Is it possible to have multiple dataProviders in r

问题:

If I have multiple distinct REST API back-ends (separate apps doing separate things), and I want a single UI (react-admin-based) app that is capable of doing CRUD to entities managed by these various back-ends, I'm curious if it's possible to wire up react-admin to do that.

I'm imagining that instead of this (single/global dataProvider):

const App = () => (
    <Admin dataProvider={simpleRestProvider('http://path.to.foo.api')}>
        <Resource name="foos" list={FooList} />
    </Admin>
);

we could do something like this (resource-specific dataProviders):

    const App = () => (
        <Admin >
            <Resource name="foos" list={FooList} 
               dataProvider={simpleRestProvider('http://path.to.foo.api')} />
            <Resource name="bars" list={BarList} 
               dataProvider={simpleRestProvider('http://path.to.bar.api')} />
        </Admin>
    );

At any rate, if you have advice on how I can do REST to multiple back-ends in react-admin, I'd appreciate it very much.

回答1:

No, but you can have a super dataProvivder which would select the appropriate one depending on the resource. Something like:

const dataProviders = [
    { dataProvider: simpleRestProvider('http://path.to.foo.api'), resources: ['foos'] },
    { dataProvider: simpleRestProvider('http://path.to.bar.api'), resources: ['bars'] },
];

export default (type, resource, params) => {
    const dataProviderMapping = dataProviders.find(dp => dp.resources.includes(resource));

    return dataProviderMapping.dataProvider(type, resource, params);
}

回答2:

In the README of recent ra release (3.4.1), there is a section (Extending a Data Provider (Example of File Upload)) that mentions: "... combine two Data Providers for two backends into a single object...". You can write a wrapper with branches to relay to different provider's implementation. An example to add your real data provider on top of their demo is:

// new file dataProvider/super.js
import simpleRestProvider from 'ra-data-simple-rest';
import delayedDataProvider from './rest'

const realDataProvider = simpleRestProvider('http://real_world_url/');

const myDataProvider = {
    ...delayedDataProvider,
    getList: (resource, params) => {
        console.log(resource)
        if (["customers", "reviews", "commands"].includes(resource)) {
            // resources for the demo
            return delayedDataProvider.getList(resource, params)
        } else {
            // your own resources
            return realDataProvider.getList(resource, params)
        }
    },
};

export default myDataProvider;

and replace the delayedDataProvider with the above myDataProvider

// file dataProvider/index.js
         case 'graphql':
             return import('./graphql').then(factory => factory.default());
         default:
-            return import('./rest').then(provider => provider.default);
+            return import('./super').then(provider => provider.default);

Disclaimer: I got the same error as previous posts "provider is not function..."

回答3:

you can make custom of resource choose to which api you will use. one admin only have one dataProvider.

      <Admin
        dataProvider={superDataProvider}
     />

but you can do like this:

 import superDataProvider from './dataProviderFactory';

following is my code you can reference

import dataProviderRuby from './dataProvider'; //handle ruby dataProvider
import dataProviderJava from './dataProviderForJava';// handle java dataProvider
import { rubyClient, javaClient } from './apolloClient';//custom two diff client one will fetch ruby service ,other will java

const IsOmsResource = resource => {
  const omsReource = [
    'markets',
    'regions',
    'countries',
    'states',
    'items',
    'salesOrganizations',
  ];
  return omsReource.some(ele => ele === resource);
}; //those resource will fetch data from java service others will go to ruby

const rubyDataProvider = async (type, resource, params) => {
  const provider = await dataProviderRuby({
    client: rubyClient,
  });
  return provider(type, resource, params);
};

const javaDataProvider = async (type, resource, params) => {
  const provider = await dataProviderJava({
    client: javaClient,
  });
  return provider(type, resource, params);
};

const superDataProvider = (type, resource, params) => {
  if (IsOmsResource(resource)) {
    console.log('当前Java', resource);
    return javaDataProvider(type, resource, params);
  }

  console.log('当前ruby', resource);
  return rubyDataProvider(type, resource, params);
};

export default superDataProvider;

following is the './apolloClient'

import ApolloClient from 'apollo-client';
import { createHttpLink } from 'apollo-link-http';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { setContext } from 'apollo-link-context';

const httpLinkRuby = createHttpLink({
  uri: '/graphql',
});
const httpLinkJava = createHttpLink({
  uri: '/oms-graphql',
});
const authLink = setContext((_, { headers }) => {
  const token = localStorage.getItem('token');
  return {
    headers: {
      ...headers,
      authorization: token ? `Bearer ${token}` : '',
    },
  };
});
export const rubyClient = new ApolloClient({
  link: httpLinkRuby,
  cache: new InMemoryCache(),
});
export const javaClient = new ApolloClient({
  link: authLink.concat(httpLinkJava),
  cache: new InMemoryCache(),
});