Crossbar HTTP 3

Module that provides methods for accessing Crossbar.io HTTP Bridge Services

Fork of the original package by Eric Chapman at The HQ, now supporting Python 2.6, 2.7 and 3+ versions.

Installation

Install Crossbar HTTP 3 with pip:

pip install crossbarhttp3

Basic usage

Call

To call a Crossbar HTTP bridge, do the following:

from crossbarhttp import Client

client = Client('http://127.0.0.1/call')
result = client.call('com.example.add', 2, 3, offset=10)

This will call the following add_something method of an ApplicationSession object:

from autobahn.twisted.wamp import ApplicationSession
from twisted.internet.defer import inlineCallbacks


class MyComponent(ApplicationSession):
    @inlineCallbacks
    def onJoin(self, details):

        def add_something(x, y, offset=0):
            print('Add was called')
            return x + y + offset

        yield self.register(add_something, 'com.example.add')

Publish

To publish to a Crossbar HTTP bridge, do the following:

from crossbarhttp import Client

client = Client('http://127.0.0.1/publish')
result = client.publish('com.example.event', event='new event')

The receiving subscription implemented in an ApplicationSession class would look like this:

from autobahn.twisted.wamp import ApplicationSession
from twisted.internet.defer import inlineCallbacks


class MyComponent(ApplicationSession):
    @inlineCallbacks
    def onJoin(self, details):

        def subscribe_something(event=None, **kwargs):
            print('Publish was called with event %s' % event)

        yield self.subscribe(subscribe_something, 'com.example.event')

Key/Secret

For bridge services that have a key and secret defined, simply include the key and secret in the instantiation of the client.

from crossbarhttp import Client

client = Client('http://127.0.0.1/publish', key='key', secret='secret')

Additional options

There are two more options available in the client instantiation:

• timeout: Lets you specify a number of seconds from which an idle request to the Crossbar.io node will be dismissed (timed out). Defaults to None, meaning that the global default timeout setting will be used.
• silently: If set to True, any failed request to the Crossbar.io node will be returned by the client as None, without raising any exception. Defaults to False, meaning that all failures will raise their correspondent exceptions.

Exceptions

The library will throw the following exceptions. Note that all exceptions subclass from ClientBaseException so you can just catch that if you don't want the granularity.

• ClientBadUrl - The specified URL is not a HTTP bridge service
• ClientBadHost - The specified host name is rejecting the connection
• ClientMissingParams - The call was missing parameters
• ClientSignatureError - The signature did not match
• ClientNoCalleeRegistered - Callee was not registered on the router for the specified procedure
• ClientCallRuntimeError - Procedure triggered an exception

Contributing

All bug-fixes or improvements to the library are welcome.

To contribute, fork the repo and submit a pull request to the develop branch. Please, try to follow this basic coding rules:

• Always include some unit tests for the new code you write or the bugs you fix. Or, update the existent unit tests if necessary.
• Stick to PEP-8 styling.

Testing

In order to test Crossbar HTTP 3 properly you must have a Crossbar.io node in HTTP Bridge mode running in localhost port 8001. You can do that by yourself if you need it, but otherwise there is a Docker image already prepared, so you don't have to bother with this.

To use that image and raise a Docker container with everything working, make sure you have Docker installed and execute this command:

docker run -t -p 8001:8001 --name crossbar-bridge joselpa/crossbar-http-bridge:0.2

Then you can run the unit tests in the regular way:

python setup.py test

License

Released under MIT License.