emailtrail 0.3.16

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EmailTrail

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<!-- <img alt="logo" title="logo" src="http://i.imgur.com/VShxJHs.png" width="450"> -->

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|PRs Welcome|

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Analyse hops taken by an Email to reach you. Get structured information
about each hop - Hostnames, Protocol used, Timestamp, and Delay.

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**In your project:** ``pip install emailtrail`` or if you use
`pipenv <http://pipenv.org/>`__ like me ``pipenv install emailtrail``

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Table of Contents
-----------------

- `Usage <#usage>`__
- `Caveats <#caveats>`__
- `Contributing <#contributing>`__
- `Miscellaneous <#miscellaneous>`__

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Usage
-----

We can analyse an email source or raw headers

.. code:: python

email = """
Delivered-To: money@capitalism.com
Received: by 10.129.52.209 with SMTP id b200csp1430876ywa;
Tue, 10 Oct 2017 01:17:02 -0700 (PDT)
X-Received: by 10.31.153.20 with SMTP id b20mr6116862vke.110.1507623422746;
Tue, 10 Oct 2017 01:17:02 -0700 (PDT)
Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65])
by mx.google.com with SMTPS id b31sor1345013uaa.124.2017.10.10.01.17.02
for <money@capitalism.com>
(Google Transport Security);
Tue, 10 Oct 2017 01:17:02 -0700 (PDT)
Received-SPF: pass (google.com: domain of bags@test_email.ua.edu designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65;
X-Received: by 10.176.85.196 with SMTP id w4mr6874179uaa.75.1507623422198; Tue, 10 Oct 2017 01:17:02 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.103.79.86 with HTTP; Tue, 10 Oct 2017 01:17:01 -0700 (PDT)
From: Mr. Money Bags <bags@moneyrules.com>
Date: Tue, 10 Oct 2017 01:17:01 -0700
Subject:
To: money@capitalism.com;
Content-Type: text/plain; charset="UTF-8"
Bcc: satan@wallstreet.com

A business opportunity awaits
"""

Lets analyse it
^^^^^^^^^^^^^^^

.. code:: python

import emailtrail
emailtrail.analyse(email)

.. code:: python

{
'To': u'money@capitalism.com;',
'From': u'Mr. Money Bags <bags@moneyrules.com>',
'Bcc': u'satan@wallstreet.com',
'Cc': u'None',
'trail': [
{
'delay': 0,
'from': '',
'protocol': 'HTTP',
'receivedBy': '10.103.79.86',
'timestamp': 1507623421
},
{
'delay': 1,
'from': 'mail-sor-f65.google.com',
'protocol': 'SMTPS',
'receivedBy': 'mx.google.com',
'timestamp': 1507623422
},
{
'delay': 0,
'from': '',
'protocol': 'SMTP',
'receivedBy': '10.129.52.209',
'timestamp': 1507623422
}
]
}

The analyse function returns a python dictionary. The trail shows the
email hops sorted in chronological order. Each intermediary email server
adds a ``Received`` header to the mail, from which the module parses the
following information:

- ``protocol`` : e.g HTTP, SMTP etc.
- ``from`` : The name the sending computer gave for itself
- ``receivedBy``: The receiving computers name
- ``timestamp`` : Unix epoch

An empty string value is set for fields which couldn't be determined. -
``delay``: The delay (in seconds) is computed by taking the difference
of two consecutive hops. In above example there was a delay of ``1 sec``
from ``10.103.79.86`` to ``mx.google.com``

Analysing a single ``Recieved`` header
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code:: python

>>> header = """from mail-vk0-x233.google.com (mail-vk0-x233.google.com. [2607:f8b0:400c:c05::233])\n by mx.google.com with ESMTPS id d124si110912930vka.142.2016.01.12.10.20.45\n for <support@peacedojo.com>\n (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);\n Wed, 16 Dec 2015 16:34:34 -0600 """

>>> from emailtrail import analyse_hop, extract_protocol_used, extract_from_label, extract_recieved_by_label, extract_timestamp

>>> extract_protocol_used(header)
"ESMTPS"

>>> extract_from_label(header)
"mail-vk0-x233.google.com"

>>> extract_recieved_by_label(header)
"mx.google.com"

>>> extract_timestamp(header)
1450305274

>>> analyse_hop(header)
{
"from": "mail-vk0-x233.google.com",
"receivedBy": "mx.google.com",
"protocol": "ESMTPS",
"timestamp": 1450305274
}

Caveats
~~~~~~~

- Sometimes during delay calculation the timestamp difference may be
negative. It's not possible for a server to recieve the email before
previous one, It means that either one or both of the servers clocks
are off. We assume a delay of ``0`` for this hop.

Contributing
------------

emailtrail uses `pipenv <http://pipenv.org/>`__ for managing virtual env
and package versions. - Fork the repo and clone it. - In project root:
``pipenv install --dev``. This installs packages required for testing
and linting - Jump into your virutal env: ``pipenv shell`` - Running
tests: ``pytest`` - If you want to understand the code, read the test
cases first. - Make your changes -> Pass the tests -> Push to your
branch -> Create pull request -> Profit ??

Miscellaneous
^^^^^^^^^^^^^

In the middle of developing this module, I switched to TDD. Albeit slow
for a first timer initially, It proved to be a very effective approach
later on. - Forces you to think how to structure your code. - Less
coupling, small functions with minimal to none side effects, well
defined interfaces. - Confidence in refactoring code quickly. (Everyone
loves it when their investments pay off)

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:target: http://makeapullrequest.com