python-epo-ops-client 0.0.1

Python client for EPO OPS.

python-epo-ops-client
=====================

python-epo-ops-client is an Apache2 Licensed client library for accessing the
[European Patent Office][EPO]'s ("EPO") [Open Patent Services][OPS] ("OPS")
v.3.1 (based on [v 1.2.10 of the reference guide][OPS guide]).

```
import epo_ops

anonymous_client = epo_ops.Client()
response = anonymous_client.published_data(
reference_type = 'publication', # publication, application, priority
input = epo_ops.Docdb('1000000', 'EP', 'A1'), # original, docdb, epodoc
endpoint = 'biblio', # optional, defaults to biblio in case of published_data
constituents = [] # optional, list of constituents
)

client = epo_ops.RegisteredClient(key='abc', secret='xyz')
client.access_token # To see the current token
response = client.published_data(…)
```

---

## Features

python_epo_ops_client abstracts away the complexities of access EPO OPS:

* Formatting the requests properly
* Bubbling up quota problems as proper HTTP errors
* Handle token authentication and renewals automatically
* Handle throttling properly

There are three main layers to python_epo_ops_client: Client, Throttler, and
Storage.

### Client

The Client contains all the formatting and token handling logic and issues the
requests using Throttler. The Client class is what you'll interact with mostly.

When you issue a request, the response is a
[`requests.Response`][requests.Response] object. If `response.status_code !=
200` then an exception will be raised, it's your responsibility to handle those
exceptions if you want to. The one case that's handled by the RegisteredClient
is when its access token has expired: in this case, the client will
automatically handle the HTTP 400 status and renew the token.

Note that the Client does not attempt to interpret the data supplied by OPS, so
it's your responsibility to parse the XML or JSON payload for your own purpose.

The following custom exceptions are raised for cases when OPS quotas are
exceeded, they are all subclasses of `requests.HTTPError` and offer the same
behavior:

* AnonymousQuotaPerMinuteExceeded
* AnonymousQuotaPerDayExceeded
* IndividualQuotaPerHourExceeded
* RegisteredQuotaPerWeekExceeded

Again, it's up to you to parse the response and decide what to do.

Currently the Client only knows how to issue request for the following
services:

* /published-data/search (search)
* /published-data (retrieval)
* /family (inpadoc)

Please submit pull requests for other services by enhancing the
`epo_ops.api.Client` class.

### Throttler

Throttler is just a thin wrapper around the [Requests][] package. It contains
all the logic for handling different throttling scenarios. Since OPS throttling
is based on a one minute rolling window, we must store historical (at least for
the past minute) throtting controls in order to know what the proper request
frequency is. Each Throttler must be instantiated with a Storage object.

### Storage

The Storage object is responsible for:

1. Knowing how to update the historical record with each request
(`Storage.update()`), making sure to observe the one minute rolling window
rule.
2. Calculating how long to wait before issuing the next request
(`Storage.delay_for()`).

Currently the only Storage backend provided is SQLite, but you can easily write
your own Storage backend (such as file, Redis, etc.). To use a custom Storage
type, just pass the Storage object when you're instantiating a Client object.
See `epo_ops.throttle.storages.Storage` for more implementation details.

---

## Tests

Tests are written using [pytest][]. To run the tests:

1. [Register a OPS user login with EPO][OPS registration]
2. Create an app
3. Record the app's consumer key and secret in `tests/secrets.py` (see
`secrets.py.example`)
4. `py.test -s --cov-report html --cov-report term --cov epo_ops tests`

The tests must be run with a working internet connection, since both OPS and
the [mock Apiary services][Apiary OPS] are online.


[EPO]: http://epo.org
[OPS]: http://www.epo.org/searching/free/ops.html
[OPS registration]: https://developers.epo.org/user/register
[OPS guide]: http://documents.epo.org/projects/babylon/eponet.nsf/0/7AF8F1D2B36F3056C1257C04002E0AD6/$File/OPS_RWS_ReferenceGuide_version1210_EN.pdf
[Requests]: http://requests.readthedocs.org/en/latest/
[requests.Response]: http://requests.readthedocs.org/en/latest/user/advanced/#request-and-response-objects
[pytest]: http://pytest.org/latest/
[Apiary OPS]: http://docs.opsv31.apiary.io


# Release History

## 0.0.1 (2014-01-21)

* Initial release