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Comment by sorenbs | Hacker News Reader

Co-author of the tutorial and founder of prisma here.

Adamkl is right, you are missing a layer in your application. postgraphile, prisma and hasura turn your database into a graphql api, but you don't want to expose that directly. Graphql Bindings allow you to construct a Graphql Api by mapping an existing Api and implementing extra logic.

This allows you to keep permission and business logic in your application layer where it belongs.

My Co-founder Johannes is giving a talk on this technique at GraphQL Europe on Friday. The talks will be available online shortly after, so I would recommend keeping an eye out for that if you are not going.

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So basically you are running two graphql services, and using the private one as an ORM?

Doesn't that drastically increase complexity in the fact that you now need to maintain multiple services? Why not just skip postgraphile and just use an ORM in your business layer? As opposed to being required to maintain multiple services.

It also feels very odd that since you can't even expose your private one to other internal services because all your authorization and access restrictions are now sitting in your business layer, which to me seems like a huge waste.

Correct, you are running at least two separate GraphQL APIs.

If you look at the architecture of modern tech companies they are already moving in this direction. Facebook has TAO for data access, and twitter has Strato: https://about.sourcegraph.com/graphql/graphql-at-twitter/ The purpose of these data services is to enable feature developers to focus on their feature instead of worrying about infrastructure, caching and scalability. Prisma is an open source version of that same pattern.

To the question of whether you should expose your database API to other internal services or not. This very much depends on the kind of architecture you are choosing. If you are building microservices you typically want to ensure that only the microservice owning the data can access and update it.

Facebook has a quite different approach where TAO enforces access control policies, and all services can query the same data. We'll explore how Prisma can support this pattern in the future.

To further this point a bit, because of GraphQLs introspection capability, it becomes easy to combine and proxy existing GraphQL services without redeclaring the schema every time. If you take a look at what Prisma is doing, it’s creating a GraphQL schema based of an underlying data source which you can then generate bindings off of to include in other applications (think auto-generated client bindings via SOAP WSDL files.

At my company, we are taking a different approach by defining GraphQL APIs that are essentially exposing pure data (similar to Prisma) and then we are merging them and proxying them through multiple layers that augment and alter the schema and data as it passes through.

We can do this because we are leveraging The ability to inspect and alter the abstract syntax trees that power GraphQL under the hood.

This sounds like a super interesting approach Adamkl! Do you have something written up about this somewhere?

I've had a few discussions about doing a formal write-up of what we are doing, but for now I can only provide a brief overview:

Our data APIs map from existing SOAP/XML services to small GraphQL sub-sections of our greater API.

Then, we merge those small APIs together with Apollo's graphql-tools, similar to what Airbnb is doing[1].

Now we are starting work on our proxy/processing layers using this[2] work-in-progress.

[1]https://medium.com/airbnb-engineering/reconciling-graphql-an...

[2]https://github.com/adamkl/graphql-proxy

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