Web Scanner

Gives your typical flatbed USB scanner a simple, yet very efficient web interface.

Quick Start

Run the application:

make run

And open it in the browser at http://127.0.0.1:5000/

Prerequisites

This is built to be used with Python 3. Update Makefile to switch to Python 2 if needed.

Some Flask dependencies are compiled during installation, so gcc and Python header files need to be present. For example, on Ubuntu:

apt install build-essential python3-dev

Development environment and release process

• create virtualenv with Flask and Web Scanner installed into it (latter is installed in develop mode which allows modifying source code directly without a need to re-install the app): make venv

• run development server in debug mode: make run; Flask will restart if source code is modified

• run tests: make test (see also: Testing Flask Applications)

• create source distribution: make sdist (will run tests first)

• to remove virtualenv and built distributions: make clean

• to add more python dependencies: add to install_requires in setup.py

• to modify configuration in development environment: edit file settings.cfg; this is a local configuration file and it is ignored by Git - make sure to put a proper configuration file to a production environment when deploying

Deployment

See Flask Deployment Options for a number of ways to deploy your web application. For example, by using Apache and mod_wsgi.

Deployment with Docker (Raspbian + Flask development server)

Install Docker (in this example, on a Raspberry Pi) following the Documentation. In the same folder as the Dockerfile, run the following to build the image:

docker build -t webscanner .

You can test the web application is working by running the following and visiting the IP address of your device on a browser:

docker run -it --rm -p 80:5000 --name webscanner_container webscanner

Leave it running in the background:

docker run -d --rm -p 80:5000 --name webscanner_container webscanner

Leave it running in the background and restart automatically, particularly on server reboot:

docker run -d -p 80:5000 --restart unless-stopped --name webscanner_container webscanner

Deployment with Docker (Alpine + nginx + uwsgi)

A more robust method for deployment on x86 machines is the following:

docker build -t webscanner -f Dockerfile.nginx-uwsgi .
docker run -d --restart=always -p 80:80 --name my_webscanner webscanner

In this case, commands can be sent from the container to the host through SSH. For example, redefine in instance/setting.py, scanner commands as follow. In this case, we need to run the commands directly on the host because scanner drivers are already installed on the host (Ubuntu/Debian) and not available for the Linux distro of the container (Alpine). Although there are other solutions for this particular problem (like using a Debian-based nginx/uwsgi image and installing the scanner drivers in it), this is also an interesting experiment of container to host communication that could be applied to other projects as well:

COMMAND_SCAN = 'ssh -o "StrictHostKeyChecking=no" daredevil@172.17.0.1 /home/daredevil/dev/webscanner/bash/scanDo.sh'
COMMAND_CLEAR = 'ssh -o "StrictHostKeyChecking=no" daredevil@172.17.0.1 /home/daredevil/dev/webscanner/bash/scanClear.sh'
COMMAND_SAVE = 'ssh -o "StrictHostKeyChecking=no" daredevil@172.17.0.1 /home/daredevil/dev/webscanner/bash/scanSave.sh'
COMMAND_SCP_COPY = 'scp -o "StrictHostKeyChecking=no" daredevil@172.17.0.1:{} {}'.format(PDF_FILE_PATH, PDF_FILE_PATH_CONTAINER)

In order for this method to work, password-less login must be enabled as followed:

docker exec -it my_webscanner ssh-keygen
docker exec -it my_webscanner cat /root/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys