From cfed11b963c50201924377faf10ed80032974277 Mon Sep 17 00:00:00 2001
From: Max Mehl <max.mehl@deutschebahn.com>
Date: Wed, 12 Aug 2026 11:37:41 +0200
Subject: [PATCH] feat: add cache feature

---
 .github/workflows/selftest.yml |  1 +
 README.md                      |  1 +
 action.yml                     | 24 ++++++++++++++++++++++--
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/selftest.yml b/.github/workflows/selftest.yml
index 16dadcd..4a5eacd 100644
--- a/.github/workflows/selftest.yml
+++ b/.github/workflows/selftest.yml
@@ -85,5 +85,6 @@ jobs:
           linkchecker_exclude: "example.com,example.org"
           linkchecker_include_fragments: true
           linkchecker_verbose: true
+          linkchecker_cache_age: "1d"
           linkchecker_extra_args: "--index-files index.html"
           gh_deployment: "preview"
diff --git a/README.md b/README.md
index 2c7040a..5dc0b4e 100644
--- a/README.md
+++ b/README.md
@@ -133,6 +133,7 @@ This behaviour is expected and is not a failure. To trigger a deployment for a f
 | `linkchecker_retry_times` | <p>Retry delay in seconds for link checking</p> | `false` | `5` |
 | `linkchecker_fail_on_errors` | <p>Fail workflow on link check errors (true/false)</p> | `false` | `false` |
 | `linkchecker_verbose` | <p>Turn on verbose linkchecker logging in action logs (true/false)</p> | `false` | `false` |
+| `linkchecker_cache_age` | <p>Cache age for link checking (e.g. 1d), <code>0</code> disables caching</p> | `false` | `0` |
 | `linkchecker_extra_args` | <p>Extra arguments to pass to the link checker (e.g. --some-flag value)</p> | `false` | `""` |
 | `sticky_comment_enabled` | <p>Whether to enable sticky comments for the pull request. Defaults to true.</p> | `false` | `true` |
 | `step_summary_enabled` | <p>Whether to enable step summaries in the GitHub Actions UI. Defaults to true.</p> | `false` | `true` |
diff --git a/action.yml b/action.yml
index aa68bd9..a7d1211 100644
--- a/action.yml
+++ b/action.yml
@@ -124,6 +124,11 @@ inputs:
     required: false
     default: "false"
 
+  linkchecker_cache_age:
+    description: "Cache age for link checking (e.g. 1d), `0` disables caching"
+    required: false
+    default: "0"
+
   linkchecker_extra_args:
     description: "Extra arguments to pass to the link checker (e.g. --some-flag value)"
     required: false
@@ -208,6 +213,7 @@ runs:
         INPUT_LINKCHECKER_OFFLINE: ${{ inputs.linkchecker_offline }}
         INPUT_LINKCHECKER_VERBOSE: ${{ inputs.linkchecker_verbose }}
         INPUT_LINKCHECKER_EXCLUDE: ${{ inputs.linkchecker_exclude }}
+        INPUT_LINKCHECKER_CACHE_AGE: ${{ inputs.linkchecker_cache_age }}
         INPUT_LINKCHECKER_EXTRA_ARGS: ${{ inputs.linkchecker_extra_args }}
       run: | # zizmor: ignore[github-env]
         echo "DATETIME=$(date '+%Y-%m-%d %H:%M:%S %Z')" >> $GITHUB_ENV
@@ -232,6 +238,11 @@ runs:
         else
           echo "LINKCHECKER_EXCLUDE=" >> $GITHUB_ENV
         fi
+        if [ -n "${INPUT_LINKCHECKER_CACHE_AGE}" ]; then
+          echo "LINKCHECKER_CACHE_AGE=--cache --max-cache-age ${INPUT_LINKCHECKER_CACHE_AGE}" >> $GITHUB_ENV
+        else
+          echo "LINKCHECKER_CACHE_AGE=" >> $GITHUB_ENV
+        fi
         if [ -n "${INPUT_LINKCHECKER_EXTRA_ARGS}" ]; then
           echo "LINKCHECKER_EXTRA_ARGS=${INPUT_LINKCHECKER_EXTRA_ARGS}" >> $GITHUB_ENV
         else
@@ -321,8 +332,8 @@ runs:
       if: env.IS_FORK_PR != 'true' && inputs.step_summary_enabled == 'true'
       shell: bash
       run: |
-          SUMMARY="# Website Deployment Summary"$'\n'"Deployed production/preview website to ${URL}"
-          echo "$SUMMARY" >> $GITHUB_STEP_SUMMARY
+        SUMMARY="# Website Deployment Summary"$'\n'"Deployed production/preview website to ${URL}"
+        echo "$SUMMARY" >> $GITHUB_STEP_SUMMARY
 
     - name: "Sticky Comment: Add or Update"
       if: env.IS_FORK_PR != 'true' && inputs.sticky_comment_enabled == 'true' && env.IS_PREVIEW == 'true'
@@ -358,6 +369,14 @@ runs:
     # ----------------------------------------------------------------------------------------------
     # LINK CHECKER
     # ----------------------------------------------------------------------------------------------
+    - name: Restore lychee cache
+      if: ${{ inputs.linkchecker_enabled == 'true' && (env.IS_PRODUCTION == 'true' || env.IS_PREVIEW == 'true' || env.IS_FORK_PR == 'true') }}
+      uses: actions/cache@caa296126883cff596d87d8935842f9db880ef25 # v5.1.0
+      with:
+        path: .lycheecache
+        key: cache-lychee-${{ github.sha }}
+        restore-keys: cache-lychee-
+
     - name: Run Link Checker
       if: ${{ inputs.linkchecker_enabled == 'true' && (env.IS_PRODUCTION == 'true' || env.IS_PREVIEW == 'true' || env.IS_FORK_PR == 'true') }}
       uses: lycheeverse/lychee-action@e7477775783ea5526144ba13e8db5eec57747ce8 # v2.9.0
@@ -369,6 +388,7 @@ runs:
           ${{ env.LINKCHECKER_OFFLINE }}
           ${{ env.LINKCHECKER_EXCLUDE }}
           ${{ env.LINKCHECKER_VERBOSE }}
+          ${{ env.LINKCHECKER_CACHE_AGE }}
           ${{ env.LINKCHECKER_EXTRA_ARGS }}
           --max-concurrency ${{ inputs.linkchecker_max_concurrency }}
           --root-dir ${{ github.workspace }}/${{ inputs.artifact_name }}