Crate juniper

GraphQL

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

Getting Started

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.

Features

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 Option<Vec<Option<Episode>>>.

Integrations

Data types

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.

• uuid
• url
• chrono
• bson

Web Frameworks

• rocket
• iron

API Stability

Juniper has not reached 1.0 yet, thus some API instability should be expected.

Re-exports

• pub use crate::util::to_camel_case;
• pub use crate::ast::Definition;
• pub use crate::ast::Document;
• pub use crate::executor::Applies;
• 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::LookAheadArgument;
• pub use crate::executor::LookAheadMethods;
• pub use crate::executor::LookAheadSelection;
• pub use crate::executor::LookAheadValue;
• pub use crate::executor::OwnedExecutor;
• pub use crate::executor::Registry;
• pub use crate::executor::ValuesStream;
• pub use crate::executor::Variables;
• pub use crate::parser::ParseError;
• pub use crate::parser::Spanning;
• pub use crate::validation::RuleError;

Modules

• executor
  Resolve the document to values
• http
  Utilities for building HTTP endpoints in a library-agnostic manner
• integrations
  Provides GraphQLType implementations for some external types
• marker
  Marker traits for GraphQL types.
• meta
  Types used to describe a GraphQL schema
• parser
  Query parser and language utilities
• validation
  Query validation related methods and data structures

Macros

• graphql_value
  Construct JSON-like values by using JSON syntax

Structs

• Arguments
  Field argument container
• EmptyMutation
  Utility type to define read-only schemas
• EmptySubscription
  Utillity type to define read-only schemas
• ExecutionOutput
  Represents the result of executing a GraphQL operation (after parsing and validating has been done).
• ID
  An ID as defined by the GraphQL specification
• Object
  A Object value
• Operation
• RootNode
  Root query node of a schema
• SchemaType
  Metadata for a schema

Enums

• DefaultScalarValue
  The default scalar value representation in juniper
• GraphQLError
  An error that prevented query execution
• InputValue
  A JSON-like value that can be passed into the query execution, either out-of-band, or in-band as default variable values. These are not constant and might contain variables.
• IntrospectionFormat
  The desired GraphQL introspection format for the canonical query (https://github.com/graphql/graphql-js/blob/8c96dc8276f2de27b8af9ffbd71a4597d483523f/src/utilities/introspectionQuery.js#L21)
• Nullable
  Nullable can be used in situations where you need to distinguish between an implicitly and explicitly null input value.
• OperationType
• Selection
  Entry in a GraphQL selection set
• Type
  A type literal in the syntax tree
• TypeKind
  GraphQL type kind
• Value
  Serializable value returned from query and field execution.

Traits

• AsDynGraphQLValue
  Conversion of a GraphQLValue to its trait object.
• ExtractTypeFromStream
  This trait is used in juniper::graphql_subscription macro to get stream’s item type that implements GraphQLValue from type alias provided by user.
• FromInputValue
  Parse an unstructured input value into a Rust data type.
• GraphQLInterface
  Maker trait for GraphQL interfaces.
• GraphQLSubscriptionType
  Extension of GraphQLType trait with asynchronous subscription execution logic.
• GraphQLSubscriptionValue
  Extension of GraphQLValue trait with asynchronous subscription execution logic. It should be used with GraphQLValue in order to implement subscription resolvers on GraphQL objects.
• GraphQLType
  Primary trait used to expose Rust types in a GraphQL schema.
• GraphQLTypeAsync
  Extension of GraphQLType trait with asynchronous queries/mutations resolvers.
• GraphQLUnion
  Maker trait for GraphQL unions.
• GraphQLValue
  Primary trait used to resolve GraphQL values.
• GraphQLValueAsync
  Extension of GraphQLValue trait with asynchronous queries/mutations resolvers.
• IntoFieldResult
  Trait for wrapping [Stream] into Ok if it’s not Result.
• ParseScalarValue
  A trait used to convert a ScalarToken into a certain scalar value type
• ScalarValue
  A trait marking a type that could be used as internal representation of scalar values in juniper
• SubscriptionConnection
  Single subscription connection.
• SubscriptionCoordinator
  Global subscription coordinator trait.
• ToInputValue
  Losslessly clones a Rust data type into an InputValue.

Functions

• execute
  Execute a query in a provided schema
• execute_sync
  Execute a query synchronously in a provided schema
• introspect
  Execute the reference introspection query in the provided schema
• resolve_into_stream
  Resolve subscription into ValuesStream

Type Aliases

• BoxFuture
  An owned dynamically typed Future for use in cases where you can’t statically type your result or need to add some indirection.
• DynGraphQLValue
  Helper alias for naming trait objects of GraphQLValue.
• DynGraphQLValueAsync
  Helper alias for naming trait objects of GraphQLValueAsync.
• LocalBoxFuture
  BoxFuture, but without the Send requirement.
• ParseScalarResult
  The result of converting a string into a scalar value

Attribute Macros

• graphql_interface
  #[graphql_interface] macro for generating a GraphQL interface implementation for traits and its implementers.
• graphql_object
  The object proc macro is the primary way of defining GraphQL resolvers that can not be implemented with the GraphQLObject derive.
• graphql_scalar
  Expose GraphQL scalars
• graphql_subscription
  A proc macro for defining a GraphQL subscription.
• graphql_union
  #[graphql_union] macro for deriving a GraphQL union implementation for traits.

Derive Macros

• GraphQLEnum
• GraphQLInputObject
• GraphQLObject
• GraphQLScalarValue
  This custom derive macro implements the #[derive(GraphQLScalarValue)] derive.
• GraphQLUnion
  #[derive(GraphQLUnion)] macro for deriving a GraphQL union implementation for enums and structs.