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Tools to help map a GraphQL schema to existing Java objects.
package graphql.kickstart.tools
import graphql.Scalars
import graphql.introspection.Introspection
import graphql.kickstart.tools.directive.SchemaGeneratorDirectiveHelper
import graphql.kickstart.tools.util.getDocumentation
import graphql.kickstart.tools.util.getExtendedFieldDefinitions
import graphql.kickstart.tools.util.unwrap
import graphql.language.*
import graphql.schema.*
import graphql.schema.idl.RuntimeWiring
import graphql.schema.idl.ScalarInfo
import graphql.schema.idl.SchemaGeneratorHelperExt
import graphql.schema.visibility.NoIntrospectionGraphqlFieldVisibility
import org.slf4j.LoggerFactory
import kotlin.reflect.KClass
/**
* Parses a GraphQL Schema and maps object fields to provided class methods.
*
* @author Andrew Potter
*/
class SchemaParser internal constructor(
scanResult: ScannedSchemaObjects,
private val options: SchemaParserOptions,
private val runtimeWiring: RuntimeWiring
) {
private val log = LoggerFactory.getLogger(javaClass)
companion object {
@JvmStatic
fun newParser() = SchemaParserBuilder()
}
private val dictionary = scanResult.dictionary
private val definitions = scanResult.definitions
private val customScalars = scanResult.customScalars
private val rootInfo = scanResult.rootInfo
private val fieldResolversByType = scanResult.fieldResolversByType
private val unusedDefinitions = scanResult.unusedDefinitions
private val extensionDefinitions = definitions.filterIsInstance()
private val inputExtensionDefinitions = definitions.filterIsInstance()
private val objectDefinitions = (definitions.filterIsInstance() - extensionDefinitions)
private val inputObjectDefinitions = (definitions.filterIsInstance() - inputExtensionDefinitions)
private val enumDefinitions = definitions.filterIsInstance()
private val interfaceDefinitions = definitions.filterIsInstance()
private val unionDefinitions = definitions.filterIsInstance()
private val permittedTypesForObject: Set = (objectDefinitions.map { it.name } +
enumDefinitions.map { it.name } +
interfaceDefinitions.map { it.name } +
unionDefinitions.map { it.name }).toSet()
private val permittedTypesForInputObject: Set =
(inputObjectDefinitions.map { it.name } + enumDefinitions.map { it.name }).toSet()
private val codeRegistryBuilder = GraphQLCodeRegistry.newCodeRegistry()
private val schemaGeneratorHelper = SchemaGeneratorHelperExt()
private val schemaGeneratorDirectiveHelper = SchemaGeneratorDirectiveHelper()
private val schemaDirectiveParameters = SchemaGeneratorDirectiveHelper.Parameters(null, runtimeWiring, null, codeRegistryBuilder)
/**
* Parses the given schema with respect to the given dictionary and returns GraphQL objects.
*/
fun parseSchemaObjects(): SchemaObjects {
if (!options.introspectionEnabled) {
codeRegistryBuilder.fieldVisibility(NoIntrospectionGraphqlFieldVisibility.NO_INTROSPECTION_FIELD_VISIBILITY)
}
// this overrides the above introspection enabled setting obviously... todo: add documentation
options.fieldVisibility?.let { codeRegistryBuilder.fieldVisibility(it) }
// Create GraphQL objects
val inputObjects: MutableList = mutableListOf()
inputObjectDefinitions.forEach {
if (inputObjects.none { io -> io.name == it.name }) {
inputObjects.add(createInputObject(it, inputObjects, mutableSetOf()))
}
}
val interfaces = interfaceDefinitions.map { createInterfaceObject(it, inputObjects) }
val objects = objectDefinitions.map { createObject(it, interfaces, inputObjects) }
val unions = unionDefinitions.map { createUnionObject(it, objects) }
val enums = enumDefinitions.map { createEnumObject(it) }
// Assign type resolver to interfaces now that we know all of the object types
interfaces.forEach { codeRegistryBuilder.typeResolver(it, InterfaceTypeResolver(dictionary.inverse(), it)) }
unions.forEach { codeRegistryBuilder.typeResolver(it, UnionTypeResolver(dictionary.inverse(), it)) }
// Find query type and mutation/subscription type (if mutation/subscription type exists)
val queryName = rootInfo.getQueryName()
val mutationName = rootInfo.getMutationName()
val subscriptionName = rootInfo.getSubscriptionName()
val query = objects.find { it.name == queryName }
?: throw SchemaError("Expected a Query object with name '$queryName' but found none!")
val mutation = objects.find { it.name == mutationName }
?: if (rootInfo.isMutationRequired()) throw SchemaError("Expected a Mutation object with name '$mutationName' but found none!") else null
val subscription = objects.find { it.name == subscriptionName }
?: if (rootInfo.isSubscriptionRequired()) throw SchemaError("Expected a Subscription object with name '$subscriptionName' but found none!") else null
val additionalObjects = objects.filter { o -> o != query && o != subscription && o != mutation }
val types = (additionalObjects.toSet() as Set) + inputObjects + enums + interfaces + unions
return SchemaObjects(query, mutation, subscription, types, codeRegistryBuilder, rootInfo.getDescription())
}
/**
* Parses the given schema with respect to the given dictionary and returns a GraphQLSchema
*/
fun makeExecutableSchema(): GraphQLSchema = parseSchemaObjects().toSchema()
/**
* Returns any unused type definitions that were found in the schema
*/
@Suppress("unused")
fun getUnusedDefinitions(): Set> = unusedDefinitions
private fun createObject(objectDefinition: ObjectTypeDefinition, interfaces: List, inputObjects: List): GraphQLObjectType {
val name = objectDefinition.name
val builder = GraphQLObjectType.newObject()
.name(name)
.definition(objectDefinition)
.description(getDocumentation(objectDefinition, options))
builder.withDirectives(*buildDirectives(objectDefinition.directives, Introspection.DirectiveLocation.OBJECT))
objectDefinition.implements.forEach { implementsDefinition ->
val interfaceName = (implementsDefinition as TypeName).name
builder.withInterface(interfaces.find { it.name == interfaceName }
?: throw SchemaError("Expected interface type with name '$interfaceName' but found none!"))
}
objectDefinition.getExtendedFieldDefinitions(extensionDefinitions).forEach { fieldDefinition ->
builder.field { field ->
createField(field, fieldDefinition, inputObjects)
codeRegistryBuilder.dataFetcher(
FieldCoordinates.coordinates(objectDefinition.name, fieldDefinition.name),
fieldResolversByType[objectDefinition]?.get(fieldDefinition)?.createDataFetcher()
?: throw SchemaError("No resolver method found for object type '${objectDefinition.name}' and field '${fieldDefinition.name}', this is most likely a bug with graphql-java-tools")
)
val wiredField = field.build()
GraphQLFieldDefinition.Builder(wiredField)
.clearArguments()
.arguments(wiredField.arguments)
}
}
val objectType = builder.build()
val directiveHelperParameters = SchemaGeneratorDirectiveHelper.Parameters(null, runtimeWiring, null, codeRegistryBuilder)
return schemaGeneratorDirectiveHelper.onObject(objectType, directiveHelperParameters)
}
private fun createInputObject(definition: InputObjectTypeDefinition, inputObjects: List,
referencingInputObjects: MutableSet): GraphQLInputObjectType {
val extensionDefinitions = inputExtensionDefinitions.filter { it.name == definition.name }
val builder = GraphQLInputObjectType.newInputObject()
.name(definition.name)
.definition(definition)
.extensionDefinitions(extensionDefinitions)
.description(getDocumentation(definition, options))
builder.withDirectives(*buildDirectives(definition.directives, Introspection.DirectiveLocation.INPUT_OBJECT))
referencingInputObjects.add(definition.name)
(extensionDefinitions + definition).forEach {
it.inputValueDefinitions.forEach { inputDefinition ->
val fieldBuilder = GraphQLInputObjectField.newInputObjectField()
.name(inputDefinition.name)
.definition(inputDefinition)
.description(getDocumentation(inputDefinition, options))
.apply { inputDefinition.defaultValue?.let { v -> defaultValueLiteral(v) } }
.type(determineInputType(inputDefinition.type, inputObjects, referencingInputObjects))
.withDirectives(*buildDirectives(inputDefinition.directives, Introspection.DirectiveLocation.INPUT_FIELD_DEFINITION))
builder.field(fieldBuilder.build())
}
}
return schemaGeneratorDirectiveHelper.onInputObjectType(builder.build(), schemaDirectiveParameters)
}
private fun createEnumObject(definition: EnumTypeDefinition): GraphQLEnumType {
val name = definition.name
val type = dictionary[definition]
?: throw SchemaError("Expected enum with name '$name' but found none!")
if (!type.unwrap().isEnum) throw SchemaError("Type '$name' is declared as an enum in the GraphQL schema but is not a Java enum!")
val builder = GraphQLEnumType.newEnum()
.name(name)
.definition(definition)
.description(getDocumentation(definition, options))
builder.withDirectives(*buildDirectives(definition.directives, Introspection.DirectiveLocation.ENUM))
definition.enumValueDefinitions.forEach { enumDefinition ->
val enumName = enumDefinition.name
val enumValue = type.unwrap().enumConstants.find { (it as Enum<*>).name == enumName }
?: throw SchemaError("Expected value for name '$enumName' in enum '${type.unwrap().simpleName}' but found none!")
val enumValueDirectives = buildDirectives(enumDefinition.directives, Introspection.DirectiveLocation.ENUM_VALUE)
getDeprecated(enumDefinition.directives).let {
val enumValueDefinition = GraphQLEnumValueDefinition.newEnumValueDefinition()
.name(enumName)
.description(getDocumentation(enumDefinition, options))
.value(enumValue)
.deprecationReason(it)
.withDirectives(*enumValueDirectives)
.definition(enumDefinition)
.build()
builder.value(enumValueDefinition)
}
}
return schemaGeneratorDirectiveHelper.onEnum(builder.build(), schemaDirectiveParameters)
}
private fun createInterfaceObject(interfaceDefinition: InterfaceTypeDefinition, inputObjects: List): GraphQLInterfaceType {
val name = interfaceDefinition.name
val builder = GraphQLInterfaceType.newInterface()
.name(name)
.definition(interfaceDefinition)
.description(getDocumentation(interfaceDefinition, options))
builder.withDirectives(*buildDirectives(interfaceDefinition.directives, Introspection.DirectiveLocation.INTERFACE))
interfaceDefinition.fieldDefinitions.forEach { fieldDefinition ->
builder.field { field -> createField(field, fieldDefinition, inputObjects) }
}
interfaceDefinition.implements.forEach { implementsDefinition ->
val interfaceName = (implementsDefinition as TypeName).name
builder.withInterface(GraphQLTypeReference(interfaceName))
}
return schemaGeneratorDirectiveHelper.onInterface(builder.build(), schemaDirectiveParameters)
}
private fun createUnionObject(definition: UnionTypeDefinition, types: List): GraphQLUnionType {
val name = definition.name
val builder = GraphQLUnionType.newUnionType()
.name(name)
.definition(definition)
.description(getDocumentation(definition, options))
builder.withDirectives(*buildDirectives(definition.directives, Introspection.DirectiveLocation.UNION))
getLeafUnionObjects(definition, types).forEach { builder.possibleType(it) }
return schemaGeneratorDirectiveHelper.onUnion(builder.build(), schemaDirectiveParameters)
}
private fun getLeafUnionObjects(definition: UnionTypeDefinition, types: List): List {
val name = definition.name
val leafObjects = mutableListOf()
definition.memberTypes.forEach {
val typeName = (it as TypeName).name
// Is this a nested union? If so, expand
val nestedUnion: UnionTypeDefinition? = unionDefinitions.find { otherDefinition -> typeName == otherDefinition.name }
if (nestedUnion != null) {
leafObjects.addAll(getLeafUnionObjects(nestedUnion, types))
} else {
leafObjects.add(types.find { type -> type.name == typeName }
?: throw SchemaError("Expected object type '$typeName' for union type '$name', but found none!"))
}
}
return leafObjects
}
private fun createField(field: GraphQLFieldDefinition.Builder, fieldDefinition: FieldDefinition, inputObjects: List): GraphQLFieldDefinition.Builder {
field
.name(fieldDefinition.name)
.description(getDocumentation(fieldDefinition, options))
.definition(fieldDefinition)
.apply { getDeprecated(fieldDefinition.directives)?.let { deprecate(it) } }
.type(determineOutputType(fieldDefinition.type, inputObjects))
fieldDefinition.inputValueDefinitions.forEach { argumentDefinition ->
val argumentBuilder = GraphQLArgument.newArgument()
.name(argumentDefinition.name)
.definition(argumentDefinition)
.description(getDocumentation(argumentDefinition, options))
.type(determineInputType(argumentDefinition.type, inputObjects, setOf()))
.apply { argumentDefinition.defaultValue?.let { defaultValueLiteral(it) } }
.withDirectives(*buildDirectives(argumentDefinition.directives, Introspection.DirectiveLocation.ARGUMENT_DEFINITION))
field.argument(argumentBuilder.build())
}
field.withDirectives(*buildDirectives(fieldDefinition.directives, Introspection.DirectiveLocation.FIELD_DEFINITION))
return field
}
private fun buildDirectives(directives: List, directiveLocation: Introspection.DirectiveLocation): Array {
val names = mutableSetOf()
val output = mutableListOf()
for (directive in directives) {
if (!names.contains(directive.name)) {
names.add(directive.name)
val graphQLDirective = GraphQLDirective.newDirective()
.name(directive.name)
.apply {
directive.arguments.forEach { arg ->
argument(GraphQLArgument.newArgument()
.name(arg.name)
.type(buildDirectiveInputType(arg.value))
.build())
}
}
.build()
output.add(schemaGeneratorHelper.buildAppliedDirective(directive, graphQLDirective, directiveLocation, runtimeWiring.comparatorRegistry))
}
}
return output.toTypedArray()
}
private fun buildDirectiveInputType(value: Value<*>): GraphQLInputType? {
when (value) {
is NullValue -> return Scalars.GraphQLString
is FloatValue -> return Scalars.GraphQLFloat
is StringValue -> return Scalars.GraphQLString
is IntValue -> return Scalars.GraphQLInt
is BooleanValue -> return Scalars.GraphQLBoolean
is ArrayValue -> return GraphQLList.list(buildDirectiveInputType(getArrayValueWrappedType(value)))
else -> throw SchemaError("Directive values of type '${value::class.simpleName}' are not supported yet.")
}
}
private fun getArrayValueWrappedType(value: ArrayValue): Value<*> {
// empty array [] is equivalent to [null]
if (value.values.isEmpty()) {
return NullValue.newNullValue().build()
}
// get rid of null values
val nonNullValueList = value.values.filter { v -> v !is NullValue }
// [null, null, ...] unwrapped is null
if (nonNullValueList.isEmpty()) {
return NullValue.newNullValue().build()
}
// make sure the array isn't polymorphic
val distinctTypes = nonNullValueList
.map { it::class.java }
.distinct()
if (distinctTypes.size > 1) {
throw SchemaError("Arrays containing multiple types of values are not supported yet.")
}
// peek at first value, value exists and is assured to be non-null
return nonNullValueList[0]
}
private fun determineOutputType(typeDefinition: Type<*>, inputObjects: List) =
determineType(GraphQLOutputType::class, typeDefinition, permittedTypesForObject, inputObjects) as GraphQLOutputType
private fun determineType(expectedType: KClass, typeDefinition: Type<*>, allowedTypeReferences: Set, inputObjects: List): GraphQLType =
when (typeDefinition) {
is ListType -> GraphQLList(determineType(expectedType, typeDefinition.type, allowedTypeReferences, inputObjects))
is NonNullType -> GraphQLNonNull(determineType(expectedType, typeDefinition.type, allowedTypeReferences, inputObjects))
is InputObjectTypeDefinition -> {
log.info("Create input object")
createInputObject(typeDefinition, inputObjects, mutableSetOf())
}
is TypeName -> {
val scalarType = customScalars[typeDefinition.name]
?: GRAPHQL_SCALARS[typeDefinition.name]
if (scalarType != null) {
scalarType
} else {
if (!allowedTypeReferences.contains(typeDefinition.name)) {
throw SchemaError("Expected type '${typeDefinition.name}' to be a ${expectedType.simpleName}, but it wasn't! " +
"Was a type only permitted for object types incorrectly used as an input type, or vice-versa?")
}
inputObjects.find { it.name == typeDefinition.name } ?: GraphQLTypeReference(typeDefinition.name)
}
}
else -> throw SchemaError("Unknown type: $typeDefinition")
}
private fun determineInputType(typeDefinition: Type<*>, inputObjects: List, referencingInputObjects: Set) =
determineInputType(GraphQLInputType::class, typeDefinition, permittedTypesForInputObject, inputObjects, referencingInputObjects) as GraphQLInputType
private fun determineInputType(expectedType: KClass,
typeDefinition: Type<*>, allowedTypeReferences: Set,
inputObjects: List,
referencingInputObjects: Set): GraphQLType =
when (typeDefinition) {
is ListType -> GraphQLList(determineType(expectedType, typeDefinition.type, allowedTypeReferences, inputObjects))
is NonNullType -> GraphQLNonNull(determineType(expectedType, typeDefinition.type, allowedTypeReferences, inputObjects))
is InputObjectTypeDefinition -> {
log.info("Create input object")
createInputObject(typeDefinition, inputObjects, referencingInputObjects as MutableSet)
}
is TypeName -> {
val scalarType = customScalars[typeDefinition.name]
?: GRAPHQL_SCALARS[typeDefinition.name]
if (scalarType != null) {
scalarType
} else {
if (!allowedTypeReferences.contains(typeDefinition.name)) {
throw SchemaError("Expected type '${typeDefinition.name}' to be a ${expectedType.simpleName}, but it wasn't! " +
"Was a type only permitted for object types incorrectly used as an input type, or vice-versa?")
}
val found = inputObjects.filter { it.name == typeDefinition.name }
if (found.size == 1) {
found[0]
} else {
val filteredDefinitions = inputObjectDefinitions.filter { it.name == typeDefinition.name }
if (filteredDefinitions.isNotEmpty()) {
val referencingInputObject = referencingInputObjects.find { it == typeDefinition.name }
if (referencingInputObject != null) {
GraphQLTypeReference(referencingInputObject)
} else {
val inputObject = createInputObject(filteredDefinitions[0], inputObjects, referencingInputObjects as MutableSet)
(inputObjects as MutableList).add(inputObject)
inputObject
}
} else {
// todo: handle enum type
GraphQLTypeReference(typeDefinition.name)
}
}
}
}
else -> throw SchemaError("Unknown type: $typeDefinition")
}
/**
* Returns an optional [String] describing a deprecated field/enum.
* If a deprecation directive was defined using the @deprecated directive,
* then a String containing either the contents of the 'reason' argument, if present, or a default
* message defined in [DEFAULT_DEPRECATION_MESSAGE] will be returned. Otherwise, `null` will be returned
* indicating no deprecation directive was found within the directives list.
*/
private fun getDeprecated(directives: List): String? =
getDirective(directives, "deprecated")?.let { directive ->
(directive.arguments.find { it.name == "reason" }?.value as? StringValue)?.value
?: DEFAULT_DEPRECATION_MESSAGE
}
private fun getDirective(directives: List, name: String): Directive? = directives.find {
it.name == name
}
}
class SchemaError(message: String, cause: Throwable? = null) : RuntimeException(message, cause)
val GRAPHQL_SCALARS = ScalarInfo.GRAPHQL_SPECIFICATION_SCALARS.associateBy { it.name }
const val DEFAULT_DEPRECATION_MESSAGE = "No longer supported"