@yeutech/ra-realtime
v2.0.0-RC2-yeutech.2
Published
A saga enabling realtime updates for react-admin
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ra-realtime
A custom saga enabling realtime update inside react-admin.
Installation
Install with:
npm install --save ra-realtime
or
yarn add ra-realtime
Usage
Define an observeRequest
function which will be called by the realtime saga whenever a CRUD_GET_LIST
or CRUD_GET_ONE
fetch
is triggered by react-admin (documentation about those).
This function will be called with the following parameters:
fetchType
: eitherCRUD_GET_LIST
orCRUD_GET_ONE
resource
: the resource's nameparams
: the fetch parameters- for
CRUD_GET_LIST
:{ pagination: { page: {int} , perPage: {int} }, sort: { field: {string}, order: {string} }, filter: {Object} }
- for
CRUD_GET_ONE
:{ id: {mixed} }
- for
This function must return an object with a subscribe
method which will be called with an observer
. If it returns null
, the query won't be updated automatically. This allows you to decide which query should be updated in real time.
The observer
have the following methods:
next(data)
: Call this method each time new data is received so that the Admin-on-rest views are updated.complete()
: Call this method to indicates this subscription won't receive any new data.error(error)
: Call this method when an error occurs.
The subscribe
method must return a subscription
object. The subscription
object must have an unsubscribe
method which will be called by the realtime saga when the query will not need to be observed anymore. This will happen each time the current route change and will give you the opportunity to clean up related sockets, apollo observable queries, etc. When called and after you cleaned up whatever needed cleaning, you must call the observer.complete
method so that the realtime saga is notified about it.
Here is a very naive example using an interval to fetch data every 5 seconds:
// In createRealtimeSaga.js
import realtimeSaga from '@yeutech/ra-realtime';
const observeRequest = restClient => (type, resource, params) => {
// Filtering so that only posts are updated in real time
if (resource !== 'posts') return;
// Use your apollo client methods here or sockets or whatever else including the following very naive polling mechanism
return {
subscribe(observer) {
const intervalId = setInterval(() => {
restClient(type, resource, params)
.then(results => observer.next(results)) // New data received, notify the observer
.catch(error => observer.error(error)); // Ouch, an error occured, notify the observer
}, 5000);
const subscription = {
unsubscribe() {
// Clean up after ourselves
clearInterval(intervalId);
// Notify the saga that we cleaned up everything
observer.complete();
}
};
return subscription;
},
};
};
export default restClient => realtimeSaga(observeRequest(restClient));