Python UPnP Example

Introduction

This code implements a SSDP server and a HTTP server, in order to notify the network that a device is here.

The base of this code was the SSDP module of coherence . I took it, converted it to Python 3, and kept only the interesting parts for this project: the parts that responds to MSEARCH queries.

Technical details

First, a SSDP client will try to search devices on the network by issuing a MSEARCH * query:

M-SEARCH * HTTP/1.1
HOST:239.255.255.250:1900
ST:upnp:rootdevice
MX:2
MAN:"ssdp:discover"

lib/ssdp.py will handle it and reply with a 200:

HTTP/1.1 200 OK
SERVER: ZeWaren example SSDP Server
LOCATION: http://192.168.4.207:8088/jambon-3000.xml
USN: uuid:e427ce1a-3e80-43d0-ad6f-89ec42e46363::upnp:rootdevice
CACHE-CONTROL: max-age=1800
EXT: 
last-seen: 1477147409.432466
ST: upnp:rootdevice
DATE: Sat, 22 Oct 2016 14:44:26 GMT

The client will then fetch the device description:

GET /jambon-3000.xml HTTP/1.1
Cache-Control: no-cache
Connection: Keep-Alive
Pragma: no-cache
Accept: text/xml, application/xml
User-Agent: FDSSDP
Host: 192.168.4.207:8088

And lib/upnp_http_server.py will build and serve that file:

HTTP/1.0 200 OK
Server: BaseHTTP/0.6 Python/3.4.3
Date: Sat, 22 Oct 2016 14:44:26 GMT
Content-type: application/xml

<root>
    <specVersion>
        <major>1</major>
        <minor>0</minor>
    </specVersion>
    <device>
        <deviceType>urn:schemas-upnp-org:device:Basic:1</deviceType>
        <friendlyName>Jambon 3000</friendlyName>
        <manufacturer>Boucherie numrique SAS</manufacturer>
        <manufacturerURL>http://www.boucherie.example.com/</manufacturerURL>
        <modelDescription>Jambon Appliance 3000</modelDescription>
        <modelName>Jambon</modelName>
        <modelNumber>3000</modelNumber>
        <modelURL>http://www.boucherie.example.com/en/prducts/jambon-3000/</modelURL>
        <serialNumber>JBN425133</serialNumber>
        <UDN>uuid:e427ce1a-3e80-43d0-ad6f-89ec42e46363</UDN>
        <serviceList>
            <service>
                <URLBase>http://xxx.yyy.zzz.aaaa:5000</URLBase>
                <serviceType>urn:boucherie.example.com:service:Jambon:1</serviceType>
                <serviceId>urn:boucherie.example.com:serviceId:Jambon</serviceId>
                <controlURL>/jambon</controlURL>
                <eventSubURL/>
                <SCPDURL>/boucherie_wsd.xml</SCPDURL>
            </service>
        </serviceList>
        <presentationURL>http://192.168.4.207:5000/</presentationURL>
    </device>
</root>

The client now knows (nearly) everything about the device.

Relevant links

• UPnP™ Device Architecture 1.1 (UPnP forum, October 15, 2008): http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf
• Coherence - DLNA/UPnP framework for the digital living: https://pypi.python.org/pypi/Coherence