make Python 3.x Slack (slackclient) use a corporate proxy

I have some Python 3 code and can make it use the module slackclient to post to channels, no problem. However if I run this code from our corporate servers where all traffic needs to go through a proxy it fails. I know the proxy server and port and have to use them to run pip from our servers, like this:

pip install --proxy proxy.evilcorp.com:8080 slackclient

That works great. If I don't proxy the pip, it fails to connect as expected. So that tells me I just need to figure out how to get my slackclient code to use the proxy, but how? Here is my code:

from slackclient import SlackClient

def get_slackclient():
    token = "blah-blah-token"
    sc = SlackClient(token)
    return sc

def post_slackmessage(username,channel,text):
    sc = get_slackclient()
    try:
        sc.api_call("chat.postMessage",channel=channel,text=text,username=username,unfurl_links="true")
    except:
        print ("failed to post messaage to slack")

post_slackmessage("test_slack", "test", "hurrah it posted")

I just can't seem to figure out where to put proxy settings, I must be missing something simple. I'm open to other outside the box ideas to make this all work but I can't really install anything on the server to make all traffic go through the proxy or change the proxy settings.

Solution

Figured it out. I'll leave this here in case somebody else has the same problem. Looks like it's built in, just pass a proxies dict in.

def get_slackclient():
    #https://api.slack.com/custom-integrations/legacy-tokens
    token = "blah-blah-blah"
    proxies = dict(https="proxy.evilcorp.com:8080", http="proxy.evilcorp.com:8080")
    sc = SlackClient(token, proxies=proxies)
    return sc

Well, that was easy :)

UPDATE

If you happen to upgrade to the latest slack module, it is a little different and only http:// proxies are supported (no secure for you!). And you pass in a str instead of a dict so just one proxy.

Just change to this:

proxy = "proxy.evilcorp.com:8080"
sc = slack.WebClient(token, timeout=60, proxy=proxy)

You'll note that actually making the call to the api has changed as well, like this:

sc.chat_postMessage(channel=thechannel, text=thetext, username=theusername, unfurl_links="true")