Use custom link, cache and cache options

[manueliglesias]

Use custom link, cache and cache options

Issue #, if available:
Fixes #3
Closes #21
Fixes #24
Closes #25
Fixes #36
Fixes #52
Closes #62
Fixes #70
Fixes #87
Fixes #90
Closes #92

Description of changes:
Allows the usage of:

• Custom link
• Custom cache
• Custom cache options

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[reggie3]

@manueliglesias Can you give an example of how to add a custom cache using your PR?

[reggie3]

Also, I tried to use the code from this pull request and received a error related to line 103 of client.js stating that super can't be used prior to this.
By the way, great work on adding these features. Thank you for working on it.

[manueliglesias]

Hi @reggie3

This is how you would use a custom cache, please note that offline support needs to be disabled (the custom cache won't know how to write to the offline store):

import { Hermes } from 'apollo-cache-hermes';
import AWSAppSyncClient from "aws-appsync";

const cache = new Hermes({ verbose: true });

const client = new AWSAppSyncClient({
  url: appSyncConfig.graphqlEndpoint,
  region: appSyncConfig.region,
  auth: {
    type: appSyncConfig.authenticationType,
    apiKey: appSyncConfig.apiKey
  },
  disableOffline: true
}, { cache });

[manueliglesias]

@reggie3 I also added a couple commits to address eslint rules (Hopefully that takes care of the webpack errors, let me know if it works for you)

Thanks for trying this SDK!

[elorzafe]

Very nice, but lets talk tomorrow. Probably I didn't understand some stuff

[elorzafe]

where is dt_str defined?

[manueliglesias]

It is part of the same var statement

[elorzafe]

lol thanks!

[elorzafe]

Why are you checking this theLink?

[manueliglesias]

Because I want to create the link only once and re-use it on subsequent link invocations. For this I am creating a closure

[elorzafe]

I would add on the error message or customLink

[manueliglesias]

Sounds good!

[elorzafe]

I would like to talk tomorrow the use of resolveClient

[manueliglesias]

Sure!

[rkuzsma]

@manueliglesias I don't have reproducible steps yet, but I can sometimes trigger an error in my app around this new area of the appsync sdk code:
TypeError: resolveClient is not a function. (In 'resolveClient(_this)', 'resolveClient' is undefined)")
It seems to be thrown when I invoke a lambda outside the context of appsync, while the app is starting up. Sorry I don't have more actionable information yet.

[rkuzsma]

When disableOffline=false, I applied this workaround to prevent the "resolveClient is not a function" error: apollographql/apollo-link#493 (comment)

[elorzafe]

What happen if someone use customCache with cacheOptions

[manueliglesias]

In that case, cacheOptions would be ignored. It is inferred that your customCache is already initialized with whatever options you chose.

[elorzafe]

this return will run before waiting hydratedPromise?

[manueliglesias]

Yes, an Observable "Returns a cleanup function which will cancel the event stream". For reference, see: https://github.com/tc39/proposal-observable#example-observing-keyboard-events

[reggie3]

@manueliglesias Thank you for working on it. I'm really excited about incorporating your work into my project.
Also, I enjoyed reading the code review between you and @elorzafe . It was informative.

[elorzafe]

👍 Nice!

[reggie3]

@manueliglesias Would the correct combination of custom cache and link-state be a combination of your example above and the one from #24? Would it be something like this?

const cache = new InMemoryCache();

const defaultState = {
  AppState:{
    __typename: 'AppState',
    geolocation: 'null'
  }
};

const stateLink = createLinkWithCache(cache => withClientState({
  cache,
  defaults: defaultState
}));

const appSyncLink = new createAppSyncLink({
  url: AppSyncConfig.graphqlEndpoint,
  region: AppSyncConfig.region,
  auth: {
    type: AppSyncConfig.authType,
    apiKey: AppSyncConfig.apiKey
  },
  disableOffline: true
}, {cache});

const link = ApolloLink.from([
  stateLink,
  appSyncLink
]);

const client = new AWSAppSyncClient({}, { link });

This is what I'm trying to us now, but it isn't working yet. I'm trying to figure out if I'm on the right track.

EDIT: Just want to add, that auth includes a variable for type which most tutorials pull from your AppSync configuration file as "authType". The relevant key is actually called "authenticationType"in the JSON file that AppSync will export for you when building your GraphQL schema.