My company, JotSpot, has a position available for a client-side engineer, aka javascript programmer. After a year of working for JotSpot, I can highly recommend the company, and this in particular is a very cool job. If you’ve got the portfolio to impress us, send your resume to jobs at jot.com, or feel free to get it touch with me (a@f.n) if you have questions about the company or position.
Archive for 2005
JotSpot Javascript Job
Friday, December 30th, 2005Testing RSS Ads
Monday, December 12th, 2005I recently started experimenting with text advertising on fettig.net. I want to get up to speed on web advertising, and the best way to learn is to use myself as a guinea pig. For the past week I’ve been putting text ads from the Yahoo! Publisher Network on my blog pages, which has been making me about a dollar a day – not much, but more than enough to cover my hosting expenses.
As the next step in this little experiment, I’m putting ads into my RSS feed. The idea of putting a little ads after each post in your RSS feed seems like a good one to me. The ad is nice and small, and doesn’t get in the way of your content, but it makes it possible to make money of your feed. I do have one concern, which is what will happen on sites that syndicate my feed. I don’t really want to be injecting ads into Planet Python or Planet Textdrive or any other site that aggregates my feed. So for now I’ve wrapped the RSS ad code in a PHP if statement so it will only show up in this post. This way I can see what happens on the Planets and other sites before I turn on RSS ads for all posts. So tell me: where are you reading this post? Do you see the ad? Is it annoying, neutral, or helpful?
XmlHttpRequest subdomain update
Wednesday, November 30th, 2005Firefox 1.5 shipped yesterday, and it brings good news for my work on cross-subdomain XmlHttpRequest calls (I’m going to start using the abbreviation XHR for XmlHttpRequest now, to save on typing). In previous releases of Firefox (and in the other browsers I tested) setting document.domain in an iframe caused the iframe to lose the ability to make XHR calls. But for Firefox 1.5, the Mozilla developers decided this was a bug, and fixed it. So going forward you no longer need to resort to any ugly hacks to make cross-subdomain XHR calls in Firefox: load an iframe from the same server you’ll be making XHR calls to, set document domain in both the original window and iframe, and then proceed to make XHR calls in the iframe. It’s beautiful. Many thanks to Peter Van der Beken and Brendan Eich at Mozilla for taking care of this.
This means that the really hacky part of the cross-subdomain XHR technique I talked about the other day is now only needed for old versions of Mozilla-based browsers. This is great news because it addresses worries about the iframe-bridge hack going away in the future: it may very well not work in future Mozilla releases, but it doesn’t matter because we’ve got a much better solution.
I’ve posted some updated code that does the right thing in Firefox 1.5, while keeping the iframe bridge hack on older versions: test5.html. This works in Firefox 1.07, Firefox 1.5, IE6, Safari 1.3/2.0, and Konqueror 3.4.3. It still doesn’t work on Opera, which is looking like a lost cause unless someone can come up with an Opera-specific hack. Here’s the iframe code:
<html>
<head>
<script type="text/javascript" src="xmlhttp.js"></script>
<script type="text/javascript">
var AJAX_URL="http://www.fettig.net/playground/ajax-subdomain/ajaxdata.php";
function getTime(){
try {
getUrl(AJAX_URL, gotTime);
} catch(e) {
// getUrl failed, probably because we're running in an older
// Moz/Firefox/Gecko and we we've changed document.domain.
// switch to the bridge hack (if we haven't already)
if (window.bridgeGotTime) {
throw e;
} else {
document.location.replace("test5-bridge.html");
}
}
}
function gotTime(status, headers, result) {
var oldDomain = document.domain;
if (window.bridgeGotTime) {
window.bridgeGotTime(result);
} else {
document.domain = "fettig.net";
window.parent.gotTime(result);
}
// try to set document.domain. this is needed for IE/Konq/Safari
// it will fail in Gecko-based browsers, which is ok in ff > 1.5, but
// which forces the use of a bridge iframe hack in earlier Geckos.
try {
document.domain = oldDomain;
} catch (e) {}
setTimeout(getTime, 1000);
}
getTime();
</script>
</head>
</html>
Note that this doesn’t do any browser sniffing, it just tries different techniques until it finds one that works (or until they all fail).
I’ve also tweaked the bridge code a bit, to clean it up and to avoid the case where it only half works and you end up with a bunch of recursively loaded iframes. Here’s the updated code:
<html>
<head>
</head>
<body>
<script type="text/javascript">
function gotTime(result) {
window.parent.gotTime(result);
}
var subframe = document.createElement('iframe');
document.body.appendChild(subframe);
function setupBridge() {
subframe.contentWindow.bridgeGotTime = gotTime;
document.domain = "fettig.net";
}
subframe.src = "test4-iframe.html";
subframe.contentWindow.onload = setupBridge;
</script>
</body>
</html>
How to make XmlHttpRequest calls to another server in your domain
Monday, November 28th, 2005
This post is more technical and detailed than what I usually
write on fettig.net. I’m going to talk about a technique I’ve been
working on to work around a limitation in the XmlHttpRequest object
used in Ajax applications. Web geeks, please read on.
Updates to this post
See this post for an updated version of this techinique that works (hack-free) in Firefox 1.5.
The problem
XmlHttpRequest objects are bound by the
same origin security policy
of browsers, which prevents a page from accessing data
from another server. This has put a serious limitation on Ajax
developers: you can use XmlHttpRequests to make background
calls to a server, but it has to be the same server that served up the
current page. Known workarounds for this limitation involve either
server-side reverse proxying
or
bypassing XmlHttpRequest entirely.
In my case neither of these approaches was
going to work. I wanted to use
LivePage, the live-update framework
developed by Donovan Preston and other brilliant hackers at
Divmod. LivePage
works because it uses Twisted,
which is good at handling lots of long-lasting network connections at
the same time. Since Apache isn’t good at handling lots of long-lasting
connections, putting an Apache reverse proxy in front of the Twisted
server would put a major hurt on performance and scalability. And
since LivePage is bound to XmlHttpRequest, I couldn’t use a
non-XmlHttpRequest alternative.
Our approach with JotSpot Live has been to let a Twisted server
handle all page requests and XmlHttpRequest calls. That’s fine as
long as JotSpot Live is a standalone, dedicated web site. But what our
customers are asking for (and what we want) is the ability to
have Live-style realtime updates in ordinary xxx.jot.com sites. And we
don’t want to put a Twisted server in front of every site in our
domain. So I’ve been trying to find a way to let any page in our domain
communicate with live.jot.com through XmlHttpRequests. As it turns out, it is
possible, but you have to jump through some hoops.
New Camera
Friday, November 11th, 2005I just ordered a new digital camera, a Panasonic Lumix DMC-FZ5. I got a great deal on Amazon.com – they had a very competitive price, plus they’re running a special where you get $23 off a memory card with the camera purchase, plus at checkout they gave me a free trial membership to Amazon Prime so I got next business day shipping for cheap. The link is to the right if you want to buy one of your own.
After a couple years of taking fairly low-quaility snapshots with my old Casio Exlim EX-S2, and then a year of extremely low quality snapshots with my mobile phone I’m stepping up to a “real” camera. I did a lot of research on cameras, but what finally pushed me over the edge to the DMC-FZ5 was a Google search for “DMC-FZ5 site:flickr.com“, which let me see a sampling of all the pictures DMC-FZ5 users have posted to Flickr. The sample photos show that this camera either naturally takes great pictures or it attracts a lot of good photographers, and one way or the other I feel good about choosing it.
Unlike previous cameras I’ve owned this one isn’t pocketable, so I won’t have it with me all the time, but at least when I do choose to bring it I’ll be able to take the pictures I want. Or, more accurately, it will be my own lack of skill holding me back rather than the camera.
Look for some action in my Flickr stream starting Monday.
Managing Mail
Thursday, November 3rd, 2005Today I finally got my email working exactly the way I want:
- Both my main addresses (jot.com and fettig.net) get forwarded to a gmail account.
- I download mail into Thunderbird from gmail via POP
- I send mail through gmail using SMTP. Until recently any mail sent through Google appeared to come from your gmail address, so I had to use my own SMTP server in order to preserve the my From: address. But now Gmail lets you set up alternative From: addresses. I like using Google’s SMTP service because my sent mail gets archived online with my received mail.
- I use the Gmail philosophy of “search, don’t sort” in Thunderbird. New mail comes into my Inbox, and when I’ve read/responded to it I put it into a folder called Archive. I also configured Thunderbird to put my sent mail in Archive, so both sides of my email conversations are in one folder.
- Dragging and dropping mail from Inbox into Archive gets old fast. Today I finally found a solution: the GmailUI extension. It adds some Gmail-inspired features to Thunderbird, making the “Y” key a shortcut for “Move this message to my Archive folder”. Now I can push messages out of my Inbox without having to use the mouse.
- That just left one problem: I want to use my jot.com address to respond to jot email, and my fettig.net address for personal email. That too was solved with a Thunderbird extension: Correct Identity. This automatically picks the right account to use when replying to mail, based on the address the original message was sent to.
I did have to create a dummy account just so Thunderbird would know about my jot.com email address, but that’s a small price to pay.(Update: not actually necessary – see comments)
Benefits of this setup:
- All my mail flows through Gmail. Gmail is essentially acting as a free mail host with all the goodies: Excellent spam filtering, a nice web UI, archiving/backup, search, SSL connections.
- My Gmail address isn’t used for sending or receiving mail. I like Gmail’s service, but I’m not going to let myself get bound to an email address at a domain I don’t control. This way I can switch off Gmail at any time in the future, and it will be completely transparent to other people.
- I have my mail locally in Thunderbird, so I don’t have to be online to read old mail.
- I have multiple accounts flowing into a single POP mailbox, but I still get the correct From: address when replying to mail.
Twisted Network Programming Essentials is a real book
Tuesday, October 25th, 2005
Last week I opened a FedEx package to find a real, printed copy of my new book, Twisted Network Programming Essentials. It was a single preview copy, hot off the presses. Bulk shipments are happening now – I should get the rest of my author’s copies soon, and TNPE should be making its way into bookstores. Already it’s listed as in-stock at Amazon and Barnes and Noble. Get your copy while they’re hot!
My wisdom tooth story
Monday, October 17th, 2005Warning: Medical story ahead.
A week ago Wednesday I had all four of my wisdom teeth removed. My dentists had been encouraging me to do it for a few years, and I finally decided to bite the bullet and get it done (as the first in a series of dental things I need to deal with). The actual procedure was pretty easy, with the typical-but-still-amazing anasthesia experience:
Doctor: You’re going to be asleep in about ten seconds.
Me: Really? (Thinking: It must have been 5 seconds already, and I don’t even feel sleepy…)
And then somebody pressed the skip-forward button and I was getting ready to go home. I felt pretty clear headed, but Hannah tells me I asked the same questions many times and kept repeating “That went really well”, so it was probably good she was driving.
Recovery was not as bad as I expected at first, but has taken longer then I expected (advice for under-21 readers: get those babies pulled early, while you’re still a fast healer). Around day five my lower right tooth cavity was still hurting, and had a downright nasty taste and smell. It was diagnosed as the dreaded dry socket, which dentists treat with the seemingly old-fashioned remedy of covering the bottom of the socket with clove oil.
This wouldn’t have been so bad, except that in the middle of dealing with the dry socket I had to take a work-related trip to California. I was nervous to be away from my oral surgeon with this unpleasant and painful hole in my jaw, and after I arrived, as I stood in line for my rental car, I realized that I was in trouble: my tooth (or rather, not-tooth) was hurting worse then ever. So I decided to throw myself at the mercy of a local oral surgeon’s office. I called 411, picked a random number from the list they gave, and called Dr. Scott Baird in Palo Alto.
And this is where I get to the reason I’m bothering to blog this: Dr Baird and his staff were absolutely great. They let me come in three times during my three-day visit, took care of my dry socket, and gave me a better explanation of what was going on than my own oral surgeon had. They even let me take the cool x-ray showing the big tooth-shaped holes in my head. They did this even though I wasn’t their regular patient and in all likelyhood would never be back. And amazingly, they didn’t charge me a thing. It was awesome.
So if you’re in Silicon Valley and need some oral surgery, I can’t recommend Dr. Baird and his staff enough. Getting your wisdom teeth out isn’t fun, but my experience is that these guys will go out of their way to help you through it.
Interview with me about Live
Thursday, September 29th, 2005Dion Almaer from Ajaxian interviewed me (via email) about JotSpot Live today. The interview is available now, worth reading if you’re interested in the technology and back story behind JotSpot Live.
JotSpot Live is Live!
Tuesday, September 27th, 2005Today’s the day: we’re releasing JotSpot Live to the world. I’ll write more later today – for now just go sign up. It’s free (for a limited number of pages) – all you need is a valid email address.