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<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title><![CDATA[Arnab's Universe]]></title>
<link href="http://arnab-deka.com/atom.xml" rel="self"/>
<link href="http://arnab-deka.com/"/>
<updated>2014-07-21T10:51:57+05:30</updated>
<id>http://arnab-deka.com/</id>
<author>
<name><![CDATA[Arnab Deka]]></name>
</author>
<generator uri="http://octopress.org/">Octopress</generator>
<entry>
<title type="html"><![CDATA[Debugging warnings in tests]]></title>
<link href="http://arnab-deka.com/posts/2013/02/debugging-warnings-in-tests/"/>
<updated>2013-02-05T14:28:00+05:30</updated>
<id>http://arnab-deka.com/posts/2013/02/debugging-warnings-in-tests</id>
<content type="html"><![CDATA[<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
</pre></td><td class='code'><pre><code class='sh'><span class='line'>Object#id will be deprecated; use Object#object_id
</span></code></pre></td></tr></table></div></figure>
<p>Hate seeing warnings in your test output? Yeah me too. Came across a
fairly weird bug today and this is how I debugged it.</p>
<!--more-->
<p>With a recent checkin I started seeing some warnings in the test
output, like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
</pre></td><td class='code'><pre><code class='sh'><span class='line'><span class="nv">$ </span>ruby -I <span class="s2">"lib:test"</span> path/to/example_controller_test.rb
</span><span class='line'>Loaded suite example_controller_test.rb <span class="o">[</span>app_name<span class="o">]</span> init ...
</span><span class='line'>Started
</span><span class='line'>........../path/to/some/_partial.html.erb:48: warning: Object#id will
</span><span class='line'>be deprecated; use Object#object_id
</span><span class='line'>.............../path/to/some/_partial.html.erb:48: warning: Object#id
</span><span class='line'>will be deprecated; use Object#object_id
</span><span class='line'>..........................................................................................
</span><span class='line'>Finished in 12.545861 seconds.
</span><span class='line'>
</span><span class='line'> 58 tests, 198 assertions, 0 failures, 0 errors
</span></code></pre></td></tr></table></div></figure>
<p>If life’s easy, you’ll see the test files name along with the
warnings. However, in this case, the trace only contains an erb
partial. The partial looked something like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
</pre></td><td class='code'><pre><code class='html'><span class='line'><span class="nt"><li></span>
</span><span class='line'> <span class="err"><</span>%= @something.try(:id) %>
</span><span class='line'><span class="nt"></li></span>
</span></code></pre></td></tr></table></div></figure>
<p>Typically this warning happens when you call <code>#id</code> on an object that
evaluates to <code>nil</code>. In this case, looks like someone already thought
of that – and used
<a href="http://api.rubyonrails.org/classes/Object.html#method-i-try"><code>#try</code></a>
specifically to avoid this warning.</p>
<p>What gives? What complicates this is that our test suite has 1000+
tests and the partial that shows the erorr is used widely. (You could
try deleting the partial and see what fails but in this case 90% of
the tests would fail).</p>
<p>After some more trial and error, I started reading the Test::Unit
source on github. That with some introspection showed that you can get
the running test’s name at runtime with the <code>#name</code> method. Duh!</p>
<p>So I added a <code>teardown</code> to the suite:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
<span class='line-number'>13</span>
<span class='line-number'>14</span>
</pre></td><td class='code'><pre><code class='rb'><span class='line'><span class="k">class</span> <span class="nc">ExampleControllerTest</span> <span class="o"><</span> <span class="ss">Test</span><span class="p">:</span><span class="ss">:Unit</span>
</span><span class='line'> <span class="c1"># setup etc.</span>
</span><span class='line'>
</span><span class='line'> <span class="k">def</span> <span class="nf">teardown</span>
</span><span class='line'> <span class="nb">puts</span> <span class="s2">"</span><span class="si">#{</span><span class="nb">name</span><span class="si">}</span><span class="se">\n</span><span class="s2">"</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'>
</span><span class='line'> <span class="nb">test</span> <span class="s2">"something should do something"</span> <span class="k">do</span>
</span><span class='line'> <span class="n">get</span> <span class="ss">:new</span>
</span><span class='line'> <span class="c1"># assert something</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'>
</span><span class='line'> <span class="c1"># more tests</span>
</span><span class='line'> <span class="k">end</span>
</span></code></pre></td></tr></table></div></figure>
<p>With that, my test suit printed out the name of every test right after
the <code>.</code> – and looking through the output for the warning showed me the
test that was causing it:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
</pre></td><td class='code'><pre><code class='sh'><span class='line'>/path/to/some/_partial.html.erb:48: warning: Object#id will be
</span><span class='line'>deprecated; use Object#object_id
</span><span class='line'>.test_something_should_do_something<span class="o">(</span>ExampleControllerTest<span class="o">)</span>
</span></code></pre></td></tr></table></div></figure>
<p>This gave me the lead I needed. Now it took some more debugging to
figure out the details (I’ll spare you the rest) but it turns out a
method 4-5 levels down was retruning <code>false</code> instead of <code>nil</code>. And
<code>#try</code> works beautifully for <code>nil</code> but not for <code>false</code>:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
</pre></td><td class='code'><pre><code class='rb'><span class='line'><span class="o">>></span> <span class="kp">nil</span><span class="o">.</span><span class="n">try</span><span class="p">(</span><span class="ss">:id</span><span class="p">)</span>
</span><span class='line'><span class="o">=></span> <span class="kp">nil</span>
</span><span class='line'><span class="o">>></span> <span class="kp">false</span><span class="o">.</span><span class="n">try</span><span class="p">(</span><span class="ss">:id</span><span class="p">)</span>
</span><span class='line'><span class="p">(</span><span class="n">irb</span><span class="p">):</span><span class="mi">9</span><span class="p">:</span> <span class="ss">warning</span><span class="p">:</span> <span class="no">Object</span><span class="c1">#id will be deprecated; use Object#object_id</span>
</span><span class='line'><span class="o">=></span> <span class="mi">0</span>
</span><span class='line'><span class="o">>></span>
</span></code></pre></td></tr></table></div></figure>
<p>So there you go. It sure was an entertaining session for me. And if
you read it till here…</p>
<p>More techniques about how I could have debugged this more easily are
most welcome.</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Hello jQuery.PrettyTextDiff]]></title>
<link href="http://arnab-deka.com/posts/2013/02/hello-jquery-prettytextdiff/"/>
<updated>2013-02-03T10:56:00+05:30</updated>
<id>http://arnab-deka.com/posts/2013/02/hello-jquery-prettytextdiff</id>
<content type="html"><![CDATA[<p>For some work I did recently, I had to produce a visual diff of text.
A visual diff makes it easy for the user to understand what exactly
changed with a quick scan.</p>
<p>There’s an excellent library from Google, called
<a href="http://code.google.com/p/google-diff-match-patch/">diff_match_patch</a>
that does a really good job of analyzing the text and producing the
diffs in a programatic manner. However, it lacks the sauce to visually
present it to the user.</p>
<p>So I wrote a jQuery library which is a wrapper around Google’s library
and makes it trivial to wow your users.</p>
<!-- more -->
<p>First, a demo (the fiddle can be found
<a href="http://jsfiddle.net/arnab/YwSVY/">here</a>):</p>
<iframe class="jsfiddle"
style="height: 430px"
src="http://jsfiddle.net/arnab/YwSVY/embedded/result,html,js,resources,css/"
allowfullscreen="allowfullscreen"
frameborder="0">
</iframe>
<p>While Google’s library is excellent from a NLP-perspective, it does
not provide a way to show the diff in a beautiful manner. They have a
reference implementation to produce the diff in HTML, but recommend
you write your own (also this implmentation is inflexible in terms of
changing style/elements etc.).</p>
<p>Also, this library is produced in 7 different languages – so the code
that uses this is not particularly pleasing to look at.</p>
<p>Here’s an example of the code you would have to write to produce a
good looking diff:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
<span class='line-number'>13</span>
<span class='line-number'>14</span>
<span class='line-number'>15</span>
<span class='line-number'>16</span>
<span class='line-number'>17</span>
<span class='line-number'>18</span>
<span class='line-number'>19</span>
<span class='line-number'>20</span>
<span class='line-number'>21</span>
<span class='line-number'>22</span>
<span class='line-number'>23</span>
<span class='line-number'>24</span>
<span class='line-number'>25</span>
<span class='line-number'>26</span>
<span class='line-number'>27</span>
</pre></td><td class='code'><pre><code class='js'><span class='line'><span class="nx">diff_match_patch</span><span class="p">.</span><span class="nx">prototype</span><span class="p">.</span><span class="nx">diff_prettyHtml</span> <span class="o">=</span> <span class="kd">function</span><span class="p">(</span><span class="nx">diffs</span><span class="p">)</span> <span class="p">{</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">html</span> <span class="o">=</span> <span class="p">[];</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">pattern_amp</span> <span class="o">=</span> <span class="sr">/&/g</span><span class="p">;</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">pattern_lt</span> <span class="o">=</span> <span class="sr">/</g</span><span class="p">;</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">pattern_gt</span> <span class="o">=</span> <span class="sr">/>/g</span><span class="p">;</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">pattern_para</span> <span class="o">=</span> <span class="sr">/\n/g</span><span class="p">;</span>
</span><span class='line'> <span class="k">for</span> <span class="p">(</span><span class="kd">var</span> <span class="nx">x</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="nx">x</span> <span class="o"><</span> <span class="nx">diffs</span><span class="p">.</span><span class="nx">length</span><span class="p">;</span> <span class="nx">x</span><span class="o">++</span><span class="p">)</span> <span class="p">{</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">op</span> <span class="o">=</span> <span class="nx">diffs</span><span class="p">[</span><span class="nx">x</span><span class="p">][</span><span class="mi">0</span><span class="p">];</span> <span class="c1">// Operation (insert, delete, equal)</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">data</span> <span class="o">=</span> <span class="nx">diffs</span><span class="p">[</span><span class="nx">x</span><span class="p">][</span><span class="mi">1</span><span class="p">];</span> <span class="c1">// Text of change.</span>
</span><span class='line'> <span class="c1">//var text = data.replace(pattern_amp, '&amp;').replace(pattern_lt, '&lt;')</span>
</span><span class='line'> <span class="c1">// .replace(pattern_gt, '&gt;').replace(pattern_para, '&para;<br>');</span>
</span><span class='line'> <span class="kd">var</span> <span class="nx">text</span> <span class="o">=</span> <span class="nx">data</span><span class="p">.</span><span class="nx">replace</span><span class="p">(</span><span class="nx">pattern_amp</span><span class="p">,</span> <span class="s1">'&amp;'</span><span class="p">).</span><span class="nx">replace</span><span class="p">(</span><span class="nx">pattern_lt</span><span class="p">,</span> <span class="s1">'&lt;'</span><span class="p">)</span>
</span><span class='line'> <span class="p">.</span><span class="nx">replace</span><span class="p">(</span><span class="nx">pattern_gt</span><span class="p">,</span> <span class="s1">'&gt;'</span><span class="p">).</span><span class="nx">replace</span><span class="p">(</span><span class="nx">pattern_para</span><span class="p">,</span> <span class="s1">'<br>'</span><span class="p">);</span>
</span><span class='line'> <span class="k">switch</span> <span class="p">(</span><span class="nx">op</span><span class="p">)</span> <span class="p">{</span>
</span><span class='line'> <span class="k">case</span> <span class="nx">DIFF_INSERT</span><span class="o">:</span>
</span><span class='line'> <span class="nx">html</span><span class="p">[</span><span class="nx">x</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'<ins style="background:#e6ffe6;">'</span> <span class="o">+</span> <span class="nx">text</span> <span class="o">+</span> <span class="s1">'</ins>'</span><span class="p">;</span>
</span><span class='line'> <span class="k">break</span><span class="p">;</span>
</span><span class='line'> <span class="k">case</span> <span class="nx">DIFF_DELETE</span><span class="o">:</span>
</span><span class='line'> <span class="nx">html</span><span class="p">[</span><span class="nx">x</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'<del style="background:#ffe6e6;">'</span> <span class="o">+</span> <span class="nx">text</span> <span class="o">+</span> <span class="s1">'</del>'</span><span class="p">;</span>
</span><span class='line'> <span class="k">break</span><span class="p">;</span>
</span><span class='line'> <span class="k">case</span> <span class="nx">DIFF_EQUAL</span><span class="o">:</span>
</span><span class='line'> <span class="nx">html</span><span class="p">[</span><span class="nx">x</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'<span>'</span> <span class="o">+</span> <span class="nx">text</span> <span class="o">+</span> <span class="s1">'</span>'</span><span class="p">;</span>
</span><span class='line'> <span class="k">break</span><span class="p">;</span>
</span><span class='line'> <span class="p">}</span>
</span><span class='line'> <span class="p">}</span>
</span><span class='line'> <span class="k">return</span> <span class="nx">html</span><span class="p">.</span><span class="nx">join</span><span class="p">(</span><span class="s1">''</span><span class="p">);</span>
</span><span class='line'> <span class="p">};</span>
</span></code></pre></td></tr></table></div></figure>
<p>So I wrote a library to wrap around it – so the client doesn’t have to
repeat this wherever they need to use it. You can find more on
<a href="https://github.com/arnab/jQuery.PrettyTextDiff/">github</a> and it can
be downloaded from the
<a href="http://plugins.jquery.com/pretty-text-diff/">jQuery plugins site</a>.</p>
<p>Now, with this library you’d have to write just a couple of lines to
produce a beautiful looking diff, like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
</pre></td><td class='code'><pre><code class='js'><span class='line'><span class="nx">$</span><span class="p">(</span><span class="nx">selector</span><span class="p">).</span><span class="nx">prettyTextDiff</span><span class="p">({</span>
</span><span class='line'> <span class="c1">// options</span>
</span><span class='line'><span class="p">});</span>
</span></code></pre></td></tr></table></div></figure>
<p>Peek inside the fiddle demo to see more. You can also customize many
of the options – check out the documentation in the github repo.</p>
<p>Hope you enjoy it!</p>
<p>PS: Some of the motivation was also to flex my muscles with
CofeeScript (haven’t had a chance to use it for the last 2-3 months)
and setting up compile and uglifying/compressing of the Javascript
with <code>cake</code>. Check out the simple
<a href="https://github.com/arnab/jQuery.PrettyTextDiff/blob/master/jquery.pretty-text-diff.coffee">coffeescript code</a>
and the
<a href="https://github.com/arnab/jQuery.PrettyTextDiff/blob/master/Cakefile">Cakefile</a>.</p>
<h3>Links</h3>
<ul>
<li><a href="http://code.google.com/p/google-diff-match-patch/">Google’s diff_match_patch library</a></li>
<li><a href="https://github.com/arnab/jQuery.PrettyTextDiff/">Plugin source on github</a></li>
<li><a href="http://plugins.jquery.com/pretty-text-diff/">jQuery plugins site</a></li>
<li><a href="http://jsfiddle.net/arnab/YwSVY/">jsFiddle demo</a></li>
</ul>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[State of e-commerce in India]]></title>
<link href="http://arnab-deka.com/posts/2012/09/state-of-e-commerce-in-india/"/>
<updated>2012-09-23T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2012/09/state-of-e-commerce-in-india</id>
<content type="html"><![CDATA[<p>So, since moving back to India 4 months ago, we’ve trying to buy stuff
off the internet, like we did back in Seattle (oh Amazon), from
diapers to audio CDs (whaaaat? I know). While the world is much much
better compared to 2006, there are still some Idiocracies in the UX
and process. There are the big players (<a href="http://www.flipkart.com/">FlipKart</a>, <a href="http://www.infibeam.com/">infibeam</a>
and the like) where (from the 4 months experience) you’d find what you
are looking almost 6-7 times out of 10. The long-tail of e-commerce in
India is the real deal though – the tail is really really long. I use
<a href="http://www.junglee.com/">Junglee.com</a> to find the long time and almost always (9+ out of
10) the things I am looking for are found somewhere. Funny thing is
that you’ll never find two things you need in one site. Over these 4
months, I don’t think any of these sites have come up more than once
in my search.</p>
<!-- more -->
<p>To highlight some of the other differences:</p>
<ul>
<li><strong>No guest checkout</strong>: Almost nobody has guest checkout. Everybody
requires you to register and require your email and phone. Most
the package tracking is done thru SMS so that’s ok, but I’ve had
some spam (email and SMS) originating from here as well. But for
the most part, they are well behaved (I don’t know why they need
my birthday or gender to ship stuff me though– anyway they get
wrong info for such questions ;))</li>
<li><strong>Weak integration with backend</strong>: More than once I have placed
orders (after signing up etc.) only to be informed later that
the item is not in stock. The websites are more like marketing
websites with a cart/checkout process and it looks like the
orders are processed completely separately.</li>
<li><strong>Cash-On-Delivery</strong>: Almost everyone takes COD orders. I know
some people don’t like the idea, but for Indian e-commerce it’s
a must. Mostly because if you pay when you order on the site and
then you don’t get the thing or get something else, there’s
pretty much nothing you can do. Most sites will process a refund
but you have to call them a few times to get that done. And some
sites only give you a coupon that you can use in their site. So
COD is heaven-sent and must-needed for such small sites.
<a href="http://www.flipkart.com/s/help/payments">FlipKart has started doing Card-On-Delivery</a>, which is even better!</li>
<li><strong>Faaaaaast and FREE shipping</strong>: Almost every order I have made
has been delivered within a few days. In one-third of the cases it’s
within 2 days. And it’s 99% of the time free shipping.</li>
</ul>
<p>To summarize, for the most part, it’s all good. You can find 9/10
things online and of that you can get 9/10 items delivered at your
doorstep within a reasonable amount of time and pay after you
get/inspect it. But that’s not why I started writing this piece today…</p>
<h2>A uniquely horrible experience at ezmaal.com</h2>
<p>What I wanted to do today was share a very bad experience on one of
these small player’s sites today. Remember the band called
<a href="http://www.amazon.com/Route-Indian-Music-Hindi-Modern/dp/B0013LKL36/">Silk Route</a>? Heard them on radio and remembered how awesome their
music was. Unfortunately the album’s not on spotify or in Amazon/MP3.
So I looked up FlipKart (out of stock) and Junglee. That’s where I
found <a href="http://www.ezmaal.com/">ezmaal.com</a> – and they had it in stock! So I went through
the registration process and signed up for an account.</p>
<p>Now, I use the <a href="https://agilebits.com/onepassword">most excellent 1Password</a> for creating random
passwords for every site and to manage signing-in/out. Did the same on
ezmaal too – and it was all fine and dandy and got an account created.
Now, just before checking out I wanted to see if the login/logout was
working (you never know with small sites). So I opened up the site in
an <a href="http://support.google.com/chrome/bin/answer.py?hl=en&answer=95464">incognito window</a> and tried loggin in. Here’s the screenshot of
what I got back: [![ezmaal login failure][11]][11]
click to see larger image</p>
<ol>
<li>They throw a really garbage un-customized ASP.net error in the
customer’s face. It means nothing to me!</li>
<li>They are trying to validate my password for script-injection. I
don’t think they are actively doing this, but it’s probably part of
ASP.net and they have not tested and not coded to handle login
failures. Really really bad if the login on your site throws up gibberish.</li>
<li><strong>Password displayed on screen</strong>: The worst part is that they
print my password three times on the screen, verbatim. Thank God I use
1Password and have a random (and more importantly, different) password
on every site. But like most customer’s if I had a
one-password-for-all and used that in here, it’s as good as being
leaked. If nowhere else, this will be on their server-logs. An
employee only need to grep for <code>Password\=</code> in the logs. On top of
this, with this kind of an experience, I have no faith that they
salt/hash the passwords. I am more willing to believe that they keep
it all in cleartext in a SQLServer database.</li>
</ol>
<p>I have seen bad e-commerce sites before, but will I shop at a place
which does not care about my online security? No way in hell (yeah, I
did not complete that order)!</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Emacs: change fonts dynamically based on screen resolution]]></title>
<link href="http://arnab-deka.com/posts/2012/09/emacs-change-fonts-dynamically-based-on-screen-resolution/"/>
<updated>2012-09-23T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2012/09/emacs-change-fonts-dynamically-based-on-screen-resolution</id>
<content type="html"><![CDATA[<p>I regularly switch between a <a href="http://www.apple.com/thunderbolt/">Thunderbolt display</a> at home and the <a href="http://www.apple.com/macbook-pro/features/">Mac’s native retina display</a> when I’m in a coffee shop or the like.</p>
<p>It bugs me that I have to adjust emac’s font manually when I switch displays – started “re-using” emacs again last week. So I automated this today:</p>
<!-- more -->
<div><script src='https://gist.githubusercontent.com/arnab/3774147.js'></script>
<noscript><pre><code>;; Gist-ed from in https://github.com/arnab/emacs-starter-kit
(defun fontify-frame (frame)
(interactive)
(if window-system
(progn
(if (> (x-display-pixel-width) 2000)
(set-frame-parameter frame 'font "Inconsolata 19") ;; Cinema Display
(set-frame-parameter frame 'font "Inconsolata 16")))))
;; Fontify current frame
(fontify-frame nil)
;; Fontify any future frames
(push 'fontify-frame after-make-frame-functions)</code></pre></noscript></div>
<p>You can see all my emacs customizations in Github <a href="https://github.com/arnab/emacs-starter-kit">arnab/emacs-starter-kit</a> repo, which is based on the excellent <a href="http://technomancy.us/153">ESK v2</a>.</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Allowing and testing CORS requests in Rails]]></title>
<link href="http://arnab-deka.com/posts/2012/09/allowing-and-testing-cors-requests-in-rails/"/>
<updated>2012-09-19T14:28:00+05:30</updated>
<id>http://arnab-deka.com/posts/2012/09/allowing-and-testing-cors-requests-in-rails</id>
<content type="html"><![CDATA[<p>I’m currently writing a <code>backbone</code>-based <code>Javascript</code> app that’s going
to directly call a <code>REST</code>-style API (implemented with <code>Rails</code> ).</p>
<blockquote><p>CORS (Cross-Origin Resource Sharing) is new technique makes it
possible for AJAX requests to directly talk to HTTP-services outside
it’s own domain. Read this <a href="http://www.nczonline.net/blog/2010/05/25/cross-domain-ajax-with-cross-origin-resource-sharing/" title="Cross Domain AJAX with CORS">awesome primer</a> to read more on CORS.</p></blockquote>
<p>While there are lots of examples that show how to allow CORS requests
in Rails (just <a href="http://goo.gl/d8g3j">google</a>), they almost never have tests with them.
While it’s simple to test the HTTP headers, you may have to look
around a little (or a lot) on how to test a HTTP “OPTIONS” request.
When you make CORS requests, the browser may make a pre-flight
“OPTIONS” request to verify that the server allows CORS.</p>
<!-- more -->
<p>To make Rails set the right HTTP headers to allow CORS requests, you
can do something like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
<span class='line-number'>13</span>
<span class='line-number'>14</span>
</pre></td><td class='code'><pre><code class='rb'><span class='line'><span class="c1"># some_controller.rb</span>
</span><span class='line'>
</span><span class='line'><span class="n">before_filter</span><span class="p">:</span> <span class="n">allow_cors</span>
</span><span class='line'>
</span><span class='line'><span class="k">def</span> <span class="nf">allow_cors</span>
</span><span class='line'> <span class="n">headers</span><span class="o">[</span><span class="s2">"Access-Control-Allow-Origin"</span><span class="o">]</span> <span class="o">=</span> <span class="s2">"*"</span>
</span><span class='line'> <span class="n">headers</span><span class="o">[</span><span class="s2">"Access-Control-Allow-Methods"</span><span class="o">]</span> <span class="o">=</span> <span class="sx">%w{GET POST PUT DELETE}</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s2">","</span><span class="p">)</span>
</span><span class='line'> <span class="n">headers</span><span class="o">[</span><span class="s2">"Access-Control-Allow-Headers"</span><span class="o">]</span> <span class="o">=</span>
</span><span class='line'> <span class="sx">%w{Origin Accept Content-Type X-Requested-With X-CSRF-Token}</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s2">","</span><span class="p">)</span>
</span><span class='line'>
</span><span class='line'> <span class="n">head</span><span class="p">(</span><span class="ss">:ok</span><span class="p">)</span> <span class="k">if</span> <span class="n">request</span><span class="o">.</span><span class="n">request_method</span> <span class="o">==</span> <span class="s2">"OPTIONS"</span>
</span><span class='line'> <span class="c1"># or, render text: ''</span>
</span><span class='line'> <span class="c1"># if that's more your style</span>
</span><span class='line'><span class="k">end</span>
</span></code></pre></td></tr></table></div></figure>
<p>A few things to note here:</p>
<ol>
<li><p>You can set the <code>Access-Control-Allow-Origin</code> header to your
domain to further restrict it.</p></li>
<li><p>While Rails is one place to do this in, you can certainly do this
in your webserver (nginx etc.). Again, just google. I prefer things to
be more testable – maybe when I see a performance problem, I’d revise
this decision (although, performance bottlenecks would probably not be
in setting HTTP headers).</p></li>
</ol>
<p>Another thing to consider when you allow CORS, is authentication – you
should do some HTTP based auth (token auth for example) so only <em>your</em>
apps can talk to this service. The thing with JS is, however uglified
it is, any developer worth his salt can figure out how to call your
backend service after reading your JS by loading your site up in a
browser.</p>
<p>In any case, how do you test this? It’s fairly trivial to test that
the right HTTP headers were set with something like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
</pre></td><td class='code'><pre><code class='rb'><span class='line'><span class="c1"># testing_cors_spec.rb</span>
</span><span class='line'><span class="n">response</span><span class="o">.</span><span class="n">headers</span><span class="o">[</span><span class="s1">'Access-Control-Allow-Origin'</span><span class="o">].</span><span class="n">should</span> <span class="o">==</span> <span class="s1">'*'</span>
</span></code></pre></td></tr></table></div></figure>
<p>To make a HTTP <code>options</code> request in RSpec, I had to dig through some
code. And googling didn’t help here, at least the way I google. Here’s
the low-down: <code>RSpec</code> <em>delegates</em> the request methods (like
<code>get</code>/<code>post</code>/<code>put</code> etc. in the controller specs) to Rails’
<code>ActionController Tests</code>. All these methods invoke
<code>ActionController::TestCase#process</code> with specific args, one of which
is the method name.</p>
<p>Now, Rails master already has support for making
<code>options</code> requests in tests (thanks to <a href="https://github.com/rails/rails/commit/0303c2325fab253adf5e4a0b738cb469c048f008#L0R438">this commit</a>), but that’s
not available in the latest Rails release (3.2.8). I think this would
make it’s way into Rails 4.</p>
<p>Looking into this commit, we get the idea
though: basically we also call the <code>process</code> method with a <code>OPTIONS</code>
argument for the request-method. Putting it all together, my tests
looked something like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
<span class='line-number'>13</span>
<span class='line-number'>14</span>
<span class='line-number'>15</span>
<span class='line-number'>16</span>
<span class='line-number'>17</span>
<span class='line-number'>18</span>
<span class='line-number'>19</span>
<span class='line-number'>20</span>
<span class='line-number'>21</span>
<span class='line-number'>22</span>
<span class='line-number'>23</span>
<span class='line-number'>24</span>
<span class='line-number'>25</span>
<span class='line-number'>26</span>
<span class='line-number'>27</span>
<span class='line-number'>28</span>
<span class='line-number'>29</span>
<span class='line-number'>30</span>
<span class='line-number'>31</span>
</pre></td><td class='code'><pre><code class='rb'><span class='line'><span class="c1"># some_controller_spec.rb</span>
</span><span class='line'>
</span><span class='line'><span class="n">shared_examples_for</span> <span class="s2">"any request"</span> <span class="k">do</span>
</span><span class='line'> <span class="n">context</span> <span class="s2">"CORS requests"</span> <span class="k">do</span>
</span><span class='line'> <span class="n">it</span> <span class="s2">"should set the Access-Control-Allow-Origin header to allow CORS from anywhere"</span> <span class="k">do</span>
</span><span class='line'> <span class="n">response</span><span class="o">.</span><span class="n">headers</span><span class="o">[</span><span class="s1">'Access-Control-Allow-Origin'</span><span class="o">].</span><span class="n">should</span> <span class="o">==</span> <span class="s1">'*'</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'>
</span><span class='line'> <span class="n">it</span> <span class="s2">"should allow general HTTP methods thru CORS (GET/POST/PUT/DELETE)"</span> <span class="k">do</span>
</span><span class='line'> <span class="n">allowed_http_methods</span> <span class="o">=</span> <span class="n">response</span><span class="o">.</span><span class="n">header</span><span class="o">[</span><span class="s1">'Access-Control-Allow-Methods'</span><span class="o">]</span>
</span><span class='line'> <span class="sx">%w{GET POST PUT DELETE}</span><span class="o">.</span><span class="n">each</span> <span class="k">do</span> <span class="o">|</span><span class="nb">method</span><span class="o">|</span>
</span><span class='line'> <span class="n">allowed_http_methods</span><span class="o">.</span><span class="n">should</span> <span class="kp">include</span><span class="p">(</span><span class="nb">method</span><span class="p">)</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'>
</span><span class='line'> <span class="c1"># etc etc</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'><span class="k">end</span>
</span><span class='line'>
</span><span class='line'><span class="n">describe</span> <span class="s2">"HTTP OPTIONS requests"</span> <span class="k">do</span>
</span><span class='line'> <span class="c1"># With Rails 4 (currently in master) we'll be able to `options :index`</span>
</span><span class='line'> <span class="n">before</span><span class="p">(</span><span class="ss">:each</span><span class="p">)</span> <span class="p">{</span> <span class="n">process</span> <span class="ss">:index</span><span class="p">,</span> <span class="kp">nil</span><span class="p">,</span> <span class="kp">nil</span><span class="p">,</span> <span class="kp">nil</span><span class="p">,</span> <span class="s1">'OPTIONS'</span> <span class="p">}</span>
</span><span class='line'>
</span><span class='line'> <span class="n">it_should_behave_like</span> <span class="s2">"any request"</span>
</span><span class='line'>
</span><span class='line'> <span class="n">it</span> <span class="s2">"should be succesful"</span> <span class="k">do</span>
</span><span class='line'> <span class="n">response</span><span class="o">.</span><span class="n">should</span> <span class="n">be_success</span>
</span><span class='line'> <span class="k">end</span>
</span><span class='line'><span class="k">end</span>
</span><span class='line'>
</span><span class='line'><span class="c1"># And similar tests for GET/POST what have you which actually test the functionality...</span>
</span></code></pre></td></tr></table></div></figure>
<h2>Update for Rails 4</h2>
<p>So
<a href="https://twitter.com/ekampp/status/385800059687690241">@ekampp on twitter</a>
brought it to my attention that this test does not work
anymore. It appears that the <code>options</code> method was
<a href="https://github.com/rails/rails/commit/0303c23">added</a> and then
<a href="https://github.com/rails/rails/commit/6a4ff5c">removed</a> from Rails
master (since a method named <code>options</code> conflicts with a lot of stuff,
as you can imagine).</p>
<p>So, in Rails 4 (and current master) you can call <code>process</code> directly
like this:</p>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
</pre></td><td class='code'><pre><code class='rb'><span class='line'><span class="n">process</span> <span class="ss">:index</span><span class="p">,</span> <span class="s1">'OPTIONS'</span> <span class="c1"># and other args as needed</span>
</span></code></pre></td></tr></table></div></figure>
<p>For example,
<a href="https://github.com/rails/rails/blob/2de0cca/actionpack/lib/action_controller/test_case.rb#L499">this</a>
is how <code>head</code> is implemented. So you are basically doing the same
thing for an <code>OPTIONS</code> request.</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Quick howto on accessing Rails Properties]]></title>
<link href="http://arnab-deka.com/posts/2011/04/quick-howto-accessing-rails-properties/"/>
<updated>2011-04-08T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2011/04/quick-howto-accessing-rails-properties</id>
<content type="html"><![CDATA[<p>When you create a new Rails app the default static page (public/index.html) page shows a lot of details about the app. Here’s a quick how-to show these details (the idea is to probably show these on a /ping route (or a debug parameter on any page maybe) – so you can quickly monitor your app – it’s state, active_record state etc.).</p>
<!-- more -->
<p><strong>Rails 3</strong>: browse the <a href="https://github.com/rails/rails/blob/v3.0.6/railties/lib/rails/info.rb">source-code at railties/lib/rails/info.rb</a></p>
<p>Or see:</p>
<div><script src='https://gist.githubusercontent.com/arnab/911091.js?file=rails_306_properties.rb'></script>
<noscript><pre><code># see https://github.com/rails/rails/blob/v3.0.6/railties/lib/rails/info.rb
@properties = {
:ruby => "#{RUBY_VERSION} (#{RUBY_PLATFORM})",
:rubygem => Gem::RubyGemsVersion,
:rack => ::Rack.release,
:rails => Rails::VERSION::STRING,
:app_root => File.expand_path(Rails.root),
:env => Rails.env,
:db_adapter => ActiveRecord::Base.configurations[Rails.env]['adapter'],
:db_schema_version => (ActiveRecord::Migrator.current_version || nil),
:middleware => Rails.configuration.middleware.map(&:inspect),
}
</code></pre></noscript></div>
<p><strong>Rails 2</strong>: browse the <a href="https://github.com/rails/rails/blob/v2.0.2/railties/builtin/rails_info/rails/info.rb">source-code at railties/builtin/rails_info/rails/info.rb</a></p>
<p>Or see:</p>
<div><script src='https://gist.githubusercontent.com/arnab/911091.js?file=rails_202_properties.rb'></script>
<noscript><pre><code># see https://github.com/rails/rails/blob/v2.0.2/railties/builtin/rails_info/rails/info.rb
@properties = {
:ruby => "#{RUBY_VERSION} (#{RUBY_PLATFORM})",
:rubygem => Gem::RubyGemsVersion,
:rails => Rails::VERSION::STRING,
:app_root => File.expand_path(RAILS_ROOT),
:env => RAILS_ENV,
:db_adapter => ActiveRecord::Base.configurations[RAILS_ENV]['adapter'],
:db_schema_version => (ActiveRecord::Migrator.current_version || nil),
}
</code></pre></noscript></div>
<p>Till the next time…</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Notes on Emacs + CL + Clojure + Slime...]]></title>
<link href="http://arnab-deka.com/posts/2010/12/notes-on-emacs-cl-clojure-slime/"/>
<updated>2010-12-30T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2010/12/notes-on-emacs-cl-clojure-slime</id>
<content type="html"><![CDATA[<p>After a day of struggling finally Emacs+CL+Clojure+Slime setup is working. I noted it all in the <a href="http://www.arnab-deka.com/posts/notes/emacs-setup/">notes section</a>.</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[1Password for Mac. Free. Really.]]></title>
<link href="http://arnab-deka.com/posts/2010/11/1password-for-mac-free-really/"/>
<updated>2010-11-26T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2010/11/1password-for-mac-free-really</id>
<content type="html"><![CDATA[<p>I use and love <a href="http://agilewebsolutions.com/onepassword">1Password</a> on my Mac every day – it has become one of those things I can’t live without, and is easily worth the $40 price.</p>
<p>Yesterday they announced their very generous ThanksGiving offer: <a href="http://agile.ws/ThankYou">Free 1-for-1 license</a>. So I can give away a Free 1Password for Mac license – and since no one else in my family has started using a Mac full-time yet, I will give it away to you!</p>
<p>Just add a comment here – saying why I should give it away to you and wait for a few hours. I will pick one person here and send them the license. Make sure you leave some contact so I can get back to you. How will I pick? The most entertaining comment of course. But yeah – don’t hold me to it, I might just randomly pick someone.</p>
<p>Thank you for playing!</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[On the Coastal Classic Train to Seward.]]></title>
<link href="http://arnab-deka.com/posts/2010/08/on-the-coastal-classic-train-to-seward/"/>
<updated>2010-08-14T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2010/08/on-the-coastal-classic-train-to-seward</id>
<content type="html"><![CDATA[<p><img src="http://posterous.com/getfile/files.posterous.com/arnab/nrJwodabpHxsDoxudxwGdGICCFpbecttjjjuIcvrsgzjEqzhyzaJbDcBuHJg/file.jpeg.scaled500.jpg" alt="" /></p>
<p>On the Coastal Classic Train to Seward. Look at the route. #Alaska #vacation via <a href="http://www.osfoora.com">Osfoora</a></p>
<p><a href="http://posterous.com">Posted via email</a> from <a href="http://arnab.posterous.com/on-the-coastal-classic-train-to-seward">arnab’s posterous</a></p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Quick MacBook setup]]></title>
<link href="http://arnab-deka.com/posts/2010/03/quick-macbook-setup/"/>
<updated>2010-03-17T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2010/03/quick-macbook-setup</id>
<content type="html"><![CDATA[<p>Just put in my notes about setting up a MacBook in <a href="http://www.arnab-deka.com/posts/notes/macbook-setup" title="MacBook setup">the notes section here</a>. I’ll keep updating – please add your thoughts in!</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Installing GLPK on a Mac]]></title>
<link href="http://arnab-deka.com/posts/2010/02/installing-glpk-on-a-mac/"/>
<updated>2010-02-26T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2010/02/installing-glpk-on-a-mac</id>
<content type="html"><![CDATA[<h2>Obsolation note:</h2>
<p>Thanks to <a href="#comment-2787">Dave Coleman’s comment</a> I found out that glpk is available through homebrew now! So you just need these 2 steps to get glpk now:</p>
<ol>
<li><a href="http://mxcl.github.com/homebrew/" title="homebrew">homebrew</a></li>
<li><code>brew install glpk</code></li>
</ol>
<p>If you still want to read on, the old way is still here…</p>
<p>So you want copy-paste instructions to install <a href="http://www.gnu.org/software/glpk">GLPK</a> on your Macbook? Here are the steps:</p>
<ol>
<li>Download the latest version of GLPK from <a href="http://www.gnu.org/software/glpk/#downloading">http://www.gnu.org/software/glpk/#downloading</a></li>
<li><em>Optional:</em> Follow the instructions to verify the download (you might need to get GNU Privacy Guard or gpg for this. You can get it at <a href="http://gnupg.org">http://gnupg.org</a>)</li>
<li><p>Say it’s downloaded to your “Downloads” directory, go there and execute the following commands (using the terminal)
cd ~/Downloads
tar -xzf glpk-4.43.tar.gz
./configure —prefix=/usr/local # see note <a href="#comment-2787">1</a>
make
sudo make install</p></li>
<li><p>At this point, you should have GLPK installed. Verify it:
which glpsol
/usr/local/bin/glpsol</p></li>
<li><p>… and try help:
glpsol —help</p></li>
</ol>
<p>Now that you are all set-up, read up this excellent introduction using GLPK: <a href="http://www.ibm.com/developerworks/linux/library/l-glpk1">http://www.ibm.com/developerworks/linux/library/l-glpk1</a></p>
<p>Notes:</p>
<ul>
<li>HiveLogic article on <a href="http://hivelogic.com/articles/using_usr_local">why using /usr/local is better</a></li>
<li>If you want MySQL support (or something “extra”) check out the INSTALL file in the package</li>
</ul>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Russian Peasant Multiplication in Ruby]]></title>
<link href="http://arnab-deka.com/posts/2010/02/russian-peasant-multiplication-in-ruby/"/>
<updated>2010-02-01T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2010/02/russian-peasant-multiplication-in-ruby</id>
<content type="html"><![CDATA[<p>Russian Peasant Multiplication: a very simple and elegant way to multiple.</p>
<p>Read more: <a href="http://mathforum.org/dr.math/faq/faq.peasant.html">School-boy example of how and why it works</a> and about <a href="http://en.wikipedia.org/wiki/Ancient_Egyptian_multiplication">Ancient Egyptian Multiplication on wikipedia</a></p>
<p>So here’s my simple implementation: (or as a <a href="http://gist.github.com/290219">gist on github</a>)</p>
<pre><code>module RussianPeasantMultiplication
def russian_peasant_multiply(b)
numbers_to_add = []
a, b = [self, b].sort #So we have the smaller number as the first
negative_operands = [a, b].select { |n| n < 0 }
result_should_be_negative = negative_operands.size.odd? # or negative_operands.size == 1
# Now get the absoultes
a, b = [a, b].map { |n| n.abs }
while( a > 1 )
a = a >> 1 # halv it
b = b < < 1 # double it
if a.odd? # or (a % 2 == 0 )
numbers_to_add << b
else
end
end
result = numbers_to_add.inject(0) { |sum, n| sum += n }
result = result * -1 if result_should_be_negative
result
end
end
class Integer
include RussianPeasantMultiplication
end
# Tests
require "test/unit"
class TestInteger < Test::Unit::TestCase
def test_russian_peasant_multiply
assert_equal(22 * 70, 22.russian_peasant_multiply(70))
end
def test_russian_peasant_multiply_for_negative_numbers
assert_equal(-22 * 70, -22.russian_peasant_multiply(70))
end
def test_russian_peasant_multiply_for_negative_arguments
assert_equal(22 * -70, 22.russian_peasant_multiply(-70))
end
def test_russian_peasant_multiply_for_negative_numbers_and_arguments
assert_equal(-22 * -70, -22.russian_peasant_multiply(-70))
end
def test_russian_peasant_multiply_for_zero
assert_equal(0 * -70, 0.russian_peasant_multiply(-70))
end
def test_russian_peasant_multiply_for_zero_arguments
assert_equal(-22 * 0, -22.russian_peasant_multiply(0))
end
def test_russian_peasant_multiply_for_zero_numbers_and_arguments
assert_equal(0 * 0, 0.russian_peasant_multiply(0))
end
end
</code></pre>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Colorado Pictures (2009 Nov)]]></title>
<link href="http://arnab-deka.com/posts/2009/12/colorado-pictures-2009-nov/"/>
<updated>2009-12-20T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2009/12/colorado-pictures-2009-nov</id>
<content type="html"><![CDATA[<p>Pics from the Colorado trip back in November, 2009 (with Ujwala and Maa). We spent two days in Rocky Mountain National Park and a day over in Colorado Springs and around (Manitou Springs, Pikes Peak – highest peak in that area).</p>
<p>It’s heavenly – have to go there again in Spring 2010 )along with the parks in Wyoming, Montana).</p>
<p>Click on the photo to get to my SmugMug page – feel free to leave a comment <img src="http://www.arnab-deka.com/posts/wp-includes/images/smilies/icon_smile.gif" alt=":)" />
[![][3]][3]</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Rails - Table join with specified fields in select]]></title>
<link href="http://arnab-deka.com/posts/2009/11/rails-join-with-select/"/>
<updated>2009-11-01T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2009/11/rails-join-with-select</id>
<content type="html"><![CDATA[<p>Figured this out after a lot of monkeying-around (I mean <code>script/console</code>).</p>
<p>Situation:</p>
<ul>
<li>I have two tables (Revisions <code>has_many</code> Inputs)</li>
<li>I can load Revisions and then for each I can find Inputs, but quickly found out that for my situation, it leads to a lot of queries. So I want to load the required fields from both tables together</li>
</ul>
<p><code>:joins</code> is the only way to do this, using <code>:includes</code> does <strong>NOT</strong> respect the select clause. Here a gist:</p>
<div><script src='https://gist.githubusercontent.com/arnab/223925.js'></script>
<noscript><pre><code> metrics_with_inputs = Revision.find(
:all,
:conditions => { :id => self.revisions.map { |r| r.id } },
:select => 'revisions.metric, revisions.snap_date, revisions.updated_at,
inputs.author, inputs.as_of_date, inputs.units',
:joins => 'join inputs on inputs.revision_id = revisions.id',
:order => 'revisions.metric, revisions.snap_date, revisions.updated_at'
)</code></pre></noscript></div>
<p>Admittedly, this is hacky, too hacky for my comfort. Comment/suggest a better/cleaner solution?</p>
<p>Note: Found out that there is a gem to do this: <a href="http://code.google.com/p/ar-select-with-include/">ar-select-with-include</a></p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[A beautiful foggy autumn morning]]></title>
<link href="http://arnab-deka.com/posts/2009/10/a-beautiful-foggy-autumn-morning-echo-lake-view-from-my-house-iphonepicb/"/>
<updated>2009-10-22T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2009/10/a-beautiful-foggy-autumn-morning-echo-lake-view-from-my-house-iphonepicb</id>
<content type="html"><![CDATA[<p>Echo lake, view from my house. Taken with my iPhone and enhanced with the free Photoshop.com app:</p>
<p><img class="left" src="http://posterous.com/getfile/files.posterous.com/arnab/FxteHueeFwrqAflpJqfdjFhCGIiqmxehipFhElFobGurIylFdmjChaegDpBm/image.jpg.scaled500.jpg" title="Echo Lake" ></p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Interesting Job Advertisement]]></title>
<link href="http://arnab-deka.com/posts/2009/09/interesting-job-advertisement/"/>
<updated>2009-09-22T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2009/09/interesting-job-advertisement</id>
<content type="html"><![CDATA[<p>A recent job opening advert (from <a href="http://vark.com/jobs#feeng">Aardvark, for a Front-End Web Developers</a>) goes:</p>
<blockquote><p>Required Skills:
* Fluency in HTML and CSS
* Experience taking mockups and turning them into standards-compliant HTML/CSS
* Expertise in achieving cross-browser compatibility in IE, Firefox, and Safari
* Experience in implementing grid-based layouts in HTML/CSS
* Experience in an agile development environment</p>
<p>Pluses:
* Interest in user experience design and graphic design
* Experience in Javascript and Ruby on Rails
* History of side projects and interest in social media, browsers, and mobile web
* Obsession with new technologies and open source tools
* Experimental, user focused, and iterative
* Previous startup experience</p></blockquote>
<p>I felt the Pluses section was very interesting, specially (you kinda see the others on Rails related job boards anyway):
* History of side projects and interest in social media, browsers, and mobile web
* Obsession with new technologies and open source tools</p>
<p>Shows how today’s start-ups value people who are really interested in what they do (and not just in for the money). An encouraging view of the world indeed – now I just have to get on it and get those much needed Plusses into my skills bag <img src="http://www.arnab-deka.com/posts/wp-includes/images/smilies/icon_smile.gif" alt=":)" /></p>
<p>Note to my employers, friends, well wishers and anyone else interested: This does not mean I am looking for a job! I love the job I have right now and am just happy to see the importance of “passion” in the world’s view of an ideal employee increasing!</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Rails Guides on my Kindle DX!!! (or any webpage for that matter)
]]></title>
<link href="http://arnab-deka.com/posts/2009/09/rails-guides-on-my-kindle-dx-or-any-webpage-for-that-matter/"/>
<updated>2009-09-18T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2009/09/rails-guides-on-my-kindle-dx-or-any-webpage-for-that-matter</id>
<content type="html"><![CDATA[<p>I got a <a href="http://www.amazon.com/gp/product/B0015TCML0?ie=UTF8&tag=arnsblo-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B0015TCML0">Amazon Kindle DX</a><img src="http://www.assoc-amazon.com/e/ir?t=arnsblo-20&l=as2&o=1&a=B0015TCML0" alt="" /> for a birthday gift! Thanks Ujwala!</p>
<p>And so far I am loving it. It’s better to read on compared to Kindle 1 (which, BTW, Ujwala had gifted to me last year) – and the native PDF support (and the search-anywhere) is awesome! The experimental browser that comes with the DX is much much improved compared to Kindle 1st Gen.</p>
<p>So I was reading more about <a href="http://guides.rubyonrails.org/routing.html">Rails Routing in the rails-guides</a>. And while I was in the bus today morning I wanted to read that on the Kindle (coz it is a pleasure to read on it). So I fired up the guides page on the experimental browser – it works, but reading a PDF or a Kindle-formatted book is so much better.</p>
<p>So I got this simple idea. Print the web page as a PDF and e-mail it to your Kindle. Here’s what I did:</p>
<ol>
<li>Go to the site</li>
<li>Print – (PDF format “saved to file” instead of sending it to a printer). I was on Linux – Mac also has the “Print to PDF/PS support by default, for Windows you’ll need to get <a href="http://www.cutepdf.com/">CutePDF</a> installed)</li>
<li>e-mail it to your Kindle address (I also uploaded it to my dropbox – so I can get it later on) and you are done!</li>
</ol>
<p>(BTW, dropbox is an amazing thing – if you use multiple computers/OS, you have to try this thing. If you are going to try it out (for free), help me out – <a href="https://www.getdropbox.com/referrals/NTEzMDYwMzk">use my Dropbox referral link</a>)</p>
<p>So there you go – another easy way to get web-content for free on your Kindle. Go on enjoy the book now.</p>
<p><strong>Blog-Notes</strong></p>
<ul>
<li><a href="http://www.amazon.com/gp/product/B0015TCML0?ie=UTF8&tag=arnsblo-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B0015TCML0">Amazon Kindle DX</a></li>
<li><a href="http://guides.rubyonrails.org">Rails Guides – excellent info on the RubyOnRails framework</a></li>
<li><a href="http://www.cutepdf.com/">CutePDF</a></li>
<li><a href="https://www.getdropbox.com/">DropBox</a></li>
</ul>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[#songsincode (twitter geek fun)]]></title>
<link href="http://arnab-deka.com/posts/2009/08/songsincode-twitter-geek-fun/"/>
<updated>2009-08-21T00:00:00+05:30</updated>
<id>http://arnab-deka.com/posts/2009/08/songsincode-twitter-geek-fun</id>
<content type="html"><![CDATA[<blockquote><p>This blog is about twitter hastags. To learn more about twitter hashtags, go <a href="http://twitter.pbworks.com/Hashtags">here</a>.</p></blockquote>
<p>So #songsincode has been <a href="http://twitter.com/#search?q=%23songsincode">ruling the twitter trends</a> for a day now. Didn’t follow it? No worries – <a href="http://www.sitepoint.com/blogs/2009/08/21/geeks-just-wanna-have-fun-songsincode/">here’s a recent blog</a> with some good (early) ones.</p>
<p>Basically, it was the most fun I have had reading hashtags. Today, after lunch I took a plunge too :)</p>