Crate juniper

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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.

Web Frameworks

rocket
iron

API Stability

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

Re-exports

pub use http::graphiql;

Modules

http

Utilities for building HTTP endpoints in a library-agnostic manner

integrations

Provides GraphQLType implementations for some external types

Macros

graphql_interface

Expose GraphQL interfaces

graphql_object

Expose GraphQL objects

graphql_scalar

Expose GraphQL scalars

graphql_union

Expose GraphQL unions

graphql_value

Construct JSON-like values by using JSON syntax

Structs

Arguments

Field argument container

EmptyMutation

Utility type to define read-only schemas

ExecutionError

Error type for errors that occur during query execution

Executor

Query execution engine

FieldError

Error type for errors that occur during field resolution

ID

An ID as defined by the GraphQL specification

LookAheadArgument

An argument passed into the query

LookAheadSelection

A selection performed by a query

Object

A Object value

Registry

A type registry used to build schemas

RootNode

Root query node of a schema

RuleError

Query validation error

Enums

Applies

An enum that describes if a field is available in all types of the interface or only in a certain subtype

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.

LookAheadValue

A JSON-like value that can is used as argument in the query execution

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.