githubPageDeploy.sh

#!/bin/bash
# modified from https://gist.github.com/domenic/ec8b0fc8ab45f39403dd

set -e # Exit with nonzero exit code if anything fails

SOURCE_BRANCH="master"
TARGET_BRANCH="gh-pages"

# if pull requests or commits to other branches except $SOURCE_BRANCH
# dont deploy
if [ "$TRAVIS_PULL_REQUEST" != "false" -o "$TRAVIS_BRANCH" != "$SOURCE_BRANCH" ]; then
    echo "Skipping deploy. Not in $SOURCE_BRANCH or it is a pull request"
    exit 0
fi

# Save some useful information
REPO=`git config remote.origin.url`
SSH_REPO=${REPO/https:\/\/github.com\//git@github.com:}
SHA=`git rev-parse --verify HEAD`
echo "Repository: $SSH_REPO , last SHA: $SHA"
echo

# changing remote to linsten to all branches
echo "Listing remote fetch......"
git config --get remote.origin.fetch

echo 
echo "Updating remote fetch......"
git config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*"
git config --get remote.origin.fetch

# fetching
echo
echo "Fetching remotes......"
git fetch
git branch -a

echo
echo "Overwriting $TARGET_BRANCH with $SOURCE_BRANCH......"
echo
# from http://superuser.com/questions/716818/git-overwrite-branch-with-master?newreg=91a88353defa444c84b70c758b119363
# checkout $SOURCE_BRANCH
git checkout $SOURCE_BRANCH
# update $SOURCE_BRANCH branch
git pull
# get $TARGET_BRANCH
git checkout $TARGET_BRANCH || git checkout -b $TARGET_BRANCH
# set git credentials
git config --global user.email "$COMMIT_AUTHOR_EMAIL"
git config --global user.name "Travis CI"
# merge using ours to $SOURCE_BRANCH (so it will be using $SOURCE_BRANCH)
git checkout $SOURCE_BRANCH
git merge -s ours $TARGET_BRANCH --no-edit
# reset $TARGET_BRANCH to make it same as $SOURCE_BRANCH
git checkout $TARGET_BRANCH
git merge $SOURCE_BRANCH --no-commit --no-ff

# Building or packaging
echo "Packaging......"
echo
webpack -p

echo 
echo "Showing git status......"
git status

# If there are no changes to origin/$TARGET_BRANCH, then exit
if ! [[ `git status --porcelain` ]]; then
    echo "No changes to the output on this push!!! exiting!!!"
    exit 0
fi

# Commit the overwrite and packaging
echo
echo "Adding files to be commited......"
git add --all
git status
git commit -m "[Travis CI] Deploy GitHubPage from: ${SHA}"
# pull with strategy favouring ours
# https://stackoverflow.com/questions/10697463/resolve-git-merge-conflicts-in-favor-of-their-changes-during-a-pull
echo
echo "Pulling $TARGET_BRANCH....."
git branch --set-upstream-to="origin/$TARGET_BRANCH" "$TARGET_BRANCH"
git pull -s recursive -X ours

# Get the deploy key by using Travis's stored variables to decrypt deploy_key.enc
ENCRYPTED_KEY_VAR="encrypted_${ENCRYPTION_LABEL}_key"
ENCRYPTED_IV_VAR="encrypted_${ENCRYPTION_LABEL}_iv"
ENCRYPTED_KEY=${!ENCRYPTED_KEY_VAR}
ENCRYPTED_IV=${!ENCRYPTED_IV_VAR}

# Decrypt the key, and put it as default key
openssl aes-256-cbc -K $ENCRYPTED_KEY -iv $ENCRYPTED_IV -in deploy_key.enc -out deploy_key -d
chmod 600 deploy_key
cp deploy_key ~/.ssh/id_rsa

# Push the commit
git push $SSH_REPO $TARGET_BRANCH