How to install Scratch 2 on Ubuntu 16.10. or 17.04 (64bit)?

I have been playing around with this couple of hours. First I tried to trace the Adobe Air Application Installer and find, what's happening inside.

$ sudo strace -s 500 -t -o air_scratch.txt Adobe\ AIR/Versions/1.0/Adobe\ AIR\ Application\ Installer ~/Downloads/Scratch-456.0.1.air 

And I found this line:

read(18, "dpkg-deb: error: treewalk root /tmp/FlashTmp.3TWnKI/build/DEBIAN is not a directory\n", 4096) = 84

It seems to new dpkg cannot handle links as the previous one. This can be fixed by wrapper script placed e.g. to ~/air/bin/dpkg and changing the PATH variable before running Adobe Air Application Installer. Unfortunately, the Scratch cannot be installed without sudo, and changing PATH for sudo is not so easy.

Then I found a polish forum of unhappy tax payers, which are solving similar problems (they need run some Air app from ministry of finance on Debian/Ubuntu): https://forum.dug.net.pl/viewtopic.php?pid=310108.

And deep inside this forum I found some hints, how to run Scratch 2 on Ubuntu 16.10/17.04 (even without adobeair.deb installation).

This is my final working solution, tested on clean installation.

# install necesary i386 libraries
$ sudo apt-get install libgtk2.0-0:i386 libstdc++6:i386 libxml2:i386 libxslt1.1:i386 libcanberra-gtk-module:i386 gtk2-engines-murrine:i386 libqt4-qt3support:i386 libgnome-keyring0:i386 libnss-mdns:i386 libnss3:i386

# make keyring visible for Adobe Air
$ sudo ln -s /usr/lib/i386-linux-gnu/libgnome-keyring.so.0 /usr/lib/libgnome-keyring.so.0
$ sudo ln -s /usr/lib/i386-linux-gnu/libgnome-keyring.so.0.2.0 /usr/lib/libgnome-keyring.so.0.2.0

# Download Adobe Air
cd ~/Downloads
wget http://airdownload.adobe.com/air/lin/download/2.6/AdobeAIRSDK.tbz2
$ sudo mkdir /opt/adobe-air-sdk
$ sudo tar jxf AdobeAIRSDK.tbz2 -C /opt/adobe-air-sdk

# Download Air runtime/SDK from Archlinux
wget https://aur.archlinux.org/cgit/aur.git/snapshot/adobe-air.tar.gz
$ sudo tar xvf adobe-air.tar.gz -C /opt/adobe-air-sdk
$ sudo chmod +x /opt/adobe-air-sdk/adobe-air/adobe-air

# Get actual scratch file URL from https://scratch.mit.edu/scratch2download/
$ sudo mkdir /opt/adobe-air-sdk/scratch
wget https://scratch.mit.edu/scratchr2/static/sa/Scratch-456.0.1.air
$ sudo cp Scratch-456.0.1.air /opt/adobe-air-sdk/scratch/
cp Scratch-456.0.1.air /tmp/
cd /tmp/
unzip /tmp/Scratch-456.0.1.air
$ sudo cp /tmp/icons/AppIcon128.png /opt/adobe-air-sdk/scratch/scratch.png

Create launcher:

$ cat << _EOF_ > /usr/share/applications/Scratch2.desktop
[Desktop Entry]
Encoding=UTF-8
Version=1.0
Type=Application
Exec=/opt/adobe-air-sdk/adobe-air/adobe-air /opt/adobe-air-sdk/scratch/Scratch-456.0.1.air
Icon=/opt/adobe-air-sdk/scratch/scratch.png
Terminal=false
Name=Scratch 2
Comment=Programming system and content development tool
Categories=Application;Education;Development;ComputerScience;
MimeType=application/x-scratch-project
_EOF_

$ chmod +x /usr/share/applications/Scratch2.desktop

And that's it. First run is a little bit longer, as the Air is unpacking Scratch 2 application to ~/.appdata/edu.media.mit.Scratch2Editor folder.