Create controller to handle Person class data .

public class PersonsController : System.Web.Http.ApiController
{
  static Person[] s_persons = new Person[]
  {
    new Person() { Name = "John", Height=180},
    new Person() { Name = "Paul", Height=170}
  };

  public IEnumerable<Person> Get()
  {
    return s_persons.ToArray();
  }

  public Person Get(int id)
  {
    return s_persons.Where(p => p.Id == id).FirstOrDefault();
  }

  public System.Net.Http.HttpResponseMessage Post(Person newPerson)
  {
    s_persons.Add(newPerson);

    // pass back to the caller success and new id (if database is used)
    System.Net.Http.HttpResponseMessage result = new System.Net.Http.HttpResponseMessage(HttpStatusCode.OK);
    result.Headers.Location = new Uri("http://localhost:34460/api/persons/" + Convert.ToString(newPerson.Id)); // Id field would be autogenerated if database is used

    return result;
  }

  public void Put(Person personArg)
  {
    Person person = m_persons.Where(p => p.Id == personArg.Id).FirstOrDefault();
    person = personArg;
  }

  public void Delete(int id)
  {
    Person person = m_persons.Where(p => p.Id == id).FirstOrDefault();
    s_persons.Remove(person);
  }
}

More info and samples on: www.devarchweb.net

Define routing (to api/persons) Create App_Start folder.
Create WebApiConfig.cs under the folder.
http://myserver/api/persons will return list of all persons, because persons will be interpreted as PersonsController
and a method starting with Get with no arguments will be used to return the data.
{id} maps to id argument (in Get(int id)).

using System.Web.Http;

namespace WebApiSimple
{
  public static class WebApiConfig
  {
    public static void Register(HttpConfiguration config)
    {
      config.Routes.MapHttpRoute(
        name: "DefaultApi",
        routeTemplate: "api/{controller}/{id}",
        defaults: new { id = RouteParameter.Optional }
      );
    }
  }
}

Create Global.asax file in the root of the project

<%@ Application Codebehind="Global.asax.cs" Inherits="WebApiSimple.WebApiApplication" Language="C#" %>

and Global.asax.cs as well. These files will register mapping defined in WebApiConfig when the application starts.

namespace WebApiSimple
{
  public class WebApiApplication : System.Web.HttpApplication
  {
    protected void Application_Start()
    {
      WebApiConfig.Register (System.Web.Http.GlobalConfiguration.Configuration);
    }
  }
}

More info and samples on: www.devarchweb.net

How looks URL for service providing people data (all people, person with id 1) type: http://myserver/api/persons to get list of persons
type: http://myserver/api/persons/1 to get person #1

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How to call web method and display all people with JavaScript/jQuery

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How to access web service from .net client with WebRequest - Create a console app
- Inlude model.cs in the project

HttpWebRequest myHttpWebRequest = (HttpWebRequest)HttpWebRequest.Create("http://localhost:34460/api/persons");
myHttpWebRequest.Method = "GET";
myHttpWebRequest.Credentials = System.Net.CredentialCache.DefaultCredentials;
myHttpWebRequest.ContentType = "application/json";
myHttpWebRequest.Accept = "application/json";

HttpWebResponse myHttpWebResponse = (HttpWebResponse)myHttpWebRequest.GetResponse();

// data in JSON format
System.IO.StreamReader myStreamReader = new System.IO.StreamReader(myHttpWebResponse.GetResponseStream());
string responseData = myStreamReader.ReadToEnd();

// deserialize the data
var p1 = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<Person[]>(responseData);

More info and samples on: www.devarchweb.net

How to access web service from .net client with HttpClient - Create console app
- Include model.cs in the projects
- Right click on References, Add Reference, System.Net.Http 2.0 (for HttpClient)
- add reference to System.Net.Http.Formatting 4.0 (ReadAsAsync)
As HttpClient calls are asynchronous, async-await" is used.

static void Main()
{
   string baseAddress = "http://localhost:34460/";
   CallWebService(baseAddress + "api/persons").Wait();
}

static async Task CallWebService(string baseAddress)
{
   HttpClientHandler handler = new HttpClientHandler();
   handler.UseDefaultCredentials = true; // needed for Windows authentication

   using (HttpClient client = new System.Net.Http.HttpClient(handler))
   {
     client.BaseAddress = new Uri(baseAddress);

     client.DefaultRequestHeaders.Accept.Clear();
     client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

     // get all items
     HttpResponseMessage httpResponseMsg = await client.GetAsync("");
     if (httpResponseMsg.IsSuccessStatusCode)
     {
       Person[] person = await httpResponseMsg.Content.ReadAsAsync<Person[]>();
     }

     // get one item
     httpResponseMsg = await client.GetAsync(baseAddress+"/1");
     if (httpResponseMsg.IsSuccessStatusCode)
     {
       Person person = await httpResponseMsg.Content.ReadAsAsync<Person>();
     }

     // add new - Post
     Person newPerson = new Person() { Id=3, Name = "George" };
     httpResponseMsg = await client.PostAsJsonAsync("", newPerson);
     if (!httpResponseMsg.IsSuccessStatusCode) { return; }

     Uri newlyAddedPersonUrl = httpResponseMsg.Headers.Location;

     // update existing
     newPerson.Name = "Ringo";
     await client.PutAsJsonAsync(newlyAddedPersonUrl, newPerson);

     // delete existing
     await client.DeleteAsync(newlyAddedPersonUrl);
   }
}

More info and samples on: www.devarchweb.net

How to receive data in XML

client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/xml"));

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How to use Fiddler to make POST web service calls -Navigate to Composer tab
-Select "POST" verb
-Enter web service address, e.g. http://myserver/api/persons
-In the Request body section, enter [{"Name": "John","Id":1}]
-Click "Execute"
If you set a break point in the Post() method, the Visual Studio will stop the web service execution there.

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How to route methods with attributes

[HttpGet]
public IEnumerable<Person> RetrieveAll() {... }

[HttpPost]
public System.Net.Http.HttpResponseMessage Add(Person newPerson) {...}

[HttpPut]
public void Update(Person personArg) { ... }

[HttpDelete]
public void Remove(int id) { ... }

More info and samples on: www.devarchweb.net

How to call delete as GET (from browser)

// enables http://localhost:34460/apiaction/persons3/delete/1
config.Routes.MapHttpRoute(
  name: "ActionApi",
  routeTemplate: "apiaction/{controller}/{action}/{id}", // prefix "apiaction" is different in order to avoid conflict with api/persons/1 and api/persons/action
  defaults: new { id = RouteParameter.Optional }
);
....
[HttpGet]
public void Delete(int id)
{
  Person person = s_persons.Where(p => p.Id == id).FirstOrDefault();
  s_persons.Remove(person);
}

More info and samples on: www.devarchweb.net

How to call multiple get methods in one controller (2 options)

public Person GetOne(int id)
{
return s_persons.Where(p => p.Id == id).FirstOrDefault();
}
public Person GetByName(string name)
{
return s_persons.Where(p => p.Name == name).FirstOrDefault();
}

You can call GetByName either http://myserver/api/persons3?name=john
or http://myserver/apiaction2/persons3/getbyname/john.
The latter requires routing like below:

config.Routes.MapHttpRoute(
  name: "ActionApi2",
  routeTemplate: "apiaction2/{controller}/{action}/{name}",
  defaults: new { id = RouteParameter.Optional }
);

because web api maps {name} to the name of the method argument "name".
If you change the argument to name1, the web api will not be able to route the apiaction2/persons3/getbyname/john.
http://myserver/api/persons3?name=john will be then routed to GetAll() method that does not have any argument.

More info and samples on: www.devarchweb.net