I prefer to use E-book device but not orielly app or web. At the beginning i want to write a spider, but i found we already have a good tools. Also The book download is for personal use only and does not involve copyright issues.
Step 1 : Get Safaribooks tool
git clone https://github.com/lorenzodifuccia/safaribooks
cd safaribooks
python -m venv test
source test/bin/activate
pip install -r requirements.txt -i http://pypi.douban.com/simple/ --trusted-host=pypi.douban.com/simple
Step 1 : Get Safaribooks tool
Step 2: Login into Orielly and get cookies
Login into Orielly and go to profile page https://learning.oreilly.com/home/
Step 3: Download it
Step 4 : Reading
Step 5: Convert to PDF