Question

I’m trying to use the salesforce-python-toolkit to make web services calls to the Salesforce API, however I’m having trouble getting the client to go through a proxy. Since the toolkit is based on top of suds, I tried going down to use just suds itself to see if I could get it to respect the proxy setting there, but it didn’t work either.

This is tested on suds 0.3.9 on both OS X 10.7 (python 2.7) and ubuntu 12.04.

an example request I’ve made that did not end up going through the proxy (just burp or charles proxy running locally):

import suds
ws = suds.client.Client('file://sandbox.xml',proxy={'http':'http://localhost:8888'})
ws.service.login('user','pass')

I’ve tried various things with the proxy – dropping http://, using an IP, using a FQDN. I’ve stepped through the code in pdb and see it setting the proxy option. I’ve also tried instantiating the client without the proxy and then setting it with:
ws.set_options(proxy={‘http’:’http://localhost:8888′})

Is proxy not used by suds any longer? I don’t see it listed directly here http://jortel.fedorapeople.org/suds/doc/suds.options.Options-class.html, but I do see it under transport. Do I need to set it differently through a transport? When I stepped through in pdb it did look like it was using a transport, but I’m not sure how.

Thank you!

Answer 1

I went into #suds on freenode and Xelnor/rbarrois provided a great answer! Apparently the custom mapping in suds overrides urllib2’s behavior for using the system configuration environment variables. This solution now relies on having the http_proxy/https_proxy/no_proxy environment variables set accordingly.

I hope this helps anyone else running into issues with proxies and suds (or other libraries that use suds). https://gist.github.com/3721801

from suds.transport.http import HttpTransport as SudsHttpTransport 


class WellBehavedHttpTransport(SudsHttpTransport): 
    """HttpTransport which properly obeys the ``*_proxy`` environment variables.""" 

    def u2handlers(self): 
        """Return a list of specific handlers to add. 

        The urllib2 logic regarding ``build_opener(*handlers)`` is: 

        - It has a list of default handlers to use 

        - If a subclass or an instance of one of those default handlers is given 
            in ``*handlers``, it overrides the default one. 

        Suds uses a custom {'protocol': 'proxy'} mapping in self.proxy, and adds 
        a ProxyHandler(self.proxy) to that list of handlers. 
        This overrides the default behaviour of urllib2, which would otherwise 
        use the system configuration (environment variables on Linux, System 
        Configuration on Mac OS, ...) to determine which proxies to use for 
        the current protocol, and when not to use a proxy (no_proxy). 

        Thus, passing an empty list will use the default ProxyHandler which 
        behaves correctly. 
        """ 
        return []

client = suds.client.Client(my_wsdl, transport=WellBehavedHttpTransport())