{"id":124,"date":"2018-03-22T23:22:00","date_gmt":"2018-03-22T22:22:00","guid":{"rendered":"https:\/\/kindsonthegenius.com\/blog\/2018\/03\/22\/restful-web-services-tutorial-3-creating-and-calling-a-post-put-and-delete-methods\/"},"modified":"2020-11-05T14:13:51","modified_gmt":"2020-11-05T13:13:51","slug":"restful-web-services-tutorial-3-creating-and-calling-a-post-put-and-delete-methods","status":"publish","type":"post","link":"https:\/\/kindsonthegenius.com\/blog\/restful-web-services-tutorial-3-creating-and-calling-a-post-put-and-delete-methods\/","title":{"rendered":"RESTful Web Services Tutorial 3 – Creating and Calling a POST, PUT and DELETE Methods"},"content":{"rendered":"
\n
In this tutorial, we would focus on creating the POST method, sending POST request and retrieving a response.<\/p>\n

Content<\/b><\/p>\n

    \n
  1. Review of Tutorials 1<\/a> and 2<\/a> <\/a><\/li>\n
  2. Build a New  REST API in Visual Studio 2017<\/a><\/li>\n
  3. Understanding the Controller File in Web API Application<\/a><\/li>\n
  4. Create the Employee Model<\/a><\/li>\n
  5. Create the Employee Controller<\/a> <\/li>\n
  6. Set up the GET methods<\/a><\/li>\n
  7. Write the POST method<\/a><\/li>\n
  8. Write the PUT and DELETE Methods<\/a><\/li>\n
  9. Next Steps<\/a><\/li>\n<\/ol>\n
    <\/a><\/div>\n

    <\/ins><\/p>\n

    <\/p>\n

    1. Review of Tutorials 1<\/a> and 2 <\/h3>\n

    <\/b>
    In Tutorial 1, we build a REST API in Visual Studio and we created an Employee Model. We also added an EmployeeController and wrote GET methods to return list of employees and another GET method to return an employee based on the ID
    In Tutorial 2, we set up a REST Client (Advanced REST Client) and made tested our API.
    In this Tutorial, we will create a new REST API and this time we will writh all the methods for GET, POST, PUT and DELETE operations. <\/p>\n

    <\/p>\n

    2. Build a New  REST API in Visual Studio 2017<\/h3>\n

    <\/b>
    This time in Visual Studio  2017 (you can download it for free from this     link<\/a>)<\/p>\n

    Start a new project to display the New Project Wizard as shown in Figure 1
    Select Web fromt he list of templates on the left <\/p>\n

     <\/a><\/div>\n
    Figure 1 <\/div>\n

    Give the Project a name (here I use Tutorial3)
    Select ASP.NET Core Web Application
    Click OK. The New AST.NET Core Web Applition templates is displayed as shown in Figure 2<\/p>\n

    <\/a><\/div>\n
    Figure 2:  <\/div>\n

    Select .NET Framework in the first box at the upper left if it is not already selecte
    Select ASP.NET Core 2.0 (or 1.1 depending on your version of Visual Studio)
    Click OK. The API application file and folders are generated for you.<\/p>\n

    Take a look at the folder structure as shown in Figure 3.
    Note that in this case, we no longer have ‘WebAPIConfig.cs’ file<\/p>\n

    Quiz<\/b>: Do you remember the configuration we made in teh WebAPIConfig file in Tutorial 1?<\/p>\n

    <\/a><\/div>\n

    <\/p>\n

    Figure 3: Folder Structure <\/div>\n

    Note that there is a controller called ValuesController in the Controllers folder
    Open the ValuesController and examine the content and check that it is as shown in Figure 6<\/p>\n

    <\/a><\/div>\n
    Figure 4: ValuesController File <\/div>\n

    Now, Run the application and see that the output depends on the first method in the ValuesController File as shown in Listing 1<\/p>\n

    The controller determines what happesn when a HTTP request is made to the API
    <\/p>\n

    \n
        [Route(\"api\/[controller]<\/span>\")]<\/span>
        public<\/span> class<\/span> ValuesController<\/span> : Controller
        {
            \/\/ GET api\/values<\/span>
            [HttpGet]<\/span>
            public<\/span> IEnumerable<string<\/span>> Get()
            {
                return<\/span> new<\/span> string<\/span>[] { \"value1\"<\/span>, \"value2\"<\/span> };
            }
    <\/pre>\n<\/div>\n
    Listing 1: Default Controller file<\/p>\n
     <\/ins>
    <\/p>\n
    3. Understanding the Controller File in WEB API Application<\/h3>\n
    <\/b>
    The class is annotated with the Route annotation which comes befor the name of the class
    The Route annotation specifies the URL strucuture of the class. In this case the path is given by<\/p>\n
    api\/[controller]<\/span><\/div>\n
    This is what comes after the base url. So if the base URL is is<\/p>\n
    http:\/\/localhost:8000<\/span><\/div>\n
    Then the url to type to get to this controller would be:<\/p>\n
    http:\/\/localhost:8080\/api\/Values<\/span><\/div>\n
    Now inside the controller file, a decision is made on what method is to be executed.
    In the case of the ValuesController, we have one method called Get(), <\/span>which is annotated with
    [HttpGet]<\/span><\/p>\n
    This means that a GET <\/span>request to this controller would execute this method.
    However if there are more than one methods annotated with the [HttpGet] annotation, then an error would be generated.
    To solve this problem, we need to modify the Route annotation of this controller to also contain the name of the method.<\/p>\n
    So we would write it as:
    api\/[controller]\/[action]<\/span><\/p>\n
    So in this case, to execute the Get() method, the Request URL and path would be something like:<\/p>\n
    http:\/\/localhost:8000\/api\/Values\/Get<\/span><\/p>\n
    REST API also supports function overloading. So we can have another Get() method in this controller, but it must have a different signature (maybe would take a parameter)<\/p>\n
    <\/p>\n
    4. Create the Employee Model<\/h3>\n
    <\/b> 
    You already know that a model is simply a class used to define objects in our API application. To create the Employee model: <\/p>\n