D520 – Week Six

Chapter 6 of IronPython in Action covers “properties, dialogs, and Visual Studio”. This seemed an obvious place to insert the material on user-interface design that is normally covered in the course, and to look a bit more deeply than the textbook does at Visual Studio itself (and the Windows Forms controls and their properties). I only scheduled a single week to cover this, but I suspected that it might take more than one (I left an empty slot in the schedule to cover one such over-run), and that was, indeed, the case. The students received notes [PDF], slightly longer this week (covering the UI design material not in the textbook, as well as the usual chapter summary, key points, and examples, and the steps required to install IronPython support in the ‘Experimental Hive’ Visual Studio SDK), and a fairly simple lab exercise [PDF]. Continue reading “D520 – Week Six” →

Mailbox flattening messages

The mailbox.py code does this to dump a message (e.g. when adding to a Maildir file):

def _dump_message(self, message, target, mangle_from_=False):
    # Most files are opened in binary mode to allow predictable seeking.
    # To get native line endings on disk, the user-friendly \n line endings
    # used in strings and by email.Message are translated here.
    """Dump message contents to target file."""
    if isinstance(message, email.Message.Message):
        buffer = StringIO.StringIO()
        gen = email.Generator.Generator(buffer, mangle_from_, 0)
        gen.flatten(message)
        buffer.seek(0)
        target.write(buffer.read().replace('\n', os.linesep))
    elif isinstance(message, str):
        if mangle_from_:
            message = message.replace('\nFrom ', '\n>From ')
        message = message.replace('\n', os.linesep)
        target.write(message)

(There’s a bit more that deals with other types of message). Unfortunately, with some messages containing Unicode characters, this breaks with a UnicodeDecodeError:

Traceback (most recent call last):
  File "", line 1, in
  File "/usr/lib/python2.5/mailbox.py", line 245, in add
    self._dump_message(message, tmp_file)
  File "/usr/lib/python2.5/mailbox.py", line 203, in _dump_message
    buffer.seek(0)
  File "/usr/lib/python2.5/StringIO.py", line 106, in seek
    self.buf += ''.join(self.buflist)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xd6 in position 106: ordinal not in range(128)

The message does flatten with message.as_string() – or str(message) – without any problems. I’m not really sure why mailbox.py doesn’t just use as_string(), rather than create a generator itself. I’m also not totally sure where the error is coming from, especially since it happens inside of seek().

For now, I can just call mailbox.add() with msg.as_string(), rather than with msg directly, and it’ll work fine. At some point, if I have time, I’ll revisit this and try and figure out if it’s a Python bug that should be reported.

Forced Materialism

Fewer people than normal (is there a “normal” after only three?) asked what to get Samuel for his birthday this year – perhaps they all asked Olyvia and she didn’t mention it, or perhaps people know him better, or perhaps it’s just easier to buy for a three-year-old. My stock response (which I tried, fairly successfully, to get Olyvia to use as well) was as follows (this didn’t apply to parents or grandparents):

Sam has so many toys that he just doesn’t have time to play with everything. He has toys in his toy box that he hasn’t even played with yet. He really doesn’t need any more at the moment. He also has heaps of books and clothes. If you want to buy him a present, then you are, of course, welcome to do so. In that case, our suggestions are:

* Make him something. He’s a bit of a fussy eater these days, unfortunately, so food might not be a good choice. If you can think of something else to make, then that would fine.
* Something to do. e.g. an IOU for a trip with you to somewhere. This could be as simple as a picnic at a park somewhere – he loves being outside.
* A donation to a charity and a card (he likes opening mail) saying what you did. He’s not going to understand it now, but when he’s older, he’ll hopefully think that was really cool, and right now he already has so much stuff.

My hope was really for the latter – we actually do quite a few things already, so there isn’t a pressing need for the middle choice. Making him something is great, but it seemed unlikely to appeal to many givers. We did actually try this once before – suggesting a donation to a charity (Starship, I think) as a Christening present. If I recall correctly, we didn’t get a single bite that time. Continue reading “Forced Materialism” →

D520 – Week Five

Chapter 5 of IronPython in Action deals with XML, although it starts out covering some of the more advanced things you can do with functions. I considered skipping this chapter (the function material is perhaps a bit advanced, and covering XML isn’t a necessity), but decided that it was worth learning about XML in .NET (since it’s so common) and that it would make using the MultiDoc example tricky (since the file format is XML) and I really wanted to use MultiDoc. I gave the students notes [PDF], again covering the textbook material that we could look at, the tools (unchanged), key points, and a link to the MultiDoc example code. We had a new lab exercise [PDF] this week (implementing Conway’s Game of Life), as well as two new recommended reading articles: a Lukas Mathis post about preferences and another Spolsky post, this one about “architecture astronauts”. Continue reading “D520 – Week Five” →

D520 – Week Four

This week continued from the previous one, covering Chapter 4 of IronPython in Action. That meant no new notes, and no new lab exercise. We basically did two things: worked through the MultiDoc example in Chapter 4, and worked on implementing the Airline lab designed in the previous week.

The first recommended reading for the week was Part 1 of Joel Spolsky’s “Talk at Yale”, wherein he tries to relate his study to his career – the part I hoped they would find interesting was the discussion of “geeks” versus “suits”. The second recommended article was Steve Yegge’s “Code’s Worst Enemy”, which is mostly about code bloat. In retrospect, these might not be the best pairing, since Yegge is always long, and this particular Spolsky article is very long (if you read all three parts). However, I was again pleasantly surprised to hear that students were actually reading these. Continue reading “D520 – Week Four” →

Yet Another New Look

As you can tell (unless you’re reading this via RSS), I’ve changed the theme for the site again. I quite liked the layout of the old theme, but the text was just too hard to read, especially with large posts (which I am prone to). Let me know if there are any issues – since this is hosted WordPress, it should be fine, of course.

D520 – Week Three

When planning the semester’s schedule for D520, I choose a few topics that seemed large and gave them a two-week time-slot. One of these was chapter 4 of IronPython in Action, which covers duck typing, design patterns, and introduces the MultiDoc example that’s used throughout the middle section of the book. One of the concepts that the course has always (at least, as long as I have known it) tried to push is the importance of design – not just user-interface design (although that’s both important and covered), but the importance of doing at least some planning before starting to write large amounts of code. In the last couple of years, I’ve moved the course away from focusing on extensive formal design to also cover design patterns and testing (particularly automated testing, like unit tests). Since this is such a major issue for the course, and since I planned on using MultiDoc as an example in class (I try to always have an example that continues on from week to week), this seemed like an obvious point for a two-week session. Continue reading “D520 – Week Three” →

Google Voice? Who really cares?

I really enjoy listening to Jason Calacanis when he’s on TWiT, and I think he generally makes a lot of sense (and considering his success, he clearly knows more than me). However, his anti-Apple rant (like so many others) is really off-base (I’m not the only one that thinks so).

There is no technical reason why the iTunes ecosystem shouldn’t allow the ability to sync with any MP3 player

The iTunes ecosystem does allow the ability to sync with any MP3 player (even more so now that music is DRM-free). You can build an application that uses the XML library description that iTunes creates to figure out where all the music/video is, and do what you like with it. The way I see it, there’s no reason that iTunes/Apple should be forced to support any MP3 player with their software. Apple clearly makes some money from the iTunes music/video sales, but it’s clearly not the main profit generator is the ecosystem – the high-margin iPods/iPhones are. Apple has spent a great deal of time and money building a store and an application to make the players more appealing. Why should any other player get to piggyback on the top of that? If (e.g.) Palm wants to create an online music store and develop an application that works with it and the Pre, then they should be able to (and I see no reason they can’t).

I like iTunes more than other media applications I’ve used, but it’s certainly not perfect, and it shows that it started out as a music player and is now a great deal more. I love the iTunes Store, but Amazon completes with it (I can’t tell how well, since they won’t see to me in NZ) as does the Zune Store – which even offers a subscription model (no idea if this is available in NZ – it’s too Windows-centric for me). There’s absolutely room for someone (e.g. Palm) to build a better store (or interface with an existing one like Amazon) and built a better application. Do that, and build a better device, and you’ll get customers. Don’t expect that Apple should have to help you compete against them.

Think for a moment about what your reaction would be if Microsoft made the Zune the only MP3 player compatible with Windows.

The iPod/iPhone isn’t the only MP3 player compatible with OS X. However, isn’t the Zune is the only MP3 player compatible with the Zune store? The “PlaysForSure” idea got thrown out some time ago.

Simple solution and opportunity: Not only let the iPhone work on any carrier,

How many countries is the iPhone locked in? It certainly isn’t locked here, or in many other countries (e.g. Australia). This is only an issue in some countries, like the U.S. – it’s a U.S. Apple problem, not an Apple problem. From what I understand, it makes business sense for Apple to have an exclusivity deal with AT&T, at least for now. I don’t see anything wrong with that. If AT&T was bad enough, then people wouldn’t use it, even if it was the only iPhone choice. If other companies made phones good enough on other carriers, then it wouldn’t matter which network the iPhone was with. I presume this is a temporary issue and the U.S. will join the other enlightened countries before long and have unlocked phones, anyway.

but put *two* SIM card slots on the iPhone

A nice idea in some ways, but about as un-Apple as you can get.

3. Draconian App Store policies that are, frankly, insulting

This is actually points 3, 4 and 5.

Yes, every application on the phone has to approved by Apple, and if you were interested in something adult in nature…well…you can’t do that.

From all accounts, the approval process needs a lot of work. One suspects that now that Jobs is officially returned to work (and Schiller is speaking openly about at least some things) that changes will happen before too long. I think Apple must surely realise that the situation is getting out of control, and will start implementing changes. For now, there are still a lot of applications that I really love, there are none that I know of (which is an issue, of course) that I wish I had, and only one that has been pulled that I love (which is Amazon’s fault, not Apple’s). I’m willing to give Apple a bit more time to fix this – I suspect that even they didn’t realise quite how successful this would be.

4. Being a horrible hypocrite by banning other browsers on the iPhone

Again, this is really just a specific case of #3. Personally, I see almost no demand for Opera anywhere apart from by a few (very extreme) fans. I don’t even see much desire for Firefox or Chrome on the iPhone.

5. Blocking the Google Voice Application on the iPhone

There’s a lot of talk about this. It seems overblown to me, considering that Google Voice isn’t even publicly available (I believe it’s an invite-only beta) and is U.S.-only. I think it’s just that a lot of the noisy tech pundits use Google Voice, and so this impacts them directly. I think there are much worse cases of App Store approval problems. In any case, this is again just another instance of #3.

Making great products does not absolve you from technology’s cardinal rule: Don’t be evil.

It seems to me that the cardinal rule is more “make great stuff”. I’ll still buy from Amazon, even after they killed my favourite iPhone application. I dislike some of how Apple handles App Store submission, but I’ll still buy various products from them. I dislike DRM in general, but the iTunes Store is good enough that it’s still worth using.

1. Do you think Apple would be more, or less, successful if they adopted a more open strategy (i.e. allowing other MP3 players in iTunes)?

Less. A huge part of the appeal of the Apple ‘ecosystem’ is that because they control all parts, everything “just works”. If you use all-Apple products, everything works so much nicer than if you mix-and-match.

2. Do you think Apple should face serious antitrust action?

No.

3. Do you think Apple’s dexterity and competence forgive their bad behavior?

Yes.

My 2GB, 4 day 0.0.1 iPhone update

A few days ago, Apple released version 3.0.1 of the iPhone OS, which addressed a pretty major SMS vulnerability. When Olyvia tried updating her 3GS to 3.0.1, something went wrong. The iPhone entered “Recovery Mode”, which means that it displays an image indicating that you need to connect it to iTunes, and you can’t do anything else (no phone calls, no iPod, no applications – absolutely nothing). Connecting the phone to iTunes prompted a message indicating that the phone needed to be recovered – doing so downloaded the 3.0.1 update, and then got stuck on the “Verifying Restore with Apple” step for a long time, until it would finally fail with error “3104”. This process could then be repeated, with the same results.

What this meant in practice was that the phone was bricked as of last Friday. An update should never be able to brick a (legitimate, not jailbroken) phone! Even more, failing to verify a restore with Apple should never leave the phone in a broken state.

I tried many thing to resolve this:

Restoring on three different computers (three OS X Leopard, one Windows XP).
Using three USB cables.
Using two Internet connections (different router, different physical location, different ISPs).
Restoring with five different user accounts, including one that was created solely for this purpose.
Removing iTunes and the Mobile Device helper completely and reinstalling.
Restoring with an administrator account (both OS X and Windows XP) and a standard account.
Redoing the restore at many different times of day, including times when most of the US would be asleep (so the server load should be fairly low), over Friday, Saturday, Sunday, and Monday.

None of this worked. It did mean that I downloaded the 300MB+ update six times (one for each user account and once to refresh) over the four days. That combined with the iTunes installation brings the total download cost to around 2GB.

I eventually gave up. Google found many other people with this problem, but only a single solution, which involved opening a terminal connection to the phone and changing an environment variable. I wasn’t particularly comfortable doing that, since if something goes wrong I want Vodafone/Apple to just replace the phone without any argument. Since there isn’t any real support available over the weekend, I waited for Monday morning.

I wasn’t sure whether to contact Apple (expecting a “please call Vodafone” answer) or Vodafone (expecting a “what do you mean you updated your phone? Can you do that?” answer). Thankfully, Vodafone NZ has a very responsive and helpful Twitter presence (@vodafoneNZ). I tweeted, asking who to call, and was asked for details. I provided these (going into more detail in an email), and got back a (unfortunately not helpful at all) suggestion. Since that didn’t work, Paul Brislen provided me with an 0800 number for the “iPhone Team” (I’d call them “iTeam”, subtitled “there’s an ‘i’ in iTeam”, but anyway…). Unfortunately, since I had to do a lot of travelling and offline things on Monday, I wasn’t able to get to this until Tuesday.

I certainly appreciate a (free) phone number I can call. However, I don’t have a great deal of time to spend talking on the phone, explaining a rather complex problem and the many steps that I’ve already done to try and resolve the problem. I also have poor cellphone coverage (Vodafone’s fault) and a rather noisy landline (Telecom‘s fault), so voice calls aren’t a great solution to a problem. Faced with a (presumably) long and difficult phone call, the ‘hack’ solution of altering the environment variable looked a little more appealing.

I downloaded iRecovery and opened a terminal (shell) connection to the iPhone. Typing “printenv” gave a list of the environment variables – the ones that had a “P” at the start were presumably non-default values (these included “auto-boot”, “bootdelay”, “backlight-level”, and “platform-uuid”). The article indicated that the “false” value for “auto-boot” was the problem (and the solution to use setenv to change it, then reboot the phone). This seemed a reasonably safe thing to do (and also easily reversed), although I imagine that it would be rather scary to a non-programmer (who has no idea what “printenv” or “setenv” might mean).

Thankfully, this worked. The iPhone rebooted – although it went straight back to the recovery page in iTunes, which wasn’t hopeful. However, this time the recovery process worked flawlessly (using the existing four-day-old copy of the download). The phone was recovered from the automatic backup, and then sync’d. Some of the settings are a bit out as you expect in a recovery, but the phone actually works, which is really all that matters.

I don’t know what would have happened if I called the “iPhone Team” (and don’t need to find out now). I suspect that we wouldn’t have got far, or maybe would have ended up doing exactly this (or perhaps having to return the phone for service). I could be wrong about that. I do feel that Vodafone (specifically @vodafoneNZ) handled this pretty well (and Apple extremely badly).

D520 Week Two

Here’s my material from the second week of “D520: Programming” (in IronPython). The students got some brief notes [PDF] and the first proper lab exercise [PDF]. The recommended reading this week was a post by Lukas Mathis about poor hardware design (and lessons to be learnt), and a post by Wil Shipley about tracking down a Delicious Library bug. The notes are again in four sections: textbook chapters (this week chapter 3, which is fairly essential reading), tools (same as last week, although I also recommended IronPython 2.6b2), key points, and example code (from chapter 3 of the textbook). The lab exercise is a modification of one from last year (when it was in Visual Basic) – I’m trying to keep as many of the previous lab exercises as possible, so that there is still a tiny bit of continuity between 2008 and 2009. Continue reading “D520 Week Two” →