Does the Windows built-in version of “curl” confuse or intimidate you? Maybe you come from a Linux or Unix background, and yearn for some of your favorite go-to tools? Newer versions of Powershell include a cmdlet for interacting with the web called Invoke-WebRequest, which is useful, but is not a great drop in replacement for those with experience in non Windows environments. The Powershell cmdlets are a move in the right direction to unifying CLI experiences but there are still many folks that have become attached to curl over the years, including myself. It is worth noting that a Windows compatible version of curl has existed for a long time, however it has always been a nuisance dealing with the zip file, just as using SSH has always been a hassle on Windows. It has always been possible to use the *nix equivalent tools, it is just clunky.
I found a low effort solution for adding curl to my Windows CLI flow, that acts as a nice middle ground between learning Invoke-WebRequest and installing curl binaries directly, which I’d like to share. This alias trick is a simple way to use curl for working with API’s and other various web testing in Windows environments without getting tangled in managing versions, and dealing with vulnerabilities. Just download the latest Docker image to update curl to the newest version, and don’t worry about its implementation across different systems.
Prerequisites are light. First, make sure to have the Docker for Windows app installed (stable or beta are both fine) as well as a semi-recent version of Powershell.
Next step. If you haven’t set up a Powershell profile, there are also lots of links and resources about how to do it. I even wrote about it recently, so I am skipping that step as well. Start by adding the following snippet to your Powershell profile (by default located in C:\Users\<user>\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1) and saving.
# Curl alias using docker
function Docker-Curl {
docker run --rm byrnedo/alpine-curl $args
}
# Aliases
New-Alias dcurl Docker-Curl
Then source you terminal and run the curl command that was just created.
dcurl -h
One issue you might notice from the snippet above is that the Docker image is not an “official” image. If this bothers you (security concerns, etc.), it is really easy to create your own, secure image. There are lots of examples of how to create minimal images with Curl pre-installed. Just be aware that your custom image will need to be maintained and occasionally rebuilt/published to guard against future vulnerabilities. For brevity, I have skipped this process, but here’s an example of creating a custom image.
Optional
To update curl, just run the docker pull command.
docker pull apline-curl
Now you have the best of both worlds. The built-in Invoke-WebRequest cmdlet provided by Powershell is available, as well as the venerable curl command.
My number one case for using curl in a container is that it has been in existence for such a long time (less bugs and edge cases) and it can be used for nearly any web related task. It is also much handier to use curl for those with a background using *nix systems, rather than digging around in unfamiliar Powershell docs for similar functionality. Having the ability to run some of my favorite tools in an easy, reproducible way on Windows has been a refreshing experience while sliding back into the Windows world.
