Checks for relative path names (JamesIves#15)

* Relative

* Update entrypoint.sh

* Update entrypoint.sh

* Another test

* Update entrypoint.sh

* Update entrypoint.sh

README.md

@@ -43,7 +43,7 @@ Below you'll find a description of what each option does.
 | ------------- | ------------- | ------------- | ------------- |
 | `ACCESS_TOKEN`  | In order for GitHub to trigger the rebuild of your page you must provide the action with a GitHub personal access token. You can [learn more about how to generate one here](https://help.github.com/en/articles/creating-a-personal-access-token-for-the-command-line). This **should be stored as a secret.**  | `secrets` | **Yes** |
 | `BRANCH`  | This is the branch you wish to deploy to, for example `gh-pages` or `docs`.  | `env` | **Yes** |
-| `FOLDER`  | The folder in your repository that you want to deploy. If your build script compiles into a directory named `build` you'd put it here. | `env` | **Yes** |
+| `FOLDER`  | The folder in your repository that you want to deploy. If your build script compiles into a directory named `build` you'd put it here. **Folder paths cannot have a leading `/` or `./`**. | `env` | **Yes** |
 | `BASE_BRANCH`  | The base branch of your repository which you'd like to checkout prior to deploying. This defaults to `master`.  | `env` | **No** |
 | `BUILD_SCRIPT`  | If you require a build script to compile your code prior to pushing it you can add the script here. The Docker container which powers the action runs Node which means `npm` commands are valid. If you're using a static site generator such as Jekyll I'd suggest compiling the code prior to pushing it to your base branch.  | `env` | **No** |
 | `CNAME`  | If you're using a [custom domain](https://help.github.com/en/articles/using-a-custom-domain-with-github-pages), you will need to add the domain name to the `CNAME` environment variable. If you don't do this GitHub will wipe out your domain configuration after each deploy. This value will look something like this: `jives.dev`.  | `env` | **No** |

action.yml

@@ -0,0 +1,9 @@
+name: 'Deploy to GitHub Pages'
+description: 'This action will handle the building and deploying process of your project to GitHub Pages.'
+author: 'James Ives <iam@jamesiv.es>'
+runs:
+  using: 'docker'
+  image: 'Dockerfile'
+branding:
+  icon: 'git-commit'
+  color: 'orange'

entrypoint.sh

@@ -20,6 +20,11 @@ then
   exit 1
 fi
 
+case "$FOLDER" in /*|./*)
+  echo "The deployment folder cannot be prefixed with '/' or './'. Instead reference the folder name directly."
+  exit 1
+esac
+
 if [ -z "$COMMIT_EMAIL" ]
 then
   COMMIT_EMAIL="${GITHUB_ACTOR}@users.noreply.github.com"