HTTP plugin

This document will help you learn about NBomber.HTTP plugin in more detail.

• Overview
• API
• Advanced logging (tracing)
• JSON parsing
• Best practices

Overview

The NBomber.Http provides a simple API to define HTTP steps, handle responses in an efficient way (without waiting on full response body but rather first bytes), calculate response size, apply assertions.

Add HTTP package

dotnet add package NBomber.Http

Create HTTP load test

F#

Program.fs

open System

open System.Net.Http

open FSharp.Control.Tasks.V2.ContextInsensitive

open NBomber.Contracts

open NBomber.FSharp

open NBomber.Plugins.Network.Ping

open NBomber.Plugins.Http.FSharp

[<EntryPoint>]

let main argv =

// it's optional Ping plugin that brings additional reporting data

let pingConfig = PingPluginConfig.CreateDefault ["nbomber.com"]

use pingPlugin = new PingPlugin(pingConfig)

let step = HttpStep.create("fetch_html_page", fun context ->

Http.createRequest "GET" "https://nbomber.com"

)

Scenario.create "nbomber_web_site" [step]

|> Scenario.withLoadSimulations [InjectPerSec(rate = 100, during = seconds 30)]

|> NBomberRunner.registerScenario

|> NBomberRunner.withWorkerPlugins [pingPlugin]

|> NBomberRunner.run

|> ignore

0 // return an integer exit code

C#

Program.cs

using System;

using NBomber.Contracts;

using NBomber.CSharp;

using NBomber.Plugins.Http.CSharp;

using NBomber.Plugins.Network.Ping;

namespace CSharp

{

public class Program

{

static void Main(string[] args)

{

var step = HttpStep.Create("fetch_html_page", context =>

Http.CreateRequest("GET", "https://nbomber.com")

);

var scenario = ScenarioBuilder

.CreateScenario("nbomber_web_site", step)

.WithLoadSimulations(new[]

{

Simulation.InjectPerSec(rate: 100, during: TimeSpan.FromSeconds(30))

});

var pingPluginConfig = PingPluginConfig.CreateDefault("nbomber.com");

var pingPlugin = new PingPlugin(pingPluginConfig);

NBomberRunner

.RegisterScenarios(scenario)

.WithWorkerPlugins(pingPlugin)

.Run();

}

}

}

API

Http step

The main thing that this plugin adds is a convenient way to define the NBomber step that creates a Http request and then sends it.

HttpStep.create (name: string,

feed: IFeed<'TFeedItem>,

createRequest: IStepContext<unit,'TFeedItem> -> Task<HttpRequest>,

completionOption: HttpCompletionOption) =

By default NBomber.Http is set completionOption = HttpCompletionOption.ResponseHeadersRead for performance optimizations. You can read about this optimization here.

// creates simple HTTP step

let step =

HttpStep.create("step", fun context ->

Http.createRequest "GET" "https://gitter.im"

|> Http.withHeader "Accept" "text/html"

)

// creates two steps that run sequentially

let step1 =

HttpStep.create("step 1", fun context ->

Http.createRequest "GET" "https://gitter.im"

|> Http.withHeader "Accept" "text/html"

)

let step2 =

HttpStep.create("step 2", fun context -> task {

let step1Response = context.GetPreviousStepResponse<HttpResponseMessage>()

let headers = step1Response.Headers

let! body = step1Response.Content.ReadAsStringAsync()

return Http.createRequest "POST" "asdsad"

|> Http.withHeader "Accept" "text/html"

})

Http headers

By default NBomber sets no headers.

Http.withHeader "Accept" "application/json"

Http body

Http.withBody(new StringContent(json))

Http.withBody(new ByteArrayContent(bytes))

Http check response

By default, NBomber is using this check for every response but you can override it for every step.

Http.withCheck(fun response -> task {

return if response.IsSuccessStatusCode then Response.Ok()

else Response.Fail("status code: " + response.StatusCode.ToString())

})

Advanced example

Here you can find a full example using all API functions.

F#

let userFeed = ["1"; "2"; "3"; "4"; "5"]

|> FeedData.fromSeq

|> Feed.createRandom "userFeed"

let getUser = HttpStep.create("get_user", userFeed, fun context ->

let userId = context.FeedItem

let url = "https://jsonplaceholder.typicode.com/users?id=" + userId

Http.createRequest "GET" url

|> Http.withCheck(fun response -> task {

let! json = response.Content.ReadAsStringAsync()

// parse JSON

let users = json

|> JsonConvert.DeserializeObject<UserResponse[]>

|> ValueOption.ofObj

match users with

| ValueSome usr when usr.Length = 1 ->

return Response.Ok(usr.[0]) // we pass user object response to the next step

| _ -> return Response.Fail("not found user: " + userId)

})

)

// this 'getPosts' will be executed only if 'getUser' finished OK.

let getPosts = HttpStep.create("get_posts", fun context ->

let user = context.GetPreviousStepResponse<UserResponse>()

let url = "https://jsonplaceholder.typicode.com/posts?userId=" + user.Id

Http.createRequest "GET" url

|> Http.withCheck(fun response -> task {

let! json = response.Content.ReadAsStringAsync()

// parse JSON

let posts = json

|> JsonConvert.DeserializeObject<PostResponse[]>

|> ValueOption.ofObj

match posts with

| ValueSome ps when ps.Length > 0 ->

return Response.Ok()

| _ -> return Response.Fail()

})

)

// it's optional Ping plugin that brings additional reporting data

let pingPluginConfig = PingPluginConfig.CreateDefault ["jsonplaceholder.typicode.com"]

let pingPlugin = new PingPlugin(pingPluginConfig)

Scenario.create "rest_api" [getUser; getPosts]

|> Scenario.withWarmUpDuration(seconds 5)

|> Scenario.withLoadSimulations [InjectPerSec(rate = 100, during = seconds 30)]

|> NBomberRunner.registerScenario

|> NBomberRunner.withWorkerPlugins [pingPlugin]

|> NBomberRunner.withTestSuite "http"

|> NBomberRunner.withTestName "advanced_test"

|> NBomberRunner.run

|> ignore

C#

var userFeed = Feed.CreateRandom(

name: "userFeed",

provider: FeedData.FromSeq(new[] {"1", "2", "3", "4", "5"})

);

var getUser = HttpStep.Create("get_user", userFeed, context =>

{

var userId = context.FeedItem;

var url = $"https://jsonplaceholder.typicode.com/users?id={userId}";

return Http.CreateRequest("GET", url)

.WithCheck(async response =>

{

var json = await response.Content.ReadAsStringAsync();

// parse JSON

var users = JsonConvert.DeserializeObject<UserResponse[]>(json);

return users?.Length == 1

? Response.Ok(users.First()) // we pass user object response to the next step

: Response.Fail($"not found user: {userId}");

});

});

// this 'getPosts' will be executed only if 'getUser' finished OK.

var getPosts = HttpStep.Create("get_posts", context =>

{

var user = context.GetPreviousStepResponse<UserResponse>();

var url = $"https://jsonplaceholder.typicode.com/posts?userId={user.Id}";

return Http.CreateRequest("GET", url)

.WithCheck(async response =>

{

var json = await response.Content.ReadAsStringAsync();

// parse JSON

var posts = JsonConvert.DeserializeObject<PostResponse[]>(json);

return posts?.Length > 0

? Response.Ok()

: Response.Fail($"not found posts for user: {user.Id}");

});

});

var scenario = ScenarioBuilder

.CreateScenario("rest_api", getUser, getPosts)

.WithWarmUpDuration(TimeSpan.FromSeconds(5))

.WithLoadSimulations(new[]

{

Simulation.InjectPerSec(rate: 100, during: TimeSpan.FromSeconds(30))

});

var pingPluginConfig = PingPluginConfig.CreateDefault(new[] {"jsonplaceholder.typicode.com"});

var pingPlugin = new PingPlugin(pingPluginConfig);

NBomberRunner

.RegisterScenarios(scenario)

.WithWorkerPlugins(pingPlugin)

.WithTestSuite("http")

.WithTestName("advanced_test")

.Run();

Advanced logging (tracing)

There may be situations when you need to trace your requests and responses. The NBomber.Http has built-in functionality for tracing every request/response. In order to start tracing you need to set minimum logging level to verbose.

important

Make sure that you always return a new instance (not from a variable) of LoggerConfiguration. This limitation is mandatory since Serilog logger does not allow to create multiple instances from the same instance of LoggerConfiguration.

NBomberRunner.withLoggerConfig(fun () ->

LoggerConfiguration().MinimumLevel.Verbose()

)

JSON parsing

To work with the JSON format, you can use any library you prefer. Here is a list of popular libraries:

• Newtonsoft.Json
• System.Text.Json
• Utf8Json

Best practices

• To test HTTP use LoadSimulation.InjectPerSec since usually web server is an open system. You can read more here.
• For debugging or tracing you can use LoadSimulation.KeepConstant with copies = 1 since for this simulation NBomber will use a single task which is easier to debug.
• Use Ping plugin to get more info about networking.