Nexus-plugin-prisma: Field and query option to limit max page size in request

[jhalborg]

Hey! 👋

I think it'd be really great if Nexus Prisma could accept a query option for max page size (i.e. first param) for lists to prevent API consumers from performing too expensive queries on the system.

For example, given the following query

query UsersWithPosts {
  users(first:500) {
    posts { # each user might have a lot of posts
      id
      content
    }
  }
}

This query could be very, very expensive, especially if users have a lot of posts. There are of course other ways of handling this like query whitelisting, but I think it'd be great if Nexus Prisma could support putting in a sane default for max page size like 50 or 100 pr type/field, depending on the underlying model and domain. Ideally, the error message should also be easily customisable.

Edit
See my two comments below for more context:
https://github.com/prisma-labs/nexus-prisma/issues/497#issuecomment-544455313
https://github.com/prisma-labs/nexus-prisma/issues/497#issuecomment-544918563

[Weakky]

Hey 👋,

Nexus Prisma should already provide pagination supports by default on all list fields.

query UsersWithPosts {
  users(first:100) {
    posts(first: 100) { # each user might have a lot of posts
      id
      content
    }
  }
}

Above query should be valid, if it doesn't work for you, it's a bug.

What we could think about though is whether we want to make the first argument required or keep it optional. GitHub for instance makes the first arg always required on paginated lists.

[jhalborg]

The first argument works fine 😄 What I'm looking for is a way to set a default/max value possible to pass to first. Actually, it's both - it'd be great if

• first could be a required param for all lists
• you could define a maximum value for that param as both
  
  
  
  • a project-wide config variable
  
  
  • a field-specific override of that
  
  
• you could define a default value for that param as both
  
  
  
  • a project-wide config variable
  
  
  • a field-specific override of that
  
  

The point is to prevent clients from making non-paginated and very expensive requests, intended/malicious or inadvertently. Our current schema is generated using vanilla graphql-js, and here we've set limits and defaults for list arguments. We're planning a move to Nexus+Nexus-Prisma, and was looking for ways to do this for the generated lists, but couldn't find any so I created this issue 😄

It's not too critical as long as all clients/consumers are built in house alongside those who build the schema/backend, but it's a fairly large issue if you plan to allow external developers to start using the schema.

[jasonkuhrt]

Thanks for the feature request @jhalborg. Can you confirm I understood the feature request correctly: You would like a way to configure nexus-prisma to enforce runtime checks on the size pages requested in pagination?

Good idea!

[jhalborg]

Almost :-)

The default values could actually be passed to the generated schema, but the max values would have to be enforced during runtime.

Also, I think it's important to be able to provide a config for each, as well as field specific overrides.

Let's do a concrete example. If we have a schema like

type User {
  posts: [Post!]!
}

type Post {
  author: User!
  comments: [Comment!]!
}

type Comment {
  author: User!
  post: Post!
}

I would be like to tell Prisma Nexus that

• the default page size for all lists, unless otherwise indicated, is 12
• the default page size for User lists specifically is 8 (if Users might be more expensive to fetch, for example)
• the default "max page size" for lists is set to 50
• the max page size for Comments is 100, though, if we assume they are more lightweight in our example.

Does that make sense? Not entirely sure if I get my point across 😄

[jasonkuhrt]

@jhalborg Crystal clear thanks!

[ManAnRuck]

this feature would be helpful :)

[theneshofficial]

Waiting for this :)

[thalesagapito]

If you're satisfied with limiting the take argument from the findMany actions, you can use the following middleware:

prisma.$use((params, next) => {
  const isFindMany = params.action === 'findMany';
  if (!isFindMany) return next(params);

  const takeParameter = params.args.take;
  const takeParameterIsUndefined = takeParameter === undefined;

  if (takeParameterIsUndefined || takeParameter > 30) {
    params.args.take = 30;
  }

  return next(params);
});

For my use case this is enough.