GraphQL

Interface for GraphQL API.

Note: This module is highly subject to change. We're still figuring where to draw the lines and what to expose.

Running queries

interpretQuery

Arguments

:: (Applicative m, HasResolver m api, HasObjectDefinition api)

=> Handler m api

Handler for the query. This links the query to the code you've written to handle it.

-> Text

The text of a query document. Will be parsed and then executed.

-> Maybe Name

An optional name for the operation within document to run. If Nothing, execute the only operation in the document. If Just "something", execute the query or mutation named "something".

-> VariableValues

Values for variables defined in the query document. A map of Variable to Value.

-> m Response

The outcome of running the query.

Interpet a GraphQL query.

Compiles then executes a GraphQL query.

interpretAnonymousQuery

Arguments

:: (Applicative m, HasResolver m api, HasObjectDefinition api)

=> Handler m api

Handler for the anonymous query.

-> Text

The text of the anonymous query. Should defined only a single, unnamed query operation.

-> m Response

The result of running the query.

Interpret an anonymous GraphQL query.

Anonymous queries have no name and take no variables.

data Response

GraphQL response.

A GraphQL response must:

• be a map
• have a "data" key iff the operation executed
• have an "errors" key iff the operation encountered errors
• not include "data" if operation failed before execution (e.g. syntax errors, validation errors, missing info)
• not have keys other than "data", "errors", and "extensions"

Other interesting things:

• Doesn't have to be JSON, but does have to have maps, strings, lists, and null
• Can also support bool, int, enum, and float
• Value of "extensions" must be a map

"data" must be null if an error was encountered during execution that prevented a valid response.

"errors"

• must be a non-empty list
• each error is a map with "message", optionally "locations" key with list of locations
• locations are maps with 1-indexed "line" and "column" keys.

Constructors

Success Object

PreExecutionFailure Errors

ExecutionFailure Errors

PartialSuccess Object Errors

Instances

Eq Response

Methods

(==) :: Response -> Response -> Bool

(/=) :: Response -> Response -> Bool

Ord Response

Methods

compare :: Response -> Response -> Ordering

(<) :: Response -> Response -> Bool

(<=) :: Response -> Response -> Bool

(>) :: Response -> Response -> Bool

(>=) :: Response -> Response -> Bool

max :: Response -> Response -> Response

min :: Response -> Response -> Response

Show Response

Methods

showsPrec :: Int -> Response -> ShowS

show :: Response -> String

showList :: [Response] -> ShowS

ToJSON Response

Methods

toJSON :: Response -> Value

toEncoding :: Response -> Encoding

toJSONList :: [Response] -> Value

toEncodingList :: [Response] -> Encoding

ToValue Response

Methods

toValue :: Response -> Value' ConstScalar

Preparing queries then running them

makeSchema :: forall api. HasObjectDefinition api => Either QueryError Schema

Create a GraphQL schema.

compileQuery :: Schema -> Text -> Either QueryError (QueryDocument VariableValue)

Turn some text into a valid query document.

executeQuery

Arguments

:: (HasResolver m api, Applicative m, HasObjectDefinition api)

=> Handler m api

Handler for the query. This links the query to the code you've written to handle it.

-> QueryDocument VariableValue

A validated query document. Build one with compileQuery.

-> Maybe Name

An optional name. If Nothing, then executes the only operation in the query. If Just "something", executes the query named @"something".

-> VariableValues

Values for variables defined in the query document. A map of Variable to Value.

-> m Response

The outcome of running the query.

Execute a GraphQL query.

data QueryError

Errors that can happen while processing a query document.

Instances

Eq QueryError

Methods

(==) :: QueryError -> QueryError -> Bool

(/=) :: QueryError -> QueryError -> Bool

Show QueryError

Methods

showsPrec :: Int -> QueryError -> ShowS

show :: QueryError -> String

showList :: [QueryError] -> ShowS

GraphQLError QueryError

Methods

formatError :: QueryError -> Text

toError :: QueryError -> Error

data Schema

An entire GraphQL schema.

This is very much a work in progress. Currently, the only thing we provide is a dictionary mapping type names to their definitions.

Instances

Eq Schema

Methods

(==) :: Schema -> Schema -> Bool

(/=) :: Schema -> Schema -> Bool

Ord Schema

Methods

compare :: Schema -> Schema -> Ordering

(<) :: Schema -> Schema -> Bool

(<=) :: Schema -> Schema -> Bool

(>) :: Schema -> Schema -> Bool

(>=) :: Schema -> Schema -> Bool

max :: Schema -> Schema -> Schema

min :: Schema -> Schema -> Schema

Show Schema

Methods

showsPrec :: Int -> Schema -> ShowS

show :: Schema -> String

showList :: [Schema] -> ShowS

type VariableValues = Map Variable Value

A map of variables to their values.

In GraphQL the variable values are not part of the query itself, they are instead passed in through a separate channel. Create a VariableValues from this other channel and pass it to substituteVariables.

GraphQL allows the values of variables to be specified, but doesn't provide a way for doing so in the language.

type Value = Value' ConstScalar

A GraphQL value which contains no variables.