Blink Cocoa

h1. Building a Python Framework to bundle inside Blink

In order to avoid using the system Python a custom Framework build is needed. Using a bundled Python version will make the package bigger in size, but all package versions are controlled and not up to the environment. Also, we can use the latest Python version, with latest bugfixes and features, since Apple only updates the system Python version on every major OS release.

The following instructions only apply for 64bit builds, 32bit builds are no longer supported.


h2. Building the Python Framework itself

* Install it using Homebrew Download the desired Python version, at the time of this writing, 2.7.9

<pre>
brew wget http://python.org/ftp/python/2.7.9/Python-2.7.9.tar.bz2
</pre>

* Uncompress and get ready to compile

<pre>
tar jxvf Python-2.7.9.tar.bz2
cd Python-2.7.9
</pre>

* Create a temporary directory for the build result

<pre>
mkdir -p /tmp/py
</pre>

* Compile Python (Framework build) with compatibility for OSX >= 10.9

<pre>
./configure --prefix=/tmp/py --enable-framework=/tmp/py MACOSX_DEPLOYMENT_TARGET=10.9
make
make install python
</pre>

The resulting framework will be installed and linked with Homebrew supplied OpenSSL and SQLite versions. Those libraries will need to be copied too. located in /tmp/py

* Change the dynamic link target in the main binary file of the Python Framework

<pre>
cd /tmp/py/Python.framework/Versions/2.7
chmod +w Python
install_name_tool -id @executable_path/../Frameworks/Python.framework/Versions/2.7/Python Python
chmod -w Python
</pre>

The framework is almost ready for inclusion on the project.

*NOTE*: Be careful when copying the framework around, it contains symlinks and if @cp -r@ is used the size will we doubled, use @cp -a@ -RH@ instead.

* Reduce the size of the Python Framework:

There are a number of things that can (and must when submitting a sandbox app to Mac App Store) be removed from the framework directory to make it smaller in size:

<pre>
*.pyc
*.pyo
Versions/Current/lib/python2.7/config/python.o
Versions/Current/Mac
Versions/Current/bin
Versions/Current/share
Versions/Current/Resources/* Versions/Current/Resources/English*
Versions/Current/Resources/*.app
Versions/Current/lib/python2.7/test
Versions/Current/lib/python2.7/plat-*
Versions/Current/lib/python2.7/idlelib
Versions/Current/lib/python2.7/curses
Versions/Current/lib/python2.7/lib2to3
Versions/Current/lib/python2.7/lib-tk
Versions/Current/lib/python2.7/bsddb
Versions/Current/lib/python2.7/lib-dynload/gdbm.so
Versions/Current/lib/python2.7/lib-dynload/readline.so
</pre>

* Prevent system paths from being used with this bundle

Replace @Versions/Current/lib/python2.7/site.py@ with an empty file.

h2. Compiling PyObjC

In order to get a PyObjC version that will work with the framework created above (Python 2.7, 64bits) an equivalent Python must be used to compile it. That is, if has to be a Python 2.7 version (it doesn't have to be the exact version) and it has to be a 64bit version. The MACOSX_DEPLOYMENT_TARGET must also be set to the appropriate value.

PyObjcC can be installed with easy_install or pip. We install it in 2 steps to save some compilation time due to a bug in the build system:

<pre>
pip install pyobjc-core
pip install pyobjc
</pre>

When compiling PyObjC a Python package will be created for every system framework, but not all of them are needed (at the moment), so just pick the ones we use:

<pre>
AddressBook
AppKit
Cocoa
CoreFoundation
Foundation
JavaScriptCore
LaunchServices
PyObjCTools
Quartz
ScriptingBridge
StoreKit
WebKit
objc
</pre>

*NOTE:* The _objc_ package is located inside a _PyObjC_ directory, just copy it from there, without the parent directory.

*NOTE:* _PyObjCTools_ is not a valid Python package, as it lacks a @__init__.py@ file, an empty one needs to be manually created.

h2. Module exceptions

When copying built Python modules into the distribution folder, care must be taken with the 2 following packages:

* zope: an empty @__init__.py@ file must be created in the @zope@ directory
* cryptography: the @*-dist.info@ must be copied too

h1. Creating a sandbox (Python virtualenv)

<pre>
sudo easy_install pip
sudo pip install virtualenv virtualenvwrapper
</pre>

Add to ~.bashrc

<pre>
# Virtualenv
export WORKON_HOME=$HOME/.virtualenvs
export PIP_VIRTUALENV_BASE=$WORKON_HOME
export PIP_RESPECT_VIRTUALENV=true
export VIRTUALENVWRAPPER_SCRIPT=/usr/local/bin/virtualenvwrapper.sh
[[ -f /usr/local/bin/virtualenvwrapper_lazy.sh ]] && source /usr/local/bin/virtualenvwrapper_lazy.sh
</pre>

Creating a sandbox:

<pre>
mkvirtualenv -p $(which python2.7) sandbox
</pre>

Exiting the sandbox:

<pre>
deactivate
</pre>

Entering the sandbox:

<pre>
workon sandbox
</pre>