Using pygsm-gateway¶

Caveats and Incompatibilities¶

pygsm-gateway is a new GSM backend or “gateway” for RapidSMS projects. It connects to the modem the same way the rapidsms.backends.gsm backend does, but instead of communicating directly with RapidSMS via Python code, it uses HTTP to send and receive machines to and from RapidSMS.

Because of this, pygsm-gateway cannot be used as a backend in the typical sense of the word, but must be used in conjunction with rapidsms-threadless-router or rapidsms-httprouter. In theory it could also be used with the rapidsms.backends.http backend, but this has not been tested and this backend may be phased out in a future release of RapidSMS.

Configuring and Running¶

To configure and run pygsm-gateway, complete the following steps:

Customize modem configuration and message handler URL in bin/pygsm-gateway.py:
```
args = {
    'url': 'http://localhost:8000/backend/pygsm-gateway/',
    'url_args': {},
    'modem_args': {
        'port': '/dev/ttyACM0',
        'baudrate': '115200',
        'rtscts': '1',
        'timeout': '10',
    }
}
```
The format is similar to that for the gsm gateway in the old INSTALLED_BACKENDS, but has been reorganized slightly to improve usability. The url and url_args parameters tell pygsm-gateway where to deliver inbound messages from the modem. url_args can be left empty unless you need to pass additional POST variables, such as a username or password, to the receiving URL. The modem_args parameter tells pygsm-gateway what arguments to pass directly to the PyGSM modem.
After customizing the configuration, create a virtual environment containing the necessary requirements and start the gateway:
```
mkvirtualenv --distribute pygsm-gateway
pip install -r requirements.txt
python setup.py install
bin/pygsm-gateway.py
```
pygsm-gateway will boot the modem, spawn a thread to poll the modem, and then start up a single-threaded HTTP server to receive outbound messages from RapidSMS.

Using with rapidsms-threadless-router¶

The simple-http backend in rapidsms-threadless-router provides the foundation for building http-powered services and works seamlessly with pygsm-gateway.

simple-http Setup

Add http app to INSTALLED_APPS:

INSTALLED_APPS = [
    # ...
    "threadless_router.backends.http",
    # ...
]

Add a simple-http backend for pygsm-gateway to INSTALLED_BACKENDS:

INSTALLED_BACKENDS = {
    # ...
    "pygsm-gateway": {
        "ENGINE": "threadless_router.backends.http.outgoing",
        "outgoing_url": 'http://localhost:8080/',
    },
    # ...
}

Add http urls:

urlpatterns = patterns('',
    # ...
    (r'^backend/', include('threadless_router.backends.http.urls')),
    # ...
)

Now incoming requests for /backend/pygsm-gateway/ will be handled by rapidsms-threadless-router.