docs: enhance explanation for EXTERNAL_REPOSITORY

README.md

@@ -29,6 +29,7 @@ Table of Contents
     - [⭐️ `GITHUB_TOKEN`](#%EF%B8%8F-github_token)
     - [⭐️ Suppressing empty commits](#%EF%B8%8F-suppressing-empty-commits)
     - [⭐️ Keeping existing files](#%EF%B8%8F-keeping-existing-files)
+    - [⭐️ Deploy to external repository](#%EF%B8%8F-deploy-to-external-repository)
 - [Tips and FAQ](#tips-and-faq)
   - [How to add `CNAME`](#how-to-add-cname)
   - [Deployment completed but you cannot read](#deployment-completed-but-you-cannot-read)
@@ -217,6 +218,26 @@ For example:
     keepFiles: true
 ```
 
+#### ⭐️ Deploy to external repository
+
+By default, your files are published to the repository which is running this action. If you want to publish to another repository on GitHub, set the environment variable `EXTERNAL_REPOSITORY` to `<username>/<external-repository>`.
+
+For example:
+
+```yaml
+- name: Deploy
+  uses: peaceiris/actions-gh-pages@v2.4.0
+  env:
+    ACTIONS_DEPLOY_KEY: ${{ secrets.ACTIONS_DEPLOY_KEY }}
+    EXTERNAL_REPOSITORY: username/username.github.io
+    PUBLISH_BRANCH: master
+    PUBLISH_DIR: ./public
+```
+
+You can use `ACTIONS_DEPLOY_KEY` or `PERSONAL_TOKEN`. When you use `ACTIONS_DEPLOY_KEY`, set your private key to the repository which includes this action and set your public key to your external repository.
+
+Be careful, `GITHUB_TOKEN` has no permission to access to external repositories.
+
 
 
 ## Tips and FAQ

entrypoint.sh

@@ -17,6 +17,13 @@ function skip() {
 }
 
 # check values
+if [ -n "${EXTERNAL_REPOSITORY}" ]; then
+    PUBLISH_REPOSITORY=${EXTERNAL_REPOSITORY}
+else
+    PUBLISH_REPOSITORY=${GITHUB_REPOSITORY}
+fi
+print_info "Deploy to ${PUBLISH_REPOSITORY}"
+
 if [ -n "${ACTIONS_DEPLOY_KEY}" ]; then
 
     print_info "setup with ACTIONS_DEPLOY_KEY"
@@ -26,20 +33,25 @@ if [ -n "${ACTIONS_DEPLOY_KEY}" ]; then
     echo "${ACTIONS_DEPLOY_KEY}" > /root/.ssh/id_rsa
     chmod 400 /root/.ssh/id_rsa
 
-    remote_repo="git@github.com:${GITHUB_REPOSITORY}.git"
+    remote_repo="git@github.com:${PUBLISH_REPOSITORY}.git"
 
 elif [ -n "${PERSONAL_TOKEN}" ]; then
 
     print_info "setup with PERSONAL_TOKEN"
 
-    remote_repo="https://x-access-token:${PERSONAL_TOKEN}@github.com/${GITHUB_REPOSITORY}.git"
+    remote_repo="https://x-access-token:${PERSONAL_TOKEN}@github.com/${PUBLISH_REPOSITORY}.git"
 
 elif [ -n "${GITHUB_TOKEN}" ]; then
 
     print_info "setup with GITHUB_TOKEN"
     print_error "Do not use GITHUB_TOKEN, See #9"
 
-    remote_repo="https://x-access-token:${GITHUB_TOKEN}@github.com/${GITHUB_REPOSITORY}.git"
+    if [ -n "${EXTERNAL_REPOSITORY}" ]; then
+        print_error "can not use GITHUB_TOKEN to deploy to a external repository"
+        exit 1
+    fi
+
+    remote_repo="https://x-access-token:${GITHUB_TOKEN}@github.com/${PUBLISH_REPOSITORY}.git"
 
 else
     print_error "not found ACTIONS_DEPLOY_KEY, PERSONAL_TOKEN, or GITHUB_TOKEN"