Crate 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.

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");

Modules

• query
  Defines the types & results for running an introspection query against a GraphQL server.

Structs

• CapabilitiesQuery
  A query that detects what capabilities a remote GraphQL server has, which can be used to determine what introspection query should be made against that server.
• CapabilitySet
  The set of capaiblities a GraphQL server supports.
• Directive
  A directive either used in the schema or available to queries
• EnumType
  GraphQL Enum types represent leaf values in a GraphQL type system which can have one of a set of possible values.
• EnumValue
  One of the possible values of an EnumType
• Field
  One of the fields of an ObjectType or InterfaceType
• FieldType
  The type of a Field or InputValue
• FieldWrapping
  A list of WrappingTypes that wrap a FieldType
• InputObjectType
  A GraphQL Input Object defines a set of input fields; the input fields are either scalars, enums, or other input objects
• InputValue
  Represents field and directive arguments as well as the fields of an input object.
• InterfaceType
  Interfaces are an abstract type where there are common fields declared.
• IntrospectionQuery
  A GraphQL Introspection Query for Cynic.
• ObjectType
  GraphQL Objects represent a list of named fields, each of which yield a value of a specific type.
• ScalarType
  Scalar types represent primitive leaf values in a GraphQL type system.
• Schema
  A GraphQL schema
• UnionType
  GraphQL Unions represent objects that could be any of a list of GraphQL Object types.

Enums

• Deprecated
  Whether a Field or EnumValue is deprecated.
• DirectiveLocation
  A location where a directive can be used
• SchemaError
  An error that can occur when building the schema
• SpecificationVersion
  Versions of the GraphQL specification that the CapabilitiesQuery can detect.
• Type
  A type defined in a Schema
• WrappingType
  Types that can wrap either named types or other wrapper types