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This is more of a "whats your opinion/Am I correct in thinking this?" question.
Trying to be as strict as possible while understanding Flux, I was trying to figure out where XHR calls are made, websockets/external stimuli handled, routing takes places, etc.
From what I read across articles, interviews and looking through facebook examples there are a few ways of handling these things. Following flux strictly, Action creators are the ones that do all the XHR calls with the possibility of a PENDING/SUCCESS/FAILURE Actions being fired before and after the request completes.
Another was, coming from facebook's Ian Obermiller, all the READ(GETs) requests are handled directly by the Stores(without involvement of an Action creator/dispatcher) and WRITE(POSTs) requests are handled by the Action Creators going through the entire action>dispatcher>store flow.
Some understandings/conclusions we drew/would like to stick to:
PENDING/PROGRESS(think file uploads)/SUCCESS/FAILURE Actions. Action>Dispatcher>Store calls are strictly synchronous to stick to the dispatches not being able to start another dispatch internally to avoid chaining events/actions. A few questions that we came to some conclusion with, but I'm not entirely satisfied with:
If you take the approach where Stores do Reads, and Actions to Writes, how do you handle situations where multiple Stores might be able to use data from a single XHR call?
Example: API calls issued by TeamStore to /api/teams/{id} which returns something like:
{
entities: {
teams: [{
name: ...,
description: ...,
members: [1, 2, 4],
version: ...
}],
users: [{
id: 1
name: ...,
role: ...,
version: ...
},
{
id: 2
name: ...,
role: ...,
version: ...
},
{
id: 3
name: ...,
role: ...,
version: ...
}]
}
}
Ideally, I'd also like to update the MemberStore with the information returned in this API. We maintain a version number for every entity which is updated on updates to the record, which is what we use internally do reject calls on stale data, etc. Using this, I could have an internal logic, where if I as a side effect of some other API call, I know my data is stale, I trigger a refresh on that record.
The solution, it would seem, is that you'd need the store to trigger an action(which would effectively update the other dependent stores). This short circuits the Store>View>Action to Store>Action and I'm not sure if its a good idea. We already have one thing out of sync with Stores doing their own XHR calls. Concessions like these would start creeping into the entire system eventually.
Or Stores that are aware of other stores and be able to communicate with them. But this breaks the Stores have no Setters rule.
A simple solution to the above problem would be that you stick to Actions being the ONLY place external incoming/outgoing stimulus happens. This simplifies the logic of multiple Stores getting updated.
But now, where and how do you handle caching? We came to the conclusion that the caching would happen at the API Utils/DAO level. (if you look at the flux diagram).
But this introduces other problems. To better understand/explain what I mean by example:
/api/teams returns a list of all the teams with which I display a list of all the teams. On clicking on a team's link, I go its details view which requires data from /api/teams/{id} if it isn't already present in the Store.
If Actions handle all the XHRs, the View would do something like TeamActions.get([id]) which does TeamDAO.get([id]). To be able to return this call immediately(since we have it cached) the DAO would have to do caching but also maintain the relation between collections/items. This logic, by design, is already present in Stores.
Here come the questions:
Do you duplicate this logic in DAOs and Stores?
How do you handle validation that involves XHR APIs? Something simple like duplicate Team names.
Views directly hit DAOs and do something like TeamDAO.validateName([name]) which returns a promise or do you do you create an Action? If you create an Action through which Store does Valid/Invalid flow back to the View considering its mostly transient data?
How do you handle Routing? I looked through react-router and I'm not sure I like it. I don't necessarily think forcing a react-ish JSX way of providing route mappings/configs are needed at all. Also, apparently, it employs a RouteDispatcher of its own, which ondoes the single dispatcher rule.
The solution I prefer came from some blog posts/SO answers where you have a the route mappings are stored in the RouteStore.
RouteStore also maintains CURRENT_VIEW. The react AppContainer component is registered with RouteStore and replaces its child views with the CURRENT_VIEW on change. Current Views inform the AppContainer when they're fully loaded and AppContainer fires RouteActions.pending/success/failure, possibly with some context, to inform other components of reaching a stable state, show/hide busy/loading indications.
Something that I have not been able to design cleanly was if you were to design routing similar to Gmail, how would you do it? Some observations of Gmail that I'm a big fan of:
Some references:
https://github.com/gaearon/flux-react-router-example
http://ianobermiller.com/blog/2014/09/15/react-and-flux-interview/
https://github.com/facebook/flux
345
It's my implementation using facebook Flux and Immutable.js that I think responds to many of your concerns, based on few rules of thumb :
STORES
Record instance via ids.WebAPIUtils for read operations and trigger actions for write operations.RecordA and FooRecordB are resolved from a RecordA instance through a foo_id params and retrieved via a call such as FooStore.get(this.foo_id)
getters methods such as get(id), getAll(), etc.APIUTILS
Promise
Promise indexed by the hash of url + paramsPromise is resolved or rejected.fooError action should certainly contains payloads with validation errors returned by the server.COMPONENTS
Perf.printWasted time, it should be very low, few ms.props as explicit as possible via propsType.var fooRecord = { foo:1, bar: 2, baz: 3}; (I'm not using Immutable.Record here for the sake of simplicity of this example) and my child component need to display fooRecord.foo and fooRecord.bar, I do not pass the entire foo object but only fooRecordFoo and fooRecordBar as props to my child component because an other component could edit the foo.baz value, making the child component re-render while this component doesn't need at all this value !ROUTING - I simply use ReactRouter
Here is a basic example :
api
apiUtils/Request.js
var request = require('superagent');
//based on http://stackoverflow.com/a/7616484/1836434
var hashUrl = function(url, params) {
var string = url + JSON.stringify(params);
var hash = 0, i, chr, len;
if (string.length == 0) return hash;
for (i = 0, len = string.length; i < len; i++) {
chr = string.charCodeAt(i);
hash = ((hash << 5) - hash) + chr;
hash |= 0; // Convert to 32bit integer
}
return hash;
}
var _promises = {};
module.exports = {
get: function(url, params) {
var params = params || {};
var hash = hashUrl(url, params);
var promise = _promises[hash];
if (promise == undefined) {
promise = new Promise(function(resolve, reject) {
request.get(url).query(params).end( function(err, res) {
if (err) {
reject(err);
} else {
resolve(res);
}
});
});
_promises[hash] = promise;
}
return promise;
},
post: function(url, data) {
return new Promise(function(resolve, reject) {
var req = request
.post(url)
.send(data)
.end( function(err, res) {
if (err) {
reject(err);
} else {
resolve(res);
}
});
});
}
};
apiUtils/FooAPI.js
var Request = require('./Request');
var FooActionCreators = require('../actions/FooActionCreators');
var _endpoint = 'http://localhost:8888/api/foos/';
module.exports = {
getAll: function() {
FooActionCreators.receiveAllPending();
Request.get(_endpoint).then( function(res) {
FooActionCreators.receiveAllSuccess(res.body);
}).catch( function(err) {
FooActionCreators.receiveAllError(err);
});
},
get: function(id) {
FooActionCreators.receivePending();
Request.get(_endpoint + id+'/').then( function(res) {
FooActionCreators.receiveSuccess(res.body);
}).catch( function(err) {
FooActionCreators.receiveError(err);
});
},
post: function(fooData) {
FooActionCreators.savePending();
Request.post(_endpoint, fooData).then (function(res) {
if (res.badRequest) { //i.e response return code 400 due to validation errors for example
FooActionCreators.saveInvalidated(res.body);
}
FooActionCreators.saved(res.body);
}).catch( function(err) { //server errors
FooActionCreators.savedError(err);
});
}
//others foos relative endpoints helper methods...
};
stores
stores/BarStore.js
var assign = require('object-assign');
var EventEmitter = require('events').EventEmitter;
var Immutable = require('immutable');
var AppDispatcher = require('../dispatcher/AppDispatcher');
var ActionTypes = require('../constants/BarConstants').ActionTypes;
var BarAPI = require('../APIUtils/BarAPI')
var CHANGE_EVENT = 'change';
var _bars = Immutable.OrderedMap();
class Bar extends Immutable.Record({
'id': undefined,
'name': undefined,
'description': undefined,
}) {
isReady() {
return this.id != undefined //usefull to know if we can display a spinner when the Bar is loading or the Bar's data if it is ready.
}
getBar() {
return BarStore.get(this.bar_id);
}
}
function _rehydrate(barId, field, value) {
//Since _bars is an Immutable, we need to return the new Immutable map. Immutable.js is smart, if we update with the save values, the same reference is returned.
_bars = _bars.updateIn([barId, field], function() {
return value;
});
}
var BarStore = assign({}, EventEmitter.prototype, {
get: function(id) {
if (!_bars.has(id)) {
BarAPI.get(id);
return new Bar(); //we return an empty Bar record for consistency
}
return _bars.get(id)
},
getAll: function() {
return _bars.toList() //we want to get rid of keys and just keep the values
},
Bar: Bar,
emitChange: function() {
this.emit(CHANGE_EVENT);
},
addChangeListener: function(callback) {
this.on(CHANGE_EVENT, callback);
},
removeChangeListener: function(callback) {
this.removeListener(CHANGE_EVENT, callback);
},
});
var _setBar = function(barData) {
_bars = _bars.set(barData.id, new Bar(barData));
};
var _setBars = function(barList) {
barList.forEach(function (barData) {
_setbar(barData);
});
};
BarStore.dispatchToken = AppDispatcher.register(function(action) {
switch (action.type)
{
case ActionTypes.BAR_LIST_RECEIVED_SUCESS:
_setBars(action.barList);
BarStore.emitChange();
break;
case ActionTypes.BAR_RECEIVED_SUCCESS:
_setBar(action.bar);
BarStore.emitChange();
break;
case ActionTypes.BAR_REHYDRATED:
_rehydrate(
action.barId,
action.field,
action.value
);
BarStore.emitChange();
break;
}
});
module.exports = BarStore;
stores/FooStore.js
var assign = require('object-assign');
var EventEmitter = require('events').EventEmitter;
var Immutable = require('immutable');
var AppDispatcher = require('../dispatcher/AppDispatcher');
var ActionTypes = require('../constants/FooConstants').ActionTypes;
var BarStore = require('./BarStore');
var FooAPI = require('../APIUtils/FooAPI')
var CHANGE_EVENT = 'change';
var _foos = Immutable.OrderedMap();
class Foo extends Immutable.Record({
'id': undefined,
'bar_id': undefined, //relation to Bar record
'baz': undefined,
}) {
isReady() {
return this.id != undefined;
}
getBar() {
// The whole point to store an id reference to Bar
// is to delegate the Bar retrieval to the BarStore,
// if the BarStore does not have this Bar object in
// its cache, the BarStore will trigger a GET request
return BarStore.get(this.bar_id);
}
}
function _rehydrate(fooId, field, value) {
_foos = _foos.updateIn([voucherId, field], function() {
return value;
});
}
var _setFoo = function(fooData) {
_foos = _foos.set(fooData.id, new Foo(fooData));
};
var _setFoos = function(fooList) {
fooList.forEach(function (foo) {
_setFoo(foo);
});
};
var FooStore = assign({}, EventEmitter.prototype, {
get: function(id) {
if (!_foos.has(id)) {
FooAPI.get(id);
return new Foo();
}
return _foos.get(id)
},
getAll: function() {
if (_foos.size == 0) {
FooAPI.getAll();
}
return _foos.toList()
},
Foo: Foo,
emitChange: function() {
this.emit(CHANGE_EVENT);
},
addChangeListener: function(callback) {
this.on(CHANGE_EVENT, callback);
},
removeChangeListener: function(callback) {
this.removeListener(CHANGE_EVENT, callback);
},
});
FooStore.dispatchToken = AppDispatcher.register(function(action) {
switch (action.type)
{
case ActionTypes.FOO_LIST_RECEIVED_SUCCESS:
_setFoos(action.fooList);
FooStore.emitChange();
break;
case ActionTypes.FOO_RECEIVED_SUCCESS:
_setFoo(action.foo);
FooStore.emitChange();
break;
case ActionTypes.FOO_REHYDRATED:
_rehydrate(
action.fooId,
action.field,
action.value
);
FooStore.emitChange();
break;
}
});
module.exports = FooStore;
components
components/BarList.react.js (controller-view component)
var React = require('react/addons');
var Immutable = require('immutable');
var BarListItem = require('./BarListItem.react');
var BarStore = require('../stores/BarStore');
function getStateFromStore() {
return {
barList: BarStore.getAll(),
};
}
module.exports = React.createClass({
getInitialState: function() {
return getStateFromStore();
},
componentDidMount: function() {
BarStore.addChangeListener(this._onChange);
},
componentWillUnmount: function() {
BarStore.removeChangeListener(this._onChange);
},
render: function() {
var barItems = this.state.barList.toJS().map(function (bar) {
// We could pass the entire Bar object here
// but I tend to keep the component not tightly coupled
// with store data, the BarItem can be seen as a standalone
// component that only need specific data
return <BarItem
key={bar.get('id')}
id={bar.get('id')}
name={bar.get('name')}
description={bar.get('description')}/>
});
if (barItems.length == 0) {
return (
<p>Loading...</p>
)
}
return (
<div>
{barItems}
</div>
)
},
_onChange: function() {
this.setState(getStateFromStore();
}
});
components/BarListItem.react.js
var React = require('react/addons');
var ImmutableRenderMixin = require('react-immutable-render-mixin')
var Immutable = require('immutable');
module.exports = React.createClass({
mixins: [ImmutableRenderMixin],
// I use propTypes to explicitly telling
// what data this component need. This
// component is a standalone component
// and we could have passed an entire
// object such as {id: ..., name, ..., description, ...}
// since we use all the datas (and when we use all the data it's
// a better approach since we don't want to write dozens of propTypes)
// but let's do that for the example's sake
propTypes: {
id: React.PropTypes.number.isRequired,
name: React.PropTypes.string.isRequired,
description: React.PropTypes.string.isRequired
}
render: function() {
return (
<li>
<p>{this.props.id}</p>
<p>{this.props.name}</p>
<p>{this.props.description}</p>
</li>
)
}
});
components/BarDetail.react.js
var React = require('react/addons');
var ImmutableRenderMixin = require('react-immutable-render-mixin')
var Immutable = require('immutable');
var BarActionCreators = require('../actions/BarActionCreators');
module.exports = React.createClass({
mixins: [ImmutableRenderMixin],
propTypes: {
id: React.PropTypes.number.isRequired,
name: React.PropTypes.string.isRequired,
description: React.PropTypes.string.isRequired
},
handleSubmit: function(event) {
//Since we keep the Bar data up to date with user input
//we can simply save the actual object in Store.
//If the user goes back without saving, we could display a
//"Warning : item not saved"
BarActionCreators.save(this.props.id);
},
handleChange: function(event) {
BarActionCreators.rehydrate(
this.props.id,
event.target.name, //the field we want to rehydrate
event.target.value //the updated value
);
},
render: function() {
return (
<form onSubmit={this.handleSumit}>
<input
type="text"
name="name"
value={this.props.name}
onChange={this.handleChange}/>
<textarea
name="description"
value={this.props.description}
onChange={this.handleChange}/>
<input
type="submit"
defaultValue="Submit"/>
</form>
)
},
});
components/FooList.react.js (controller-view component)
var React = require('react/addons');
var FooStore = require('../stores/FooStore');
var BarStore = require('../stores/BarStore');
function getStateFromStore() {
return {
fooList: FooStore.getAll(),
};
}
module.exports = React.createClass({
getInitialState: function() {
return getStateFromStore();
},
componentDidMount: function() {
FooStore.addChangeListener(this._onChange);
BarStore.addChangeListener(this._onChange);
},
componentWillUnmount: function() {
FooStore.removeChangeListener(this._onChange);
BarStore.removeChangeListener(this._onChange);
},
render: function() {
if (this.state.fooList.size == 0) {
return <p>Loading...</p>
}
return this.state.fooList.toJS().map(function (foo) {
<FooListItem
fooId={foo.get('id')}
fooBar={foo.getBar()}
fooBaz={foo.get('baz')}/>
});
},
_onChange: function() {
this.setState(getStateFromStore();
}
});
components/FooListItem.react.js
var React = require('react/addons');
var ImmutableRenderMixin = require('react-immutable-render-mixin')
var Bar = require('../stores/BarStore').Bar;
module.exports = React.createClass({
mixins: [ImmutableRenderMixin],
propTypes: {
fooId: React.PropTypes.number.isRequired,
fooBar: React.PropTypes.instanceOf(Bar).isRequired,
fooBaz: React.PropTypes.string.isRequired
}
render: function() {
//we could (should) use a component here but this answer is already too long...
var bar = <p>Loading...</p>;
if (bar.isReady()) {
bar = (
<div>
<p>{bar.get('name')}</p>
<p>{bar.get('description')}</p>
</div>
);
}
return (
<div>
<p>{this.props.fooId}</p>
<p>{this.props.fooBaz}</p>
{bar}
</div>
)
},
});
Let's go through an entire loop for FooList:
FooListcontroller-view componentFooListcontroller-view component calls FooStore.getAll()
_foos map is empty in FooStore so FooStore performs a request via FooAPI.getAll()
FooList controller-view component renders itself as loading state since its state.fooList.size == 0.Here's the actual look of our list :
++++++++++++++++++++++++
+ +
+ "loading..." +
+ +
++++++++++++++++++++++++
FooAPI.getAll() request resolves and triggers the FooActionCreators.receiveAllSuccess actionFooStore receive this action, updates its internal state, and emits change.FooList controller-view component receive change event and update its state to get the list from the FooStore
this.state.fooList.size is no longer == 0 so the list can actually renders itself (note that we use toJS() to explicitly get a raw javascript object since React does not handle correctly mapping on not raw object yet).FooListItem component.foo.getBar() we're telling to the FooStore that we want the Bar record back.getBar() method of Foo record retrieve the Bar record through the BarStore
BarStore does not have this Bar record in its _bars cache, so it triggers a request through BarAPI to retrieve it.Foo in this.sate.fooList of FooList controller-view component++++++++++++++++++++++++ + + + Foo1 "name1" + + Foo1 "baz1" + + Foo1 bar: + + "loading..." + + + + Foo2 "name2" + + Foo2 "baz2" + + Foo2 bar: + + "loading..." + + + + Foo3 "name3" + + Foo3 "baz3" + + Foo3 bar: + + "loading..." + + + ++++++++++++++++++++++++
-Now let's say the BarAPI.get(2) (requested by Foo2) resolves before BarAPI.get(1) (request by Foo1). Since it's asynchronous it's totally plausible.
- The BarAPI triggers the BAR_RECEIVED_SUCCESS' action via theBarActionCreators.
- TheBarStore` responds to this action by updating its internal store and emits change. That's the now the fun part...
FooList controller-view component responds to the BarStore change by updating its state.render method is calledfoo.getBar() call now retrieve a real Bar record from BarStore. Since this Bar record has been effectively retrieved, the ImmutablePureRenderMixin will compare old props with current props and determine that the Bar objects has changed ! Bingo, we could re-render the FooListItem component (a better approach here would be to create a separate FooListBarDetail component to let only this component to re-render, here we also re-rendering the Foo's details that have not changed but for the sake of simplicity let's just do that).++++++++++++++++++++++++ + + + Foo1 "name1" + + Foo1 "baz1" + + Foo1 bar: + + "loading..." + + + + Foo2 "name2" + + Foo2 "baz2" + + Foo2 bar: + + "bar name" + + "bar description" + + + + Foo3 "name3" + + Foo3 "baz3" + + Foo3 bar: + + "loading..." + + + ++++++++++++++++++++++++
If you want me to add more details from a non detailed part (such as action creators, constants, routing, etc., use of BarListDetail component with form, POST, etc.) just tell me in the comments :).
200
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