Tech Ramblings

MySql Ruby Examples

admin — Fri, 16 Jul 2010 05:30:38 +0000

Decided to learn a little more about Ruby by writing a Ruby program to manipulate some MySql tables that I have. I could have used "ActiveRecord" but I wanted to use Ruby classes only.
Originally I had errors because it was not finding the MySql gem. They may be some setting for in some configuration file, but the solution that works for me was to 'include rubygems'. Here is a basic Ruby program to connect to a database and select some information.

Code:

require 'rubygems'
require 'mysql'
 
  con = Mysql.new('localhost', 'root', '', 'db')
  puts "Server version: " + con.get_server_info
  stmt = "select id, name from users where id = 1"
  rs = con.query(stmt)
  puts "Number of rows returned: #{rs.num_rows}"

Of course it would be nice to see the results. The reasonably written documentation has no examples so I have included them here. There are different ways of fetching rows, using each or each_hash. I prefer the hash because I like to use column names rather then numbers.

Code:

rs.each_hash do |row| 
  puts "ID:#{row['id']} Name:#{row['name']}."
end

And here is each:

Code:

rs.each do |row|
  puts "ID:#{row[0]} Name:#{row[1]}."
end

Now that we have selected, lets try a couple of other functions:

Code:

# Now insert!
stmt = "Insert into users (name) values ('fred')"
con.query(stmt) 
puts "Number of rows inserted: #{con.affected_rows}"
 
# Now update
stmt = "update users set email='fred@flintstone.ca'  where name='fred' "
con.query(stmt) 
puts "Number of rows updated: #{con.affected_rows}"

Of course you can also perform other functions like creating tables, adding columns, you get the idea. Just for added fun, here are some other snippets, this first one prints out fields names of a table, in this case the 'secrets' table followed by a list of databases:

Code:

con.list_fields('secrets').fetch_fields.each do |f|
  puts "Field name : #{f.name} "
end 
 
con.list_dbs.each do |db|
  puts "db = #{db} "
end

Original post blogged on b2evolution.

Fabricating Robots

admin — Tue, 13 Jul 2010 17:11:14 +0000

Working today on a Rails app that groups client generated webapges and we need to have the ability to screen out "child safety challenged" and "naughtyware" from being indexed by google so we are not blacklisted from adwords. The final step was generating the robots meta tag to either index or not. So I was able to use the line:

Code:

<meta name="robots" content="<%= fabricate_robots %>" />

After looking at that line, I suddenly really enjoyed the fact that it appears that I am fabricating robots...

Original post blogged on b2evolution.

Firefox Addon

admin — Tue, 15 Jun 2010 19:33:53 +0000

Built my first firefox plugin! Fun to see something like this working. Here are the steps to just get a basic one up and running.

Turn on All Debugging
You should have:

In about:config set to true:

extensions.logging.enabled
javascript.options.showInConsole
browser.dom.window.dump.enabled (note: you add this one!)

Setup an Projects directory under mozilla
win: \path2\Mozilla\Firefox\Projects\yourExtensionName
linux: ~/.mozilla/firefox/Projects\yourExtensionName

Note that Projects and Profiles are not to be confused! You may want a different Project/Profile name. I chose the same to know what project & what profile to use for testing!

Setup an Profiles directory under mozilla
win: \path2\Mozilla\Firefox\Profiles\yourExtensionName
linux: ~/.mozilla/firefox/Profile\yourExtensionName

Setup a profile on firefox
Place the profile you are about to create under the above created directories. To do this use Firefox's profile manager:

Code:

firefox firefox -p  // win
   (may have to set windows env var: MOZ_NO_REMOTE=1  ???
firefox -ProfileManager -no-remote    // Linux

In my case I used the yourExtensionName as the profile name.

Setup Files Required
Google it to find the directory structure you need as well as the base content for the following base files:

install.rdf
chrome.manifest
XUL files (this in directory content, its your coding!)

These files will be in the
Projects/yourExtensionName/
directory.

Development Tip
You will want Firefox to automatically load the addon each time you code changes to the extension, so in the folder
Projects/yourExtensionName/extensions
have a file name like:
extensionname@your.unique.name.
This should match the id tag in the install.rdf manifest file. Note you will have to restart firefox to pick up the changes.

Gotchas
In the install.rdf file make sure that the tags:

Code:

<em:minVersion>3.0</em:minVersion>
  <em:maxVersion>3.6.4</em:maxVersion>

allow for your version of Firefox!

Original post blogged on b2evolution.

Passing Ruby vars to Javascript

admin — Thu, 10 Jun 2010 19:50:42 +0000

It may not be the best way of doing things, but it is the way I am doing it. I need to pass a Ruby variable to a javascript function, here's how:

<%  @x = "#{params[:shortened_url]}"  %>
<a href="javascript:task('<%=  @x -%>')">Do it</a>

Original post blogged on b2evolution.

New Installation Headaches

admin — Sat, 05 Jun 2010 05:59:49 +0000

I need to have a Linux instance running for a Rails app that I am to fix. That means I need Ruby, Rails, and MySql. Not sure yet about apache-passenger.
I like the command line, but since I have not used it much lately I am learning by being burnt by simple mistakes and just not knowing. When I know what I want to do and cannot do it because of some simple mistake, its frustrating. I have done all this on windows awhile ago and know how to do it easily & quickly. Now on Linux I want it to go just as fast and I don't do well knowing what has to be done and seeing very slow progress.
Headache city as I know more about software then installation of these. I am having trouble with mysql mostly, getting permissions and things working. I am trying to run:

Code:

mysqlimport -u clusterurl -p clusterurl_development clusterurl_production.backupfile.sql

and am getting Access Denied errors. I did it quickly on the first attempt on my windows mysql installation, but the Linux one I'm setting permissions and there is a small piece missing somewhere as its late and I typed priviledge a dozen times instead of privilege. I've been at it a couple of hours.
I think I will post a little list of MySql commands that I know I will be using often.
Off to bed...

Original post blogged on b2evolution.

Virtualbox

admin — Sat, 05 Jun 2010 05:47:49 +0000

Need to have a Linux instance running on my windows xp laptop. Have downloaded and installed Virtualbox and it runs like a charm. Its Open Source (GPL) and is has full virtualization, meaning that the OS that runs in it runs unmodified! I downloaded a Ubuntu v10 iso and Virtualbox will use that as a mounted CD and install smoothly! So nice.
I got it up and running without a hitch. Two thumbs up.

Original post blogged on b2evolution.

Geolocation and PHP

admin — Fri, 28 May 2010 23:48:03 +0000

Geo location is now so easy:

Code:

$geo = unserialize(file_get_contents('http://www.geoplugin.net/php.gp?ip='.$_SERVER['REMOTE_ADDR']));
print_r($geo);
echo "City: " . $geo['geoplugin_city'];
...

Thanks geoPlugin!

Original post blogged on b2evolution.

MySQL Raw SQL files

admin — Mon, 05 Apr 2010 22:29:39 +0000

Had problems upgrading to wampserver 2, so migrated back to wamp5. In the process I toasted the MySQL 5.1.36 version that I had with wamp5, but had all the raw sql files.

I reinstalled wamp5 (c:\wamp5) and then tried to move the old raw sql files (c:\wampOLD\mysql\data\))over to the new MySQL data directory (c:\wamp5\mysql\data\), but no luck. Something was amiss. Aha! The version of MySql with wamp5 was 5.0.15 and I had raw sql files from 5.1.36.

So I installed MySQL 5.1.36 to a new location (c:\mysql51), moved the old raw sql files over to this data directory (c:\mysql\data\) and crossed my fingers and it worked. So now I have to properly export the SQL tables and reload into the earlier version of MySQL that comes with wamp5.

Originally I did not copy over these files! You need to.

ibdata1
ib_logfile0
ib_logfile1

There may be an easier way, but this way is done.

Original post blogged on b2evolution.

	`require 'rubygems'`
	`require 'mysql'`

	`con = Mysql.new('localhost', 'root', '', 'db')`
	`puts "Server version: " + con.get_server_info`
	`stmt = "select id, name from users where id = 1"`
	`rs = con.query(stmt)`
	`puts "Number of rows returned: #{rs.num_rows}"`

	`# Now insert!`
	`stmt = "Insert into users (name) values ('fred')"`
	`con.query(stmt)`
	`puts "Number of rows inserted: #{con.affected_rows}"`

	`# Now update`
	`stmt = "update users set email='fred@flintstone.ca' where name='fred' "`
	`con.query(stmt)`
	`puts "Number of rows updated: #{con.affected_rows}"`

	`con.list_fields('secrets').fetch_fields.each do \|f\|`
	`puts "Field name : #{f.name} "`
	`end`

	`con.list_dbs.each do \|db\|`
	`puts "db = #{db} "`
	`end`

	`$geo = unserialize(file_get_contents('http://www.geoplugin.net/php.gp?ip='.$_SERVER['REMOTE_ADDR']));`
	`print_r($geo);`
	`echo "City: " . $geo['geoplugin_city'];`
	`...`

	`rs.each_hash do \|row\|`
	`puts "ID:#{row['id']} Name:#{row['name']}."`
	`end`

	`rs.each do \|row\|`
	`puts "ID:#{row[0]} Name:#{row[1]}."`
	`end`

	`firefox firefox -p // win`
	`(may have to set windows env var: MOZ_NO_REMOTE=1 ???`
	`firefox -ProfileManager -no-remote // Linux`

	`<em:minVersion>3.0</em:minVersion>`
	`<em:maxVersion>3.6.4</em:maxVersion>`