stevenjmesser/fe-detection

Simple bash script to try to find what version of GOV.UK Frontend is being used on a service

GOV.UK Frontend Detection

Bash script to try to find what version of GOV.UK Frontend is being used on a service. Point the script at a services CSS file to guess the version used.

Example command:

./bin/fe-test.sh -u https://raw.githubusercontent.com/alphagov/govuk-frontend/v4.3.0/dist/govuk-frontend-4.3.0.min.css

Use on a live services

Running the following command:

./bin/fe-test.sh -u https://create-energy-label.service.gov.uk/assets/static/css/main.css

Gives the following output:

✓ 1.0.0 present
✓ 1.1.0 present
✓ 1.2.0 present
✓ 1.3.0 present
✓ 2.0.0 present
✓ 2.1.0 present
✓ 2.2.0 present
✓ 2.5.0 present
✓ 2.6.0 present
✓ 2.7.0 present
✓ 2.9.0 present
✓ 2.10.0 present
✓ 2.11.0 present
✓ 3.0.0 present
✓ 3.1.0 present
✓ 3.3.0 present
✓ 3.6.0 present
✓ 3.7.0 present
✓ 3.8.0 present
✓ 3.9.0 present
✓ 3.10.0 present
✓ 3.11.0 present

So version 3.11.0 of GOV.UK Frontend is most likely being used on this service.

Use on a CSS file

Some services restrict the downloading of assets via curl, so you can download via the browser then pass them into the script using the -f flag:

./bin/fe-test.sh -f css-filename.css

Methodology

The 'dist` version of the CSS it taken and differences between versions are identified, then used to pin down a particular version of GOV.UK Frontend being used. Use the following command to do this:

curl -s https://raw.githubusercontent.com/alphagov/govuk-frontend/v4.3.0/dist/govuk-frontend-4.3.0.min.css | cssbeautify-cli -s > ./css/govuk-frontend-4.3.0.css

Generating diffs

For future reference it is possible to generate file diffs using git with the following command:

./generate-diffs.sh

Caveats

This is always going to be an approximate version test. If all services were using the dist version of the CSS it would be easy. But as service teams can pick / choose certain components to include in their build process. So at some point they may not include CSS that is being used to pin down a particular version.

Testing

Tests written using Bats: Bash Automated Testing System. Run using the bats fe-test.bats command.

Depends on:

• cURL
• cssbeautify-cli
• Bats

To add a new version of GOV.UK Frontend

# Download and beautify the css
# e.g. curl -s https://raw.githubusercontent.com/alphagov/govuk-frontend/v4.3.0/dist/govuk-frontend-4.3.0.min.css | cssbeautify-cli -s > ./css/govuk-frontend-4.3.0.css
curl -s https://raw.githubusercontent.com/alphagov/govuk-frontend/v[VERSION]/dist/govuk-frontend-[VERSION].min.css | cssbeautify-cli -s > ./css/govuk-frontend-[VERSION].css

# generate the new diffs
./generate-diffs.sh

# Examine the new version diff looking for a unique change for this version
# Add version + unique change to `fe-test.sh`
# Add new test to `fe-test.bats` and run test
bats ./bin/fe-test.bats