Installing the HTTPie command-line utility

Before getting to the heart of the topic, there is one last tool that we’ll install. FastAPI is, as you probably know, mainly about building REST APIs. Thus, we need a tool to make HTTP requests to our API. To do so, we have several options:

• FastAPI automatic documentation
• Postman: A GUI tool to perform HTTP requests
• cURL: The well-known and widely used command-line tool to perform network requests

Even if visual tools such as FastAPI automatic documentation and Postman are nice and easy to use, they sometimes lack some flexibility and may not be as productive as command-line tools. On the other hand, cURL is a very powerful tool with thousands of options, but it can be complex and verbose for testing simple REST APIs.

This is why we’ll introduce HTTPie, a command-line tool aimed at making HTTP requests. Compared to cURL, its syntax is much more approachable and easier to remember, so you can run complex requests off the top of your head. Besides, it comes with built-in JSON support and syntax highlighting. Since it’s a command-line interface (CLI) tool, we keep all the benefits of the command line: for example, we can directly pipe a JSON file and send it as the body of an HTTP request. It’s available to install from most package managers:

• macOS users can use this:

  $ brew install httpie

• Ubuntu users can use this:

  $ sudo apt-get update && sudo apt-get install httpie

Let’s see how to perform simple requests on a dummy API:

1. First, let’s retrieve the data:

   $ http GET https://603cca51f4333a0017b68509.mockapi.io/todos>>>HTTP/1.1 200 OKAccess-Control-Allow-Headers: X-Requested-With,Content-Type,Cache-Control,access_tokenAccess-Control-Allow-Methods: GET,PUT,POST,DELETE,OPTIONSAccess-Control-Allow-Origin: *Connection: keep-aliveContent-Length: 58Content-Type: application/jsonDate: Tue, 08 Nov 2022 08:28:30 GMTEtag: "1631421347"Server: CowboyVary: Accept-EncodingVia: 1.1 vegurX-Powered-By: Express[    {        "id": "1",        "text": "Write the second edition of the book"    }]

As you can see, you can invoke HTTPie with the http command and simply type the HTTP method and the URL. It outputs both the HTTP headers and the JSON body in a clean and formatted way.

2. HTTPie also supports sending JSON data in a request body very quickly without having to format the JSON yourself:

   $ http -v POST https://603cca51f4333a0017b68509.mockapi.io/todos text="My new task"POST /todos HTTP/1.1Accept: application/json, */*;q=0.5Accept-Encoding: gzip, deflateConnection: keep-aliveContent-Length: 23Content-Type: application/jsonHost: 603cca51f4333a0017b68509.mockapi.ioUser-Agent: HTTPie/3.2.1{    "text": "My new task"}HTTP/1.1 201 CreatedAccess-Control-Allow-Headers: X-Requested-With,Content-Type,Cache-Control,access_tokenAccess-Control-Allow-Methods: GET,PUT,POST,DELETE,OPTIONSAccess-Control-Allow-Origin: *Connection: keep-aliveContent-Length: 31Content-Type: application/jsonDate: Tue, 08 Nov 2022 08:30:10 GMTServer: CowboyVary: Accept-EncodingVia: 1.1 vegurX-Powered-By: Express{    "id": "2",    "text": "My new task"}

By simply typing the property name and its value separated by =, HTTPie will understand that it’s part of the request body in JSON. Notice here that we specified the -v option, which tells HTTPie to output the request before the response, which is very useful to check that we properly specified the request.

3. Finally, let’s see how we can specify request headers:

   $ http -v GET https://603cca51f4333a0017b68509.mockapi.io/todos "My-Header: My-Header-Value"GET /todos HTTP/1.1Accept: */*Accept-Encoding: gzip, deflateConnection: keep-aliveHost: 603cca51f4333a0017b68509.mockapi.ioMy-Header: My-Header-ValueUser-Agent: HTTPie/3.2.1HTTP/1.1 200 OKAccess-Control-Allow-Headers: X-Requested-With,Content-Type,Cache-Control,access_tokenAccess-Control-Allow-Methods: GET,PUT,POST,DELETE,OPTIONSAccess-Control-Allow-Origin: *Connection: keep-aliveContent-Length: 90Content-Type: application/jsonDate: Tue, 08 Nov 2022 08:32:12 GMTEtag: "1849016139"Server: CowboyVary: Accept-EncodingVia: 1.1 vegurX-Powered-By: Express[    {        "id": "1",        "text": "Write the second edition of the book"    },    {        "id": "2",        "text": "My new task"    }]

That’s it! Just type your header name and value separated by a colon to tell HTTPie it’s a header.