Fixing a Bifold Closet Door

Paul R. Brown @ 2008-01-09T05:23:19Z

Somehow, one of the bifold closet doors in the house got broken. The door has a hollow construction with pivota at the top and bottom set into 3/8" holes in relatively small pieces of wood (maybe 2x2s?). Whatever happened broke a chunk of wood out of the piece of wood on the bottom of the door in the worst possible place, taking half the hole with it and pushing the front and back surface of the door out. To make matters worse, we discovered this when the door fell out and attacked my wife when she tried to open it...

Replacing the door wasn't an option, since it is part of a bank of four such doors that all match and also match other doors in the house, and the doors lack any sort of identifying marks as to the manufacturer. My best guess was Jeld Wen, but there is a huge variety of different dimensions, proportions, and styles. So I set out to repair it as a weekend project.

Pipe Clamp and Guide Completed Repair

Here was the process:

  1. Craft a piece of wood to roughly match the missing tetrahedron.
  2. Reglue the front/back/side of the door onto the remaining wood with carpenter's glue. Clamp to shape and wipe off excess; let dry.
  3. Glue the custom-made hunk of wood into place with some Gorilla Glue. It's the right glue for the job because it expands as it dries, ensuring a tight fit. The only odd thing is that you need to moisten the wood before gluing. I clamped the door into the right shape with some scrap 1x4 to ensure that it didn't force the door apart. Let cure.
  4. Use a razor blade to ensure that the bottom surface of the door is flat and smooth.
  5. Construct a guide for the 3/8" hole by drilling through a piece of scrap lumber. This is important, as there's no way to hand-hold the drill steady enough to drill the half a hole that you need.
  6. Use a pipe clamp (cheap and useful!) to clamp the guide in place on the bottom of the door and a piece of scrap lumber on the top of the door.
  7. Drill the hole using the guide, remove the clamp, and tap in the sleeve for the bottom pivot with a mallet.
  8. Install the door.

That was fun.

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"Hello World" for Perpubplat

Paul R. Brown @ 2008-01-04T08:48:32Z

Setting up perpubplat to talk to a web server takes a bit of work, but once you've got the code, bootstrapping a post can be done with just ghci.

The perpubplat configuration in the Darcs repository expects to find posts and comments stored under /tmp/content and drafts stored under /tmp/drafts. (Clearly, a different configuration would be desirable for production use...) Create those directories and then a file /tmp/drafts/hello-world.draft with the following contents:

title: Hello, World!
tags: one two three

--- START BODY ---

<p>Hello, World!</p>

--- END BODY ---

Next, load up the code in ghci:

$ cd perpubplat/perpubplat/src
$ ghci Blog.BackEnd.IoOperations Blog.Model.Entry \
  Blog.BackEnd.ModelTransformations Blog.FrontEnd.Presentation \
  Blog.FrontEnd.Views
GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
[ 1 of 13] Compiling Blog.Widgets.FlickrBadge ( Blog/Widgets/FlickrBadge.hs, interpreted )
[...]
Ok, modules loaded: Utilities, Blog.Constants, Blog.Model.Entry, [...]
*Blog.BackEnd.IoOperations> :set prompt "> "
> :m + Blog.BackEnd.ModelTransformations Blog.FrontEnd.Views Blog.FrontEnd.Presentation
> m <- boot
> (s,m') <- ingest_draft m "hello-world.draft"

The ingest_draft function does the work of adding the post parsed from the draft to the internal data structure (some maps and lists bundled together) and storing the new post in the content directory. You can find it in /tmp/content/hello-world/content.ppp.

For a little more exercise, here's how to render the "all posts" view containing the new post:

> assemble_view (All Nothing) m'
Loading package xhtml-3000.0.2.1 ... linking ... done.
"<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" [...]

Which is the XHTML that would be displayed in the browser. As to the content of the internal data model for the post we just created:

> :m + Blog.Model.Entry
> s
"hello-world"
> post_by_permatitle m' s
Item {internal_id = 0, kind = Post, title = "Hello, World!" [...]

And that's all there is to it.

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Darcs Repository for Perpubplat

Paul R. Brown @ 2008-01-04T08:45:59Z

I succumbed to some mild peer pressure, posted a Darcs repository, cleaned-up the Cabal files for perpubplat, and fixed a few minor bugs. If you have darcs installed, you can pull down a copy of the source code — a grand total of less than 1500 lines according to SLOCCount — with:

darcs get http://datapr0n.com/repos/perpubplat

You can also browse the repository at the same URL, but Apache will serve those files to you as text/x-haskell, i.e., your browser probably won't display them as plain text in the browser. The Darcs-maintained revision history is here.

The README file contains instructions on building, but if you've already got GHC 6.8.2 and FastCGI libraries installed, it's as easy as:

$ cd perpubplat
$ cd perpubplat
$ chmod +x Setup.lhs
$ ./Setup.lhs configure && ./Setup.lhs build && sudo ./Setup.lhs install
$ cd ../perpubplat_servlet
$ ./Setup.lhs configure && ./Setup.lhs build

The FastCGI handler is dist/build/perpubplat.fcgi/perpubplat.fcgi.

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Random Idea: Cellphone Booth

Paul R. Brown @ 2008-01-03T21:13:36Z

My first startup's offices were in a classic Chicago loft with minimal build-out, and by minimal I mean that no wall went more than half-way to the fifteen-foot ceilings. It was a great arrangement in many ways (see, e.g., Dick Costolo on the subject), but it was challenging in situations where privacy was necessary, like hiring or compensation discussions, sales calls (when you don't necessarily want your potential customer listening to a heated foosball match), or Board business. There have been many times when I needed or wanted to take a private call while in a public space or on-site visiting a customer.

Cellular Phone Booth And this brings me to the idea of a cellphone booth. Why not have low-tech (in fact, no-tech) booths for cellphone users that can be dropped into airports, building lobbies, cafes, and offices like a "portapotty" on a construction site? It probably isn't that expensive to construct a booth (plywood, some acoustical foam), and the obvious twist is to brand it and place print advertising on the inside and outside to create a revenue stream. I can't claim that the idea is original, as I used a cellphone booth in the United lounge in Copenhagen once upon a time, but I haven't seen one anywhere else. (Also, a similar idea was suggested back in the 1960s...)

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perpubplat 0.9 — You're Looking at It

Paul R. Brown @ 2008-01-03T07:10:14Z

I started thinking about replacing Typo back in October of 2006, and my home-brew project to do so is at the point where it's usable as a replacement. In fact, I cut over this morning, so you're looking at it right now.

The current implementation represents an investment of around 60 hours of learning and hacking time spent on Apache, FastCGI, Atom, XHTML, and Haskell.

Why Not X?

It is reasonable to ask "Why not use X?" where reasonable values for X include default blogging tools like Wordpress or Roller, a more recent version of Typo, some language other than Haskell (like Erlang or OCaml or Scala), or an existing Haskell framework like HApps or Hope. The short answer is that I rolled my own because I wanted to roll my own.

Tooling and Methodology

I used the default tooling stack of Emacs (the Aquamacs flavor) with haskell-mode, GHC, and Darcs for revision control. My workflow loop was equivalently simple: I worked in Emacs until I thought that something might work and then loaded a module into ghci to experiment with.

Basic Architecture

The basic architecture is straightforward; here are the highlights:

  1. Container: FastCGI handler implemented in Haskell that parses request URIs to determine how to respond. Apache with mod_fastcgi is configured as described in an earlier post.
  2. Storage: Plain text, simple file storage of entities (posts, comments, drafts, etc.) in a human editable, human readable format.
  3. Concurrency: An event loop that listens on a Haskell Chan and manages a single in-memory instance of the data. The event loop runs on a lightweight background thread that gets forked when Apache spins-up the FastCGI handler, and the approach is equivalent to the one I used for the sequence number generator experiment.
  4. Browser Views: XHTML rendering via the Text.XHtml combinator package.
  5. Atom Feeds: A modified version of the lightweight Atom library that I posted on previously.

Early Returns and Open Items

My expectations are met so far. The implementation is deployed on my virtual server at Linode. Some ad hoc benchmarking shows that it will support sustained 50 req/sec loads with 10 or 20 concurrent clients without issue, and that's a stark contrast to Typo's performance of four requests per second (downhill and with the wind). (Benchmarking traffic may well be saturating the network between here and there, so it might even do a bit more.) Turning on profiling shows that most of the time is taken in string concatenation for a page view or a feed. One option would be to set up conditional GET and some basic caching, and switching to Data.ByteString would be another.

There are two open items I'm still thinking about: dynamic content in the browser and comments.

For dynamic content in the browser, i.e., integration via Javascript clients to HTTP APIs, I experimented a bit with in-page widgets that do a bit of DOM rewriting to display fancy badges from del.icio.us or Reddit or shared items from Google Reader, but pages load more slowly, it requires clients to have Javascript enabled, and it's incompatible with XHTML. (The one compromise for the moment is the Flickr montage, since it adds a splash of color.) Instead, I'm planning to add additional background threads to the application to poll del.icio.us, Flickr, and other services via HTTP APIs and then vend cached data to sidebar widgets.

The second item is support for comments, trackbacks, referrers, and the like, and that's just a matter of me deciding how I want to manage the workflow and ensure a good experience for repeat commenters or correspondents (i.e., people who link here).

Open Source?

I will make source code available as a Darcs repository at some point in the near future, but it's not a priority for me. The milestone I'd like to achieve before releasing the source is to have the cabal builds all squeaky clean, and that's not far off. (Right now, things are just built with ghc --make.) Even then, I still wouldn't call it "open source". Calling something "open source", to me, should carry with it an implicit promise of usefulness and fitness for purpose, but as the name might suggest, I intend this to be a personal publishing platform.

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Administrivia

Paul R. Brown @ 2008-01-02T20:03:19Z

I've switched my publishing engine from Typo to a home-brew platform called "perpubplat" which appears to be stable enough (i.e., better than Typo) but will remain a work in progress. (I'll post more on perpubplat later; I'm happy to share source code with folks and will post Darcs repository information once I've cleaned things up a bit.)

Of relevance to feed subscribers (and perhaps how you ended up here):

  • RSS feeds are no longer provided in any form. What would have been a request for an RSS feed directs to an Atom feed containing this post.
  • As a corollary of the non-existence of RSS, categories (as semantic artifacts of RSS) no longer exist. Instead, you can pick out a relevant by-tag feed, e.g., for posts tagged Haskell, Java, or entrepreneurship. (For any by-tag or by-date view, there is an associated feed available via autodiscovery.)
  • Comment feeds by article internal identifier are no longer supported. (Comment feeds by article are supported with a different, permatitle-based URI; check the autodiscovery links on a single article page.)

Of relevance to visitors:

  • For the time being, new comments aren't supported directly on this blog, but that shouldn't stop you from commenting on your own blog or posting to a community site like Reddit or DZone. The plumbing for comments (as well as trackbacks and backreferences) is present, but I haven't decided how I want to restrict content and control spam yet. Historical comments and trackbacks are present.
  • I've made some effort (i.e., using FeedValidator and xmllint) to ensure that specification compliance is provided when advertised, including cleaning up the content of older posts, but please let me know if something falls short.
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Phishing Without a Pole

Paul R. Brown @ 2007-12-19T09:15:26Z

The following phishing email showed up in my GMail inbox today:

Even if I was to be taken in by the ploy, there is no web link or other way to submit the form. Maybe I'm supposed to reply to the email? Too bad it's not as amusing as other stupid criminal tricks.

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