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ASP.NET Web API Methods

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In ASP.NET MVC 5, Web API methods are typically part of a controller that handles HTTP requests like GET, POST, PUT, DELETE, etc. Below is an overview of the most common Web API methods and their associated HTTP verbs:

1. GET

The GET method is used to retrieve data from the server. In Web API, this method retrieves a collection of resources or a single resource.

public class ProductsController : ApiController
{
// GET api/products
public IEnumerable Get()
{
return productService.GetAllProducts();
}
// GET api/products/{id}
public IHttpActionResult Get(int id)
{
var product = productService.GetProductById(id);
if (product == null)
{
return NotFound();
// Return a 404 if not found
}
return Ok(product);
// Return a 200 with the product data
}
}

2. POST

The POST method is used to send data to the server to create a new resource.

public class ProductsController : ApiController
{
// POST api/products
public IHttpActionResult Post([FromBody] Product product)
{
if (product == null)
{
return BadRequest("Invalid product data");
}
productService.AddProduct(product);
return CreatedAtRoute("DefaultApi", new { id = product.Id }, product);
// 201 Created
}
}

3. PUT

The PUT method is used to update an existing resource on the server.

public class ProductsController : ApiController
{
// PUT api/products/{id}
public IHttpActionResult Put(int id, [FromBody] Product product)
{
if (product == null || product.Id != id)
{
return BadRequest("Product data is invalid.");
}
var existingProduct = productService.GetProductById(id);
if (existingProduct == null)
{
return NotFound(); // 404 if the product does not exist
}
productService.UpdateProduct(product);
return StatusCode(HttpStatusCode.NoContent);
 // 204 No Content
}
}

4. DELETE

The DELETE method is used to delete a resource from the server.

public class ProductsController : ApiController
{
// DELETE api/products/{id}
public IHttpActionResult Delete(int id)
{
var product = productService.GetProductById(id);
if (product == null)
{
return NotFound();
// 404 Not Found
}
productService.DeleteProduct(id);
return StatusCode(HttpStatusCode.NoContent);
// 204 No Content
}
}

5. PATCH (Optional)

The PATCH method is used to apply partial updates to a resource.

public class ProductsController : ApiController
{
// PATCH api/products/{id}
public IHttpActionResult Patch(int id, [FromBody] JsonPatchDocument patchDocument)
{
var product = productService.GetProductById(id);
if (product == null)
{
return NotFound();
}
patchDocument.ApplyTo(product);
productService.UpdateProduct(product);
return Ok(product);
}
}

Key Considerations:

  • Use IHttpActionResult as the return type for better flexibility in returning various HTTP status codes (OK, NotFound, BadRequest, etc.).
  • The [FromBody] attribute indicates that the data will be sent in the body of the request, typically in JSON format.
  • These methods follow RESTful conventions, where each method corresponds to a specific HTTP verb.

By implementing these Web API methods, you can build a full CRUD (Create, Read, Update, Delete) API for your application.

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