api-reference.md

API Reference

This document provides comprehensive API documentation for all classes, attributes, and methods in the Lambda.GraphQL library.

Table of Contents

• Core Attributes
  • GraphQLTypeAttribute
  • GraphQLFieldAttribute
  • GraphQLArgumentAttribute
• Operation Attributes
  • GraphQLQueryAttribute
  • GraphQLMutationAttribute
  • GraphQLSubscriptionAttribute
• Advanced Type Attributes
  • GraphQLUnionAttribute
  • GraphQLEnumValueAttribute
• Modifier Attributes
  • GraphQLIgnoreAttribute
  • GraphQLNonNullAttribute
  • GraphQLTimestampAttribute
• Directive Attributes
  • GraphQLDirectiveAttribute
  • GraphQLApplyDirectiveAttribute
  • GraphQLAuthDirectiveAttribute
• Configuration Attributes
  • GraphQLSchemaAttribute
  • GraphQLResolverAttribute
  • GraphQLScalarAttribute
• Enums and Types
  • GraphQLTypeKind
  • AuthMode
  • DirectiveLocation

---

Core Attributes

GraphQLTypeAttribute

Marks a class, interface, or enum as a GraphQL type.

Namespace: Lambda.GraphQL.Attributes
Targets: Class, Interface, Enum

Constructors

public GraphQLTypeAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL type name. If null, uses the C# type name.
Description	string?	Description for the GraphQL type.
Kind	GraphQLTypeKind	The kind of GraphQL type (Object, Input, Interface, Enum, Union).

Examples

// Basic object type
[GraphQLType("Product")]
public class Product { }

// Input type with description
[GraphQLType("CreateProductInput", Kind = GraphQLTypeKind.Input)]
public class CreateProductInput { }

// Interface type
[GraphQLType("Node", Kind = GraphQLTypeKind.Interface)]
public interface INode { }

// Enum type with custom name
[GraphQLType("ProductCategory")]
public enum Category { }

GraphQLFieldAttribute

Marks a property or field as a GraphQL field.

Namespace: Lambda.GraphQL.Attributes
Targets: Property, Field

Constructors

public GraphQLFieldAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL field name. If null, uses the property name.
Description	string?	Description for the GraphQL field.
Deprecated	bool	Whether the field is deprecated.
DeprecationReason	string?	Reason for deprecation.

Examples

public class Product
{
    [GraphQLField(Description = "Product identifier")]
    public Guid Id { get; set; }
    
    [GraphQLField("displayName", Description = "Product display name")]
    public string Name { get; set; }
    
    [GraphQLField(Deprecated = true, DeprecationReason = "Use displayPrice instead")]
    public decimal Price { get; set; }
}

GraphQLArgumentAttribute

Marks a method parameter as a GraphQL argument.

Namespace: Lambda.GraphQL.Attributes
Targets: Parameter

Constructors

public GraphQLArgumentAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL argument name. If null, uses the parameter name.
Description	string?	Description for the GraphQL argument.

Examples

[GraphQLQuery("getProduct")]
public async Task<Product> GetProduct(
    [GraphQLArgument(Description = "Product ID")] Guid id,
    [GraphQLArgument("includeDetails")] bool details = false)
{
    // Implementation
}

---

Operation Attributes

GraphQLQueryAttribute

Marks a Lambda function as a GraphQL query operation.

Namespace: Lambda.GraphQL.Attributes
Targets: Method

Constructors

public GraphQLQueryAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL query name. If null, uses the method name.
Description	string?	Description for the GraphQL query.

Examples

[LambdaFunction]
[GraphQLQuery("getProduct", Description = "Get a product by ID")]
public async Task<Product> GetProduct(Guid id) { }

[LambdaFunction]
[GraphQLQuery] // Uses method name "ListProducts"
public async Task<List<Product>> ListProducts() { }

GraphQLMutationAttribute

Marks a Lambda function as a GraphQL mutation operation.

Namespace: Lambda.GraphQL.Attributes
Targets: Method

Constructors

public GraphQLMutationAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL mutation name. If null, uses the method name.
Description	string?	Description for the GraphQL mutation.

Examples

[LambdaFunction]
[GraphQLMutation("createProduct", Description = "Create a new product")]
public async Task<Product> CreateProduct(CreateProductInput input) { }

GraphQLSubscriptionAttribute

Marks a Lambda function as a GraphQL subscription operation.

Namespace: Lambda.GraphQL.Attributes
Targets: Method

Constructors

public GraphQLSubscriptionAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL subscription name. If null, uses the method name.
Description	string?	Description for the GraphQL subscription.

Examples

[LambdaFunction]
[GraphQLSubscription("orderStatusChanged", Description = "Subscribe to order status changes")]
public async Task<Order> OrderStatusChanged(Guid orderId) { }

---

Advanced Type Attributes

GraphQLUnionAttribute

Marks a class as a GraphQL union type with specified member types.

Namespace: Lambda.GraphQL.Attributes
Targets: Class

Constructors

public GraphQLUnionAttribute(string? name = null, params string[] memberTypes)

Properties

Property	Type	Description
Name	string?	The GraphQL union name. If null, uses the class name.
Description	string?	Description for the GraphQL union.
MemberTypes	string[]	Array of member type names for the union.

Examples

[GraphQLUnion("SearchResult", "Product", "User", "Order")]
public class SearchResult { }

[LambdaFunction]
[GraphQLQuery("search")]
public async Task<List<object>> Search(string term)
{
    // Return mixed types - AppSync handles union resolution
    return results;
}

GraphQLEnumValueAttribute

Provides metadata for GraphQL enum values.

Namespace: Lambda.GraphQL.Attributes
Targets: Field (enum members)

Constructors

public GraphQLEnumValueAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL enum value name. If null, uses the enum member name.
Description	string?	Description for the GraphQL enum value.
Deprecated	bool	Whether the enum value is deprecated.
DeprecationReason	string?	Reason for deprecation.

Examples

[GraphQLType("OrderStatus")]
public enum OrderStatus
{
    [GraphQLEnumValue(Description = "Order is pending")]
    Pending,
    
    [GraphQLEnumValue(Deprecated = true, DeprecationReason = "Use Shipped instead")]
    Processing,
    
    Shipped
}

---

Modifier Attributes

GraphQLIgnoreAttribute

Excludes a property or field from the GraphQL schema.

Namespace: Lambda.GraphQL.Attributes
Targets: Property, Field

Examples

public class Product
{
    [GraphQLField]
    public string Name { get; set; }
    
    [GraphQLIgnore]
    public DateTime InternalTimestamp { get; set; } // Not included in schema
}

GraphQLNonNullAttribute

Overrides nullability to make a field non-null in GraphQL.

Namespace: Lambda.GraphQL.Attributes
Targets: Property, Field

Examples

public class Product
{
    [GraphQLField]
    [GraphQLNonNull]
    public string? RequiredField { get; set; } // Becomes String! in GraphQL
}

GraphQLTimestampAttribute

Marks a field as an AWS timestamp scalar (AWSTimestamp).

Namespace: Lambda.GraphQL.Attributes
Targets: Property, Field

Examples

public class User
{
    [GraphQLField(Description = "Account creation timestamp (Unix seconds)")]
    [GraphQLTimestamp]
    public long CreatedAtTimestamp { get; set; } // Becomes AWSTimestamp! in GraphQL
}

---

Directive Attributes

GraphQLDirectiveAttribute

Defines a custom GraphQL directive.

Namespace: Lambda.GraphQL.Attributes
Targets: Assembly
AllowMultiple: true

Constructors

public GraphQLDirectiveAttribute(string name)

Properties

Property	Type	Description
Name	string	The directive name.
Description	string?	Description for the directive.
Locations	DirectiveLocation	Where the directive can be applied.
Arguments	string?	Directive arguments definition.

Examples

[assembly: GraphQLDirective("auth", 
    Locations = DirectiveLocation.FieldDefinition,
    Arguments = "requires: String!")]

GraphQLApplyDirectiveAttribute

Applies a directive to a GraphQL type or field.

Namespace: Lambda.GraphQL.Attributes
Targets: Class, Property, Method, Field
AllowMultiple: true

Constructors

public GraphQLApplyDirectiveAttribute(string directiveName)

Properties

Property	Type	Description
DirectiveName	string	The name of the directive to apply.
Arguments	string?	Arguments for the directive.

Examples

[GraphQLField]
[GraphQLApplyDirective("auth", Arguments = "requires: \"ADMIN\"")]
public string AdminOnlyField { get; set; }

GraphQLAuthDirectiveAttribute

Applies AWS authentication directives to GraphQL types or fields.

Namespace: Lambda.GraphQL.Attributes
Targets: Class, Property, Method, Field, Enum
AllowMultiple: true

Constructors

public GraphQLAuthDirectiveAttribute(AuthMode authMode)

Properties

Property	Type	Description
AuthMode	AuthMode	The AWS authentication mode.
CognitoGroups	string?	Comma-separated list of Cognito groups.
IamResource	string?	IAM resource ARN.

Examples

[GraphQLType("AdminData")]
[GraphQLAuthDirective(AuthMode.UserPools, CognitoGroups = "admin")]
public class AdminData { }

[GraphQLField]
[GraphQLAuthDirective(AuthMode.IAM, IamResource = "arn:aws:dynamodb:*")]
public string SensitiveData { get; set; }

---

Configuration Attributes

GraphQLSchemaAttribute

Provides assembly-level schema configuration.

Namespace: Lambda.GraphQL.Attributes
Targets: Assembly

Constructors

public GraphQLSchemaAttribute(string name)

Properties

Property	Type	Description
Name	string	The schema name.
Description	string?	Description for the schema.
Version	string?	Schema version.

Examples

[assembly: GraphQLSchema("ProductsAPI", 
    Description = "Product catalog GraphQL API",
    Version = "1.0.0")]

GraphQLResolverAttribute

Configures resolver settings for GraphQL operations.

Namespace: Lambda.GraphQL.Attributes
Targets: Method

Properties

Property	Type	Description
DataSource	string?	The AppSync data source name.
Kind	string?	Resolver kind ("Unit" or "Pipeline").
RequestMapping	string?	Custom request mapping template.
ResponseMapping	string?	Custom response mapping template.
Functions	string[]?	Pipeline function names (for pipeline resolvers).

Examples

[LambdaFunction]
[GraphQLQuery("getProduct")]
[GraphQLResolver(DataSource = "ProductsLambda")]
public async Task<Product> GetProduct(Guid id) { }

[LambdaFunction]
[GraphQLMutation("processOrder")]
[GraphQLResolver(Kind = "Pipeline", Functions = new[] { "ValidateOrder", "ProcessPayment", "CreateOrder" })]
public async Task<Order> ProcessOrder(OrderInput input) { }

GraphQLScalarAttribute

Marks a class as a custom GraphQL scalar type.

Namespace: Lambda.GraphQL.Attributes
Targets: Class, Struct

Constructors

public GraphQLScalarAttribute(string? name = null)

Properties

Property	Type	Description
Name	string?	The GraphQL scalar name. If null, uses the class name.
Description	string?	Description for the scalar.

Examples

[GraphQLScalar("DateTime")]
public class CustomDateTime { }

---

Enums and Types

GraphQLTypeKind

Specifies the kind of GraphQL type.

Namespace: Lambda.GraphQL.Attributes

Values

Value	Description
Object	GraphQL object type (default)
Input	GraphQL input type
Interface	GraphQL interface type
Enum	GraphQL enum type
Union	GraphQL union type

AuthMode

AWS AppSync authentication modes.

Namespace: Lambda.GraphQL.Attributes

Values

Value	Description
ApiKey	API key authentication
UserPools	Cognito User Pools authentication
IAM	AWS IAM authentication
OpenIDConnect	OpenID Connect authentication
Lambda	Lambda authorizer authentication

DirectiveLocation

Specifies where a directive can be applied.

Namespace: Lambda.GraphQL.Attributes

Values

Value	Description
Query	Query operation
Mutation	Mutation operation
Subscription	Subscription operation
Field	Field selection
FragmentDefinition	Fragment definition
FragmentSpread	Fragment spread
InlineFragment	Inline fragment
VariableDefinition	Variable definition
Schema	Schema definition
Scalar	Scalar type definition
Object	Object type definition
FieldDefinition	Field definition
ArgumentDefinition	Argument definition
Interface	Interface type definition
Union	Union type definition
Enum	Enum type definition
EnumValue	Enum value definition
InputObject	Input object type definition
InputFieldDefinition	Input field definition

---

Type Mappings

Lambda.GraphQL automatically maps C# types to GraphQL types:

C# Type	GraphQL Type	Notes
string	String
int, long	Int
float, double, decimal	Float
bool	Boolean
Guid	ID
DateTime	AWSDateTime	AWS AppSync scalar
DateTimeOffset	AWSDateTime	AWS AppSync scalar
DateOnly	AWSDate	AWS AppSync scalar
TimeOnly	AWSTime	AWS AppSync scalar
System.Net.Mail.MailAddress	AWSEmail	AWS AppSync scalar
System.Uri	AWSURL	AWS AppSync scalar
System.Net.IPAddress	AWSIPAddress	AWS AppSync scalar
System.Text.Json.JsonElement	AWSJSON	AWS AppSync scalar
T? (nullable)	T	Nullable in GraphQL
List<T>, T[]	[T]	GraphQL list
Custom classes	Custom Object/Input types
Enums	GraphQL Enums

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For more examples and usage patterns, see the Attributes Guide and Examples.