py3-pmp-wrapper

Description

This package has been designed to facilitate browsing and retrieving content from the Public Media Platform (PMP) API. It makes it easy to generate signed requests and browser hypermedia resources returned by the PMP API.

For more information about PMP, read the documentation <https://github.com/publicmediaplatform/pmpdocs/wiki>_

This application has been created at KBPS Public Broadcasting in San Diego by Erik Aker and it has been licensed under GPL v2.

To Do

1. Testing: pmp_client module requires unit-tests
2. Documentation: Clean and write more.
3. Create Collectiondoc class for creating new collectiondocs

Installation

py3-pmp-wrapper has been written for Python3.3 and Python3.4. It is not compatible with Python2.7 and below. All references below to installing this application refer only to Python versions 3.3 and 3.4.

Distribute & Pip

To install py3-pmp-wrapper with pip <https://pip.pypa.io>_, just run this in your terminal::

$ pip install py3-pmp-wrapper

or, with easy_install <http://pypi.python.org/pypi/setuptools>_::

$ easy_install py3-pmp-wrapper

Get the Code

py3-pmp-wrapper is on GitHub, where the code is available <https://github.com/KPBS/py3-pmp-wrapper>_.

You can clone the public repository::

$ git clone https://github.com/KPBS/py3-pmp-wrapper

Once you have a copy of the source, you can embed it in your Python package, or install it into your site-packages easily::

$ python setup.py install

.. _quickstart:

Quickstart

Create a PMP Client

After the application has been installed, you can create a Client object:

>>> from pmp_api.pmp_client import Client
>>> client = Client("https://api-pilot.pmp.io")

Authenticate Your Client

With a working client, you will need to authenticate using your client-id and client-secret

>>> client.gain_access(CLIENT-ID, CLIENT-SECRET)

Make Requests

Now you're ready to make requests:

>>> home_doc = client.home() # Get homedoc
>>> random_request = client.get("https://Some/arbitrary/endpoint?params=someparam")
>>> random_request
<Navigable Doc: https://Some/arbitrary/endpoint?params=someparam>
 >>> client.document # Most recent result is saved here
<NavigableDoc: https://api-pilot.pmp.io/docs?params=someparam>

The Client will automatically sign all requests and it should renew your access token if it expires.

Navigating

Using the fetched document's navigation object, the Client can follow navigation, if it's present:

# If the document defines a 'next' navigation element, we can follow it
>>> client.next() 
<NavigableDoc: https://api-pilot.pmp.io/docs?guid=SOME_GUID&offset=10>
>>> client.prev() # Same as above, returns None if nothing there...
>>>
>>> client.last()  # requests 'last' page of results as given by document
>>> client.first() # requests 'first' page of results as given by document

We can also go back or forward, like a browser, re-requesting the previous document:

 >>> client.document
<NavigableDoc: https://api-pilot.pmp.io/docs?params=someparam>
>>> client.back()  # This issues a new request; does not pull from cache
<NavigableDoc: https://api-pilot.pmp.io/docs?guid=SOME_GUID>
>>> client.forward()  # same as `back`
<NavigableDoc: https://api-pilot.pmp.io/docs?params=someparam>

Most of the useful navigation is done via urn, the primary method for accessing content, and the Client object provides a query method for use with a urn. For example, let's look at urn:collectiondoc:query:docs, which contains information for querying documents.

>>> document = client.query('urn:collectiondoc:query:docs', 
		   		params={"tag": "samplecontent", 
			        "profile": "story"})
<NavigableDoc: https://api-pilot.pmp.io/docs?guid=SOME_GUID>

NavigableDoc objects

To really get interesting information back, we need to have some way of managing it. For this reason, the Client object returns NavigableDoc elements. These have a number of methods and properties, which should make it easier to extract information from the document.

>>> document = client.query('urn:collectiondoc:query:docs', 
		   		params={"tag": "samplecontent", 
				"profile": "story"})
<NavigableDoc: https://api-pilot.pmp.io/docs?guid=SOME_GUID> 
>>> document.links
{'item': [{'href': 'https://api-pilot.pmp.io/docs/SOMEGUID ...
>>> client.document.items
[{'attributes': {'valid': {'to': '3014-07-29T18:08:11+00:00', 'from': ...
>>> document.querylinks
[{'rels': ['urn:collectiondoc:query:users'], 'href-template': ...

In order to get interesting results back, we generally want to issue queries, but it can be tough to know how to make queries. The NavigableDoc object can help with that.

>>> document.template('urn:collectiondoc:query:docs')
'https://api-pilot.pmp.io/docs{?guid,limit,offset,tag,collection,text,searchsort,has,author,distributor,distributorgroup,startdate,enddate,profile,language}'

In addition, we can find options associated with the urn:

>>> document.options('urn:collectiondoc:query:docs')
{'rels': ['urn:collectiondoc:query:docs'], 'href-template': ...

What if we want to know which urns are listed at a particular endpoint? We must ask the document for its query_types:

>>> for item in document.query_types():
...     print(item)
('Query for users', ['urn:collectiondoc:query:users'])
('Query for schemas', ['urn:collectiondoc:query:schemas'])
('Access documents', ['urn:collectiondoc:hreftpl:docs'])
('Query for documents', ['urn:collectiondoc:query:docs'])
etc.

Finally, you can always retrieve all of the results inside a document by accessing its collectiondoc attribute. This will return a dictionary of all values contained in the document:

>>> document.collectiondoc
{ALL-The_Data ...}

This should cover most use-cases for browsing PMP API content.