I have a simple Meteor subscription, and I display a loading message while the data is being loaded. But I don't know how to display error message if subscription failed.
export const MyAwesomeComponent = createContainer(() => {
let sub = Meteor.subscribe('some-data');
if (!sub.ready()) return { message: 'Loading...'};
if (sub.failed()) return { message: 'Failed.' }; // How to do this?
return {
data: Data.find().fetch()
}
}, MyInternalRenderComponent);
Problem is, the subscription object doesn't have a failed() method, only a ready() query. How to pass the failure of a subscription as props in a createContainer() method?
I know the Meteor.subscribe method has an onStop callback for this case, but I don't know how to glue it toghether that to pass a property.
After a lot of researching I managed to get this working and I think it answers your question.
Bear in mind I'm using Meteor 1.6, but it should give you the info to get it working on your side.
On the publication/publish:
try {
// get the data and add it to the publication
...
self.ready();
} catch (exception) {
logger.error(exception);
// send the exception to the client through the publication
this.error(new Meteor.Error('500', 'Error getting data from API', exception));
}
On the UI Component:
const errorFromApi = new ReactiveVar();
export default withTracker(({ match }) => {
const companyId = match.params._id;
let subscription;
if (!errorFromApi.get()) {
subscription = Meteor.subscribe('company.view', companyId, {
onStop: function (e) {
errorFromApi.set(e);
}
});
} else {
subscription = {
ready: () => {
return false;
}
};
}
return {
loading: !subscription.ready(),
company: Companies.findOne(companyId),
error: errorFromApi.get()
};
})(CompanyView);
From here all you need to do is get the error prop and render the component as desired.
This is the structure of the error prop (received on the onStop callback from subscribe):
{
error: String,
reason: String,
details: String
}
[Edit]
The reason there is a conditional around Meteor.subscribe() is to avoid an annoying infinite loop you'd get from the natural withTracker() updates, which would cause new subscriptions / new errors from the publication and so on.
Related
I am trying to create a plugin for rxdb.
I want to catch the exception raised by insert and return an hash with
{[fieldName: string] => [error:string]}
When using my new method though, I am getting an exception, and it seems like the method is getting called directly on the prototype rather than on each RxColletion<T, T2, T3> instance.
The error i am getting is:
TypeError: Cannot read property 'fillObjectWithDefaults' of undefined
which happens here: https://github.com/pubkey/rxdb/blob/ac9fc95b0eda276110f371afca985f949275c3f1/src/rx-collection.ts#L443
because this.schema is undefined.. The collection I am running this method on does have a schema though..
Here is my plugin code:
export const validatedInsertPlugin: RxPlugin = {
rxdb: true,
prototypes: {
RxCollection(proto: IRxCollectionBaseWithValidatedInsert) {
proto.validatedInsert = async function validatedInsert<T, D>(
doc: T
): Promise<Insert<T>> {
try {
// this is the line that raises:
const product = await proto.insert(doc);
return [true, product];
} catch (e) {
// extract errors
return [false, {} as Errors<T>];
}
};
},
},
overwritable: {},
hooks: {},
};
To answer my own question,
proto.insert is targeting the prototype, which is not what I want.
function(this: RxCollection) is what I want. I have to use this which will target the actual instance.
proto.validatedInsert = async function validatedInsert<T1>(
this: RxCollection,
doc: T1
): Promise<ValidatedInsert<T1>> {
try {
const product = await this.insert(doc); // this, not proto
return [true, product];
} catch (e) {
...
I have a function that prepares the errors from backend to be easy for displaying in the components - it's named prepareErrorMessages. It accepts the response from the backend and some default error message.
So - in the saga I have this:
function* updateSomethingFlow(action) {
try {
const response = yield call(updateSomething, action.payload);
if (response) {
yield put({
type: UPDATE_SUCCESS
});
}
} catch (err) {
yield put({
type: UPDATE_FAILURE,
payload: prepareErrorMessages(err, 'Failed to update. Please, try again.')
});
}
}
So - am I wrong to modify the errors from the backend here?
Or is it better to do this in the reducer?
case UPDATE_FAILURE:
nextState = {
...state,
loading: false,
errors: prepareErrorMessages(payload, 'Failed to update. Please, try again.'),
};
break;
And also - why is it better to update there?
Personally, I think its right to do it in the reducer.
That is where you handle the responses. Action creators should only set the payload which could be some static data or a promise.
Dont see why you cannot transform/modify the received data there.
Personally, I would prefer to have it in the saga because I think it is the right place of handling this kind of logic.
I prefer my reducers to only be responsible for changing state, not for data transformation.
But it is my personal opinion.
We are using a Transformer for transforming the response getting from the Api. Transformer is the function which takes the input and provide the desired output. Designing the transformer makes the code clean and easy to test.
For example :-
function* updateSomethingFlow(action) {
try {
const response = yield call(updateSomething, action.payload);
// after getting the response from the api pass through the transformer.
const transformedResponse =apiTransformer(action.payload);
if (response) {
yield put({
type: UPDATE_SUCCESS,
data: trasnformedResponse
});
}
} catch (error) {
yield put({
type: UPDATE_FAILURE,
error: error)
});
}
}
const apiTransformer = function(apiResponse) {
// implement the logic. This function returns the transformed Response
}
Using this you can move reducer free from the error. Makes the code testable and making mocks easy.
For global backend Errors make a global errorHandler using Redux Middleware, like this
const errorTracking = store => next => action => {
if (/_FAILURE$/.test(action.type)) {
const errorCode = parseInt(
_.get(action, ['error', 'response', 'status'])
)
// this was for my use case
if (errorCode === 403) {
// launch an Global error handler action
return next(ErrorHandlerAction())
} else return next(action)
}
return next(action)
}
While for not genric error You can implement HOC wrap it around the component for visualisation. Thus you can have global implementation for the errors.
I am fairly new to Angular 2, TypeScript and RxJS and I am creating a simple application that leverages the Salesforce Ajax Toolkit connections library.
I am trying to write a handler to catch when a token has expired any time a method from the connections library is called. I have created a service that essentially wraps the connections library to use observables. For example if we look at the insert function I have created my own wrapper function:
public insert(object: sforce.SObject): Observable<any> {
return new Observable(observer => {
// successfully inserted the record
let insertSuccess = (result) => {
observer.next(result);
observer.complete();
}
// An error occured inserting the record
let insertError = (result) => {
// This does not work yet
if (result.faultcode.indexOf('INVALID_SESSION_ID') != -1) {
this.refreshToken();
}
else {
observer.error(result);
}
}
let callback = { onSuccess: insertSuccess, onFailure: insertError };
sforce.connection.create([object], callback);
});
}
I have another function that refreshes the access token:
public refreshToken(): void {
this.loginService.login().subscribe(
response => {
Globals.SESSION_TOKEN = response.access_token;
//initialize the salesforce connection
this.init(Globals.SESSION_TOKEN, this.loginService.AuthParams.SOAP_URL);
},
error => {
}
);
}
I essentially want the original insert function to wait for refreshToken to complete. If it is successful I want to retry the same insert again, otherwise I want the original insert observable to call observer.error.
I've looked into retry and retryWhen, however I haven't been able to figure out how to implement it to wait for the refreshToken() function to complete. Any guidance or advice on this matter would be greatly appreciated. Thank you in advance.
The catch operator accepts a function which processes an error and the source Observable. This means that if you catch an error you can determine whether you want to resubscribe to the original source in the catch block:
public insert(object: sforce.SObject): Observable<any> {
return new Observable(observer => {
// successfully inserted the record
let insertSuccess = (result) => {
observer.next(result);
observer.complete();
}
// An error occured inserting the record
let insertError = (result) => observer.error(result);
let callback = { onSuccess: insertSuccess, onFailure: insertError };
sforce.connection.create([object], callback);
}).catch((err, source) => {
if (err.faultcode.indexOf('INVALID_SESSION_ID') != -1) {
//This waits for the refresh to complete and then resubscribes
//to the source
//If the refresh errors then it will skip the resubscribe
return this.refreshToken().flatMapTo(source);
}
//Non-authentication error
return Observable.throw(err);
});
}
Then make your refreshToken function into something like so:
public refreshToken(): Observable<any> {
return this.loginService.login()
.tap(response => {
Globals.SESSION_TOKEN = response.access_token;
//initialize the salesforce connection
this.init(Globals.SESSION_TOKEN, this.loginService.AuthParams.SOAP_URL);
});
}
So, I see on an error, redux-promise hands me back error: true, along with the payload, but that is once it hits the reducer... to me, decoupling the request AND error condition is a bit odd, and seems inappropriate. What is an effective way to also deal with error condition when using axios w/ reduc-promise (middleware).. here is the gist of what i have..
in action/
const request = axios(SOME_URL);
return {
type: GET_ME_STUFF,
payload: request
}
in reducer/
const startState = {
whatever: [],
error: false
}
case GET_ME_STUFF:
return {...state, startState, {stuff:action.payload.data, error: action.error? true : false}}
etc... then I can deal with the error.. so, my api call is now split into two seperate areas and that seems wrong.... there must be something I am missing here. I would think in the /actions I can pass in a callback that handles a new action etc.. or something, but not split it.
I've had to go through a similar situation. The challenge is that you likely won't be able to evaluate the results of the promise until it is at the reducer. You could handle your exceptions there but it's not the best pattern. From what I've read reducers are meant only to return appropriate pieces of state based on action.type and do nothing else.
So, enter an additional middleware, redux-thunk. Instead of returning an object, it returns a function, and it can coexist with promise.
It's explained quite well at http://danmaz74.me/2015/08/19/from-flux-to-redux-async-actions-the-easy-way/ [archived here]. Essentially, you can evaluate the promise here and dispatch through the other action creators before the promise result hits the reducers.
In your actions file, add additional action creators that would handle the success and error (and any other) states.
function getStuffSuccess(response) {
return {
type: GET_ME_STUFF_SUCCESS,
payload: response
}
}
function getStuffError(err) {
return {
type: GET_ME_STUFF_ERROR,
payload: err
}
}
export function getStuff() {
return function(dispatch) {
axios.get(SOME_URL)
.then((response) => {
dispatch(getStuffSuccess(response))
})
.catch((err) => {
dispatch(getStuffError(err))
})
}
}
return null
This is roughly to how you might translate your pseudocode to what is explained at the link. This handles evaluating the promise directly in your action creator and firing off the appropriate actions and payloads to your reducers which follows the convention of action -> reducer -> state -> component update cycle. I'm still pretty new to React/Redux myself but I hope this helps.
The accepted answer doesn't make use of redux-promise. Since the question is actually about handling errors using redux-promise I provide another answer.
In the reducer you should inspect the existence of the error attribute on the action object:
// This is the reducer
export default function(previousState = null, action) {
if (action.error) {
action.type = 'HANDLE_XHR_ERROR'; // change the type
}
switch(action.type) {
...
And change the type of the action, triggering a state change for an error handling component that you have set up for this.
You can read a bit more about it here on github.
It looks like you can catch the error where you make the dispatch, then make an separate error dispatch if it happens. It's a bit of a hack but it works.
store.dispatch (function (dispatch) {
dispatch ({
type:'FOO',
payload:axios.get(url)
})
.catch (function(err) {
dispatch ({
type:"FOO" + "_REJECTED",
payload:err
});
});
});
and in the reducer
const reducer = (state=initialState, action) => {
switch (action.type) {
case "FOO_PENDING": {
return {...state, fetching: true};
}
case "FOO_REJECTED": {
return {...state, fetching: false, error: action.payload};
}
case "FOO_FULFILLED": {
return {
...state,
fetching: false,
fetched: true,
data: action.payload,
};
}
}
return state;
};
Still using redux-promises you can do something like this which I think is an elegant way to deal with this problem.
First, set a property in the redux state that will hold any ajax errors that may occurred.
ajaxError: {},
Second, setup a reducer to handle ajax errors:
export default function ajaxErrorsReducer(state = initialState.ajaxError, action) {
if (action.error) {
const { response } = action.payload;
return {
status: response.status,
statusText: response.statusText,
message: response.data.message,
stack: response.data.stack,
};
}
return state;
}
Finally, create a very simple react component that will render errors if there are any (I am using the react-s-alert library to show nice alerts):
import React, { Component } from 'react';
import { connect } from 'react-redux';
import PropTypes from 'prop-types';
import Alert from 'react-s-alert';
class AjaxErrorsHandler extends Component {
constructor(props, context) {
super(props, context);
this.STATUS_GATE_WAY_TIMEOUT = 504;
this.STATUS_SERVICE_UNAVAILABLE = 503;
}
componentWillReceiveProps(nextProps) {
if (this.props.ajaxError !== nextProps.ajaxError) {
this.showErrors(nextProps.ajaxError);
}
}
showErrors(ajaxError) {
if (!ajaxError.status) {
return;
}
Alert.error(this.getErrorComponent(ajaxError), {
position: 'top-right',
effect: 'jelly',
timeout: 'none',
});
}
getErrorComponent(ajaxError) {
let customMessage;
if (
ajaxError.status === this.STATUS_GATE_WAY_TIMEOUT ||
ajaxError.status === this.STATUS_SERVICE_UNAVAILABLE
) {
customMessage = 'The server is unavailable. It will be restored very shortly';
}
return (
<div>
<h3>{ajaxError.statusText}</h3>
<h5>{customMessage ? customMessage : ajaxError.message}</h5>
</div>
);
}
render() {
return (
<div />
);
}
}
AjaxErrorsHandler.defaultProps = {
ajaxError: {},
};
AjaxErrorsHandler.propTypes = {
ajaxError: PropTypes.object.isRequired,
};
function mapStateToProps(reduxState) {
return {
ajaxError: reduxState.ajaxError,
};
}
export default connect(mapStateToProps, null)(AjaxErrorsHandler);
You can include this component in your App component.
This might not be the best approach but it works for me. I pass the 'this' of my component as var context. Then when i get response back i just execute the methods defined in my components context. In my component i have successHdl and errorHdl. From there i can trigger more redux actions as normal. I checked all the previous answers and seem too daunting for such a trivial task.
export function updateJob(payload, context){
const request = axios.put(UPDATE_SOMETHING, payload).then(function (response) {
context.successHdl(response);
})
.catch(function (error) {
context.errorHdl(error);
});;
return {
type: UPDATE_SOMETHING,
payload: payload,
}
}
Don't use redux-promise. It overcomplicates something that's actually super simple to do yourself.
Instead read the redux docs: http://redux.js.org/docs/advanced/AsyncActions.html
It'll give you a much better understanding of how to handle this kind of interactions and you'll learn how to write something (better than) redux-promise yourself.
I'm using balanced-payments and their version 1.1 of balanced.js within Meteor.
I'm trying to create a new customer using
balanced.marketplace.customers.create(formData);
Here is my CheckFormSubmitEvents.js file
Template.CheckFormSubmit.events({
'submit form': function (e, tmpl) {
e.preventDefault();
var recurringStatus = $(e.target).find('[name=is_recurring]').is(':checked');
var checkForm = {
name: $(e.target).find('[name=name]').val(),
account_number: $(e.target).find('[name=account_number]').val(),
routing_number: $(e.target).find('[name=routing_number]').val(),
recurring: { is_recurring: recurringStatus },
created_at: new Date
}
checkForm._id = Donations.insert(checkForm);
Meteor.call("balancedCardCreate", checkForm, function(error, result) {
console.log(result);
// Successful tokenization
if(result.status_code === 201 && result.href) {
// Send to your backend
jQuery.post(responseTarget, {
uri: result.href
}, function(r) {
// Check your backend result
if(r.status === 201) {
// Your successful logic here from backend
} else {
// Your failure logic here from backend
}
});
} else {
// Failed to tokenize, your error logic here
}
// Debuging, just displays the tokenization result in a pretty div
$('#response .panel-body pre').html(JSON.stringify(result, false, 4));
$('#response').slideDown(300);
});
}
});
Here is my Methods.js file
var wrappedDelayedFunction = Async.wrap(balanced.marketplace.customers.create);
Meteor.methods({
balancedCardCreate: function (formData) {
console.log(formData);
var response = wrappedDelayedFunction(formData);
console.log(response);
return response;
}
});
I get nothing back when I submit the form, except that on the server console I do see the log of the form data.
I'm sure I'm not calling some of these async functions correctly. The hard part for me here is that the balanced function are async, but I don't know if they fit into the same mold as some of the examples I've seen.
I've tried to follow this example code.
http://meteorhacks.com/improved-async-utilities-in-meteor-npm.html
Is there a specific change that needs to be done in regard to working with balanced here? Does anyone have any tips for working with Async functions or see something specific about my code that I've done wrong?
Thanks
The NPM utilities Async.wrap does the same thing as the undocumented Meteor function Meteor._wrapAsync, in that it takes an asynchronous function with the last argument function(err, result) {} and turns it into a synchronous function which takes the same arguments, but either returns a result or throws an error instead of using the callback. The function yields in a Fiber until the asynchronous callback returns, so that other code in the event loop can run.
One pitfall with this is that you need to make sure that the function you wrap is called with the correct context. So if balanced.marketplace.customers.create is a prototype method that expects this to be set to something, it will not be set properly unless you bind it yourself, using function.bind or any of the other various library polyfills.
For more information, see https://stackoverflow.com/a/21542356/586086.
What I ended up doing was using a future. This works great, I just need to do better at catching errors. Which will be a question for a pro I think ; - )
Credit should go to user3374348 for answering another similar question of mine, which solved both of these.
https://stackoverflow.com/a/23777507/582309
var Future = Npm.require("fibers/future");
function extractFromPromise(promise) {
var fut = new Future();
promise.then(function (result) {
fut["return"](result);
}, function (error) {
fut["throw"](error);
});
return fut.wait();
}
Meteor.methods({
createCustomer: function (data) {
balanced.configure(Meteor.settings.balancedPaymentsAPI);
var customerData = extractFromPromise(balanced.marketplace.customers.create({
'name': data.fname + " " + data.lname,
"address": {
"city": data.city,
"state": data.region,
"line1": data.address_line1,
"line2": data.address_line2,
"postal_code": data.postal_code,
},
'email': data.email_address,
'phone': data.phone_number
}));
var card = extractFromPromise(balanced.marketplace.cards.create({
'number': data.card_number,
'expiration_year': data.expiry_year,
'expiration_month': data.expiry_month,
'cvv': data.cvv
}));
var associate = extractFromPromise(card.associate_to_customer(customerData.href).debit({
"amount": data.total_amount*100,
"appears_on_statement_as": "Trash Mountain" }));
});
As Andrew mentioned, you need to set the context for the method.
Here's the way you can do that with Async.wrap
Async.wrap(balanced.marketplace.customers, "create");