path: root/external_libs/python/jsonrpclib-pelix-0.2.5/README.rst

JSONRPClib (patched for Pelix)
##############################

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This library is an implementation of the JSON-RPC specification.
It supports both the original 1.0 specification, as well as the
new (proposed) 2.0 specification, which includes batch submission, keyword
arguments, etc.

It is licensed under the Apache License, Version 2.0
(http://www.apache.org/licenses/LICENSE-2.0.html).


About this version
******************

This is a patched version of the original ``jsonrpclib`` project by
Josh Marshall, available at https://github.com/joshmarshall/jsonrpclib.

The suffix *-pelix* only indicates that this version works with Pelix Remote
Services, but it is **not** a Pelix specific implementation.

* This version adds support for Python 3, staying compatible with Python 2.
* It is now possible to use the dispatch_method argument while extending
  the SimpleJSONRPCDispatcher, to use a custom dispatcher.
  This allows to use this package by Pelix Remote Services.
* It can use thread pools to control the number of threads spawned to handle
  notification requests and clients connections.
* The modifications added in other forks of this project have been added:

  * From https://github.com/drdaeman/jsonrpclib:

    * Improved JSON-RPC 1.0 support
    * Less strict error response handling

  * From https://github.com/tuomassalo/jsonrpclib:

    * In case of a non-pre-defined error, raise an AppError and give access to
      *error.data*

  * From https://github.com/dejw/jsonrpclib:

    * Custom headers can be sent with request and associated tests

* The support for Unix sockets has been removed, as it is not trivial to convert
  to Python 3 (and I don't use them)
* This version cannot be installed with the original ``jsonrpclib``, as it uses
  the same package name.


Summary
*******

This library implements the JSON-RPC 2.0 proposed specification in pure Python.
It is designed to be as compatible with the syntax of ``xmlrpclib`` as possible
(it extends where possible), so that projects using ``xmlrpclib`` could easily
be modified to use JSON and experiment with the differences.

It is backwards-compatible with the 1.0 specification, and supports all of the
new proposed features of 2.0, including:

* Batch submission (via MultiCall)
* Keyword arguments
* Notifications (both in a batch and 'normal')
* Class translation using the ``__jsonclass__`` key.

I've added a "SimpleJSONRPCServer", which is intended to emulate the
"SimpleXMLRPCServer" from the default Python distribution.


Requirements
************

It supports ``cjson`` and ``simplejson``, and looks for the parsers in that
order (searching first for ``cjson``, then for the *built-in* ``json`` in 2.6+,
and then the ``simplejson`` external library).
One of these must be installed to use this library, although if you have a
standard distribution of 2.6+, you should already have one.
Keep in mind that ``cjson`` is supposed to be the quickest, I believe, so if
you are going for full-on optimization you may want to pick it up.

Since library uses ``contextlib`` module, you should have at least Python 2.5
installed.


Installation
************

You can install this from PyPI with one of the following commands (sudo
may be required):

.. code-block:: console

   easy_install jsonrpclib-pelix
   pip install jsonrpclib-pelix

Alternatively, you can download the source from the GitHub repository
at http://github.com/tcalmant/jsonrpclib and manually install it
with the following commands:

.. code-block:: console

   git clone git://github.com/tcalmant/jsonrpclib.git
   cd jsonrpclib
   python setup.py install


SimpleJSONRPCServer
*******************

This is identical in usage (or should be) to the SimpleXMLRPCServer in the
Python standard library. Some of the differences in features are that it
obviously supports notification, batch calls, class translation (if left on),
etc.
Note: The import line is slightly different from the regular SimpleXMLRPCServer,
since the SimpleJSONRPCServer is distributed within the ``jsonrpclib`` library.

.. code-block:: python

   from jsonrpclib.SimpleJSONRPCServer import SimpleJSONRPCServer

   server = SimpleJSONRPCServer(('localhost', 8080))
   server.register_function(pow)
   server.register_function(lambda x,y: x+y, 'add')
   server.register_function(lambda x: x, 'ping')
   server.serve_forever()

To start protect the server with SSL, use the following snippet:

.. code-block:: python

   from jsonrpclib.SimpleJSONRPCServer import SimpleJSONRPCServer

   # Setup the SSL socket
   server = SimpleJSONRPCServer(('localhost', 8080), bind_and_activate=False)
   server.socket = ssl.wrap_socket(server.socket, certfile='server.pem',
                                   server_side=True)
   server.server_bind()
   server.server_activate()

   # ... register functions
   # Start the server
   server.serve_forever()


Notification Thread Pool
========================

By default, notification calls are handled in the request handling thread.
It is possible to use a thread pool to handle them, by giving it to the server
using the ``set_notification_pool()`` method:

.. code-block:: python

   from jsonrpclib.SimpleJSONRPCServer import SimpleJSONRPCServer
   from jsonrpclib.threadpool import ThreadPool

   # Setup the thread pool: between 0 and 10 threads
   pool = ThreadPool(max_threads=10, min_threads=0)

   # Don't forget to start it
   pool.start()

   # Setup the server
   server = SimpleJSONRPCServer(('localhost', 8080), config)
   server.set_notification_pool(pool)

   # Register methods
   server.register_function(pow)
   server.register_function(lambda x,y: x+y, 'add')
   server.register_function(lambda x: x, 'ping')

   try:
       server.serve_forever()
   finally:
       # Stop the thread pool (let threads finish their current task)
       pool.stop()
       server.set_notification_pool(None)


Threaded server
===============

It is also possible to use a thread pool to handle clients requests, using the
``PooledJSONRPCServer`` class.
By default, this class uses pool of 0 to 30 threads. A custom pool can be given
with the ``thread_pool`` parameter of the class constructor.

The notification pool and the request pool are different: by default, a server
with a request pool doesn't have a notification pool.

.. code-block:: python

   from jsonrpclib.SimpleJSONRPCServer import PooledJSONRPCServer
   from jsonrpclib.threadpool import ThreadPool

   # Setup the notification and request pools
   nofif_pool = ThreadPool(max_threads=10, min_threads=0)
   request_pool = ThreadPool(max_threads=50, min_threads=10)

   # Don't forget to start them
   nofif_pool.start()
   request_pool.start()

   # Setup the server
   server = PooledJSONRPCServer(('localhost', 8080), config,
                                thread_pool=request_pool)
   server.set_notification_pool(nofif_pool)

   # Register methods
   server.register_function(pow)
   server.register_function(lambda x,y: x+y, 'add')
   server.register_function(lambda x: x, 'ping')

   try:
       server.serve_forever()
   finally:
       # Stop the thread pools (let threads finish their current task)
       request_pool.stop()
       nofif_pool.stop()
       server.set_notification_pool(None)

Client Usage
************

This is (obviously) taken from a console session.

.. code-block:: python

   >>> import jsonrpclib
   >>> server = jsonrpclib.ServerProxy('http://localhost:8080')
   >>> server.add(5,6)
   11
   >>> server.add(x=5, y=10)
   15
   >>> server._notify.add(5,6)
   # No result returned...
   >>> batch = jsonrpclib.MultiCall(server)
   >>> batch.add(5, 6)
   >>> batch.ping({'key':'value'})
   >>> batch._notify.add(4, 30)
   >>> results = batch()
   >>> for result in results:
   >>> ... print(result)
   11
   {'key': 'value'}
   # Note that there are only two responses -- this is according to spec.

   # Clean up
   >>> server('close')()

   # Using client history
   >>> history = jsonrpclib.history.History()
   >>> server = jsonrpclib.ServerProxy('http://localhost:8080', history=history)
   >>> server.add(5,6)
   11
   >>> print(history.request)
   {"id": "f682b956-c8e1-4506-9db4-29fe8bc9fcaa", "jsonrpc": "2.0",
    "method": "add", "params": [5, 6]}
   >>> print(history.response)
   {"id": "f682b956-c8e1-4506-9db4-29fe8bc9fcaa", "jsonrpc": "2.0",
    "result": 11}

   # Clean up
   >>> server('close')()

If you need 1.0 functionality, there are a bunch of places you can pass that in,
although the best is just to give a specific configuration to
``jsonrpclib.ServerProxy``:

.. code-block:: python

   >>> import jsonrpclib
   >>> jsonrpclib.config.DEFAULT.version
   2.0
   >>> config = jsonrpclib.config.Config(version=1.0)
   >>> history = jsonrpclib.history.History()
   >>> server = jsonrpclib.ServerProxy('http://localhost:8080', config=config,
                                       history=history)
   >>> server.add(7, 10)
   17
   >>> print(history.request)
   {"id": "827b2923-5b37-49a5-8b36-e73920a16d32",
    "method": "add", "params": [7, 10]}
   >>> print(history.response)
   {"id": "827b2923-5b37-49a5-8b36-e73920a16d32", "error": null, "result": 17}
   >>> server('close')()

The equivalent ``loads`` and ``dumps`` functions also exist, although with minor
modifications. The ``dumps`` arguments are almost identical, but it adds three
arguments: ``rpcid`` for the 'id' key, ``version`` to specify the JSON-RPC
compatibility, and ``notify`` if it's a request that you want to be a
notification.

Additionally, the ``loads`` method does not return the params and method like
``xmlrpclib``, but instead a.) parses for errors, raising ProtocolErrors, and
b.) returns the entire structure of the request / response for manual parsing.


Additional headers
******************

If your remote service requires custom headers in request, you can pass them
as as a ``headers`` keyword argument, when creating the ``ServerProxy``:

.. code-block:: python

   >>> import jsonrpclib
   >>> server = jsonrpclib.ServerProxy("http://localhost:8080",
                                       headers={'X-Test' : 'Test'})

You can also put additional request headers only for certain method invocation:

.. code-block:: python

   >>> import jsonrpclib
   >>> server = jsonrpclib.Server("http://localhost:8080")
   >>> with server._additional_headers({'X-Test' : 'Test'}) as test_server:
   ...     test_server.ping(42)
   ...
   >>> # X-Test header will be no longer sent in requests

Of course ``_additional_headers`` contexts can be nested as well.


Class Translation
*****************

I've recently added "automatic" class translation support, although it is
turned off by default. This can be devastatingly slow if improperly used, so
the following is just a short list of things to keep in mind when using it.

* Keep It (the object) Simple Stupid. (for exceptions, keep reading.)
* Do not require init params (for exceptions, keep reading)
* Getter properties without setters could be dangerous (read: not tested)

If any of the above are issues, use the _serialize method. (see usage below)
The server and client must BOTH have use_jsonclass configuration item on and
they must both have access to the same libraries used by the objects for
this to work.

If you have excessively nested arguments, it would be better to turn off the
translation and manually invoke it on specific objects using
``jsonrpclib.jsonclass.dump`` / ``jsonrpclib.jsonclass.load`` (since the default
behavior recursively goes through attributes and lists / dicts / tuples).

 Sample file: *test_obj.py*

.. code-block:: python

   # This object is /very/ simple, and the system will look through the
   # attributes and serialize what it can.
   class TestObj(object):
       foo = 'bar'

   # This object requires __init__ params, so it uses the _serialize method
   # and returns a tuple of init params and attribute values (the init params
   # can be a dict or a list, but the attribute values must be a dict.)
   class TestSerial(object):
       foo = 'bar'
       def __init__(self, *args):
           self.args = args
       def _serialize(self):
           return (self.args, {'foo':self.foo,})

* Sample usage

.. code-block:: python

   >>> import jsonrpclib
   >>> import test_obj

   # History is used only to print the serialized form of beans
   >>> history = jsonrpclib.history.History()
   >>> testobj1 = test_obj.TestObj()
   >>> testobj2 = test_obj.TestSerial()
   >>> server = jsonrpclib.Server('http://localhost:8080', history=history)

   # The 'ping' just returns whatever is sent
   >>> ping1 = server.ping(testobj1)
   >>> ping2 = server.ping(testobj2)

   >>> print(history.request)
   {"id": "7805f1f9-9abd-49c6-81dc-dbd47229fe13", "jsonrpc": "2.0",
    "method": "ping", "params": [{"__jsonclass__":
                                  ["test_obj.TestSerial", []], "foo": "bar"}
                                ]}
   >>> print(history.response)
   {"id": "7805f1f9-9abd-49c6-81dc-dbd47229fe13", "jsonrpc": "2.0",
    "result": {"__jsonclass__": ["test_obj.TestSerial", []], "foo": "bar"}}

This behavior is turned by default. To deactivate it, just set the
``use_jsonclass`` member of a server ``Config`` to False.
If you want to use a per-class serialization method, set its name in the
``serialize_method`` member of a server ``Config``.
Finally, if you are using classes that you have defined in the implementation
(as in, not a separate library), you'll need to add those (on BOTH the server
and the client) using the ``config.classes.add()`` method.

Feedback on this "feature" is very, VERY much appreciated.

Why JSON-RPC?
*************

In my opinion, there are several reasons to choose JSON over XML for RPC:

* Much simpler to read (I suppose this is opinion, but I know I'm right. :)
* Size / Bandwidth - Main reason, a JSON object representation is just much smaller.
* Parsing - JSON should be much quicker to parse than XML.
* Easy class passing with ``jsonclass`` (when enabled)

In the interest of being fair, there are also a few reasons to choose XML
over JSON:

* Your server doesn't do JSON (rather obvious)
* Wider XML-RPC support across APIs (can we change this? :))
* Libraries are more established, i.e. more stable (Let's change this too.)

Tests
*****

Tests are an almost-verbatim drop from the JSON-RPC specification 2.0 page.
They can be run using *unittest* or *nosetest*:

.. code-block:: console

   python -m unittest discover tests
   python3 -m unittest discover tests
   nosetests tests