diff --git a/README.rst b/README.rst index 4c3d79314..8fe8de646 100644 --- a/README.rst +++ b/README.rst @@ -1,4 +1,3 @@ -==================== OpenStack Python SDK ==================== diff --git a/doc/source/index.rst b/doc/source/index.rst index 4f5c179a6..b987636c6 100644 --- a/doc/source/index.rst +++ b/doc/source/index.rst @@ -11,4 +11,12 @@ Contents: contributing glossary +Classes +======= + +.. toctree:: + :maxdepth: 1 + + transport + .. include:: ../../README.rst diff --git a/doc/source/transport.rst b/doc/source/transport.rst new file mode 100644 index 000000000..dcbb25316 --- /dev/null +++ b/doc/source/transport.rst @@ -0,0 +1,112 @@ +Transport +========= + +Class ``openstack.transport.Transport`` is a subclass of ``requests.Session`` that +adds some features that are common in OpenStack APIs or can be globally controlled +by an application. Its use is incredibly similar to ``requests.Session`` such +that we only will cover the differences in detail here. + +Transport object +---------------- + +Class ``openstack.transport.Transport(user_agent=None, verify=True, redirect=DEFAULT_REDIRECT_LIMIT, ...)`` + +Create a new ``Transport`` object. In addition to those listed below, all +arguments available to ``requests.Session`` are available here: + +* user_agent - Set the default ``User-Agent`` header (default: ``None``) +* verify - If ``True``, the SSL cert will be verified. It can also be set to + a CA_BUNDLE path. (default: ``True``) +* redirect - Disallow redirects if ``False``, or allow ``requests.Session`` to + handle redirects if ``True``. An integer can instead be passed to specify + the maximum number of redirections followed. + +Method ``Transport.request(method, url, redirect=None, **kwargs)`` + +Perform an HTTP request. The following arguments differ from ``requests.Session``: + +* redirect - (integer) The maximum number of redirections followed in a request. + (boolean) No redirections if False, ``requests.Session`` handles redirection + if True. (default: ``openstack.transport.DEFAULT_REDIRECT_LIMIT``) +* json - Request body to be encoded as JSON. Overwrites ``data`` argument if present. + (default: ``None``) +* user_agent - Set the default ``User-Agent`` header (default: ``None``) + +Examples +-------- + +Basic HTTP GET +~~~~~~~~~~~~~~ + +Making a basic HTTP GET call is very simple:: + + from openstack import transport + trans = transport.Transport() + versions = trans.get('cloud.example.com:5000').json + +will retrieve the version data served by the Identity API into a Python dict. + +HTTP POST +~~~~~~~~~ + +Creating a new object in an OpenStack service is similarly simple:: + + from openstack import transport + trans = transport.Transport() + new_record = {'name': 'The White Albumn', 'artist': 'The Beatles'} + resp = trans.post('cloud.example.com:4999/record', json=new_record) + +Passing in the new_record dict with the ``json`` keyword argument performs the +``json.dumps()`` prior to the request being sent. This is an addition to +the capabilities of ``requests.Session``. + +Additional HTTP Methods +~~~~~~~~~~~~~~~~~~~~~~~ + +Just as in ``requests.Session``, all of the HTTP verbs have corresponding +methods in the ``Transport`` object. + +SSL/TLS and Certificates +~~~~~~~~~~~~~~~~~~~~~~~~ + +The ``verify`` argument to ``Transport.request()`` can now be set when the +Transport object is created. It can still be overwritten during any +individual call to ``request()`` or the HTTP verb methods. + +To set the default hostname verification for the Transport to use a custom +CA certificate file:: + + from openstack import transport + trans = transport.Transport(verify='/etc/tls/local-ca-certs.crt') + +The same usage from ``requests`` is still available. To use the default CA +certificate file for a single request:: + + versions = trans.get('cloud.example.com:5000', verify=True) + +Or hit on a host with a self-signed certificate:: + + versions = trans.get('cloud.example.com:5000', verify=None) + +Redirection +~~~~~~~~~~~ + +Redirection handling differs from ``requests`` by default as this module is +expected to be primarily used for querying REST API servers. The redirection +model differs in that ``requests`` follows some browser patterns where it +will redirect POSTs as GETs for certain statuses which is not want we want +for an API. + +See: https://en.wikipedia.org/wiki/Post/Redirect/Get + +User Agent +~~~~~~~~~~ + +The ``User-Agent`` header may be set when the Transport object is created in +addition to the existing per-request mode. The determination of how to set +the ``User-Agent`` header is as follows: + +* If the ``user_agent`` argument is included in the ``request()`` call use it +* Else if ``User-Agent`` is set in the headers dict use it +* Else if ``user_agent`` argument is included in the ``Transport`` construction use it +* Else use ``transport.DEFAULT_USER_AGENT``