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

* Download the desired Python version, at the time of this writing, 2.7.9

<pre>

wget http://python.org/ftp/python/2.7.9/Python-2.7.9.tar.bz2

</pre>

* Uncompress and get ready to compile

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tar jxvf Python-2.7.9.tar.bz2

cd Python-2.7.9

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* Create a temporary directory for the build result

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mkdir -p /tmp/py

</pre>

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

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./configure --prefix=/tmp/py --enable-framework=/tmp/py MACOSX_DEPLOYMENT_TARGET=10.9

make

make install

</pre>

The resulting framework will be 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 -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/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

</pre>

* Prevent system paths from being used with this bundle

Edit @Versions/Current/lib/python2.7/site.py@:

Near the top of the file, locate the @ENABLE_USER_SITE@ variable, and set it to False:

<pre>

ENABLE_USER_SITE = False

</pre>

Add the following lines at the end on the @main()@ function body:

<pre>

    # Remove system paths so that only things contained in this Framework are used

    sys.path = [x for x in sys.path if not x.startswith(('/System', '/Library', '/usr/local'))]

</pre>

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

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*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:

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mkvirtualenv -p $(which python2.7) sandbox

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Exiting the sandbox:

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deactivate

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Entering the sandbox:

<pre>

workon sandbox

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