Crate juniper

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§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:

§Web server frameworks

§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::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::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.

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