Category Archives: information

Firebug error “invalid label” with Rails + UJS + jQuery

I’ve been playing more with Rails’ UJS via jQuery and I came across an error that took a while to track down. It turned out to be a content type problem.

Making the form was easy:

And the JavaScript hookup was also easy:

So was the Rails controller:

But Firebug kept showing the error “invalid label”. After much Googling and playing around with things I came to realize that there was one thing that was left out: the content type. Rails was returning the JSON as a string, not as a JSON data type. So a minor tweak to the controller solved everything:

Web pages with small fonts, 12px/0.9em at the very least please

So an interesting thing happened the other day. I was reading a popular site that deals with creating web content and I caught myself doing one of the tell-tale things that users do when the fonts on a web page are too small: they lean inward. Now, I know that I’m not exactly in my early 20s anymore and it is true that I do wear glasses almost all of the time now, but my eyesight really isn’t that bad. And I’ve read this site off and on for a while and I don’t remember having to have this lean-in problem before. Then I remembered one thing: I have a new laptop.

Yes, if you’ve read previous posts you know how I used to rave about my old 2008-edition MacBook Air. So light, so powerful, so fast, yada yada. And then I switched up to a 2010 edition at the end of last year. Bigger SSD, higher resolution, dual USB ports, yada yad—wait. Higher resolution? Yes, in fact I now have a 13″ display that has almost 128 dots per inch compared to the old 113 dots per inch. So how much of a difference does that make? Apparently a lot.

For comparison, let me put up this image:

Previously I had a 1280px-wide display that has about 11.26″ horizontal length. Now I have a 1440px display. That means those web sites with tiny fonts just got a heckuva lot tinier. I mean, you would think that 12% smaller might not be a great big deal, but I really do think it does.

I went around the web this morning looking at other examples of font sizing. It seems the smallest comfortable font size for me now is 12px high. The website which has the tiny fonts above works out to about 11px high. But if they just increased it a smidge …

We’re clearly into a time where LCD display technology has gotten so good that we now have displays *AT* (not “approaching”) print resolution. Case in point: Apple’s Retina Display technology gives us 300 ppi. A couple of years ago I had been looking at a Sony ultraportable that was at 220 ppi. We’ve reached the point where small definitely means small.

I don’t exactly know what the solution is here. We could ask browser manufacturers to set their default browser font sizes at a certain ppi. There are some web pages that depend on fonts being only a certain height. Maybe the new tablet era of computing with it’s pinch-zoom mitigates all of this because users just expand the text content until it looks comfortable.

In the meanwhile I’m recommending that anyone making web UIs not use a font smaller than 12px high or 0.90em high.

Making your bash prompt Git-aware (a.k.a. the superprompt)

I recently started on a project where I’m doing some pair programming and someone yesterday brought up the Pivotal Git scripts that help modify your Git via a single command: git-pair [person1] [person2]. Then it was the case that another person said that they learned a trick of modifying their shell prompt to show the current so you’d be reminded who you were working with—so you wouldn’t accidentally give attribution to someone you’re not pairing with. This turns out to be really helpful if you’re a freelancer like me who hops around different projects.

Later a nice addition was to show the current branch you’ve checked out. This is critical for me because I never remember and I’ve more than once created a new branch and forgotten to check it out.

And … today I was talking to some more devs and the request came up: “it’d be nice to know if I have modified files in my repo.”

So, I present to you a bunch of commands to add to your .bash_profile that do all of this:

function current_uname {
    uname -a | cut -d' ' -f2 | sed -e 's/..*$//'

function current_git_user {
    git config --get

function current_git_branch {
    git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* (.*)/; 1/'

function git_repo_has_modified_files {
    git status 2> /dev/null | sed -e 's/^#.*modified:.*$/*/' -e '/^#/d' -e '/^[^*]/d' | uniq

export PS1='$(current_uname) [$(current_git_user)$(current_git_branch)$(git_repo_has_modified_files)] A w > '
export PS2='  > '