GraphQL is a data query language developed by Facebook intended to serve mobile and web application frontends.
Juniper makes it possible to write GraphQL servers in Rust that are type-safe and blazingly fast. We also try to make declaring and resolving GraphQL schemas as convenient as possible as Rust will allow.
Juniper does not include a web server - instead it provides building blocks to make integration with existing servers straightforward. It optionally provides a pre-built integration for the Iron and Rocket frameworks, including embedded Graphiql for easy debugging.
- Cargo crate
- API Reference
- Book: Guides and Examples
The best place to get started is the Juniper Book, which contains guides with plenty of examples, covering all features of Juniper.
To get started quickly and get a feel for Juniper, check out the Quickstart section.
For specific information about macros, types and the Juniper api, the API Reference is the best place to look.
You can also check out src/tests/schema.rs to see a complex schema including polymorphism with traits and interfaces. For an example of web framework integration, see the rocket and iron examples folders.
Juniper supports the full GraphQL query language according to the specification, including interfaces, unions, schema introspection, and validations. It does not, however, support the schema language.
As an exception to other GraphQL libraries for other languages, Juniper builds
non-null types by default. A field of type
Vec<Episode> will be converted into
[Episode!]!. The corresponding Rust type for e.g.
[Episode] would be
Juniper has automatic integration with some very common Rust crates to make building schemas a breeze. The types from these crates will be usable in your Schemas automatically.
Juniper has not reached 1.0 yet, thus some API instability should be expected.
pub use crate::executor::Context;
pub use crate::executor::ExecutionError;
pub use crate::executor::ExecutionResult;
pub use crate::executor::Executor;
pub use crate::executor::FieldError;
pub use crate::executor::FieldResult;
pub use crate::executor::FromContext;
pub use crate::executor::IntoFieldError;
pub use crate::executor::IntoResolvable;
pub use crate::executor::Registry;
pub use crate::executor::ValuesStream;
pub use crate::executor::Variables;
Nullablecan be used in situations where you need to distinguish between an implicitly and explicitly null input value.
GraphQLValueto its trait object.
juniper::graphql_subscriptionmacro to get stream’s item type that implements
GraphQLValuefrom type alias provided by user.
GraphQLTypetrait with asynchronous subscription execution logic.
GraphQLValuetrait with asynchronous subscription execution logic. It should be used with
GraphQLValuein order to implement subscription resolvers on GraphQL objects.
GraphQLTypetrait with asynchronous queries/mutations resolvers.
GraphQLValuetrait with asynchronous queries/mutations resolvers.
ScalarTokeninto a certain scalar value type
Futurefor use in cases where you can’t statically type your result or need to add some indirection.
BoxFuture, but without the
#[graphql_interface]macro for generating a GraphQL interface implementation for traits and its implementers.
objectproc macro is the primary way of defining GraphQL resolvers that can not be implemented with the GraphQLObject derive.
#[graphql_union]macro for deriving a GraphQL union implementation for traits.
#[derive(GraphQLUnion)]macro for deriving a GraphQL union implementation for enums and structs.