MySQL and Leopard

I had such problems on my macbook (though not on the macpro) in getting mysql running.

This article seems to have helped.

checkboxes for multiple items

I am doing an interface where I want to list a bunch of things (index) and have a checkbox next to each of them. Then, using a button, edit or show all those selected items.
I am always running into this problem of checkboxes (maybe I am just stupid) so I spent some time and figured out a way that works for me. There are probably other solutions, but here is what I do:

First, in the index.html I have this javascript code:

<% content_for :javascript do %>
<script type="text/javascript" charset="utf-8">
/* <![CDATA[ */
    function editDevices() {
        var device_count = document.getElementsByName('device[]').length; 
        var total="";
        for(var i=0; i < device_count; i++){
            if(document.forms['group_edit'].elements['device[]'][i].checked) {
                if (total.length > 0) {
                    total += ","
                }
                total +=document.forms['group_edit'].elements['device[]'][i].value;
            }
        }

        new Ajax.Request('<%= group_edit_devices_path %>', { 
            parameters: { 
                authenticity_token: encodeURIComponent('<%=form_authenticity_token%>'),
                device_ids: total
            } 
        } 
        );
    }
    
    function showDevices() {
        var device_count = document.getElementsByName('device[]').length; 
        var total="";
        for(var i=0; i < device_count; i++){
            if(document.forms['group_edit'].elements['device[]'][i].checked) {
                if (total.length > 0) {
                    total += ","
                }
                total +=document.forms['group_edit'].elements['device[]'][i].value;
            }
        }

        new Ajax.Request('<%= group_show_devices_path %>', { 
            parameters: { 
                authenticity_token: encodeURIComponent('<%=form_authenticity_token%>'),
                device_ids: total
            } 
        } 
        );
    }
    /* ]]> */
</script>
<% end %>

Then I have the table of devices:

<table border="0" cellspacing="5" cellpadding="5">
    <thead>
        <tr>
            <th>&nbsp;</th>
            <th>Uid</th>
            <th>Name</th>
            <th>Ip</th>
            <th># Displays</th>
        </tr>
    </thead>
        <tfoot>
            <tr>
                <td colspan="5">
                    <ul class="tabs">
                        <li><%= link_to_function "Show", "showDevices()"  %></li>
                        <li><%= link_to_function "Edit", "editDevices()" %></li>
                        <li><%= link_to "Delete" %></li>
                    </ul>
                </td>
            </tr>
        </tfoot>
        <tbody>
            <% for device in @devices %>
            <tr>
                <td><%= check_box_tag("device[]", device.id, false, :id => "device_#{device.id}") %></td>
                <td><%=link_to_remote h(device.uid), :url => formatted_device_path(device, :js), :method => "get" %></td>
                <td><%=h device.name %></td>
                <td><%=h device.ip %></td>
                <td><%= device.displays.count %></td>
            </tr>
            <% end %>
        </tbody>
</table>

The result is that my ajax function will be called with a comma separated list of the ids of the selected devices.

&@$%^£& IE 7 and insecure content!

What a morning!

A user kindly reported that he couldn't log in to FilmAmora using IE7. IE6 worked, FireFox worked. Safari worked.

IE7 (for me) was coming up first with the 'there is insecure content on this page do you wish to show it?' (the login in page is under https). Clicking yes or no had the same result: the page would flash but then IE7 reported that it couldn't show the page. (It should have, it turns out, said 'I am choosing not to show the page').

The issue was that insecure content. For me, specifically it was the statcounter call. But your issue may be other calls. Anyway, I removed all calls to anything outside of my domain and that seems to have fixed it!

unfuddle

I use unfuddle as a git host and bug tracking, etc service. But, because I have so many projects on the go I ran into this problem where you can only have an ssh key in ONE account on unfuddle. So, I wrote to the support guys and asked them how to handle multiple accounts from one machine.
Here is their response:

The easiest way to deal with need multiple keys for multiple accounts is to actually just create them using different filenames in your ~/.ssh/ directory. For instance, if you have 2 accounts, "account1" and "account2", you would want to run "ssh-keygen -t rsa" twice, each time specifying a different filename:

~/.ssh/unfuddle_account1_id_rsa
~/.ssh/unfuddle_account2_id_rsa

Now, by default, ssh will use the file ~/.ssh/id_rsa when connecting to a remote server. As neither of your keys is in this file, you must tell SSH (not git) which private keyfile to use when connecting to each account. This is done using the SSH config file.

For instance, create or edit a file named .ssh/config with the following contents:


Host account1.unfuddle.com
User git
IdentityFile ~/.ssh/unfuddle_account1_id_rsa

Host account2.unfuddle.com
User git
IdentityFile ~/.ssh/unfuddle_account2_id_rsa


I have followed this model for my own accounts (of which I have many) and it has worked perfectly. I hope this helps you as well.

Creating a summary

I have an app that has rows of statistics. We wanted to create summaries of arbitrary rows.
This method seems to work:

  def self.create_summary_row(array)
    unless array.blank?
      klazz = array.first.class
      sum_stat = klazz.new
      array.each do |line|
        if line.is_a?(klazz)
          line.attributes.each do |k,v|
            unless v.nil? || v.is_a?(Time) || v.is_a?(Date)
              if sum_stat[k].nil?
                sum_stat[k] = v 
              else
                sum_stat[k] += v
              end 
            end
          end
        end
      end
      sum_stat
    end
  end

ec2onrails

This is so great - goodbye other hosting companies that can't compete!

Amazon has hosting facilities known as ec2 (elastic compute cloud). You pay by the hour ($.10 for a small installation). That works out to around $70/month. But, the power you get is much better than your average hosting.

Paul Dowman has released a great ec2 instance called ec2onrails that can get your rails app up and running on ec2 in about 30 minutes. I am now using it for FilmAmora as well as for another client.

It is awesome!

One thing I discovered today was the sweet built-in support for cron jobs. Write a script and plop it in your app's script directory. Call it hourly, daily or weekly (perhaps monthly? I didn't check). This script will get run automatically by an already existing cron job! No need to figure out those silly cron settings. Very cool!

I highly recommend it. FilmAmora is running much much better on it than on the old hosting (where I had to restart it every day just to hopefully have enough memory to run 2 mongrels).

secure forms

One thing I struggled with in RoR was creating forms that submitted to https. So I ended up writing a couple of helpers:

  def secure_form_for(record_or_name_or_array, *args, &proc)
    unless RAILS_ENV == 'production'
      url_options = {}
    else
      url_options = {:protocol => 'https://', :only_path => false }
    end
    
    options = args.last.is_a?(Hash) ? args.pop : {}
    if !options[:url].nil?
      options[:url] = url_options.merge options[:url]
    else
      options[:url] = url_options
    end

    return form_for(record_or_name_or_array, options, &proc)
  end

and

  def secure_form_tag(*args, &proc)
    logger.debug("secure_form_tag args #{args.inspect}")
    unless RAILS_ENV == 'production'
      url_options = {}
    else
      url_options = {:protocol => 'https://', :only_path => false }
    end

    options = args.last.is_a?(Hash) ? args.pop : {}
    if !options[:url].nil?
      options[:url] = url_options.merge options[:url]
    else
      options[:url] = url_options
    end

    logger.debug("secure_form_tag options #{options.inspect}")

    return form_tag(options, &proc)
  end

The should be simple replacements for form_for and form_tag. Now, I have to admit I wrote these when I was using Rails 1.2.5, so there might be some things in 2.x that make these redundant, but, they work for me.
The only caveat is that if you are doing a form where you are not passing in the action, just the object e.g

<% form_for @object do %>

Then you are going to have to supply the actions. I am looking into this now, and I might rewrite this post if I sort it out!