Shallow Thoughts

Learning about Firefox 3 extensions

Oops! Right after I posted that last entry, I discovered that my little kitfox extension wasn't working as well as I'd thought. And the more I hacked it, the less well it worked, and the more I discovered was missing, like a chrome.manifest file (which firefox 2 hadn't seemed to need).

Eventually some very helpful folks on #extdev pointed me to Ted Mielczarek's excellent Extension Wizard. Give it some details about your extension (its name and version, your name, and a couple things you might want like a toolbar button, a prefs panel and a context menu) and it generates a zipped directory containing a bare bones extension, even including niceties like internationalized strings.

Even better, your new extension skeleton includes a readme that tells you how to leave the extension expanded while you work on it. That's quite a bit easier than building the XPI file and installing it each time.

So kitfox has a 0.3 version (in the unlikely event that anybody besides me wants it).

There's a project called fizzypop to develop and extend useful Mozilla dev tools like the Extension Wizard ... watch that space for more details.

Tags: mozilla, firefox, open source
[ 20:12 Jul 04, 2008    More tech/web | permalink to this entry ]

Making Firefox 3 livable

I finally broke down and spent the time to get Firefox 3 working properly for me ... meaning, mostly, finding replacement extensions for the bare minimum of what I need in a browser: control over cookies (specifically, enabling/disabling them for specific sites), flashblock, and blocking of animated images. I'd downloaded extensions for all those a few weeks ago, but I found that although Firefox 3.0 said the FF3 extensions were active, and Firefox 2 said the old ones were, neither set actually worked.

I decided to start from scratch: remove all extensions -- rm -rf .mozilla/firefox/extensions/* .mozilla/firefox/extensions.* plus apt-get remove firefox-2-dom-inspector -- then install a new set of Firefox 3 add-ons.

After much hunting (I sure wish addons.mozilla.org would offer a way to limit the view to only extensions that work with Firefox 3! Combing through 15 pages of extensions looking for the handful that will actually install gets old fast) I found the replacements I needed: CS Lite for the cookie controls, a newer Flashblock, and Custom Toolbar Buttons as a stopgap for image animation (though I suspect updating anidisable will be a better solution in the long run). This time, with the old firefox 2 extensions purged, the new ones took hold and worked.

I also added a nice extension called OpenBook that fixes the horrible Firefox "Add bookmark" dialog. You know: the one that has two nearly identical dropdown category menus side by side, with the bigger one giving you only a tiny subset of your bookmark categories, and the smaller one being the real one. The one that doesn't offer a space for keyword, so to set up a bookmarklet you have to Add Bookmark, OK, Organize Bookmarks, find the bookmark you just added, Ctrl-I to get the Bookmark info dialog, and finally you can add your keyword. OpenBook gives you a dialog where you can set the keyword to begin with, and it only gives you one menu to list categories so you aren't constantly tempted to click on the wrong one.

Now for the urlbar -- that new firefox 3 "smarter" urlbar that slows down typing in the middle of a word so it can pop up a big fancy window full of guesses (all wrong) about where I might be trying to go. Actually, even if the guesses were right, it wouldn't help, because I'd have to stop typing, search the list visually, then if one of the suggestions was right, move my hand to the mouse or the arrow keys to choose that suggestion. That takes way longer than just typing the url.

But I guess I don't mind unhelpful suggestions popping up as long as it doesn't mess up focus (preventing me from clicking or tabbing to other apps on my screen) or slow down typing. Firefox 3 seems to be handling the focus issue better than firefox 2 did, but the slowdown was quite noticeable on the poor old laptop. So I wanted a way to disable the behavior. A little googling revealed that the Firefox crew immodestly calls their new urlbar the "awesomebar", which aside from giggle factor also proves quite useful in googling: a search on firefox disable awesomebar reveals that I'm not the only one who doesn't like it, and got me several preferences I could tweak in about:config plus a couple of extensions to turn it off entirely. I won't try to summarize, since the best settings depend on your machine's spec, plus personal preference.

Making progress! Now the only issue was getting my urlbar tweaks working, so that typing <Ctrl-Return> after typing a URL opened the URL in a new tab instead of tacking on various silly extensions (oh, yes, of course I wanted to go to http://www.firefox disable awesomebar.com rather than googling for those terms in a new tab). Fortunately, it turned out that the javascript that runs the urlbar has changed very little since firefox 2, and I hardly needed to change anything to get my kitfox extension (v. 0.2) working in Firefox 3.

Only one more issue: this blog. The CSS that handles the right sidebar wasn't displaying right. Seems that Firefox 2 has changed something about its interpretation of CSS, so it was floating the right sidebar way down to the bottom of the page below the last content line. Eventually (after adding firefox-3.0-dom-inspector, another extension that had stopped working in the transition) I discovered the problem: the #content was set to width: 77% while the #rightsidebar's left-margin was at 76%. Apparently Firefox 2 rounded up as needed, whereas Firefox 3 just ignores the left-margin if it would overlap the content, and then floats the sidebar anywhere it thinks it can fit it. Fixing those percentages helped quite a bit, and I added an overflow-x: hidden (on a tip from a helpful person in #firefox) so that wide calendar doesn't hurt layout for narrow windows. I think it's working now ... any readers having problems with the layout in any browser, by all means let me know.

Tags: mozilla, firefox, user interface, css
[ 11:04 Jul 04, 2008    More tech/web | permalink to this entry ]

Making Firefox default to Portrait printing

I discovered a handy tip for Linux Firefox' printing Page Setup today.

Normal web page printing uses "Portrait" mode: you read the page with the paper oriented so that it's taller than it is wide.

Once a week, I need to print a form from a club web site to bring to the meetings. It's a table that's much wider than it is tall, so I want to print it that way: in "Landscape" mode.

In Firefox 2 (at least on Linux), you can't do that from the Print dialog -- there's no Portrait/Landscape option. So you have to use a separate dialog, Page Setup, following these steps:

1. Run Page Setup
2. Change Portrait to Landscape
3. Click OK
4. Print (bring up the Print dialog and click OK)
5. Run Page Setup
6. Change Landscape to Portrait
7. Click OK

Kind of a lot of steps just to print one landscape page! But if you forget, the next page you print from Firefox will be printed in Landscape mode and will take twice as many pages as it should (if you don't notice what's happening and dive for the printer's OFF switch in time, that being the only way to cancel a printing job once it hits the printer).

This morning, it finally occurred to me that Firefox was storing this setting somehow, most likely in prefs.js. If I could find the setting and force it in user.js (which takes precedence over prefs.js and is not updated by Firefox), I could make Firefox set itself back to Portrait every time it starts up. (prefs.js and user.js are both generally found in $HOME/.mozilla/firefox/).

Some greppery-pokery revealed the solution. I needed only to add a line in user.js that looks like this:

user_pref("print.printer_CUPS/Epson.print_orientation", 0);

and presto! my problem was solved.

Oddly, it's set separately for every printer you have defined, even though there's no way to set one printer to Landscape while another one is still on Portrait (the Page Setup dialog is global, and applies to every printer Firefox knows about). "Epson" is the CUPS name of my primary printer; replace that with your printer's name (as set in CUPS), and add a similar line for each printer you have. For the printers I've used, 0 is Portrait and 1 is Landscape, but you can verify that by typing:

grep orientation prefs.js | grep name

That command will also help you if you're not sure what printers you have defined, or you don't use CUPS but want to try this under a different print spooler. (Don't be misled by all the orientation prefs with "tmp" in the name.)

As a minor digression, there's actually a secret pref that's supposed to give another way around the problem:

user_pref("print.whileInPrintPreview", true);

This lets you do all your printing from the Print Preview window, which offers its own Portrait and Landscape buttons. That would be a nice solution. Alas, the Portrait and Landscape buttons in that dialog currently don't work, and since this preference is undocumented and unmaintained, filing more bugs isn't likely to help.

(I should mention that this all pertains to Firefox 2. I haven't switched to Firefox 3 yet, so I don't know the state of its printing UI, or whether this preference is either helpful or effective there.)

Tags: mozilla, firefox, printing, tips
[ 20:07 Jun 12, 2008    More tech/web | permalink to this entry ]

Wrapping plaintext files in Firefox

A friend pointed me to a story she'd written. It was online as a .txt file. Unfortunately, it had no line breaks, and Firefox presented it with a horizontal scrollbar and no option to wrap the text to fit in the browser window.

But I was sure that was a long-solved problem -- surely there must be a userContent.css rule or a bookmarklet to handle text with long lines. The trick was to come up with the right Google query. Like this one: firefox OR mozilla wrap text userContent OR bookmarklet

I settled on the simple CSS rule from Tero Karvinen's page on Making preformated <pre> text wrap in CSS3, Mozilla, Opera and IE:

pre {
 white-space: -moz-pre-wrap !important;
}

Add it to chrome/userContent.css and you're done.

But some people might prefer not to apply the rule to all text. If you'd prefer a rule that can be applied at will, a bookmarklet would be better. Like the word wrap bookmarklet from Return of the Sasquatch or the one from Jesse Ruderman's Bookmarklets for Zapping Annoyances collection.

[ 10:47 Apr 08, 2008    More tech/web | permalink to this entry ]

Firefox, caching, and fast Back/Forward buttons

I remember a few years ago the Mozilla folks were making a lot of noise about the "blazingly fast Back/Forward" that was coming up in the (then) next version of Firefox. The idea was that the layout engine was going to remember how the page was laid out (technically, there would be a "frame cache" as opposed to the normal cache which only remembers the HTML of the page). So when you click the Back button, Firefox would remember everything it knew about that page -- it wouldn't have to parse the HTML again or figure out how to lay out all those tables and images, it would just instantly display what the page looked like last time.

Time passed ... and Back/Forward didn't get faster. In fact, they got a lot slower. The "Blazingly Fast Back" code did get checked in (here's how to enable it) but somehow it never seemed to make any difference.

The problem, it turns out, is that the landing of bug 101832 added code to respect a couple of HTTP Cache-Control header settings, no-store and no-cache. There's also a third cache control header, must-revalidate, which is similar (the difference among the three settings is fairly subtle, and Firefox seems to treat them pretty much the same way).

Translated, that means that web servers, when they send you a page, can send some information along with the page that asks the browser "Please don't keep a local copy of this page -- any time you want it again, go back to the web and get a new copy."

There are pages for which this makes sense. Consider a secure bank site. You log in, you do your banking, you view your balance and other details, you log out and go to lunch ... then someone else comes by and clicks Back on your browser and can now see all those bank pages you were just viewing. That's why banks like to set no-cache headers.

But those are secure pages (https, not http). There are probably reasons for some non-secure pages to use no-cache or no-store ... um ... I can't think of any offhand, but I'm sure there are some.

But for most pages it's just silly. If I click Back, why wouldn't I want to go back to the exact same page I was just looking at? Why would I want to wait for it to reload everything from the server?

The problem is that modern Content Management Systems (CMSes) almost always set one or more of these headers. Consider the Linux.conf.au site. Linx.conf.au is one of the most clueful, geeky conferences around. Yet the software running their site sets

  Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
  Pragma: no-cache

on every page. I'm sure this isn't intentional -- it makes no sense for a bunch of basically static pages showing information about a conference several months away. Drupal, the CMS used by LinuxChix sets Cache-Control: must-revalidate -- again, pointless. All it does is make you afraid to click on links because then if you want to go Back it'll take forever. (I asked some Drupal folks about this and they said it could be changed with drupal_set_header).

(By the way, you can check the http headers on any page with: wget -S -O /dev/null http://... or, if you have curl, curl --head http://...)

Here's an excellent summary of the options in an Opera developer's blog, explaining why the way Firefox handle caching is not only unfriendly to the user, but also wrong according to the specs. (Darn it, reading sensible articles like that make me wish I wasn't so deeply invested in Mozilla technology -- Opera cares so much more about the user experience.)

But, short of a switch to Opera, how could I fix it on my end? Google wasn't any help, but I figured that this must be a reported Mozilla bug, so I turned to Bugzilla and found quite a lot. Here's the scoop. First, the code to respect the cache settings (slowing down Back/Forward) was apparently added in response to bug 101832. People quickly noticed the performance problem, and filed 112564. (This was back in late 2001.) There was a long debate, but in the end, a fix was checked in which allowed no-cache http (non-secure) sites to cache and get a fast Back/Forward. This didn't help no-store and must-revalidate sites, which were still just as slow as ever.

Then a few months later, bug 135289 changed this code around quite a bit. I'm still getting my head around the code involved in the two bugs, but I think this update didn't change the basic rules governing which pages get revalidated.

(Warning: geekage alert for next two paragraphs. Use this fix at your own risk, etc.)

Unfortunately, it looks like the only way to fix this is in the C++ code. For folks not afraid of building Firefox, the code lives in nsDocShell::ShouldDiscardLayoutState and controls the no-cache and no-store directives. In nsDocShell::ShouldDiscardLayoutState (currently lie 8224, but don't count on it), the final line is:

    return (noStore || (noCache && securityInfo));

Change that to

    return ((noStore || noCache) && securityInfo);

and Back/Forward will get instantly faster, while still preserving security for https. (If you don't care about that security issue and want pages to cache no matter what, just replace the whole function with return PR_FALSE; )

The must-validate setting is handled in a completely different place, in nsHttpChannel. However, for some reason, fixing nsDocShell also fixes Drupal pages which set only must-validate. I don't quite understand why yet. More study required. (End geekage.)

Any Mozilla folks are welcome to tell me why I shouldn't be doing this, or if there's a better way (especially if it's possible in a way that would work from an extension or preference). I'd also be interested in from Drupal or other CMS folks defending why so many CMSes destroy the user experience like this. But please first read the Opera article referenced above, so that you understand why I and so many other users have complained about it. I'm happy to share any comments I receive (let me know if you want your comments to be public or not).

Tags: tech, web
[ 19:32 Oct 20, 2007    More tech/web | permalink to this entry ]

Make Amazon pages narrow enough to read

I like buying from Amazon, but it's gotten a lot more difficult since they changed their web page design to assume super-wide browser windows. On the browser sizes I tend to use, even if I scroll right I can't read the reviews of books, because the content itself is wider than my browser window. Really, what's up with the current craze of insisting that everyone upgrade their screen sizes then run browser windows maximized?

(I'd give a lot for a browser that had the concept of "just show me the page in the space I have". Opera has made some progress on this and if they got it really working it might even entice me away from Firefox, despite my preference for open source and my investment in Mozilla technology ... but so far it isn't better enough to justify a switch.)

I keep meaning to try the greasemonkey extension, but still haven't gotten around to it. Today, I had a little time, so I googled to see if anyone had already written a greasemonkey script to make Amazon readable. I couldn't find one, but I did find a page from last October trying to fix a similar problem on another website, which mentioned difficulties in keeping scripts working under greasemonkey, and offered a Javascript bookmarklet with similar functionality.

Now we're talking! A bookmarklet sounds a lot simpler and more secure than learning how to program Greasemonkey. So I grabbed the bookmarklet, a copy of an Amazon page, and my trusty DOM Inspector window and set about figuring out how to make Amazon fit in my window.

It didn't take long to realize that what I needed was CSS, not Javascript. Which is potentially a lot easier: "all" I needed to do was find the right CSS rules to put in userContent.css. "All" is in quotes because getting CSS to do anything is seldom a trivial task.

But after way too much fiddling, I did finally come up with a rule to get Amazon's Editorial Reviews to fit. Put this in chrome/userContent.css inside your Firefox profile directory (if you don't know where your profile directory is, search your disk for a file called prefs.js):

div#productDescription div.content { max-width: 90% !important; }

You can replace that 90% with a pixel measurement, like 770px, or with a different percentage.

I spent quite a long time trying to get the user reviews (a table with two columns) to fit as well, without success. I was trying things like:

#customerReviews > div.content > table > tbody > tr > td { max-width: 300px; min-width: 10px !important; }
div#customerReviews > div.content > table { margin-right: 110px !important; }

but nothing worked, and some of it (like the latter of those two lines) actually interfered with the div.content rule for reasons I still don't understand. (If any of you CSS gurus want to enlighten me, or suggest a better or more complete solution, or solutions that work with other web pages, I'm all ears!)

I'll try for a more complete solution some other time, but for now, I'm spending my July 4th celebrating my independance from Amazon's idea of the one true browser width.

Tags: tech, web
[ 20:01 Jul 04, 2007    More tech/web | permalink to this entry ]

Xkcd Search Bookmarklet

Today's topics are three: the excellent comic called xkcd, the use of google to search a site but exclude parts of that site, and, most important, the useful Mozilla technique called Bookmarklets.

I found myself wanting to show someone a particular xkcd comic (the one about dreams). Xkcd, for anyone who hasn't been introduced, is a wonderfully geeky, smart, and thoughtful comic strip drawn by Randall Munroe.

How to search for a comic strip? Xkcd has an archive page but that seems to have a fairly small subset of all the comics. But fortunately the comics also have titles and alt tags, which google can index.

But googling for dreams site:xkcd.org gets me lots of hits on xkcd's forum and blag pages (which I hadn't even known existed) rather than just finding the comic I wanted. After some fiddling, though, I managed to find a way to exclude all the fora and blag pages: google for xkcd dreams site:xkcd.com -site:forums.xkcd.com -site:fora.xkcd.com -site:blag.xkcd.com
Nifty!

In fact, it was so nifty that I decided I might want to use it again. Fortunately, Mozilla browsers like Firefox have a great feature called bookmarklets. Bookmarklets are like shell aliases in Linux: they let you assign an alias to a bookmark, then substitute in your own terms each time you use it.

That's probably not clear, so here's how it works in this specific case:

1. I did the google search I listed above, which gave me this long and seemingly scary URL: http://www.google.com/search?hl=en&q=xkcd+dreams+site%3Axkcd.com+-site%3Aforums.xkcd.com+-site%3Afora.xkcd.com+-site%3Ablag.xkcd.com&btnG=Search
2. Bookmarks->Bookmark this page. Unfortunately Firefox doesn't let you change any bookmark properties at the time you make the bookmark, so:
3. Bookmarks->Organize Bookmarks, find the new bookmark (down at the bottom of the list) and Edit->Properties...
4. Change the Name to something useful (I called it Xkcd search) then choose a simple word for the Keyword field. This is the "alias" you'll use for the bookmark. I chose xkcd.
5. In the Location field, find the term you want to be variable. In this case, that's "dreams", because I won't always be searching for the comic about dreams, I might want to search for anything. Change that term to %s.
   (Note to non-programmers: %s is a term often used in programming languages to mean "replace the %s with a string I'll provide later.")
   So now the Location looks like: http://www.google.com/search?hl=en&q=xkcd+%s+site%3Axkcd.com+-site%3Aforums.xkcd.com+-site%3Afora.xkcd.com+-site%3Ablag.xkcd.com&btnG=Search
6. Save the bookmarklet (click OK) and, optionally, drag it into a folder somewhere where it won't clutter up your bookmarks menu. You aren't ever going to be choosing this from the menu.

Now I had a new bookmarklet. To test it, I went to the urlbar in Firefox and typed:

xkcd "regular expressions"

Voila! The first hit was exactly the comic I wanted.

(You'll find many more useful bookmarklets by googling on bookmarklets.)

Tags: tech, web
[ 21:13 Jun 30, 2007    More tech/web | permalink to this entry ]

A Kitfox Extension

For a bit over a year I've been running a patched version of Firefox, which I call Kitfox, as my main browser. I patch it because there are a few really important features that the old Mozilla suite had which Firefox removed; for a long time this kept me from using Firefox (and I'm not the only one who feels that way), but when the Mozilla Foundation stopped supporting the suite and made Firefox the only supported option, I knew my only choice was to make Firefox do what I needed. The patches were pretty simple, but they meant that I've been building my own Firefox all this time.

Since all my changes were in JavaScript code, not C++, I knew this was probably all achievable with a Firefox extension. But never around to it; building the Mozilla source isn't that big a deal to me. I did it as part of my job for quite a few years, and my desktop machine is fast enough that it doesn't take that long to update and rebuild, then copy the result to my laptop.

But when I installed the latest Debian, "Etch", on the laptop, things got more complicated. It turns out Etch is about a year behind in its libraries. Programs built on any other system won't run on Etch. So I'd either have to build Mozilla on my laptop (a daunting prospect, with builds probably in the 4-hour range) or keep another system around for the purpose of building software for Etch. Not worth it. It was time to learn to build an extension.

There are an amazing number of good tutorials on the web for writing Firefox extensions (I won't even bother to link to any; just google firefox extension and make your own choices). They're all organized as step by step examples with sample code. That's great (my favorite type of tutorial) but it left my real question unanswered: what can you do in an extension? The tutorial examples all do simple things like add a new menu or toolbar button. None of them override existing Javascript, as I needed to do.

Canonical URL to the rescue. It's an extension that overrides one of the very behaviors I wanted to override: that of adding "www." to the beginning and ".com" or ".org" to the end of whatever's in the URLbar when you ctrl-click. (The Mozilla suite behaved much more usefully: ctrl-click opened the URL in a new tab, just like ctrl-clicking on a link. You never need to add www. and .com or .org explicitly because the URL loading code will do that for you if the initial name doesn't resolve by itself.) Canonical URL showed me that all you need to do is make an overlay containing your new version of the JavaScript method you want to override. Easy!

So now I have a tiny Kitfox extension that I can use on the laptop or anywhere else. Whee!

Since extensions are kind of a pain to unpack, I also made a source tarball which includes a simple Makefile: kitfox-0.1.tar.gz.

Tags: tech, web
[ 10:59 May 27, 2007    More tech/web | permalink to this entry ]