A couple of weekend's ago I threw in the towel and wrote my own mini-version of TwitterFeed that would work for users of my minimal blogging tool. I've released the code as an OPML Editor tool, so at least in theory it could be installed by others. That's the plan, eventually, that it will be running on lots of servers, so as to spread out the load. TwitterFeed, while it's a marvelous public service, suffers from being centralized, in many of the same ways Twitter itself does. 

Anyway, I've mostly got it working. However it fails to post some messages. Twitter says they have an incorrect signature. Here are a few of the tweets. 

Coming soon: A Twitter camera. (Scripting News). http://r2.ly/a9rk 

'The Suburbs of Manhattan' - Living in the West 70s. http://r2.ly/a9rh 

Quote For The Day II (from Andrew Sullivan's new home at TDB). http://r2.ly/a9qm 

What do they have in common? Punctuation.  

But here's the thing -- it looks like Twitter's encoding and mine agree. They echo back the parameters. Not sure if it's their version they're echoing or mine (hence the confusion).  

Wondering if any of you guys have been down this path and can offer some suggestions? 

I looked for a Twitter OAuth debugger. Maybe there is one... 

Help much appreciated. 

Update: Solved with the help of Simon Jenson. I was not encoding left and right parens or single quotes. The OAuth spec is pretty clear. Thanks! 

Update #2: Here's a table of the encodings for each of the characters generated by string.urlEncode, a built-in verb in OPML Editor that I've been updating to make this encoding work.