API to get newest headless version string

[xng]

I know you can download the latest headless version through https://factorio.com/get-download/lates ... ss/linux64 , but is there any API/URI to fetch just the latest version string?

It feels a little bit wasteful to always have to download the whole package to just check if there's a new version.

[PunPun]

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wget -S --spider https://factorio.com/get-download/latest/headless/linux64 2>&1| grep 'filename'

This currently gives me

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"Content-Disposition: attachment; filename=factorio_headless_x64_0.17.32.tar.xz"

Incase someone needs to know how this works.

This part will only fetch the header of the request without actually downloading the file.

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wget -S --spider https://factorio.com/get-download/latest/headless/linux64

And the latter part will pipe it through grep and get a single line containing the filename of the file that would be sent if you made a full http request.

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2>&1| grep 'filename'

If you want to pipe the result into a file then add

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> 'outputfilename'

Then ofcourse you need some code to compare the result to what you got last time.

Also note that if the request fails for some reason this will result in an empty line being output so you need to check for that too.

Edit:
You can also use

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wget -S --spider https://factorio.com/get-download/latest/headless/linux64 2>&1| grep 'Last-Modified'

to get the time the file was last modified. Incase you use this approach on an url that always returns an identically named file.

[TruePikachu]

IIRC grep can be made to return a nonzero status code if the pattern doesn't match, and wget/curl will return nonzero if it fails.

[PunPun]

IIRC grep can be made to return a nonzero status code if the pattern doesn't match, and wget/curl will return nonzero if it fails.

wget(and cURL) will return a fail message yes but that message contains neither "filename" nor "Last-Modified" so grep will filter everything out and return an empty line. It can indeed be made to output a failure to locate any statement when that happens but this is unneccessary as that only replaces the check if the line was empty to check if we recieved the failure message(which is actually more code) and would not make a difference to the functionality of the script.

Personally I would just add a comment in the script stating "if wget fails to retrieve the header we get an empty line so we just check if the length of the output is longer than 0 before we try to parse the version string." and return a failure code of my own from there if it failed. No need to overcomplicate the script if you know what it is doing and why.

[xng]

I don't know why I didn't get a notification for this response, but thanks a lot @PunPun for your help. It's a perfect solution for me!

[xng]

Here's the resulting script to compare online latest version with the current version:

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#!/bin/bash

online=$( wget -S --spider https://factorio.com/get-download/latest/headless/linux64 2>&1 | grep --color=never -Po '(?<=filename=factorio_headless_x64_).*(?=.tar.xz)' )
installed=$( ./bin/x64/factorio --version | grep --color=never -Po '(?<=Version\: )[0-9.]+' )
if [ "$online" == "$installed" ]
then
  echo "Installed version $installed is the same as the most recent online."
else
  echo "There's another version $online than your current version $installed."
fi

You can of course replace one of the echo statements with a call to your update script.

//Cheers

[Bilka]

There is now an official endpoint https://factorio.com/api/latest-releases, thanks to Sanqui :)

[xng]

There is now an official endpoint https://factorio.com/api/latest-releases, thanks to Sanqui

That's awesome, thanks for the info!

[mrvn]

IIRC grep can be made to return a nonzero status code if the pattern doesn't match, and wget/curl will return nonzero if it fails.

The error from wget won't be visible unless you use bash and set the pipe fail option or check the individual return codes for all piped commands.

For posix shell you have to redirect wget output into a tempfile or variable, check the return code and then grep separately.

[xng]

Anyway, here's the same script using the new API:

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#!/bin/bash

online=$( curl -s https://factorio.com/api/latest-releases | jq -crM '.experimental.headless' )
installed=$( ./bin/x64/factorio --version | grep --color=never -Po '(?<=Version\: )[0-9.]+' )
if [ "$online" == "$installed" ]
then
  echo "Installed version $installed is the same as the most recent online."
else
  echo "There's another version $online than your current version $installed."
fi

The main difference is that it responds slightly quicker and that it is the recommended way of retrieving the version number.

The bash app 'jq' to parse the json can be installed with either apt or snap.