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Published March 7, 2024

Graphql C# (How It Works For Developers)

GraphQL has gained significant popularity in recent years as a powerful alternative to traditional REST APIs. Its flexibility, efficiency, and ability to address specific data-fetching needs make it a preferred choice for many developers.

In the C# ecosystem, integrating GraphQL into applications has become increasingly popular, thanks to libraries and frameworks that simplify the process.

In this article, we'll explore C# GraphQL, understand its key concepts, and learn how to implement GraphQL in C# applications.

Understanding GraphQL Basics

GraphQLserves as a specialized query language designed for APIs, enabling clients to precisely request only the data essential for their needs, thereby optimizing data retrieval and enhancing efficiency in communication between clients and servers.

Unlike REST, where endpoints are fixed and predefined, GraphQL schema definition language exposes a single GraphQL endpoint, and clients define the structure of the response. This flexibility of GraphQL service enables efficient data fetching and reduces over-fetching or under-fetching of data.

Key Concepts

1. Schema: The schema defines the types of data that can be queried and the relationships between them. It serves as a contract between the client and the server.

2. Query: Clients send a query to request specific data. The query structure mirrors the expected response structure, allowing clients to request exactly what they need. There is no query class for this purpose. A simple string-type query with exactly the fields required is used to make a request.

3. Mutation: Mutations are used to modify data on the server. They are similar to queries but are intended for write operations.

4. Subscription: Subscriptions enable real-time data updates. This allows clients to subscribe to specific events, and the server pushes updates when relevant data changes.

Integrating GraphQL in C#

To work with GraphQL in C#, developers can leverage libraries like HotChocolate and GraphQL.NET. These libraries simplify the process of creating GraphQL servers and clients, making it easier for C# developers to adopt GraphQL in their .NET Core C# projects.

HotChocolate

HotChocolate is a GraphQL implementation of server-side runtime for .NET and C#. It supports ASP.NET Core and provides a range of features for building robust GraphQL requests APIs.

Installation

dotnet add package HotChocolate.AspNetCore

dotnet add package HotChocolate.AspNetCore

'INSTANT VB TODO TASK: The following line uses invalid syntax:
'dotnet add package HotChocolate.AspNetCore

Creating a GraphQL Schema

Define GraphQL types and queries using C# classes. For example:

public class Query
{
    [GraphQLName("hello")]
    public string GetHello() => "Hello, GraphQL!";
}

public class Query
{
    [GraphQLName("hello")]
    public string GetHello() => "Hello, GraphQL!";
}

Public Class Query
	<GraphQLName("hello")>
	Public Function GetHello() As String
		Return "Hello, GraphQL!"
	End Function
End Class

Setting Up the Server

Configure the GraphQL server in the Startup.cs file:

services
    .AddGraphQLServer()
    .AddQueryType<Query>();

services
    .AddGraphQLServer()
    .AddQueryType<Query>();

services.AddGraphQLServer().AddQueryType(Of Query)()

Running the Server

Start the server in the Main method:

webBuilder.UseStartup<Startup>();

webBuilder.UseStartup<Startup>();

webBuilder.UseStartup(Of Startup)()

GraphQL.NET

GraphQL.NET is another popular library for working with GraphQL backend in C#. It provides a set of tools for building GraphQL schemas, executing queries, and handling resolvers.

Installation

dotnet add package GraphQL

dotnet add package GraphQL

'INSTANT VB TODO TASK: The following line uses invalid syntax:
'dotnet add package GraphQL

Schema Definition

Define GraphQL types and queries using C# classes, similar to HotChocolate.

public class HelloWorldQuery : ObjectGraphType
{
    public HelloWorldQuery()
    {
        Field<StringGraphType>(
            "hello",
            resolve: context => "Hello, GraphQL!"
        );
    }
}

public class HelloWorldQuery : ObjectGraphType
{
    public HelloWorldQuery()
    {
        Field<StringGraphType>(
            "hello",
            resolve: context => "Hello, GraphQL!"
        );
    }
}

Public Class HelloWorldQuery
	Inherits ObjectGraphType

	Public Sub New()
		Field(Of StringGraphType)("hello", resolve:= Function(context) "Hello, GraphQL!")
	End Sub
End Class

Setting Up the Server

Configure the GraphQL server in the Startup.cs file:

var schema = new Schema { Query = new HelloWorldQuery() };
app.UseGraphQL<ISchema>("/graphql", schema);

var schema = new Schema { Query = new HelloWorldQuery() };
app.UseGraphQL<ISchema>("/graphql", schema);

Dim schema As New Schema With {.Query = New HelloWorldQuery()}
app.UseGraphQL(Of ISchema)("/graphql", schema)

Running the Server

Start the server in the Main method:

CreateHostBuilder(args).Build().Run();

CreateHostBuilder(args).Build().Run();

CreateHostBuilder(args).Build().Run()

Building a GraphQL Client in C#

For building GraphQL clients in C#, you can use libraries like GraphQL.Client or StrawberryShake.

GraphQL.Client

GraphQL.Client is a lightweight GraphQL client for .NET. It simplifies sending GraphQL queries and handling responses.

Installation

dotnet add package GraphQL.Client

dotnet add package GraphQL.Client

'INSTANT VB TODO TASK: The following line uses invalid syntax:
'dotnet add package GraphQL.Client

Sending Queries

var graphQLClient = new GraphQLHttpClient("https://example.com/graphql");
var response = await graphQLClient.SendQueryAsync("query { hello world }");

var graphQLClient = new GraphQLHttpClient("https://example.com/graphql");
var response = await graphQLClient.SendQueryAsync("query { hello world }");

Dim graphQLClient = New GraphQLHttpClient("https://example.com/graphql")
Dim response = Await graphQLClient.SendQueryAsync("query { hello world }")

StrawberryShake

StrawberryShake is a more feature-rich GraphQL client that supports code generation for strongly typed queries.

Installation

dotnet add package StrawberryShake.CodeGeneration.CSharp

dotnet add package StrawberryShake.CodeGeneration.CSharp

'INSTANT VB TODO TASK: The following line uses invalid syntax:
'dotnet add package StrawberryShake.CodeGeneration.CSharp

Defining Queries

Write GraphQL queries in .graphql files and generate C# code using the dotnet graphql CLI command.

Using Generated Code

Use the generated C# classes to interact with the GraphQL API.

var result = await client.SendQueryAsync(
    new GetHelloQuery()
);

var result = await client.SendQueryAsync(
    new GetHelloQuery()
);

Dim result = Await client.SendQueryAsync(New GetHelloQuery())

Introducing IronPDF

IronPDF is a popular C# library for working with PDF files, allowing developers to create, manipulate, and process PDF documents seamlessly. It simplifies tasks such as generating PDFs from HTML, images, and other formats, as well as adding annotations, watermarks, and more.

Setting up IronPDF

To get started with IronPDF, you can install the library via NuGet Package Manager Console:

Install-Package IronPdf

Creating a PDF

Using IronPDF is straightforward. For instance, to generate a PDF from an HTML string:

var renderer = new IronPdf.HtmlToPdf();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello, IronPDF!</h1>");
pdf.SaveAs("output.pdf");

var renderer = new IronPdf.HtmlToPdf();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello, IronPDF!</h1>");
pdf.SaveAs("output.pdf");

Dim renderer = New IronPdf.HtmlToPdf()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello, IronPDF!</h1>")
pdf.SaveAs("output.pdf")

Advanced Features

IronPDF provides advanced features like adding headers, footers, watermarks, and even converting PDFs to images. It is a versatile tool for handling various PDF-related tasks in C# applications. For more features and implementation, please visit this code examples page.

Using GraphQL with IronPDF

While IronPDF itself doesn't have direct integration with GraphQL, it's important to note that the primary use cases for these technologies differ. GraphQL is typically employed for efficient data querying and manipulation, whereas IronPDF focuses on PDF document generation and manipulation.

However, it is conceivable to use GraphQL query language in conjunction with IronPDF within a larger application. For instance, you might have a C# application that uses GraphQL to fetch dynamic content or data from a server. Once the data is retrieved, IronPDF could be employed to dynamically generate a PDF document based on that data.

Here's a hypothetical code example where a GraphQL query fetches data, and IronPDF is used to generate a PDF report:

// Assume you have a GraphQL client for querying data
var graphQLClient = new MyGraphQLClient();
// Fetch data using GraphQL
var data = await graphQLClient.SendQueryAsync("query { someData }");
// Use IronPDF to generate a PDF based on the retrieved data
var pdfRenderer = new ChromePdfRenderer();
var htmlContent = $"<h1>Report for {data}</h1>";
var pdf = pdfRenderer.RenderHtmlAsPdf(htmlContent);
pdf.SaveAs("report.pdf");

// Assume you have a GraphQL client for querying data
var graphQLClient = new MyGraphQLClient();
// Fetch data using GraphQL
var data = await graphQLClient.SendQueryAsync("query { someData }");
// Use IronPDF to generate a PDF based on the retrieved data
var pdfRenderer = new ChromePdfRenderer();
var htmlContent = $"<h1>Report for {data}</h1>";
var pdf = pdfRenderer.RenderHtmlAsPdf(htmlContent);
pdf.SaveAs("report.pdf");

' Assume you have a GraphQL client for querying data
Dim graphQLClient = New MyGraphQLClient()
' Fetch data using GraphQL
Dim data = Await graphQLClient.SendQueryAsync("query { someData }")
' Use IronPDF to generate a PDF based on the retrieved data
Dim pdfRenderer = New ChromePdfRenderer()
Dim htmlContent = $"<h1>Report for {data}</h1>"
Dim pdf = pdfRenderer.RenderHtmlAsPdf(htmlContent)
pdf.SaveAs("report.pdf")

In the above-proposed code, GraphQL is employed to obtain dynamic data, and IronPDF is subsequently used to generate a PDF report based on that data. While the two technologies are not directly integrated, they can complement each other within a broader application architecture.

Conclusion

Integrating GraphQL into C# applications provides developers with a flexible and efficient way to handle data. Whether building GraphQL servers with HotChocolate or GraphQL.NET, or creating GraphQL clients with GraphQL.Client or StrawberryShake, C# developers have powerful tools at their disposal.

As GraphQL continues to evolve, its adoption in the C# ecosystem is likely to grow, offering even more possibilities for building modern and scalable applications.

In summary, IronPDF is a powerful tool for PDF manipulation in C# applications, and while it doesn't have built-in support for GraphQL, the two technologies can be used together to enhance the functionality of your applications.

For more information on IronPDF and its complete functionality, please visit the official documentationand API Reference.

IronPDF offers a free trialpage here. Download the library from hereand give it a try.