1 Reply Latest reply on Oct 2, 2017 1:15 AM by Michael Wood

    Trouble connecting to Web Data Connector via HTTPS

    Michael Wood
    Michael Wood Sep 28, 2017 7:57 AM

      I am trying to build a Web Data Connector to allow Tableau (I'm testing on OS X) to fetch some data, but I'm struggling to get Tableau to successfully finish the SSL negotiation with the server, let alone query the Web Data Connector.

      Tableau is able to talk to other HTTPS web sites, so there's something about my servers that it doesn't like. Unfortunately Tableau is not giving any reasons for its inability to finish the negotiation. The GUI just says:

      Unable to load the following URL:

      and the logs give slightly more info:

      Network error occurred: Error 6 (SSL handshake failed).

      As far as I can make out, Tableau uses Qt5's QWebView to talk to Web Data Connectors, so I tried writing a simple Python app to use a QWebView to connect to the server. The Python app connects without problems.

      I've used https://www.ssllabs.com/ssltest/ to test the server and have fixed all warnings so that the server gets an A+ rating. I've connected to https://www.ssllabs.com/ssltest/viewMyClient.html using Tableau's Web Data Connector window and that says "Your user agent has good protocol support." The user agent is reported as:

      Mozilla/5.0 (Macintosh; Intel Mac OS X) AppleWebKit/538.1 (KHTML, like Gecko) Tableau Public/10.4 Safari/538.1

      I have no trouble connecting using Firefox, Chrome, Safari, but not Tableau.

      I came across some info on debugging Tableau web data connectors that apparently only works on Windows, so I downloaded a trial version of Tableau for Windows and that works! The user agent is very similar:

      Mozilla/5.0 (Windows NT 6.2; Win64; x64) AppleWebKit/538.1 (KHTML, like Gecko) Tableau/10.4 Safari/538.1

      Maybe this has something to do with certificate chains or CAs, but all browsers on the Mac work fine. It's just Tableau that has a problem.

      How can I troubleshoot this?

        • 1. Re: Trouble connecting to Web Data Connector via HTTPS
          Michael Wood
          Michael Wood Oct 2, 2017 1:15 AM (in response to Michael Wood)

          I've tried Tableau Public on another Mac and the results are the same. Also, a Tableau sales person phoned me on Friday and seemed not to be surprised that there might be issues with the Mac version that do not occur with the Windows version.

           

          I've done further testing of the certificate chain and have not been able to alter the behaviour by altering the certificate chain served by the server. Also, when the test by Qualys' ssllabs.com reports no problems with the certificate chain, Tableau still can't finish the SSL negotiation.

           

          So given this, it seems that the Mac version is unusable with Web Data Connectors hosted on some web servers with SSL configurations that pass Qualys' SSL server test and also work with all browsers I've tested with.

           

          This is disappointing.