel);
// subscriptions is lost here !
}
});
});
At last I've solved my own question with knockout.reactor plugin,
If we remove all auxiliary constructions, it will look like:
var ViewModel = ko.mapping.fromJS(test_data);
ko.applyBindings(ViewModel);
ko.watch(ViewModel, { depth: -1 }, function(parents, child, item) {
// here we need to filter watches and update only when needed, see jsfiddle
ko.mapping.fromJS(test_data2, {}, ViewModel);
});
This way we update selects and don't have troubles with subscription recursions.
full version (see console output for details): http://jsfiddle.net/r7Lo7502/

Mongoose - RangeError: Maximum Call Stack Size Exceeded

I am trying to bulk insert documents into MongoDB (so bypassing Mongoose and using the native driver instead as Mongoose doesn't support bulk insert of an array of documents). The reason I'm doing this is to improve the speed of writing.
I am receiving the error "RangeError: Maximum Call Stack Size Exceeded" at console.log(err) in the code below:
function _fillResponses(globalSurvey, optionsToSelectRegular, optionsToSelectPiped, responseIds, callback) {
Response.find({'_id': {$in: responseIds}}).exec(function(err, responses) {
if (err) { return callback(err); }
if (globalSurvey.questions.length) {
responses.forEach(function(response) {
console.log("Filling response: " + response._id);
response.answers = [];
globalAnswers = {};
globalSurvey.questions.forEach(function(question) {
ans = _getAnswer(question, optionsToSelectRegular, optionsToSelectPiped, response);
globalAnswers[question._id] = ans;
response.answers.push(ans);
});
});
Response.collection.insert(responses, function(err, responsesResult) {
console.log(err);
callback()
});
} else {
callback();
}
});
}
So similar to: https://stackoverflow.com/questions/24356859/mongoose-maximum-call-stack-size-exceeded
Perhaps it's something about the format of the responses array that Mongoose returns that means I can't directly insert using MongoDB natively? I've tried .toJSON() on each response but no luck.
I still get the error even with a very small amount of data but looping through and calling the Mongoose save on each document individually works fine.
EDIT: I think it is related to this issue: http://howtosjava.blogspot.com.au/2012/05/nodejs-mongoose-rangeerror-maximum-call.html
My schema for responses is:
var ResponseSchema = new Schema({
user: {
type: Schema.ObjectId,
ref: 'User'
},
randomUUID: String,
status: String,
submitted: Date,
initialEmailId: String,
survey: String,
answers: [AnswerSchema]
});
So, answers are a sub-document within responses. Not sure how to fix it though....
I was having this same issue and I started digging through the mongoose source code (version 3.8.14). Eventually it led me to this line within
mongoose/node_modules/mongodb/lib/mongodb/collection/core.js -> insert(...) -> insertWithWriteCommands(...) ->
mongoose/node_modules/mongodb/lib/mongodb/collection/batch/ordered.js -> bulk.insert(docs[i]) -> addToOperationsList(...) -> bson.calculateObjectSize(document, false);
var bsonSize = bson.calculateObjectSize(document, false);
Apparently, this calls BSON.calculateObjectSize, which calls calculateObjectSize which then infinitely recurses. I wasn't able to dig that far in to what caused it, but figured that it may have something to do with the mongoose wrapper binding functions to the Schema. Since I was inserting raw data into mongoDB, once I decided to change the bulk insert in mongoose to a standard javascript object, the problem went away and bulk inserts happened correctly. You might be able to do something similar.
Essentially, my code went from
//EDIT: mongoose.model needs lowercase 'm' for getter method
var myModel = mongoose.model('MyCollection');
var toInsert = myModel();
var array = [toInsert];
myModel.collection.insert(array, {}, function(err, docs) {});
to
//EDIT: mongoose.model needs lowercase 'm' for getter method
var myModel = mongoose.model('MyCollection');
var toInsert = { //stuff in here
name: 'john',
date: new Date()
};
var array = [toInsert];
myModel.collection.insert(array, {}, function(err, docs) {});
Confirmed, but not a bug. Model.collection.insert() bypasses Mongoose and so you're telling the node driver to insert an object that contains mongoose internals like $__, etc. The stack overflow is probably because bson is trying to compute the size of an object that references itself indirectly.
Long story short, use Document.toObject(), that's what its for: http://mongoosejs.com/docs/api.html#document_Document-toObject
Response.find({}).exec(function(err, responses) {
if (err) {
return callback(err);
}
if (true) {
var toInsert = [];
responses.forEach(function(response) {
console.log("Filling response: " + response._id);
response.answers = [];
[{ name: 'test' }].forEach(function(ans) {
response.answers.push(ans);
});
toInsert.push(response.toObject());
});
Response.collection.insert(toInsert, function(err, responsesResult) {
console.log(err);
});
} else {
callback();
}
});
Also, the code you specified won't work even if you fix the stack overflow. Since you're trying to insert() docs that are already in the database, all the inserts will fail because of _id conflicts. You'd really be much better off just using a stream() to read the results one at a time and then save() them back into the db.
guys! I've faced that weird error today. It happened because of I had a Schema with ref properties and tried to pass in create/update whole related document. I've changed argument to _id only and that did the trick. Works like a charm. I found the answer here (scroll down to February 21, 2013, 8:05 pm gustavohenke comment).
I have faced similar issue.
//manyvalues is array of objects
schema.methods.somemethod = function(manyvalues,callback) {
this.model(collection).collection.insertMany(manyvalues,callback);
}
But this caused error [RangeError: Maximum call stack size exceeded].
So I have created new model from manyvalues and used it as below and it worked.
schema.methods.somemethod = function(manyvalues,callback){
var list = JSON.parse(JSON.stringify(manyvalues));//created a new object.
this.model(collection).collection.insertMany(list,callback);
}
The problem may be caused if manyvalues is changed internally.
This also happens if there's a duplication of of the _id value. Most situations will be when you might create an new record from an existing record.
Deleting the _id and inserting the record and letting Mongoose/MongoDb take care of the creation of the id.
I had the same issue. Mongoose version is 5.13.14. My stack trace is:
RangeError: Maximum call stack size exceeded
at minimize (...\node_modules\mongoose\lib\document.js:3564:18)
at minimize (...\node_modules\mongoose\lib\document.js:3576:18)
at minimize (...\node_modules\mongoose\lib\document.js:3576:18)
at minimize (...\node_modules\mongoose\lib\document.js:3576:18)
at minimize (...\node_modules\mongoose\lib\document.js:3576:18)
at minimize (...\node_modules\mongoose\lib\document.js:3576:18)
at minimize (...\node_modules\mongoose\lib\document.js:3576:18)
I found 2 ways to fix the issue:
Using toObject() method:
const model = await MyModel.findOne(conditions);
return model?.toObject();
Using minimize: false in toJSON option of the schema:
export const MySchema = new Schema({
...
}, {
...
toJSON: {
getters: true,
// !!! HERE !!!
minimize: false,
},
...
});
Check for circular references in the responses object. I Faced a similar issue due to circular references.
I had a similar problem, it was that I was querying a field that didn't exist in the schema using the $ne(other query operators may have a similar problem)
var TestSchema = new Schema({
test:[]
});
...
models.Test.findOne({"test2": {$ne: "t"} })...
In the example above I am testing for test2 instead of test

Backbone collection not updating with JSONP request

I just recently started using Backbone.js and I'm working on an app now using Brunch that does a JSONP request to an external API to populate my collection and models. I'm following these previous posts (this and this) on doing JSONP requests with Backbone, but my collection still isn't getting the data for some reason.
My model (app/models/model.js):
module.exports = Backbone.Model.extend({
});
My collection (app/models/collection.js):
var Post = require('./model');
module.exports = Backbone.Collection.extend({
model: Post,
url: "http://somedata.com/api/posts/list/stuff",
sync: function(method, model, options) {
options.timeout = 10000;
options.dataType = "jsonp";
options.jsonp = "JSONPcallback";
return Backbone.sync(method, model, options);
},
parse: function(response) {
if (response) {
var parsed = [];
for(var i = 0; i < response.results.length; i++) {
parsed.push(response.results[i][0]);
}
return parsed;
}
}
});
Then, in the initialize method in app/application.js I'm calling it by:
var Category = require('models/collection');
this.cat = new Category();
this.cat.fetch();
Now, when I look at the parse function in console.log, I see the data being fetched, so the request is going through successfully. However, when my views are rendered and I do console.log(application.cat.models) in app/views/view.js, I get nothing -- why's this happening? Is there anything wrong with the code on my model/collection?
Also, the JSONP data has the following format, which is why looping through for response.results[i][0] and returning an array with all of it, that should do the trick, right?
{"results":[
{"0":{"id":xxx,"title":xxx,"link":xxx},
"description":xxx},
{"0":{"id":xxx,"title":xxx,"link":xxx},
"description":xxx},
{"0":{"id":xxx,"title":xxx,"link":xxx},
"description":xxx},...
]}
Would really appreciate any help...
I have 2 comments here :
I see that you have names both your model and collection as module.exports , a common practice is to make the model as singular (module.export) and make the collection for those models plural module.exports , just common practice , nothing "wrong" otherwise
You can have 2 callbacks in your code , when the collection is done fetching data(asynchronous event) also considering module.exports as your collection here ,
A. You could do this :
module.exports.fetch({
success : function(data){
console.log(JSON.stringiy(data));
//do remaining programming here
}
});
B. you could have a event listener for reset , from the documentation here , the collection fires a reset event when it completes the fetch , so could add an event listener on the collection like this :
module.exports.on('reset',function(data){
console.log(JSON.stringify(data));
//do remaining programming here
},this);

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