Skip to main content

HTTP

To work with HTTP, NBomber provides NBomber.Http plugin that includes:

  • API to create, send request, receive response with tracking of data transfer and status codes.
  • HttpMetricsPlugin to get real-time metrics about the current Http connections.
info

To start working with NBomber.Http plugin you should install it:

dotnet add package NBomber.Http

Http CreateRequest​

This method should be used to create HTTP request. 

public static HttpRequestMessage CreateRequest(string method, string url)

Example:

var scenario = Scenario.Create("my scenario", async context =>
{
    var request = Http.CreateRequest("GET", "https://nbomber.com")
                      .WithHeader("Accept", "text/html");
                      // .WithHeader("Accept", "application/json")
                      // .WithBody(new StringContent("{ id: 1 }", Encoding.UTF8, "application/json");
                      // .WithBody(new ByteArrayContent(new [] {1,2,3}))
    ... 
});

Http Send​

This method should be used to send HTTP request.

public static Task<Response<HttpResponseMesage>> Send(HttpClient client, HttpRequestMessage request);

public static Task<Response<HttpResponseMesage>> Send(HttpClient client, HttpClientArgs clientArgs, HttpRequestMessage request);

Example 1:

using var httpClient = new HttpClient();

var scenario = Scenario.Create("my scenario", async context =>
{
    var request = Http.CreateRequest("GET", "https://nbomber.com")
                      .WithHeader("Accept", "text/html");
                      // .WithHeader("Accept", "application/json")
                      // .WithBody(new StringContent("{ id: 1 }", Encoding.UTF8, "application/json");
                      // .WithBody(new ByteArrayContent(new [] {1,2,3}))
    
    var response = await Http.Send(httpClient, request);

    return response;
});

Example 2: in this example we use HttpClientArgs

using var httpClient = new HttpClient();

var scenario = Scenario.Create("my scenario", async context =>
{
    var request = Http.CreateRequest("GET", "https://nbomber.com")
                      .WithHeader("Accept", "application/json");
                      // .WithHeader("Accept", "application/json")
                      // .WithBody(new StringContent("{ id: 1 }", Encoding.UTF8, "application/json");
                      // .WithBody(new ByteArrayContent(new [] {1,2,3}))
    
    // with HttpClientArgs you can add:
    // -- CancellationToken
    // -- HttpCompletionOption - https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpcompletionoption?view=net-7.0

    var clientArgs = new HttpClientArgs(HttpCompletionOption.ResponseHeadersRead, CancellationToken.None);
            
    var response = await Http.Send(httpClient, clientArgs, request);

    return response;
});

HttpMetricsPlugin​

HttpMetricsPlugin - provides a monitoring layer for HTTP connections.

Example:

NBomberRunner
    .RegisterScenarios(scenario)
    .WithWorkerPlugins(new HttpMetricsPlugin(new [] { HttpVersion.Version1 }))
    // .WithWorkerPlugins(new HttpMetricsPlugin(new [] { HttpVersion.Version1, HttpVersion.Version2 }))
    .Run();

After running with HttpMetricsPlugin, you will get real-time HTTP connections metrics for the Console output:

Also, after running with HttpMetricsPlugin, you will get HTTP connections history metrics for the HTML report:

Connections limit​

You may need to limit the sockets connections count.

var socketsHandler = new SocketsHttpHandler
{
    MaxConnectionsPerServer = 3
};

using var httpClient = new HttpClient(socketsHandler);

Best practices​

Blog posts​

Load simulation​

HTTP services should be considered as Open system. Open systems - it's where you control the arrival rate of users. For Open systems NBomber provides the following load simulations: Inject, RampingInject and InjectRandom.

HttpClient​

HttpClient should be used carefully since the wrong use of it can cause socket exhaustion problems. You can read more about this problem in this article: You are using HttpClient wrong. The basic recommendations are:

  • Use a singleton HttpClient (shared instance) per Scenario.
  • Do not create many HttpClient instances. Instead just reuse a single instance per Scenario.
  • Disposing HttpClient is not a cheap operation. It can cause socket exhaustion problems.
// this usage is WRONG
// since HttpClient will be created and disposed for each Scenario iteration

var scenario = Scenario.Create("my scenario", async context =>
{   
    using var httpClient = new HttpClient();
    
    var request = Http.CreateRequest("GET", "https://nbomber.com")
    var response = await Http.Send(httpClient, request);

    ...
});
// this usage is OK
// since HttpClient will be created once and then reused for each Scenario iteration

using var httpClient = new HttpClient(); 

var scenario = Scenario.Create("my scenario", async context =>
{
    var request = Http.CreateRequest("GET", "https://nbomber.com")
    var response = await Http.Send(httpClient, request);
    
    ...
});