Adding Proxy support to Ubuntu One
(TL;DR: Proxy support is a complex matter. We asked our Ubuntu One users to help us with a Proxy survey to understand how proxies are used. We’re releasing the results so other developers can benefit from it.)
During the past few weeks I’ve been working on researching the intricacies of adding proxy support to the Ubuntu One client. Allowing proxies to be used is not as easy as it sounds: our codebase relies on many different libraries and frameworks to access the network, and each of those libraries has a range of support for all the various proxy protocols and the many proxy authentication schemes, that varies from “incomplete” to “non-existent”.
Also we need it to work both for the Linux client and for the new Windows client; we need to test all this with a combination of Proxy server software, protocols, authentication schemes and configurations; and we need to take into account that our file synchronization protocol is not based on the very common and well supported HTTP protocol, but instead it uses a custom protocol optimized for our file synchronization use case, and like all non-HTTP protocols it requires special handling when crossing some types of proxies.
After multiplying of all the above issues, Proxy support ends up sounding a bit complicated in fact. So we decided to run a survey with the Ubuntu One users, asking them about the Proxies that they need to use, to help us understand the most common scenarios and to focus our development efforts.
At this point I need to send a huge “THANK YOU” to our Ubuntu One users: just a day after our initial tweet we got the help of a lot of users that need Proxy support. They filled in our small survey, but they gave us a lot of insight into this matter.
Here are the summary graphs (pdf, 93kb), and since the results of this survey may be useful for other developers wanting to implement Proxy support in their own projects we decided to also release the raw survey data (csv, 43kb).
And a few of my thoughts on the survey:
- I expected most users to use a Proxy at work or at an educational institution, but did not expect so many people using proxies at home. From the “other” descriptions, they are mostly used for VPNs and for anonymizing proxies.
- Most people don’t know the proxy brand, nor type of authentication that they need to use. I expected this, and it’s just fine! All proxy enabled software should just work.
- Authentication schemes are more important than the small number of replies, since they are needed to support the big percentage of users that need to use credentials.
- Site filtering may prove a big issue for some users: many proxy servers are configured to disallow access to video sites, likely on the basis of conserving network bandwidth, and those network admins may be reluctant to allow file synchronization services like Ubuntu One.
- Protocol filtering will be a challenge for us: a significant number of proxy installations do not allow network traffic other than HTTP and HTTPS, so we’ll need to tunnel our synchronization protocol thru some of the allowed protocols, probably using the CONNECT HTTP method of some proxy servers. And there’s no easy solution for proxy servers that allow only HTTP or HTTPS but not CONNECT.
- I didn’t expect so many answers in so short a time. Ubuntu One users rule!
