Query parameters don't get converted to appropriate GraphQL types

[thecodeboss]

Description

When passing arguments in a query string, there is no type conversion step. So strings don't get converted into integers, etc. For example, an HTTP request like this one:

GET https://myapi.com/projects?limit=100

would attempt to pass the limit parameter as a string "100" instead of consulting the GraphQL schema and realizing it is supposed to take an Int type instead.

It's possible to define a middleware that converts these, however I'd like to suggest it as a feature instead. Most GraphQL built-in scalar types I think could be automatically converted, but obviously custom scalars or non-scalars would still require custom middleware to be built.

Another workaround is to use the request body instead of the query string, as JSON allows you to specify scalars without ambiguity.

I would be happy to take a stab at creating a pull request for this if there's no immediate objection to the idea.

Steps to Reproduce

Set up a graphql2rest project with the following GraphQL Schema:

type Project {
  id: ID!
}

type Query {
  projects(limit: Int): [Project!]!
}

this manifest.json:

{
  "endpoints": {
    "/projects": {
      "get": {
        "operation": "projects"
      }
    }
  }
}

and then execute this HTTP request:

GET https://myapi.com/projects?limit=100

You should get a GraphQL error like the following:

Variable "$limit" got invalid value "100"; Expected type Int. Int cannot represent non-integer value: "100"

[roy-mor]

Thanks for this issue @thecodeboss.

Just to clarify - what you specified under "You should get a GraphQL error like the following" is the current behavior, yes? Which is a problem because the API user specified an integer value for the query parameter, but it got interpreted as a string, thereby violating the schema and so the input validation failed, resulting in an API request with valid input failing to execute?

[MatthewHerbst]

Just to clarify - what you specified under "You should get a GraphQL error like the following" is the current behavior, yes? Which is a problem because the API user specified an integer value for the query parameter, but it got interpreted as a string, thereby violating the schema and so the input validation failed, resulting in an API request with valid input failing to execute?

Yes, that's the current behavior. The steps above are listed under a Steps to Reproduce heading

[thecodeboss]

Just to clarify - what you specified under "You should get a GraphQL error like the following" is the current behavior, yes?

Yes

[roy-mor]

@thecodeboss OK good. I wanted to make sure. Please go ahead and create a pull request for this. Please make sure to add appropriate tests for your change. Thank you!

[roy-mor]

@thecodeboss any progress on your suggested PR?

[shuffledex]

We need that PR ASAP!