The preferred way to install mitmproxy - whether you're installing the latest release or from source - is to use pip. If you don't already have pip on your system, you can find installation instructions here.
pip install mitmproxy
If you also want to install the optional packages AMF, protobuf and CSS content views, do this:
pip install "mitmproxy[contentviews]"
The easiest way to get up and running on OSX is to download the pre-built binary packages from mitmproxy.org. If you still want to install using pip, there are a few things to keep in mind:
There are a few bits of customization you might want to do to make mitmproxy comfortable to use on OSX. The default color scheme is optimized for a dark background terminal, but you can select a palette for a light terminal background with the --palette option. You can use the OSX open program to create a simple and effective ~/.mailcap file to view request and response bodies:
application/*; /usr/bin/open -Wn %s audio/*; /usr/bin/open -Wn %s image/*; /usr/bin/open -Wn %s video/*; /usr/bin/open -Wn %s
On Ubuntu, you will need the following native packages to install mitmproxy from source: