Python module for communicating via GPRS

[kedarm]

Hi!

I am trying to build an application that communicates with a webserver using GPRS. Is there a tutorial/example/etc that gives the basics of GPRS communication using Python?

I have generally always used the Python Code Examples site as a starting point for any module I have attempted to develop. However, the only GPRS related example I find is titled 'How to close an active GPRS connection'

Does anyone know a site/book where I can get some tutorials, etc on GPRS communication?

Thanks

[gaba88]

Hi!

I am trying to build an application that communicates with a webserver using GPRS. Is there a tutorial/example/etc that gives the basics of GPRS communication using Python?

I have generally always used the Python Code Examples site as a starting point for any module I have attempted to develop. However, the only GPRS related example I find is titled 'How to close an active GPRS connection'

Does anyone know a site/book where I can get some tutorials, etc on GPRS communication?

Thanks

hello kedarm

sorry but if you let us know some specific problems then we can get you some pointers. Like if you want to use the network part in Python you can have a look at the urllib and httplibmodule that offers a lot.

Apart from that you can go through this wiki article to get a basic idea of working with web servers using PyS60.

Hope this helps you.

[kedarm]

sorry but if you let us know some specific problems then we can get you some pointers. Like if you want to use the network part in Python you can have a look at the urllib and httplibmodule that offers a lot.

Hi!

Well, I am trying to build an application that sends some data over GPRS to a server (say my computer at home), and then receives some data.
It's just a very basic application, as I am still learning how to use GPRS, python, etc.

Can I use Python socket programming methods to connect to a server on the net and transfer data? Something along the lines of, creating a tcp connection between the phone and my computer and sending data?

Thanks
Kedar

[pavan.pareta]

Hi!

Well, I am trying to build an application that sends some data over GPRS to a server (say my computer at home), and then receives some data.
It's just a very basic application, as I am still learning how to use GPRS, python, etc.

Can I use Python socket programming methods to connect to a server on the net and transfer data? Something along the lines of, creating a tcp connection between the phone and my computer and sending data?

Thanks
Kedar

Hi kedarm,

As Gaba88 suggested you can communication with urllib and httplib module, rest of this you can also used ftplib and TCP/IP socket modules in ftplib module but you must install the ftplib library on your phone then use ftplib module there is some example/sample code available please check it out.

http://mobilenin.com/pys60/info_networking.htm

hope this helps you.

[kedarm]

So, the normal POST methods and GET method from here should work, right?

[gaba88]

So, the normal POST methods and GET method from here should work, right?

hello kedar

ya that should work, for sending data from your mobile to web server.

Regards,

[kedarm]

Hi!

First and foremost, thanks everyone for the help - the GPRS module is working fine! I used the standard GET method given in the Python documentation, and I can access the net.

Is there any way one can pre-select the Access Point? When I start the module to access the internet, I have to choose an "Access Point" from a drop down menu. I get the following options -

"Hutch Access"
"Hutch MMS"
"Hutch World"

I get a similar menu with Airtel (another service provider).
Is there some way to select the access point so that it chooses option 1 every time, instead of offering me the choice? I need to make the application as simple as possible, giving the user as few choices as possible.

I am unsure if the following problem is country-specific (or service provider specific). I am using this phone in India and am using the GPRS facility offered by Vodafone (formerly Hutch) and Airtel.

[croozeus]

Hi!

First and foremost, thanks everyone for the help - the GPRS module is working fine! I used the standard GET method given in the Python documentation, and I can access the net.

Is there any way one can pre-select the Access Point? When I start the module to access the internet, I have to choose an "Access Point" from a drop down menu. I get the following options -

I get a similar menu with Airtel (another service provider).
Is there some way to select the access point so that it chooses option 1 every time, instead of offering me the choice? I need to make the application as simple as possible, giving the user as few choices as possible.

I am unsure if the following problem is country-specific (or service provider specific). I am using this phone in India and am using the GPRS facility offered by Vodafone (formerly Hutch) and Airtel.

Search the forum for "set default access point".

[kedarm]

Hi!

This thread is really useful.

Here is my code to do the same. It checks in a file (ap.txt) for the default access point.

import socket, os
def set_ap():
	if (os.path.isfile(u"C:\\ap.txt"):
		f = open(u"C:\\mordor\\ap.txt","r")
		apid = f.read()
		f.close()
		apo = socket.access_point(int(apid))
		socket.set_default_access_point(apid)
	else:
		apid = socket.select_access_point()
		f = open(u"C:\\mordor\\ap.txt","w")
		f.write(repr(apid))
		f.close()
		socket.set_default_access_point(apid)

Hope this helps someone else searching for setting ap id..

[kedarm]

Hi!

Just came across one more problem. Any idea how to go about this one?

In the GPRS section of the app I am building, I send some data to a specific url. The code (which works fine on the computer) is rather simple -

import httplib, urllib
params = urllib.urlencode({'test': 1})
headers = {"Content-type": "application/x-www-form-urlencoded","Accept": "text/plain"}
conn = httplib.HTTPConnection("sahyadrians.110mb.com:80")
conn.request("POST", "/home.html", params, headers)
response = conn.getresponse()
print response.status, response.reason
# 200 OK
data = response.read()
conn.close()

This code works fine, both on the phone as well as on the computer. Now, if the server is down or the url (in conn.request) is wrong, one would expect to get a simple error from this script saying -

404 Not Found

However, when I tweaked the code (and gave a non-legitimate site) -

import httplib, urllib
params = urllib.urlencode({'test': 1})
headers = {"Content-type": "application/x-www-form-urlencoded","Accept": "text/plain"}
conn = httplib.HTTPConnection("sahyadrians.110mb.com:80")
conn.request("POST", "/non_existent_page.html", params, headers)
response = conn.getresponse()
print response.status, response.reason
# 200 OK
data = response.read()
conn.close()

I got the following errors -

Traceback (most recent call last)
File "<console>", line 1, in ?
File "c:\resource\httplib.py",line 459, in request
self._send_request(method, url, body, headers)
File "c:\resource\httplib.py", line 470, in send_request
self.putrequest(method,url)
File "c:\resource\httplib.py", line 415, in putrequest
raise CannotSendRequest

Any idea why the code does not give me the (expected) 404 error? When I try the same in the emulator, I get the "404 Not Found" error (like expected)

I tried using something like -

try:
conn.request("POST", "/non_existent_page.html", params, headers)
except ValueError:
print "Error"

But it still throws an error.

Any help would be super! Please...

Thanks

[marcelobarrosalmeida]

kedarm,

When accessing http://sahyadrians.110mb.com/non_existent_page.html from PC I was redirected to http://vobyz.com.br/ instead the (expected) 404 error. So, the request was valid, no error at all.

[kedarm]

kedarm,

When accessing http://sahyadrians.110mb.com/non_existent_page.html from PC I was redirected to http://vobyz.com.br/ instead the (expected) 404 error. So, the request was valid, no error at all.

Sorry - my bad! I wanted to give an example of a non-existent page. I didn't realize the server would automatically redirect non-existent page requests to http://vobyz.com.br/.
I guess something like - http://www.iitm.ac.in/tinda or something would be a better example.

The problem is, if attempting to access a legitimate address, and the server fails, the whole application will abort at the error.

Sorry for the bad example.

[kedarm]

Hi!

Just in case there was someone following this thread, I figured it out!

import socket, httplib
conn = httplib.HTTPConnection("www.thissitesurelydoesnotexist:80")
try:
	conn.request("GET","")
except socket.error, msg:
	print "Error - ",msg

Phew! That's a relief!

[marcelobarrosalmeida]

Phew! That's a relief!

Great ! Just an aside: you can handle dns errors and socket errors separately:

import socket
s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
try:
    s.connect(('nokiacom',2222))
except socket.gaierror, e:
    print "ADDR ERROR: %s" % e
except socket.error, e:
    print "ERROR: %s" % e