Crate juniper

Juniper (GraphQL server library for Rust)

• Juniper Book (current | edge)
• Changelog

GraphQL is a data query language developed by Facebook and 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 Rust will allow.

Juniper doesn’t include a web server - instead it provides building blocks to make integration with existing servers straightforward, including embedded GraphiQL and/or GraphQL Playground for easy debugging.

Getting Started

The best place to get started is 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 docs is the best place to look.

Features

Juniper supports the full GraphQL query language according to October 2021 GraphQL 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

Types

Juniper provides out-of-the-box integration for some very common Rust crates to make building schemas a breeze. The types from these crates will be usable in your schemas automatically after enabling the correspondent self-titled Cargo feature:

• bigdecimal
• bson
• chrono, chrono-tz
• rust_decimal
• time
• url
• uuid

Web server frameworks

• actix-web (juniper_actix crate)
• axum (juniper_axum crate)
• hyper (juniper_hyper crate)
• rocket (juniper_rocket crate)
• warp (juniper_warp crate)

API stability

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

License

This project is licensed under BSD 2-Clause License.

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::LookAheadChildren;
• pub use crate::executor::LookAheadList;
• pub use crate::executor::LookAheadObject;
• 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::ScalarToken;
• pub use crate::parser::Span;
• 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
• tests
  Library tests and fixtures
• validation
  Query validation related methods and data structures

Macros

• assert_field
  Asserts validness of [Field] [Arguments] and returned [Type].
• assert_field_args
  Asserts validness of the [Field]s arguments. See spec for more info.
• assert_implemented_for
  Asserts that #[graphql_interface(for = ...)] has all the types referencing this interface in the impl = ... attribute argument.
• assert_interfaces_impls
  Asserts that impl = ... attribute argument has all the types referencing this GraphQL type in #[graphql_interface(for = ...)].
• assert_subtype
  Asserts validness of a [Field] return type.
• assert_transitive_impls
  Asserts that all transitive interfaces (the ones implemented by the $interface) are also implemented by the $implementor.
• checked_hash
  Ensures that the given $impl_ty implements [Field] and returns a [fnv1a128] hash for it, otherwise panics with understandable message.
• const_concat
  Concatenates const strs in a const context.
• format_type
  Formats the given [Type] and [WrappedValue] into a readable GraphQL type name.
• graphql_input_value
  Constructs InputValues via JSON-like syntax.
• graphql_value
  Constructs Values via JSON-like syntax.
• graphql_vars
  Constructs Variables via JSON-like 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
  An Object value
• Operation
• RootNode
  Root query node of a schema
• SchemaType
  Metadata for a schema

Enums

• DefaultScalarValue
  The default ScalarValue 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/90bd6ff72625173dd39a1f82cfad9336cfad8f65/src/utilities/getIntrospectionQuery.ts#L62)
• 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

• 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
  Parsing of an unstructured input value into a Rust data type.
• GraphQLInterface
  Maker trait for GraphQL interfaces.
• GraphQLObject
  Maker trait for GraphQL objects.
• 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.
• 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
  #[graphql_object] macro for generating a GraphQL object implementation for structs with computable field resolvers (declared via a regular Rust impl block).
• graphql_scalar
  #[graphql_scalar] macro.is interchangeable with #[derive(GraphQLScalar)] macro, and is used for deriving a GraphQL scalar implementation.
• graphql_subscription
  #[graphql_subscription] macro for generating a GraphQL subscription implementation for structs with computable field resolvers (declared via a regular Rust impl block).
• graphql_union
  #[graphql_union] macro for deriving a GraphQL union implementation for traits.

Derive Macros

• GraphQLEnum
  #[derive(GraphQLEnum)] macro for deriving a GraphQL enum implementation for Rust enums.
• GraphQLInputObject
  #[derive(GraphQLInputObject)] macro for deriving a GraphQL input object implementation for a Rust struct. Each non-ignored field type must itself be GraphQL input object or a GraphQL scalar.
• GraphQLInterface
  #[derive(GraphQLInterface)] macro for generating a GraphQL interface implementation for traits and its implementers.
• GraphQLObject
  #[derive(GraphQLObject)] macro for deriving a GraphQL object implementation for structs.
• GraphQLScalar
  #[derive(GraphQLScalar)] macro for deriving a GraphQL scalar implementation.
• GraphQLUnion
  #[derive(GraphQLUnion)] macro for deriving a GraphQL union implementation for enums and structs.
• ScalarValue
  #[derive(ScalarValue)] macro for deriving a ScalarValue implementation.