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Fragment matcher #1483

Merged
merged 15 commits into from
Mar 25, 2017
Merged

Fragment matcher #1483

merged 15 commits into from
Mar 25, 2017

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helfer
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@helfer helfer commented Mar 23, 2017

Fixes #1337 #1363 #1379 #1113 #857 #771 #1297 #1273 #961 #933

Not 100% sure all of these issues will be fixed, but it should fix a good number of them.

TODO:

  • If this PR is a new feature, reference an issue where a consensus about the design was reached (not necessary for small changes)
  • Make sure all of the significant new logic is covered by tests
  • Rebase your changes on master so that they can be merged easily
  • Make sure all tests and linter rules pass
  • Update CHANGELOG.md with your change
  • Add your name and email to the AUTHORS file (optional)
  • If this was a change that affects the external API, update the docs and post a link to the PR in the discussion

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A few requests. There are also some comments left in from debugging.

isTest,
} from '../util/environment';

export interface FragmentMatcherInstance {
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This name is confusing because I usually thing Instance means not the interface. Perhaps FragmentMatcher or FragmentMatcherInterface would be a better name.

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Yeah, I'll probably go for interface then, because there's already a FragmentMatcher in graphql-anywhere, and that one's a function.

// This function runs fetchQuery without initializing the fragment matcher.
// We always want to initialize the fragment matcher, so this function should not be accessible outside.
// The only place we call this function from is within fetchQuery after initializing the fragment matcher.
private fetchQueryWithoutInit<T>(
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I'd call this fetchQueryAfterFragmentMatcherInit to be really explicit that you should only call it in that circumstance.

throw new Error('FragmentMatcher.match() was called before FragmentMatcher.init()');
}

// invariant(isIdValue(idValue), 'boo hoo, I am sad');
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Should be deleted

return;
})
.catch( (err: any) => {
throw err;
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There's definitely a possibility of a bad outcome here if we couldn't fetch the introspection result. I think a good option could be to set this.readyPromise = null so that we try to init again on the next query.

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Yeah, probably worth a try 👍

/**
* The init method has to get called before the match function can be used.
*/
public init(queryManager: QueryManager): Promise<void> {
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This is a bit nitpicky, but I think a name like ensureReady would be better because that would indicate that this function is called every time, not just once to initialize.

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yup, agreed. The function evolved quite a bit, and it's no longer just an init function.

export interface FragmentMatcherInstance {
canBypassInit: (query: DocumentNode) => boolean;
init(queryManager?: QueryManager): Promise<void>;
match(idValue: IdValue, typeCondition: string, context: ReadStoreContext): boolean;
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Should this take an obj instead of an idValue? Seems like both implementations just do obj = context.store[idValue.id] as the first statement. I can see that we still want context so we can set returnPartialData.

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Yeah, I thought about that for a second, but then decided against it, because we might have a store in the future where the typename is stored in the path or in the id, in which case we could theoretically save the lookup. It also saves us from having to update graphql-anywhere or wrapping the fragmentMatcher function before passing it in. I think it's a little bit simpler this way, so we should keep it.

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Sounds good. This is a small enough piece that if we change the store format or anything else later, rewriting this will be the least of our worries.

@helfer
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helfer commented Mar 25, 2017

It's worth noting that client.readFragment and client.readQuery might break if the FragmentMatcher is not initialized. If they are called before the first query returns, the user has to ensure that the fragment matcher has been initialized if it needs to be.

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Yeah I guess there's no way to get around that if store reading is synchronous.

@helfer helfer merged commit 581ef1e into master Mar 25, 2017
@helfer helfer deleted the fragment-matcher branch March 25, 2017 17:28
@csillag
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csillag commented Mar 25, 2017

Hurray!

Where will be the next RC release?

@helfer
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helfer commented Mar 25, 2017

@csillag I'll release it in a couple of minutes, but I won't tag it as latest yet, so you'll have to install that specific version or @next to get it.

To use the introspection fragment matcher for now, you'll also need to specifically provide it:

import ApolloClient, { IntrospectionFragmentMatcher } from 'apollo-client';

const client = new ApolloClient({
  fragmentMatcher: new IntrospectionFragmentMatcher(),
});

I'm doing this because I'd like to make sure that there will not be any unintended consequences of having to fetch (or pre-populate) some schema information before enabling it for everyone by default.

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csillag commented Mar 25, 2017

Awesome. I will take it for a spin on Monday.

@helfer helfer changed the title WIP: Fragment matcher Fragment matcher Mar 25, 2017
@helfer
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helfer commented Mar 25, 2017

cc @fubhy @mdebbar @bgentry @TSMMark @thebigredgeek I've merged a solution for fragment matching.

It would be great if you could test it by [email protected] and explicitly using the IntrospectionFragmentMatcher as per the instructions above. Once we've confirmed that it works for your apps, we'll flip the switch and roll it out for everyone 🎉

@bgentry
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bgentry commented Mar 25, 2017

reposting from slack:

@helfer AFAICT the Interface type stuff is fixed 🎉

Unfortunately the upgrade breaks some of my tests around error handling of 4xx server responses. I thought that my observer's error() wasn't getting called anymore in that scenario, but it's slightly more complicated than that.

I manipulated a cookie on my app to achieve the same effect outside of tests, and the result is that my actual app is broken by this change.

The reason is due to the fact that this change adds the following introspection query, which runs before any of my app's actual queries:

{
  __schema {
    types {
      kind
      name
      possibleTypes {
        name
      }
    }
  }
}

My tests assume that the first request that's made is one to load the current user, and the server just always returns a 401 in these tests (as it would IRL when an auth token is invalid for some reason). Thus the introspection query fails on a 401 status.

Likewise, my actual app (outside of tests) tries to load the current user immediately to check if auth is valid, and if not will invalidate the session and cause a login. But my current user query is never even running, presumably due to an error received on this introspection query.

I don't think this is viable because it requires the graphql endpoint to be publicly accessible with no authentication requirement, at least for the sake of this introspection query. My server's graphql endpoint is only available with a valid session, and I don't think that's a use case that can safely be ignored.

@stubailo
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@bgentry would adding a build step to inline that type information on startup work for you? Do you have the ability to run introspection locally from your development environment?

@helfer
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helfer commented Mar 26, 2017

@bgentry I don't think there's any way of doing this without schema information. Having schema information requires that you either

A) Include the schema at build time (for example by importing, or by doing an additional build step)
B) Fetch the schema at runtime

For option B importing is only reasonable if your schema is already in JS, which isn't the case for everyone. It would also incur a bundle size penalty. It's pretty easy to implement such a fragment matcher with the interface available today, so if that's the option you want to go for, I'm happy to assist.
Option B could still be optimized such that queries can still be executed without the matcher being ready as long as the matcher isn't needed (store is empty or queries don't contain fragments, etc.). This solution would be quite a bit more complex however, which is why I'd rather not go too far down that path.

One of our most important goals with Apollo is that it works out of the box and doesn't require a build step or tooling for the most common use-cases.

@bgentry: just so I understand. How is it that your current user query can succeed but not the introspection query? Or are you using the fact that the currentUser query fails to set in motion some kind of login process? If so, could you just use the fact that the introspectionQuery fails for doing the same thing?

@helfer
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helfer commented Mar 26, 2017

@TSMMark yes, it should work out of the box. Are you passing addTypename: false to Apollo by any chance?

@stubailo
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@bgentry how about if you could do option (2), but you had a script that generated the necessary data? So basically:

  1. Generate a .js file using a very simple script that has the relevant schema information
  2. Import that js file into your frontend code just like anything else, so it should work fine with the Ember build

In this setup, you would need re-run the script from (1) when you modify the interfaces or unions to your schema.

I'd much rather embed my whole schema in the frontend app if necessary than deal with a more tangled bootstrapping process

How does this compare to the process above for you?

@TSMMark
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TSMMark commented Mar 27, 2017

Whoops, my bad @helfer. We had a custom dataIdFromObject which was throwing that.

const dataIdFromObject = (result) => {
  if (!result.__typename) {
    throw new Error('GraphQL response missing __typename: ' + JSON.stringify(result))
  }

I guess dataIdFromObject is applied to objects in the response of the schema query too. Intended? Seems a little odd that any part of the schema would need a dataId, no?

Edit: It appears that our dataIdFromObject was not needed so I removed it and now everything works great, and the new fragment matching seems to have done the trick. Thanks so much!

@bgentry
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bgentry commented Mar 27, 2017

I don't think there's any way of doing this without schema information.

Yep, totally get that!

One of our most important goals with Apollo is that it works out of the box and doesn't require a build step or tooling for the most common use-cases.

I think this is an important goal and it's one that I share.

@bgentry: just so I understand. How is it that your current user query can succeed but not the introspection query? Or are you using the fact that the currentUser query fails to set in motion some kind of login process? If so, could you just use the fact that the introspectionQuery fails for doing the same thing?

I am using the fact that the currentUser query fails (specifically with a 401) to determine that the session should be invalidated. Both the currentUser query and the introspection query fail in the same way, however afaict I have no way to know about the failed introspection query. None of my error handlers or promise catches were being called when I tested this out (though I could see that the Apollo query manager was receiving the error, that's as far as I got w/ debugging).

As far as bundling my schema, I am indeed already doing that for usage in my test suite, so it wouldn't be much different to put it in a place where the app itself could use it too.

Since Apollo Client never used the schema before this fragment matcher was added, am I correct to assume that there isn't a documented way to provide a schema? Would I need to implement a custom FragmentMatcherInterface, and if so, how much customization would be required? Since I'm sure I won't be the only one needing to do this, it's probably worthwhile to make sure it's easy to do and documented (the latter I can maybe help with).

@stubailo
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@bgentry the current design allows you to pass a static object with the data in the constructor: https://github.com/apollographql/apollo-client/pull/1483/files#diff-2223acc12993ca0745c660713b0c4f78R40

@booboothefool
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booboothefool commented Mar 27, 2017

Hi, I arrived at this issue from #1436 and wanted to try this out. Upgrading from rc.6 to rc.7 and adding:

const client = new ApolloClient({
  ...
  fragmentMatcher: new IntrospectionFragmentMatcher(),
  ...

Appears to have broken a few of my initial startup queries (which use fragments), which were previously working in rc.6.

@robertvansteen
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It doesn't seem to work for me either. I've added the IntrospectionFragmentMatcher, but the data I receive in my component doesn't contain the results from the server anymore.

@csillag
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csillag commented Mar 27, 2017

Here are my test results:

Behavior with 1.0.0-rc.6:

  • loading data with apollo.query - ❌ data is undefined
  • loading data with apollo.watchQuery - ❌ data is undefined
  • loading data with the react wrapper - ✅ OK
  • checking the data after mutation directly in apollo's store - ✅ OK
  • checking data after mutation with apollo.query - ❌ data is still undefined
  • reacting to mutations with apollo.watchQuery - ❌ no reaction
  • reacting to mutations with the react wrapper - ❌ no reaction

Behavior with 1.0.0-rc.7, with fragmentMatcher configured:

  • loading data with apollo.query - ✅ Works
  • loading data with apollo.watchQuery - ✅ Works
  • loading data with the react wrapper - ❌ Fails
  • checking the data after mutation directly in apollo's store - ✅ OK
  • checking data after mutation with apollo.query - ✅ Correct
  • reacting to mutations with apollo.watchQuery - ✅ Yes!
  • reacting to mutations with the react wrapper - ❌ since the react wrapper is defunct, N/A

@csillag
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csillag commented Mar 27, 2017

... so, to summarize: rc.7 it works great, except that (for whatever reason) it totally breaks the React integration, which mostly worked, up to this point, even without fragmentMatcher.

@csillag
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csillag commented Mar 27, 2017

Further analysis shows that the problem with the React wrapper is caused by the ObservableQuery.currentResult function being broken.

@csillag
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csillag commented Mar 27, 2017

To use the introspection fragment matcher for now, you'll also need to specifically provide it:
[...]
I'm doing this because I'd like to make sure that there will not be any unintended consequences of having to fetch (or pre-populate) some schema information before enabling it for everyone by default.

One more bit of info: as far as I can tell, not engaging the the fragmentMatcher doesn't prevent the regression on ObservableQuery.currentResult.

@helfer
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helfer commented Mar 27, 2017

Thanks @csillag! That's very interesting, let me look into it.

@helfer
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helfer commented Mar 27, 2017

@rovansteen @booboothefool @csillag Could you guys try if your queries work when you pass { options: { notifyOnNetworkStatusChange: true } } to them? That seems to fix the errors I'm seeing in the react-apollo tests.

PS: We recently decided to set the default of notifyOnNetworkStatusChange back to false because it was causing lots of re-renders for people and it was hard for them to track down the issue.

@csillag
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csillag commented Mar 27, 2017

Could you guys try if your queries work when you pass { options: { notifyOnNetworkStatusChange: true } } to them?

For me, it doesn't seem to do anything. (currentResult() still returns an empty object for data.)

However, I can confirm that using lastResult instead of currentResult() seems to return the desired result. (Regardless of notifyOnNetworkStatusChange.)

@helfer
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helfer commented Mar 28, 2017

Thanks for the feedback @csillag. Would you be able to make a PR with a failing test or provide a reproduction with react-apollo-error-template?

For me all the tests pass with currentResult. Using getLastResult breaks a whole bunch of tests, so I think currentResult still does something we need...

@csillag
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csillag commented Mar 28, 2017

I'll try to do that tomorrow.

FWIW, I didn't use getLastResult(); I used lastResult.

@helfer
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helfer commented Mar 28, 2017

I think observableQuery.getLastResult() just returns observableQuery.lastResult ;)

@csillag
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csillag commented Mar 28, 2017

OK, so I have prepared a reproduction based on react-apollo-error-template.

Please test the following two branches:

  • csillag/use-fragments - This one uses rc6. The react wrapper works, but running queries normally does.
  • csillag/use-fragments-rc7 - This one uses rc7 and fragmentMatcher. React wrapper doesn't work, but running queries manually does.

Testing manual query execution

Run this command on the console:

apollo.query({query: getPeople}).then(result => console.log(result.data))
  • On rc.6, this yields: Loaded data: undefined
  • On rc.7, this yields: Loaded data: Object {people: Array(3), Symbol(id): "ROOT_QUERY"}

Testing the React wrapper

The loaded data is automatically displayed on both the browser console and rendered on the UI.

@robertvansteen
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Any progress on this? I see 1.0 is released but it looks like this bug is still there.

@csillag
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csillag commented Mar 30, 2017 via email

@helfer
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helfer commented Mar 31, 2017

@rovansteen We didn't make it the default, so you have to specifically pass the fragment matcher and initialize it with the relevant part of your schema:

const fm = new IntrospectionFragmentMatcher({
 introspectionQueryResultData: {
  __schema: {
    types: [{
      kind: 'UNION',
      name: 'Item',
      possibleTypes: [{ name: 'GreenItem' }, { name: 'RedItem }]
    }]
  }
});

First we also wanted the fragment matcher initialize itself, but the code ended up being more complicated to maintain than we wanted, so we ditched that for now.

We'll try to provide some instructions for how to seed the fragment matcher with a build script or server-side rendering.

@robertvansteen
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robertvansteen commented Mar 31, 2017

@helfer Is there any clear documentation on this? I can't get it to work. If I don't setup the IntrospectionFragmentMatcher my first result works fine, but if I use the fetchMore method I get no data, even though the server returns the data without any problems. If I do use the fragmentMatcher, I get no data at all for all my queries. I tried it with a partial schema (just the union part) and a complete schema of everything. Both break all my queries.

Edit: Ok, small correction. The fragmentMatcher breaking all my queries was to a mistake on my side in my schema. Now I've got the schema correct, but the issue remains that fetchMoreResult is undefined on my updateQuery method.

I've created a separate issue with example repo (the one from csillag with a few changes, thanks!) to illustrate this issue. #1523

@stayclean
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The problem is solved with the solution, but before we found the solution,
this document which does not work is kind of misleading. Please fix or check the document on the doc website.

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Schema knowledge needed for fragmentMatcher
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