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.
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.
Utilities for building HTTP endpoints in a library-agnostic manner
Provides GraphQLType implementations for some external types
Types used to describe a
Query parser and language utilities
Expose GraphQL interfaces
Expose GraphQL objects
Expose GraphQL scalars
Expose GraphQL unions
Construct JSON-like values by using JSON syntax
Field argument container
Utility type to define read-only schemas
Error type for errors that occur during query execution
Query execution engine
Error type for errors that occur during field resolution
An ID as defined by the GraphQL specification
An argument passed into the query
A selection performed by a query
A Object value
A type registry used to build schemas
Root query node of a schema
Query validation error
An enum that describes if a field is available in all types of the interface or only in a certain subtype
An error that prevented query execution
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.
A JSON-like value that can is used as argument in the query execution
Entry in a GraphQL selection set
A type literal in the syntax tree
GraphQL type kind
Serializable value returned from query and field execution.
Marker trait for types that can act as context objects for
Conversion trait for context types
Parse an unstructured input value into a Rust data type.
Primary trait used to expose Rust types in a GraphQL schema
Custom error handling trait to enable Error types other than
A set of common methods for
Losslessly clones a Rust data type into an InputValue.
Execute a query in a provided schema
The result of resolving an unspecified field
The result of resolving the value of a field of type
The map of variables used for substitution during query execution