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Shayne Boyer for .NET

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Testing RESTful Services from the command-line with HttpRepl

Tools are the way we get things done and anytime a new one surfaces I am quick to jump in to see if it will help get my job done faster, better, write less code, test more effectively or even just promote ideas for better workflows.

This week, the .NET team published a new version on of the HttpRepl, an open-source command-line tool for interacting with RESTful services.

Now, there is already a number of tools for testing APIs. Postman is well known, curl works for simple calls and then there is HTTPie too for the command line.

dotnet httprepl is a bit different offering you the ability to work with your service(s) in the same manner you work with file and folders.

dotnet httprepl http://localhost:3000
(Disconnected)~ set base "http://localhost:3000"

http://localhost:3000/~ set swagger http://localhost:3000/api-docs.json

http://localhost:3000/~ ls
.       [get]
hello   [get]
echo    [post]
todo    [get|put]

http://localhost:3000/~ cd todo
/todo    [get|put]

http://localhost:3000/todo~ ls
.      [get|put]
..     [get]
{id}   [get]

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In order to retrieve the list of ToDo items, the get operation is called on the /todo route just as you would do in a browser.

Note that this example is written in Node.js using express. Although this is a .NET Core tool, it can be used for any HTTP RESTful service.

http://localhost:3000/~ get /todo
HTTP/1.1 200 OK
Connection: keep-alive
Content-Length: 150
Content-Type: application/json; charset=utf-8
Date: Thu, 08 Aug 2019 14:27:34 GMT
ETag: W/"96-xKQHQ6FTlo6NIFgo7DqTLvOqhgU"
X-Powered-By: Express

    "id": 1,
    "name": "School supplies",
    "complete": false
    "id": 2,
    "name": "Haircut",
    "complete": true
    "id": 3,
    "name": "Pick up dog from vet",
    "complete": false

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Installing and configuration

The HttpRepl is a dotnet global tool, requiring the .NET Core SDK to be installed.

dotnet tool install -g Microsoft.dotnet-httprepl --version "3.0.0-*"
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Enabling your HTTP Services

Out of the box, there is nothing you need to do to support the HttpRepl global tool. However, in order to support the ls operation to show the endpoints your API or service must have an OpenAPI (aka Swagger) specification to point to. By default, the HttpRepl will look for /swagger/v1/swagger.json

In ASP.NET Core NSwag and Swashbuckle are two options for creating an OpenAPI specification. See the docs for how to achieve this in a few steps.

For the Node.js ToDo example, I used swagger-jsdoc and created a route for the Swagger UI at /swagger

app.get("/api-docs.json", (req, res) => {
  res.setHeader("Content-Type", "application/json");

app.use("/swagger", swaggerUi.serve, swaggerUi.setup(swaggerSpec));
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So I can easily test my API using the UI as well.

Setting up in VSCode

We could easily start the API from VSCode, fire up another terminal and type the starting command to initialize the HttpRepl, but where's the efficiency in that?

Visual Studio Code has the concept of compounds allowing you to set up multiple configurations in the launch.json file, starting up multiple debug configs. This is especially helpful in situations where you might have a front-end and back-end system needing to debug as once.

In the following configuration, the nodejsapi is set to start as well as the httprepl.

  // Use IntelliSense to learn about possible attributes.
  // Hover to view descriptions of existing attributes.
  // For more information, visit:
  "version": "0.2.0",
  "compounds": [
      "name": "Launch w/HttpRepl",
      "configurations": [
  "configurations": [
      "name": "httprepl",
      "type": "coreclr",
      "request": "launch",
      "program": "dotnet",
      "args": ["httprepl", "http://localhost:3000"],
      "cwd": "${workspaceFolder}",
      "stopAtEntry": false,
      "console": "integratedTerminal"
      "type": "node",
      "request": "launch",
      "name": "nodejsapi",
      "program": "${workspaceFolder}/nodeapi/app.js"
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Hitting F5, or Debug to start the configurations and starts the API as well as the HttpRepl in the integrated terminal and I can test the get /todo and get methods without leaving VS Code and hit the breakpoints.


It's open-source, please provide feedback on GitHub!

Read the docs, Test web APIs with the HTTP REPL. There is much more that you can do with customization, running script files and more.

Participate in make your tools better. Thanks!

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