Lib.rs

Cynic Introspection

cynic-introspection defines a GraphQL introspection query that can be run using cynic, a rust GraphQL client

This can be used for any reason you'd want to introspect a GraphQL server - including when you're using cynic as a library in your own project.

Features

• Support for introspecting servers that support both GraphQL 2021 and GraphQL 2018.
• Contains a capability detection query that can determine which version of the GraphQL specification a server supports prior to querying it.

Usage

See the documentation on docs.rs for instructions on using cynic-introspection.

lib.rs:

cynic-introspection defines a GraphQL introspection query that can be run using cynic, a rust GraphQL client.

This can be used for any reason you'd want to introspect a GraphQL server - including when you're using cynic as a library in your own project.

It also provides a [Schema] abstraction on top of the introspection query results, which provides some stronger typing than using the introspection results directly.

use cynic::{QueryBuilder, http::ReqwestBlockingExt};
use cynic_introspection::IntrospectionQuery;

// We can run an introspection query and unwrap the data contained within
let introspection_data = reqwest::blocking::Client::new()
    .post("https://swapi-graphql.netlify.app/.netlify/functions/index")
    .run_graphql(IntrospectionQuery::build(()))
    .unwrap()
    .data
    .unwrap();

// And then convert it into a schema for easier use.
let schema = introspection_data.into_schema().unwrap();

assert_eq!(schema.query_type, "Root");

GraphQL Versions

GraphQL servers currently commonly support two different versions of the GraphQL specification:

• The June 2018 Specification
• The October 2021 Specification

The fields available for introspection differ between these two versions. By default we query only for fields supported in the June 2018 specification. You can request a different version of the query using InstrospectionQuery::with_capabilities:

use cynic::http::ReqwestBlockingExt;
use cynic_introspection::{IntrospectionQuery, SpecificationVersion};

// We can run an introspection query and unwrap the data contained within
let introspection_data = reqwest::blocking::Client::new()
    .post("https://spacex-production.up.railway.app/")
    .run_graphql(
        IntrospectionQuery::with_capabilities(
            SpecificationVersion::October2021.capabilities()
        )
    )
    .unwrap()
    .data
    .unwrap();

// And then convert it into a schema for easier use.
let schema = introspection_data.into_schema().unwrap();

assert_eq!(schema.query_type, "Query");

Detecting Capabilities

cynic-introspection also provides [CapabilitiesQuery], a query which can determine the capabilites of a remote GraphQL server. This can be paired with Introspection::with_capabilities:

use cynic::{QueryBuilder, http::ReqwestBlockingExt};
use cynic_introspection::{CapabilitiesQuery, IntrospectionQuery};

// First we run a capabilites query to check what the server supports
let capabilities = reqwest::blocking::Client::new()
    .post("https://swapi-graphql.netlify.app/.netlify/functions/index")
    .run_graphql(CapabilitiesQuery::build(()))
    .unwrap()
    .data
    .unwrap()
    .capabilities();

// Now we can safely run introspection, only querying for what the server supports.
let introspection_data = reqwest::blocking::Client::new()
    .post("https://swapi-graphql.netlify.app/.netlify/functions/index")
    .run_graphql(IntrospectionQuery::with_capabilities(capabilities))
    .unwrap()
    .data
    .unwrap();

// And then convert it into a schema for easier use.
let schema = introspection_data.into_schema().unwrap();

assert_eq!(schema.query_type, "Root");