This article will explain how to send XML requests to an API with ASP.NET MVC Core using the CREATE and AMEND operations. It will also provide some code examples and resources for further learning.
Table of Contents
What is XML and Why Use It?
XML stands for eXtensible Markup Language. It is a standard way of encoding data in a text format that is both human-readable and machine-readable. XML can be used to store and transport data between different systems or applications. XML can also be used to define the structure and rules of data, such as the data types, attributes, and relationships.
One of the advantages of using XML is that it is platform-independent and language-neutral. This means that XML data can be processed by any system or application that supports XML, regardless of the operating system or programming language. Another advantage of using XML is that it is self-describing and extensible. This means that XML data can contain metadata that describes the meaning and purpose of the data, and that new elements and attributes can be added without breaking the existing structure or rules.
What is an API and How Does It Work?
An API stands for Application Programming Interface. It is a set of rules and specifications that define how different systems or applications can communicate and exchange data. An API can be seen as a contract between a provider and a consumer of data. The provider of data is the system or application that exposes the API, and the consumer of data is the system or application that uses the API.
An API can have different formats and protocols, such as REST, SOAP, GraphQL, etc. In this article, we will focus on the REST format, which stands for Representational State Transfer. A REST API is based on the HTTP protocol, which is the standard protocol for web communication. A REST API uses HTTP methods, such as GET, POST, PUT, PATCH, DELETE, etc., to perform different operations on the data. A REST API also uses HTTP status codes, such as 200, 201, 400, 404, 500, etc., to indicate the success or failure of the operations.
A REST API can accept and return data in different formats, such as JSON, XML, HTML, etc. In this article, we will focus on the XML format, which is one of the most common formats for data exchange.
How to Send XML Requests to an API with ASP.NET MVC Core
ASP.NET MVC Core is a framework for building web applications using the Model-View-Controller (MVC) pattern. MVC is a design pattern that separates the application logic into three components: the model, the view, and the controller. The model represents the data and the business logic of the application. The view represents the user interface of the application. The controller handles the user requests and interacts with the model and the view.
To send XML requests to an API with ASP.NET MVC Core, we need to do the following steps:
- Install the Microsoft.AspNetCore.Mvc.Formatters.Xml NuGet package. This package provides the functionality to serialize and deserialize XML data in ASP.NET MVC Core.
- Configure the XML serializer formatter in the Startup class. This class is responsible for configuring the services and middleware of the application. In the ConfigureServices method, we need to call the AddXmlSerializerFormatters extension method on the services collection. This method adds the XmlSerializerInputFormatter and the XmlSerializerOutputFormatter to the application. These formatters are used to read and write XML data from and to the HTTP requests and responses.
- Create a model class that represents the data that we want to send or receive in XML format. This class should have public properties that match the elements and attributes of the XML data. We can also use data annotations, such as [XmlElement], [XmlAttribute], [XmlRoot], etc., to customize the XML serialization and deserialization of the class.
- Create a controller class that handles the HTTP requests and responses. This class should have a [Route] attribute that specifies the URL path of the controller. It should also have one or more action methods that have [HttpPost], [HttpPut], [HttpPatch], or [HttpDelete] attributes that specify the HTTP method of the action. These action methods should have a [Consumes(“application/xml”)] attribute that indicates that they expect XML data in the request body. They should also have a [Produces(“application/xml”)] attribute that indicates that they return XML data in the response body. The action methods should have a parameter that has a [FromBody] attribute that binds the XML data from the request body to the model class. The action methods should also return an IActionResult that contains the XML data of the model class.
- Use an HTTP client, such as Postman, to send XML requests to the API endpoint and receive XML responses. The HTTP client should set the Content-Type header to application/xml and the Accept header to application/xml. The HTTP client should also include the XML data in the request body.
Code Examples
The following code examples show how to send XML requests to an API with ASP.NET MVC Core using the CREATE and AMEND operations. The examples assume that we have an API that manages a list of books. Each book has an id, a title, an author, and a price. The CREATE operation adds a new book to the list, and the AMEND operation updates an existing book in the list.
Model Class
The following code shows the model class that represents a book:
using System.Xml.Serialization;
namespace XmlApiExample.Models
{
[XmlRoot("book")]
public class Book
{
[XmlAttribute("id")]
public int Id { get; set; }
[XmlElement("title")]
public string Title { get; set; }
[XmlElement("author")]
public string Author { get; set; }
[XmlElement("price")]
public decimal Price { get; set; }
}
}
Controller Class
The following code shows the controller class that handles the XML requests and responses:
using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
using System.Linq;
using XmlApiExample.Models;
namespace XmlApiExample.Controllers
{
[Route("api/books")]
[ApiController]
public class BooksController : ControllerBase
{
// A static list of books for demonstration purposes
private static readonly List<Book> books = new List<Book>
{
new Book { Id = 1, Title = "The Hitchhiker's Guide to the Galaxy", Author = "Douglas Adams", Price = 12.99M },
new Book { Id = 2, Title = "The Lord of the Rings", Author = "J.R.R. Tolkien", Price = 19.99M },
new Book { Id = 3, Title = "Harry Potter and the Philosopher's Stone", Author = "J.K. Rowling", Price = 9.99M }
};
// A static variable to generate new book ids
private static int nextId = 4;
// A method to create a new book
[HttpPost]
[Consumes("application/xml")]
[Produces("application/xml")]
public IActionResult Create([FromBody] Book book)
{
// Generate a new id for the book
book.Id = nextId++;
// Add the book to the list
books.Add(book);
// Return a 201 Created response with the book in the body
return CreatedAtAction(nameof(GetById), new { id = book.Id }, book);
}
// A method to amend an existing book
[HttpPut("{id}")]
[Consumes("application/xml")]
[Produces("application/xml")]
public IActionResult Amend(int id, [FromBody] Book book)
{
// Find the book with the given id in the list
var existingBook = books.FirstOrDefault(b => b.Id == id);
// If the book does not exist, return a 404 Not Found response
if (existingBook == null)
{
return NotFound();
}
// Update the properties of the existing book with the values from the request body
existingBook.Title = book.Title;
existingBook.Author = book.Author;
existingBook.Price = book.Price;
// Return a 200 OK response with the updated book in the body
return Ok(existingBook);
}
// A method to get a book by id
[HttpGet("{id}")]
[Produces("application/xml")]
public IActionResult GetById(int id)
{
// Find the book with the given id in the list
var book = books.FirstOrDefault(b => b.Id == id);
// If the book does not exist, return a 404 Not Found response
if (book == null)
{
return NotFound();
}
// Return a 200 OK response with the book in the body
return Ok(book);
}
}
}
Startup Class
The following code shows the Startup class that configures the XML serializer formatter:
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
namespace XmlApiExample
{
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers()
.AddXmlSerializerFormatters(); // Add the XML serializer formatter
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
}
HTTP Client
The following screenshots show how to use Postman to send XML requests to the API endpoint and receive XML responses.
How to Test the API
To test the API, we can use the following steps:
- Run the ASP.NET MVC Core application in Visual Studio or another IDE of your choice. This will launch the application on a local web server, such as http://localhost:5000.
- Open Postman or another HTTP client of your choice. Create a new request with the following settings:
- Method: POST
- URL: http://localhost:5000/api/books
- Headers: Content-Type: application/xml, Accept: application/xml
- Body: raw, XML
- Enter the following XML data in the body of the request:
<book>
<title>The Da Vinci Code</title>
<author>Dan Brown</author>
<price>14.99</price>
</book>
- Send the request and observe the response. You should see a 201 Created status code and the following XML data in the body of the response:
<book id="4">
<title>The Da Vinci Code</title>
<author>Dan Brown</author>
<price>14.99</price>
</book>
This means that the API has successfully created a new book with the given data and assigned it an id of 4.
- Create another request with the following settings:
- Method: PUT
- URL: http://localhost:5000/api/books/4
- Headers: Content-Type: application/xml, Accept: application/xml
- Body: raw, XML
- Enter the following XML data in the body of the request:
<book>
<title>The Da Vinci Code</title>
<author>Dan Brown</author>
<price>12.99</price>
</book>
- Send the request and observe the response. You should see a 200 OK status code and the following XML data in the body of the response:
<book id="4">
<title>The Da Vinci Code</title>
<author>Dan Brown</author>
<price>12.99</price>
</book>
This means that the API has successfully amended the existing book with the given id and updated its price.
- Create another request with the following settings:
- Method: GET
- URL: http://localhost:5000/api/books/4
- Headers: Accept: application/xml
- Send the request and observe the response. You should see a 200 OK status code and the following XML data in the body of the response:
<book id="4">
<title>The Da Vinci Code</title>
<author>Dan Brown</author>
<price>12.99</price>
</book>
This means that the API has successfully returned the book with the given id.
Frequently Asked Questions (FAQs)
Question: What is the difference between CREATE and AMEND?
Answer: CREATE and AMEND are two common operations that are used to manipulate data in an API. CREATE is used to add a new record to the data source, while AMEND is used to update an existing record in the data source. For example, in our API, we use CREATE to add a new book to the list of books, and we use AMEND to update the properties of an existing book in the list.
Question: How can I send multiple XML requests in one batch?
Answer: One way to send multiple XML requests in one batch is to use the SOAP protocol, which is another format for web services. SOAP stands for Simple Object Access Protocol. It is a protocol that uses XML to define the structure and rules of the messages that are exchanged between the systems or applications. SOAP messages are wrapped in a SOAP envelope, which contains a SOAP header and a SOAP body. The SOAP header contains information about the message, such as the sender, the receiver, the action, etc. The SOAP body contains the actual data of the message, which can be one or more XML requests or responses.
To send multiple XML requests in one batch using SOAP, we need to do the following steps:
- Install the Microsoft.AspNetCore.Mvc.Formatters.Soap NuGet package. This package provides the functionality to serialize and deserialize SOAP messages in ASP.NET MVC Core.
- Configure the SOAP formatter in the Startup class. In the ConfigureServices method, we need to call the AddSoapFormatter extension method on the services collection. This method adds the SoapInputFormatter and the SoapOutputFormatter to the application. These formatters are used to read and write SOAP messages from and to the HTTP requests and responses.
- Create a SOAP service class that handles the SOAP requests and responses. This class should have a [Route] attribute that specifies the URL path of the service. It should also have a [SoapService] attribute that specifies the namespace of the service. The service class should have one or more methods that have [SoapMethod] attributes that specify the names of the SOAP actions. These methods should have parameters and return values that match the XML requests and responses. The service class should also implement the ISoapService interface, which provides a method to handle SOAP faults.
- Use an HTTP client, such as Postman, to send SOAP messages to the service endpoint and receive SOAP messages. The HTTP client should set the Content-Type header to text/xml and the SOAPAction header to the name of the SOAP action. The HTTP client should also include the SOAP message in the request body.
Summary
In this article, we have learned how to send XML requests to an API with ASP.NET MVC Core using the CREATE and AMEND operations. We have also learned how to use the XML serializer formatter, how to create a model class, how to create a controller class, how to configure the Startup class, and how to test the API with an HTTP client. We have also learned how to send multiple XML requests in one batch using the SOAP protocol. We hope that this article has been helpful and informative for you. If you have any questions or feedback, please feel free to contact us.
Disclaimer: This article is for educational purposes only and does not constitute professional advice. The author and the publisher are not liable for any damages or losses that may result from the use or misuse of the information or code in this article. The reader is responsible for verifying the accuracy and validity of the information and code before using it in any situation. The reader is also responsible for complying with any applicable laws and regulations when using the information or code in this article.