python-screenshot-server

A web server for creating webpage screenshot or thumbnail (from url), with cache feature.

Installation

Install git:

    # Ubuntu
    apt-get install git-core python python-setuptools
    # or Centos
    yum install git-core python python-setuptools

Then you can clone the repository:

    cd /opt
    mkdir python-screenshot-server
    git clone --recursive https://github.com/Deisss/python-screenshot-server.git python-screenshot-server

We need to install everything for making python-webkit2png working:

    # Ubuntu (as doc suggest)
    apt-get install python-qt4 libqt4-webkit xvfb flashplugin-installer
    # or Centos
    # You will need EPEL for PyQt4-webkit, here is for Centos 6 (search on internet if this link is broken):
    su -c 'rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm'
    yum install -y python PyQt4 PyQt4-webkit xorg-x11-server-Xvfb

Now the system include the python-webkit2png git also (threw clone --recursive), so lets finish installation:

    cd python-screenshot-server/python-webkit2png
    python setup.py install

Finally, you will need python bottle (and tornado as server) to handle incomming user requests:

    pip install bottle tornado

The system should now be correctly setup. But you may need extra content, especially on headless server.

    # On CentOS
    yum groupinstall fonts

This will install most of basic fonts for rendering text on image. You will also need Xvfb to render graphics.

Configuration

You can configure the server (port, cache, how to find python-webkit2png, ...), by editing config.ini:

    cd /opt/python-screenshot-server
    vim config.ini

Here is a detailled list of available configuration:

Section: WEBKIT2PNG

• root: the main path to find webkit2png (can be relative or absolute path)
• app: From the root path, where to find webkit2png script (should not be needed to change)
• timeout: Integer value to describe timeout before considering a site is not responding

Section: SERVER

• url: The url to bind on server, leave blank should be nice
• port: Integer value to specify the current port to use
• localhost: Boolean, define if we allow localhost url (true) or not (false)

Section: CACHE

• enable: boolean to indicate if cache should be working or not (strongly pro for true)
• lifetime: The time an image will be consider as valid. You can put few days without trouble here
• path: The folder to store cache inside
• garbadge: A thread is running in parallel to clear old image, indicate how long to wait before new gargadge pass

Start server

Just run python python server.py

And that's it the server is running and ready to handle requests.

Now, you may still get blank image with the following error: 'Cannot connect to X server'. It means you need Xvfb to run before:

    Xvfb :25 -screen 0 4096x10000x24 2>/dev/null &
    export DISPLAY=127.0.0.1:25.0

Should correct this, even on headless server.

You may also be interested into the font packages to render font (you may see trouble with font on headless server), on CentOS:

    yum groupinstall fonts

Should remove blank fonts to show everything as expected!

Usage

You can change the rendering behaviour threw parameter you pass to url: The most basic url should looks like this: http://localhost:9494/url=http://www.google.fr

Parameter you can send are:

• url: needed, specify the full url of the page (including http/https)
• xvfb: Start and xvfb instance with the given size, example 90*60 which means 90px and 60px (width/height).
• geometry: The geometry of the screenshot browser, example 250*80 wich means 250px and 80px (width/height).
• scale: The image scale (to this size), example 300*200 wich means 300px and 200px (width/height).
• aspect-ratio: The aspect ratio to use, can be "ignore", "keep", "crop", "expand".
• wait: Any positive integer. Wait X seconds before taking the screenshot, take care of timeout limit.
• transparent: Any value except "false" and "0" will be taken as true. Ask webkit2png to use transparent image (need CSS transparent in html page).
• encoded-url: Any value except "false" and "0" will be taken as true. Say to webkit2png the url is encoded.

Some test you can run to check if it's working:

• goole thumbnail
• twitter thumbnail

Enjoy !