addywaddy

Barefoot Running

I've been running on and off now for the past 11 years and after an
'off' of nearly half a year, decided to pick it up again. Although
there are two public running tracks near where I live, I'm so
weak-willed that if I plan to do 20 laps, half way round I'll cut that
to 18 and eventually stop at 16. So to avoid that I go to google maps
and plan a circular run around the neighbourhood, the idea being that
if I stop half way, I've at least got to walk all the way back.

Anyway, I planned my route, dusted off my shoes and set off. I have
this daydream sometimes of a svelte me running effortlessly, smiling
as I go and feeling as if I could keep going forever. Halfway through
the run I'm far from the daydream - my feet are slapping the pavement
like two wet fish, and I'm doing all I can to keep going. I end up
taking about three breaks during the run, the last one being due to
something that plagues nearly every run I undertake - blisters.

Five runs later and I'm getting frustrated. I definitely feel fitter
but the blisters mean I have to have at least 3 days recovery between
each run. I resort to the prophylactic use of plasters which helps but
then I run a bot further and get blisters elsewhere on my feet
instead. I own two pairs of running shoes which give me blisters on
both feet in different areas and so decide to go to a specialist
running shop to get some advice on a new pair of shoes. But before I
do, I get onto google and start searching for "running blisters".

I can't quite remember how, but after about half an hour of searching
and clicking I landed on this article in Mens Health article by Christopher McDougall.
It's an excerpt from McDougall's book "Born to Run". Read it :) 

I spent the next few weeks obsessively googling barefoot running, came
across Vibram Five Fingers shoes (basically a glove for you feet - I'm
hopefully going to order a pair at the end of this month), ordered and
consumed "Born to Run", and then one day bit the bullet and went for a
1k run with my wife. Have you got children? If they're anything like
mine, they a) love taking their shoes off and b) will often run where
we adults tend to walk and actually seem to enjoy it. And that's how
that 1k run felt to me - childlike. I actually enjoyed it! And I got
some attention from passers to boot.

I've been building up since then, taking it slowly (my feet have been
pampered for the last 35 years in shoes and need toughening up a bit)
and building up the distance. I've overdone it a couple of times and
came home with wounded feet but last night I went for a 5 mile run
with a neighbour and my feet were dirty afterwards but otherwise
absolutely fine. That's 5 miles running through a city and all that
city roads, paths and pavements entail: having to run over gravel;
running through muddy puddles; and all the while avoiding glass and
dog poo ( a common sight on Berlin's pavements).

My main motivation for running has changed now. It used to be to get
fit. Plan a distance and a time, then run while gritting my teeth and
bearing it. It's now to be mindful and enjoy it. The fitness side is a
bonus :)

Useful links:

http://zenhabits.net/barefoot-running/
http://www.chrismcdougall.com/
http://www.barefootted.com/
http://therunningbarefoot.com/
http://birthdayshoes.com/

UPDATE: gratuitous foot photo:

Introducing CouchSurfer

I recently switched over from dm-couchdb-adapter to couchrest for a little project I've been working on for far too long now. One of the reasons was to force me to think more about CouchDB views and avoid accidentally using temporary views.

CouchRest comes with CouchRest::Model, which provides a nice ORM. I wrote a mix-in which sat in my lib/folder and implemented basic associations and validations and worked well for my needs. And left it at that. For about 2 days.

I then heard that Chris was planning on extracting CouchRest::Model out of CouchRest and setting it up as a separate project and, fancying a go at it myself while include the above mentioned features, I set about building my very first gem. The first step was to implement the model, which involved copious amounts of copy and paste (although I made the task a bit harder for myself by rewriting it as a mix-in). I then added associations, validations (using the Validatable gem plus writing a validates_uniqueness_of method) also as mix-ins. The fruits of my labour can be found here:
 
 http://github.com/addywaddy/couchsurfer
 
Check out the README for a basic introduction to what it can do. I must say, although I've been programming Rails/Ruby/Merb for a while now, I've never had much of a use-case for meta-programming so it's been great fun getting from how I wanted the DSL to look to implementing it so that it actually worked.

Now, back to that little project … :)

CouchDB and Pagination

It's taken me a while to figure out how to implement pagination with CouchDB but after trawling the interweb I finally posted my question on the couch-db user group and got the reply I needed (Thanks Paul Carey!). I have some results which need to be paginated

First Page Query:  -----------------  /my_db/_view/document/all    ?count=25    &startkey_docid=null    &group=true    &endkey=["5455a49f69aeb7e9e6573159d4dfbca9",{}]    &descending=false    &startkey=["5455a49f69aeb7e9e6573159d4dfbca9",null]  Next Pages Query:  -----------------  /my_db/_view/document/all    ?count=25    &startkey_docid=e2a9572739696a257cc2fb25a7f6e495    &group=true    &endkey=["5455a49f69aeb7e9e6573159d4dfbca9",{}]    &descending=false    &startkey=["5455a49f69aeb7e9e6573159d4dfbca9",       "e2a9572739696a257cc2fb25a7f6e495"]    Previous Pages Query:  ---------------------  /my_db/_view/document/all    ?count=25    &startkey_docid=e2a9572739696a257cc2fb25a7f6e495    &group=true    &endkey=["5455a49f69aeb7e9e6573159d4dfbca9",null]    &descending=true    &startkey=["5455a49f69aeb7e9e6573159d4dfbca9",       "e2a9572739696a257cc2fb25a7f6e495"]

Spot the differences between Previous and Next? To list results in reverse order in couch, you set 'descending' to true. I'd seen this in the pagination Futon, but I was still was getting unexpected results. Paul's reply fixed this though: I hadn't changed to endkey to refer to the start of my results (using null instead of {} in the second part of my composite key). The only thing left to do was reverse my results when descending using Array#reverse! Two things I still want to implement. I don't want the show the 'Next' link when I'm on the last page. I'd prefer to use numbered links alá "1 2 3 4 … 25" instead of "Previous/Next".

Counting Elements with XPath

I've been trying to figure out for the last couple of evenings how to check that a table in one of my specs has the correct amount of rows.Finally, I've found out how to do it:

it "should have 10 rows" do    html = request("/resource/with/table").body    html.should have_xpath("//table/tbody/tr[count(../*)=10]")  end

I've no idea what the "../*" means but it works!

Update:

From the interweb ( http://www.zvon.org/xxl/XPathTutorial/Output/example1.html ):

"The basic XPath syntax is similar to filesystem addressing."

So, we're going up a level (..) and selecting all tr's in tbody (*).

Upgrading your Merb app

Just a quick one here. If you want to upgrade an app generated from an older gem version, cd into your app's folder and run:

$ merb-gen app .

Merb's Generator will then interactively show you what's new and where conflicts exist in a similar manner to when you run 'rails .' in an existing rails app.

CouchDB on Merb

I recently stumbled across this series of blog posts regarding couchdb and rails and, having a couple of small merb projects behind me, thought I'd find out how to integrate couchdb into a merb application.

NOTE: The following example application is built on merb 0.96 and DM 0.96.

So let's generate our new app and call it .. er .. 'cd_collection'.

merb-gen app cd_collection    cd cd_collection

We're going to use datamapper for our ORM so first things first, in init.rb:

use_orm :datamapper

Now run 'rake dm:db:database_yaml' on the command line and rename the template created in config/ database.yml. Edit this as follows:

adapter:  couchdb    database: cd_collection    host:     127.0.0.1    port:     5984

The adapter tells datamapper to use the dm-couchdb-adapter gem which you should have if you installed dm-more.

Aimee's blog covers how to install couchdb but if you're on a mac and running leopard, there is a nice installer available here.
Start couchdb, click on the magnifying glass and a tab should open in your browser with the admin interface for couchdb. Create a database 'cd_collection'.

Let's generate a cd resource for our merb app:

merb-gen resource cd

and edit the cd.rb model:

property :id, String, :serial => true, :key => true, :field => :_id    property :rev, String, :field => :_rev    property :title, String

The RDoc for dm-couchdb-adapter mentions only 'property :name, String' but I couldn't get it properly working without the :key and :field attributes.

Now lets make our merb app aware of our cd resource in router.rb:

r.resources :cds

Before we start our app, we need to add our fields to the forms created my our merb-gen resource command. Edit the 'new' and 'edit' views in cds/ to include:

<%= partial(:form) %>

and then create a '_form.html.erb' containing:

<%= text_field :title %>

While we're at it, let's change the index and show views to display our CDs' titles (I'll leave that up to you:-)). One more thing before we start our app. The views added by our resource generation contain methods (specifically the link, form and error helpers) that merb won't understand out of the box. Back to init.rb:

dependencies "merb-assets", "merb_helpers", "dm-validations"

So let's start up our merb app and navigate to /cds. New -> Enter title -> Save ... Striker! Our first CD has been saved in couchdb. Couchdb uses uuids instead of autoincrement by default which may disappoint those of you wanting to see cd/1 after saving in the address bar.

So there we go. I've added 10 CDs now, and I'd like to differentiate them by artist. An artist can have many CDs ... Here's something quit cool about Datamapper. Lets say that you want to keep your CDs in couchdb but would rather have your artists in an relational database. Firstly we need to inform Datamapper about our additional 'repository' in database.yml:

repositories:      sqlite:        adapter:  sqlite3        database: /path/to/cd_artists.sqlite3        host:     localhost

We can now generate an artist resource as we did for our cds previously. Open up artist.rb and add the following:

property :id, Integer, :serial => true    property :name, String    has 0..n, :cds    def self.default_repository_name      :sqlite    end

We're telling our Artist model to use the repository named :sqlite. Our association however will look in the default repository which in our case is couchdb. Lets edit the views again for our artists and add an extra field to our cds '_form' partial:

<%= text_field :title %>    <%= select :artist_id, :collection => Artist.all.map{|a| [a.id, a.name]} %>

So we can associate a CD to a particular artist. Likewise, we can edit our 'show' view for artists to list their CDs:

<ul>    <% @artist.cds.each do |cd| %>      <li>        <%= cd.title %>      </li>    <% end %>    </ul>

We didn't need to migrate our CD model as couchdb doesn't require a set schema. We will need to now though to get our Artist model up and running so on the command line run 'rake dm:db:automigrate'. You should see CREATE TABLE "artists" somewhere there in the output.
OK. Lets start our app again. You should now be able to add artists and associate CDs to a particular artist. Me like!

Download CD Collection here