Java in Firefox after v52.0 (Checkpoint VPN)

Firefox has changed a few things in its plugin infrastructure and that means Java will no longer work properly after version 52.0 (especially if you are using Checkpoint VPN to access work).

Fortunately one can always install older versions, present here:

Also, be sure to disable automatic updates in the settings to prevent the browser from updating itself (default).

Bonus step (if you are on the mac configuring Checkpoint):

The newest OSX has a safety feature called SIP (System Integration Protection) that will prevent the checkpoint from installing the required files in the system. To work around this, you need to disable it temporarily:

  • Boot into recovery mode (restart and press Command + R on hearing the beep)
  • Open the terminal and type:
  • csrutil disable
  • Reboot
  • Access the vpn and the snx_extender installation step will work.
  • Go back into recovery and enable SIP again:
  • csrutil enable

Happy VPN'ing

OCR using the new open Google Cloud Vision API

Just create a new api key in the developer console, replace it in the code below and it should work. Then you can call "whatever_you_call_the_file.rb /Downloads/some_image_with_text.jpg" and google will OCR-it and the script will print out the recognized text.
require "base64"
require 'net/http'
require 'json'

# Base 64 the input image
b64_data = Base64.encode64([0], "rb").read)

# Stuff we need
api_key = "<YOUR_GOOGLE_API_KEY>"
content_type = "Content-Type: application/json"
url = "{api_key}"
data = {
  "requests": [
      "image": {
        "content": b64_data
      "features": [
          "type": "TEXT_DETECTION",
          "maxResults": 1

# Make the request
url = URI(url)
req =, initheader = {'Content-Type' =>'application/json'})
req.body = data
res =, url.port)
res.use_ssl = true

# res.set_debug_output $stderr

detected_text = ""
res.start do |http| 
  puts "Querying Google for image: #{ARGV[0]}"
  resp = http.request(req)
  # puts resp
  json = JSON.parse(resp.body)
  # puts json
  if json && json["responses"] && json["responses"][0]["textAnnotations"] && json["responses"][0]["textAnnotations"][0]["description"]
    detected_text = json["responses"][0]["textAnnotations"][0]["description"]

puts "Google says the image is: #{detected_text}"

Lock and unlock Ubuntu using your iPhone

If, like me, you suffer from lazius extremis (lazy bastard, for the layman), you probably hate having to lock your computer when you leave and entering a password when you come back.

Fear not, young padawan, UDEV and xdotool to the rescue!

Here's how it works: UDEV (a linux mechanism that detects device events (including USB)) can be configured with rules that fire whenever something changes (i.e. a device is connected or disconnect from the system). When that happens, you want to run a script to lock or unlock your system, based on the type of rule that was fired. So, let's get started:

1. Create the UDEV rules:
1.1. Create a new file at /etc/udev/rules.d/100-lock-unlock-with-iphone.rules, with the following contents:

SUBSYSTEM=="usb", ENV{PRODUCT}=="2bc/12c8/520", ENV{DEVTYPE}=="usb_device", ACTION=="add",    RUN+="/home/youruser/bin/unlock"
SUBSYSTEM=="usb", ENV{PRODUCT}=="2bc/12c8/520", ENV{DEVTYPE}=="usb_device", ACTION=="remove", RUN+="/home/youruser/bin/lock"

1.2. In those lines, replace 2bc/12c8/520 with your device product id, which you can find running the following command in the terminal:

udevadm monitor --environment -u | grep PRODUCT

1.3. Disconnect or connect your iphone and you should see something like this:


1.4. That's the value you put in the rules.
1.5. Replace youruser with your own user name, by the way.

2. Which leaves us with the /home/youruser/bin/lock and unlock scripts to create. Here is the lock script:

export XAUTHORITY=/home/youruser/.Xauthority
export DBUS_SESSION_BUS_ADDRESS=`ps -u youruser e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35`
echo `date` "-" `whoami` "- Locking system..." >> $log
su youruser -c "DISPLAY=:0 gnome-screensaver-command -a"
echo `date` "-" `whoami` "- System locked!" >> $log

2.1. Again, replace youruser with your own.
2.2. You might be wondering what those lines about DBUS and the X server are all about. The reason for those is that UDEV runs stuff as root. And we want to lock and unlock the screen as our own user. Those lines make sure of that.
2.3. For the unlock script we need to install a tool called xdotool. It's basically an automation command that allows you to make the computer type stuff and control the mouse automatically. The reason to use this is because there is no way in hell you can unlock a locked screensaver (believe me, i've tried). This tool simulates user input (moves the mouse a little bit and the enters your password and presses enter). I know it's not the most secure thing in the world but it's the only way i could make it work. Install it with:

sudo apt-get install xdotool

2.4. Here's the unlock script:

 export XAUTHORITY=/home/youruser/.Xauthority
 export DBUS_SESSION_BUS_ADDRESS=`ps -u youruser e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35`
 echo `date` "-" `whoami` "- Unlocking system..." >> $log
 export DISPLAY=:0
 xdotool mousemove 0 0 && xdotool type yourpassword && xdotool key Return
 echo `date` "-" `whoami` "- System unlocked!" >> $log

2.5. Replace youruser with your own user and yourpassword with your user password.

3. Reload the UDEV rules with:

sudo udevadm control --reload-rules

4. And now when you disconnect your phone from the computer, it should lock it. When you plug it back in it should unlock.

5. Happy hacking!