dO-BoY

Even part-time freeware developers look forward to new OSX releases, but our software doesn’t always make the transition very smoothly. My screensaver “The Tube” is a bit of a CPU and RAM hog, so when OSX 10.6 broke it, I kind of bid it adieu and got on with other projects. After some prodding, though, I considered that faster CPUs and plentiful RAM nowadays mean this five-year-old resource hog might have new life yet.

But it wasn’t as simple as just opening the old Xcode project and clicking “Build”. This is probably because the old build designations “Development” and “Deployment” don’t really have a place in Xcode these days. (Now it’s simply “Debug” and “Release”.) Curiosity led me to create a brand new project and then add the resources and classes from my old project, then simply click “Build”. And it worked…sort of.

I also had  to adapt the default class files (declaration and implementation) to match the old versions. It might have worked to add a modern build target to the old project, but in a way it was easier to do the rote work of going method by method pasting code into place. Once the resources were included, we were off to the races.

Now I’m reminded of the pleasantly hypnotic movement of the London Underground map and its gently flickering train. If you have OSX 10.6 (Snow Leopard) you can check it out here.

At a high level, all software development–perhaps all invention–breaks down into three steps:

1. Build it the way you thought it should work
2. Do it from scratch the way you should have done it to begin with, as you learned during the previous step
3. Optimize step 2 from scratch so you can actually ship it.

And of course, loop on steps 2 and 3 from then on.

Sometimes you’ve done step 1 so often, you hit the ground running with step 2, but not if it’s a new technology. And I can’t say I’ve always gone through all three steps for every project, but I’ve always wished I could.

As if there aren’t enough other details to worry about, developing for iPhone has been doubly difficult for me because my provisioning certificate kept getting lost by Xcode. Exasperated, I’d delete/revoke/regenerate/reinstall, and it would work. Problem solved.

For a while. Then it would break again.

Even this Apple Developer Q&A article doesn’t mention it, but my friend Todd did: your login keychain must be the default in the Keychain Access utility’s list of keychains. And just now, when my provisioning failed yet again, I checked Keychain Access to discover that 1Password’s keychain is the default.

This is evidently a known issue, even to the application developers. The linked article mentions a new keychain format that solves the problem.

Also, it looks like new users won’t have the same trouble now as they’ll be using the new Agile Keychain format, in a file stored at ~/Library/Application Support/1Password/1Password.agilekeychain. Existing users–especially iPhone developers–should switch to this format; see the “Keychain” tab of 1Password’s preferences window.

For a lot of applications, this kind of crap would earn a one-way ticket to the Trash. But I really like 1Password, and have probably recommended it to people more than any other. I’m glad I’ve found a way for 1Password to peacefully co-exist with Xcode and iPhone provisioning.

My friends’ band Surrender is heading off on a European tour. (Yes, I’m jealous.) In addition to their other merchandise, they wanted to be able to include MP3 downloads with their vinyl records, or even just sell the downloads directly. This is a service United Record Pressing offers but it’s a little, ah, invasive, and not available a la carte, as it were, if they don’t also press your record.

My band played a show with The Measure [SA] this year, and their record came with a download option as well, and it’s pretty DIY. But Surrender wanted something DIYer, with more control over things. I had been intrigued by the VinylDownloads.com style, and figured it wouldn’t be too hard to build something similar, at least for one band. So I tried.

First is the db: one table with a list of unique download keys and how many times each was used:

+----------+-------------+------+-----+-------------------+
| Field    | Type        | Null | Key | Default           |
+----------+-------------+------+-----+-------------------+
| id       | int(11)     | NO   | PRI | NULL              |
| key      | varchar(16) | NO   |     | 0                 |
| used     | tinyint(1)  | NO   |     | 0                 |
| mod_date | timestamp   | NO   |     | CURRENT_TIMESTAMP |
+----------+-------------+------+-----+-------------------+

I generated the keys–16 alphanumerics–and the MySQL commands for inserting each one into the table in a PHP script. Here are the lines of interest:

$key = substr(md5(rand()),0,16);

$query = "INSERT INTO file_keys (`key`,`used`,`add_date`) VALUES('$key','0',NOW());";

mysql_query($query,$DB_CONNECTION);

I didn’t explicitly check for uniqueness of the key values. What can I say? I have faith in MD5, even if collisions have been found.

The last part is getting the file to download without actually providing direct access to it. PHP makes this pretty easy, although there are some gotchas related to IE and Safari:

// Stuff only IE seems to need
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false); 

// We'll be outputting a ZIP
header("Content-type: application/zip");
// It will be called surrender.zip
// (double-quote file name in header or Safari will be sad)
header('Content-Disposition: attachment; filename="surrender.zip"');

header("Content-Transfer-Encoding: binary");
header("Content-Length: " . filesize($DL_FILE_PATH) ); 

// The ZIP source is in $DL_FILE_PATH
readfile($DL_FILE_PATH);

So after checking for whether the download key can be used–each one can be used up to three times–a session variable is set:

$_SESSION['downloadfile'] = 'secret';

Another issue is how to message the user about what’s happening. If a code is valid, we redirect to the “downloading now” page, or else the user sees the “sorry” page. To actuate the download, I went back to some 20th century web technology: a META tag to “refresh” the page to the page that does the download:

<meta http-equiv="refresh" content="2;url=getfile.php">

This sends the user to getfile.php, which doesn’t actually display in the browser but just starts a file download (solving the problem of triggering both the download and a message to the user to let him know what’s going on). The download happens and everybody’s happy.

The last step is to unset the session variable:

$_SESSION['downloadfile'] = '';

I’m working on more generic code to share, or maybe this would be a good SourceForge project?

I guess you really can post to a blog from an iPhone. I’m not sure how valuable this is, though. Yet?

At the Day Job I was called upon to make form fields with rounded corners. There’s a lot of approaches out there, but most of them are a bit too complex for my liking. Generally, it’s some variation on the old-tymey technique of putting something in the center of a 3×3 table, but with DIVs or what-have-you.

Forget that, I want something simple, just a bit of CSS I can tack onto text input objects. The simple approach seemed to work:

input{

   width: 90px;

   height: 26px;

   background: url(/images/text-field.png)

     no-repeat;

}

…at first. It turns out Internet Explorer anchors the background image to the text field, and if you type beyond the border, the image scrolls off to the left as you type.

Well, that’s okay, you can just anchor the background with “background-attachment: fixed;” like so:

input{

   width: 90px;

   height: 26px;

   background: url(/images/text-field.png)

     fixed no-repeat;

}

Ah, but there’s a slight problem now: Firefox and Safari respond to this new attribute by not showing the background image at all. I have to say, and this could be a first for me, my opinion is that IE gets this one right. Scrolling makes sense, and a “fixed” background is the right solution.

But such is the life of a web developer, making things work the way they are, not the way they ought to be. So, alas, I left the “fixed” attribute out of the CSS–works for Safari and Firefox–and used jQuery’s “document ready” function for IE:

$(document).ready(function(){

if ( $.browser.msie )

    $('input').css('background-attachment','fixed');

});

It’s a little weak, I know, but sometimes quick and dirty is the best solution. Besides, without JavaScript, the rest of the site will fail much worse than this form field.

My friend is embarking on a tour to promote his new book. He’ll be on the road so email is going to be the best way to announce what’s going on to interested parties. However, sending email from his Yahoo! account to multiple recipients proved problematic: emails addressed To: a complete list of recipients raised some ire from people not wanting their emails revealed to other recipients.

The next attempt went a little better: he addressed it to himself and BCC’ed actual recipients. But so do spammers, and a lot of people never even saw this one. The alternative is to send the email over and over to each individual, which is even more work than the tedium of adding all email addresses to a BCC field with Yahoo!’s address book.

Obviously, this is something where a computer should be doing the heavy lifting, but the options out there are either not free, or contain intrusive ads. (Which, come to think of it, Yahoo! Mail also does.) Given the nature of the book, this is undesirable.

I wanted to help, so I threw together a little three-page web app to store email addresses and names, and loop over each item to send an individual email to every person. We also want to do the right thing by sending a MIME multi-part style email, so email clients do the right thing based on each user’s preferences. PHP’s mail() function, with some custom headers, to the rescue.

These lines set up the headers:

$to = "\"$rname\" <$remail>"; # recipient
$from = "\"$sname\" <$semail>"; # sender
$headers = 'From: ' . $from . "\n";
$headers .= 'To: ' . $to . "\n";
$headers .= 'Return-Path: ' . $from . "\n";
$headers .= 'MIME-Version: 1.0' ."\n";
$headers .= 'Content-Type: multipart/alternative; boundary="'
. $boundary . '"' . "\n\n";
$headers .= $body_simple . "\n";
$headers .= '--' . $boundary . "\n";
$headers .= 'Content-Type: text/plain; charset=ISO-8859-1' ."\n";
$headers .= 'Content-Transfer-Encoding: 8bit'. "\n\n";
$headers .= $body_plain . "\n";
$headers .= '--' . $boundary . "\n";
$headers .= 'Content-Type: text/HTML; charset=ISO-8859-1' ."\n";
$headers .= 'Content-Transfer-Encoding: 8bit'. "\n\n";
$headers .= $body_html . "\n";
$headers .= '--' . $boundary . "--\n";

Each section of a multi-part email is set off by a unique boundary string, defined in this case as follows:

$boundary = md5(uniqid(time()));

Now “abuse” mail() as follows:

mail('', $subject,'', $headers);

Does anyone NOT want to write a toy iPhone web application? It was pretty much the first thing I wanted to do with my new phone. I messed around with some cool JavaScript gizmos, played with the resize-on-rotate thing, and…time passed.

Today I was looking at Wikipedia and came across some information on alternate ways of getting information from their database (q.v.). In particular, I was intrigued by the feature whereby you can get a list of a given Wikipedia page’s outbound links. A couple of hours later, I’ve got a crude little demo that lists a topic’s related links in pairs: the first links to a similar page with a list of links for that topic; the second links to the actual Wikipedia page. If you have an iPhone, try it out!

It doesn’t seem to mean anything to anyone I talk to, but I’ve always thought of the hod-carrier as the very emblem of hard work. The construction site would grind to a halt without his quiet, dedicated labor. He toils at this thankless job, willing to let others grab the glory, content that he played a small part in the overall accomplishment.

I’m like that hod-carrier, happy to pitch in when others have some pressing need, when there’s something needing doing that they don’t understand. They take the high-level view, they take the credit at the end, and I don’t care. I did what I did, and I’m just glad to make it all happen more smoothly.

That’s him there in the upper right-hand corner. Hooray for the hod-carrier!