Problem
So far, I’ve got the following code:
public class Class1
{
private const string URL = "https://sub.domain.com/objects.json?api_key=123";
private const string DATA = @"{""object"":{""name"":""Name""}}";
static void Main(string[] args)
{
Class1.CreateObject();
}
private static void CreateObject()
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
request.Method = "POST";
request.ContentType = "application/json";
request.ContentLength = DATA.Length;
StreamWriter requestWriter = new StreamWriter(request.GetRequestStream(), System.Text.Encoding.ASCII);
requestWriter.Write(DATA);
requestWriter.Close();
try {
WebResponse webResponse = request.GetResponse();
Stream webStream = webResponse.GetResponseStream();
StreamReader responseReader = new StreamReader(webStream);
string response = responseReader.ReadToEnd();
Console.Out.WriteLine(response);
responseReader.Close();
} catch (Exception e) {
Console.Out.WriteLine("-----------------");
Console.Out.WriteLine(e.Message);
}
}
}
The issue is that I believe the exception block is being triggered (since I get a server error (500) message when I remove the try-catch). However, I am unable to locate the Console. I laid out lines in the catch block.
My Console:
The thread 'vshost.NotifyLoad' (0x1a20) has exited with code 0 (0x0).
The thread '<No Name>' (0x1988) has exited with code 0 (0x0).
The thread 'vshost.LoadReference' (0x1710) has exited with code 0 (0x0).
'ConsoleApplication1.vshost.exe' (Managed (v4.0.30319)): Loaded 'c:\users\l. preston sego iii\documents\visual studio 11\Projects\ConsoleApplication1\ConsoleApplication1\bin\Debug\ConsoleApplication1.exe', Symbols loaded.
'ConsoleApplication1.vshost.exe' (Managed (v4.0.30319)): Loaded 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Configuration\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll', Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
A first chance exception of type 'System.Net.WebException' occurred in System.dll
The thread 'vshost.RunParkingWindow' (0x184c) has exited with code 0 (0x0).
The thread '<No Name>' (0x1810) has exited with code 0 (0x0).
The program '[2780] ConsoleApplication1.vshost.exe: Program Trace' has exited with code 0 (0x0).
The program '[2780] ConsoleApplication1.vshost.exe: Managed (v4.0.30319)' has exited with code 0 (0x0).
Asked by NullVoxPopuli
Solution #1
The previously described WCF Web API has been superseded with the ASP.NET Web API.
Since most of these responses are from early 2012, and this forum is one of the top results when searching for “call restful service C#,” I thought I’d post an updated answer.
To consume a RESTful service, Microsoft recommends using the Microsoft ASP.NET Web API Client Libraries. Microsoft.AspNet.WebApi.Client is a NuGet package that contains this functionality. This NuGet package must be installed in your solution.
Here’s how your example would look when implemented using the ASP.NET Web API Client Library:
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
namespace ConsoleProgram
{
public class DataObject
{
public string Name { get; set; }
}
public class Class1
{
private const string URL = "https://sub.domain.com/objects.json";
private string urlParameters = "?api_key=123";
static void Main(string[] args)
{
HttpClient client = new HttpClient();
client.BaseAddress = new Uri(URL);
// Add an Accept header for JSON format.
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
// List data response.
HttpResponseMessage response = client.GetAsync(urlParameters).Result; // Blocking call! Program will wait here until a response is received or a timeout occurs.
if (response.IsSuccessStatusCode)
{
// Parse the response body.
var dataObjects = response.Content.ReadAsAsync<IEnumerable<DataObject>>().Result; //Make sure to add a reference to System.Net.Http.Formatting.dll
foreach (var d in dataObjects)
{
Console.WriteLine("{0}", d.Name);
}
}
else
{
Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
}
// Make any other calls using HttpClient here.
// Dispose once all HttpClient calls are complete. This is not necessary if the containing object will be disposed of; for example in this case the HttpClient instance will be disposed automatically when the application terminates so the following call is superfluous.
client.Dispose();
}
}
}
You should reuse your HttpClient object if you plan on making repeated requests. For further information on why a using statement was not used on the HttpClient object in this circumstance, see this question and its answers: Is it necessary to dispose of HttpClient and HttpClientHandler between requests?
See Call a Web API From a.NET Client (C#) for more information and examples.
This blog post might be useful as well: Consuming ASP.NET Web API REST Services with HttpClient
Answered by Brian Swift
Solution #2
RestSharp would be my recommendation. With very little boilerplate code, you can access REST services and have them cast into POCO objects without having to comb through the response. This will not fix your specific error, but it will answer your general question on how to call REST services. It should pay dividends in terms of ease of use and resilience in the future if you have to update your code to use it. But that’s just my two cents.
Example:
namespace RestSharpThingy
{
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Reflection;
using RestSharp;
public static class Program
{
public static void Main()
{
Uri baseUrl = new Uri("https://httpbin.org/");
IRestClient client = new RestClient(baseUrl);
IRestRequest request = new RestRequest("get", Method.GET) { Credentials = new NetworkCredential("testUser", "P455w0rd") };
request.AddHeader("Authorization", "Bearer qaPmk9Vw8o7r7UOiX-3b-8Z_6r3w0Iu2pecwJ3x7CngjPp2fN3c61Q_5VU3y0rc-vPpkTKuaOI2eRs3bMyA5ucKKzY1thMFoM0wjnReEYeMGyq3JfZ-OIko1if3NmIj79ZSpNotLL2734ts2jGBjw8-uUgKet7jQAaq-qf5aIDwzUo0bnGosEj_UkFxiJKXPPlF2L4iNJSlBqRYrhw08RK1SzB4tf18Airb80WVy1Kewx2NGq5zCC-SCzvJW-mlOtjIDBAQ5intqaRkwRaSyjJ_MagxJF_CLc4BNUYC3hC2ejQDoTE6HYMWMcg0mbyWghMFpOw3gqyfAGjr6LPJcIly__aJ5__iyt-BTkOnMpDAZLTjzx4qDHMPWeND-TlzKWXjVb5yMv5Q6Jg6UmETWbuxyTdvGTJFzanUg1HWzPr7gSs6GLEv9VDTMiC8a5sNcGyLcHBIJo8mErrZrIssHvbT8ZUPWtyJaujKvdgazqsrad9CO3iRsZWQJ3lpvdQwucCsyjoRVoj_mXYhz3JK3wfOjLff16Gy1NLbj4gmOhBBRb8rJnUXnP7rBHs00FAk59BIpKLIPIyMgYBApDCut8V55AgXtGs4MgFFiJKbuaKxq8cdMYEVBTzDJ-S1IR5d6eiTGusD5aFlUkAs9NV_nFw");
request.AddParameter("clientId", 123);
IRestResponse<RootObject> response = client.Execute<RootObject>(request);
if (response.IsSuccessful)
{
response.Data.Write();
}
else
{
Console.WriteLine(response.ErrorMessage);
}
Console.WriteLine();
string path = Assembly.GetExecutingAssembly().Location;
string name = Path.GetFileName(path);
request = new RestRequest("post", Method.POST);
request.AddFile(name, File.ReadAllBytes(path), name, "application/octet-stream");
response = client.Execute<RootObject>(request);
if (response.IsSuccessful)
{
response.Data.Write();
}
else
{
Console.WriteLine(response.ErrorMessage);
}
Console.ReadLine();
}
private static void Write(this RootObject rootObject)
{
Console.WriteLine("clientId: " + rootObject.args.clientId);
Console.WriteLine("Accept: " + rootObject.headers.Accept);
Console.WriteLine("AcceptEncoding: " + rootObject.headers.AcceptEncoding);
Console.WriteLine("AcceptLanguage: " + rootObject.headers.AcceptLanguage);
Console.WriteLine("Authorization: " + rootObject.headers.Authorization);
Console.WriteLine("Connection: " + rootObject.headers.Connection);
Console.WriteLine("Dnt: " + rootObject.headers.Dnt);
Console.WriteLine("Host: " + rootObject.headers.Host);
Console.WriteLine("Origin: " + rootObject.headers.Origin);
Console.WriteLine("Referer: " + rootObject.headers.Referer);
Console.WriteLine("UserAgent: " + rootObject.headers.UserAgent);
Console.WriteLine("origin: " + rootObject.origin);
Console.WriteLine("url: " + rootObject.url);
Console.WriteLine("data: " + rootObject.data);
Console.WriteLine("files: ");
foreach (KeyValuePair<string, string> kvp in rootObject.files ?? Enumerable.Empty<KeyValuePair<string, string>>())
{
Console.WriteLine("\t" + kvp.Key + ": " + kvp.Value);
}
}
}
public class Args
{
public string clientId { get; set; }
}
public class Headers
{
public string Accept { get; set; }
public string AcceptEncoding { get; set; }
public string AcceptLanguage { get; set; }
public string Authorization { get; set; }
public string Connection { get; set; }
public string Dnt { get; set; }
public string Host { get; set; }
public string Origin { get; set; }
public string Referer { get; set; }
public string UserAgent { get; set; }
}
public class RootObject
{
public Args args { get; set; }
public Headers headers { get; set; }
public string origin { get; set; }
public string url { get; set; }
public string data { get; set; }
public Dictionary<string, string> files { get; set; }
}
}
Answered by Justin Pihony
Solution #3
I’m sure it’s unrelated, but to ensure correct disposal, encapsulate your IDisposable objects in blocks:
using System;
using System.Net;
using System.IO;
namespace ConsoleProgram
{
public class Class1
{
private const string URL = "https://sub.domain.com/objects.json?api_key=123";
private const string DATA = @"{""object"":{""name"":""Name""}}";
static void Main(string[] args)
{
Class1.CreateObject();
}
private static void CreateObject()
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
request.Method = "POST";
request.ContentType = "application/json";
request.ContentLength = DATA.Length;
using (Stream webStream = request.GetRequestStream())
using (StreamWriter requestWriter = new StreamWriter(webStream, System.Text.Encoding.ASCII))
{
requestWriter.Write(DATA);
}
try
{
WebResponse webResponse = request.GetResponse();
using (Stream webStream = webResponse.GetResponseStream() ?? Stream.Null)
using (StreamReader responseReader = new StreamReader(webStream))
{
string response = responseReader.ReadToEnd();
Console.Out.WriteLine(response);
}
}
catch (Exception e)
{
Console.Out.WriteLine("-----------------");
Console.Out.WriteLine(e.Message);
}
}
}
}
Answered by Jesse C. Slicer
Solution #4
In C#, there are a number different ways to call an external API (updated 2019).
.NET’s built-in ways:
NuGet Packages are free, open-source packages that provide a significantly better developer experience than.built-in NET’s clients:
All the above packages provide a great developer experience (i.e., concise, easy API) and are well maintained.
(*) Current as of August 2019
Using ServiceStack to retrieve a Todo item from a fictitious Rest API. Text. The syntax of the other libraries is pretty similar.
class Program
{
static void Main(string[] args)
{
// Fake rest API
string url = "https://jsonplaceholder.typicode.com/todos/1";
// GET data from API & map to POCO
var todo = url.GetJsonFromUrl().FromJson<Todo>();
// Print the result to screen
todo.PrintDump();
}
public class Todo
{
public int UserId { get; set; }
public int Id { get; set; }
public string Title { get; set; }
public bool Completed { get; set; }
}
}
The output of running the preceding example in a.NET Core Console app is as follows.
NuGet is used to install these packages.
Install-Package ServiceStack.Text, or
Install-Package RestSharp, or
Install-Package Flurl.Http
Answered by Walter
Solution #5
For your REST API request, please use the code below.
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Json;
namespace ConsoleApplication2
{
class Program
{
private const string URL = "https://XXXX/rest/api/2/component";
private const string DATA = @"{
""name"": ""Component 2"",
""description"": ""This is a JIRA component"",
""leadUserName"": ""xx"",
""assigneeType"": ""PROJECT_LEAD"",
""isAssigneeTypeValid"": false,
""project"": ""TP""}";
static void Main(string[] args)
{
AddComponent();
}
private static void AddComponent()
{
System.Net.Http.HttpClient client = new System.Net.Http.HttpClient();
client.BaseAddress = new System.Uri(URL);
byte[] cred = UTF8Encoding.UTF8.GetBytes("username:password");
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(cred));
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
System.Net.Http.HttpContent content = new StringContent(DATA, UTF8Encoding.UTF8, "application/json");
HttpResponseMessage messge = client.PostAsync(URL, content).Result;
string description = string.Empty;
if (messge.IsSuccessStatusCode)
{
string result = messge.Content.ReadAsStringAsync().Result;
description = result;
}
}
}
}
Answered by Srinivasan Radhakrishnan
Post is based on https://stackoverflow.com/questions/9620278/how-do-i-make-calls-to-a-rest-api-using-c