Difficulty: 2 out of 5 stars
It was because of working with Corizon that I became more interested in creating Mash-ups*.
During the last 2 years, I’ve seen a lot of mash-up tools, From the easy (”Lego-like”) Popfly from Microsoft which is recently discontinued, to large handy API’s or serverside Java frameworks; such as the nice but heavy SiteMesh framework.
But it was the Corizon mash-up toolkit that I started to realize, coding mash-ups can have it’s ups and downs.

In my opinion creating a mash-up should be easy & fast. Not buggy and heavy (running 2 or 3 Tomcat servers in the background *kuch*). Also it’s an unwritten rule that for a mash-up you should not first destroy and rebuild it’s components before you gonna mix them up. This means you can only mash-up content what’s in your maintenance and when one of your components changes, your mash-up is broken.
It’s not a wonder that I became extremely positive about YQL, when I first saw this working.
And now, after Fronteers 2009, where I had a presentation and talk with Chris Heilmann from Yahoo.

With YQL (Yahoo Query Language), you can make the same mash-ups, client or serverside and you don’t need thousands lines of code.
Why you should use YQL for a mash-up?

• You won’t use your own bandwidth, but the bandwidth from Yahoo.
• It’s easy, just the basic SQL knowledge is required.
• It’s lightweight.
• It’s fast.

But like every Mashup tool, there are also downside’s. So it’s good to consider:

Why you shouldn’t use YQL for a mash-up?

• When one of the including components is slow or has timeouts, you result object will be null.

Mash-ups with YQL

Ok enough with the theory. Let’s practice with a simple YQL mash-up. As you might know, I like videogames. So I want to have a website with the release dates of games on my website, which I can watch on YouTube. Fokzine Games (http://games.fok.nl/overzicht.php?action=release) has a nice game release list.

• For using this tutorial, you will need a Yahoo Developer Account, which you can create for free.
• Unless you like to write full XPath lines without any help,
  you’ll also need Mozilla Firefox browser with the Firebug plugin installed.

1. Register your Yahoo Dev account.
   Go to the below URL, register your Yahoo account and login
   to the YQL console: http://developer.yahoo.com/yql
2. Query the content.
   YQL is quite similar to SQL. To query content (the videogame
   release list) from an external website, I will select all the HTML nodes from an URL. With Xpath I can point to the part of the website I will need. (Now you’ll need Firebug, inspect the website, till you’ll reach the table tag of the release list. – In top of your Firebug screen, you will see the full Xpath line.
   – Just right click, and “Copy Xpath”. This will be your YQL query for selecting the table tag on Fok.nl Game Release Page:

   select * from html where url ='http://games.fok.nl/overzicht.php?action=release' and xpath ='//*[@id="itemtext"]'
   //or select the tr tag on Fok.nl Game Release page
   //(note that I removed “tbody” from the xpath line to make it work)
   select * from html where url ='http://games.fok.nl/overzicht.php?action=release' and xpath ='/html/body/div[4]/table/tr/td[2]/div[2]/div/table/tr'
   

   Hit enter (or press “Test”) and you can switch between formatted view or tree view to see the result. Result can be in XML of JSON.
   Also note that you can copy the REST URL Query, from the console:
   
   http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%20%3D%20′http%3A%2F%2Fgames.fok.nl%2Foverzicht.php%3Faction%3Drelease’%20and%20xpath%20%3D%20′%2Fhtml%2Fbody%2Fdiv%5B4%5D%2Ftable%2Ftr%2Ftd%5B2%5D%2Fdiv%5B2%5D%2Fdiv%2Ftable%2Ftr’&format=xml
   
   

3. How the retrieved XML looks like:

   <query xmlns:yahoo="http://www.yahooapis.com/v1/base.rng"yahoo:count="50" yahoo:created="2009-09-25T12:14:12Z"yahoo:lang="en-US" yahoo:updated="2009-09-25T12:14:12Z"
   yahoo:uri="http://query.yahooapis.com/v1/yql?q=select+*+from+html+where+url+%3D+%27http%3A%2F%2Fgames.fok.nl%2Foverzicht.php%3Faction%3Drelease%27+and+xpath+%3D+%27%2Fhtml%2Fbody%2Fdiv%5B4%5D%2Ftable%2Ftr%2Ftd%5B2%5D%2Fdiv%5B2%5D%2Fdiv%2Ftable%2Ftr%27">
   <diagnostics>
   <publiclyCallable>true</publiclyCallable>
   <url execution-time="263" proxy="DEFAULT"><![CDATA[http://games.fok.nl/overzicht.php?action=release]]></url>
   <user-time>272</user-time>
   <service-time>263</service-time>
   <build-version>3130</build-version>
   </diagnostics>
   <results>
    <tr bgcolor="#E0E0E0">
     <td>
      <img alt="PC" src="http://images.fok.nl/ads/games/IB_PC.png"/>
     </td>
     <td>
      <p>29-09-2009</p>
     </td>
     <td>
      <a class="invisiblelink" href="gameinfo.php?gameid=9985">Tales of Monkey Island episode 3</a>
     </td>
    </tr>
     ..
   </results>
   </query>

   How your JSON (Javascript object looks like:

   releaseList({
    "query":{
    "count":"50",
    "created":"2009-09-25T12:10:17Z",
    "lang":"en-US",
    "updated":"2009-09-25T12:10:17Z",
    "uri":"http://query.yahooapis.com/v1/yql?q=select+*+from+html+where+url+%3D+%27http%3A%2F%2Fgames.fok.nl%2Foverzicht.php%3Faction%3Drelease%27+and+xpath+%3D+%27%2Fhtml%2Fbody%2Fdiv%5B4%5D%2Ftable%2Ftr%2Ftd%5B2%5D%2Fdiv%5B2%5D%2Fdiv%2Ftable%2Ftr%27",
    "diagnostics":{
     "publiclyCallable":"true",
     "url":{
      "execution-time":"28",
      "proxy":"DEFAULT",
      "content":"http://games.fok.nl/overzicht.php?action=release"
     },
    "user-time":"36",
    "service-time":"28",
    "build-version":"3130"
    },
   "results":{
    "tr":[{
    "bgcolor":"#E0E0E0",
    "td":[.. ]
    }
   ..
    ]
   }}});

4. Use the YQL widget.
   Create a new HTML page. In this page, you’ll include the YQL JS Widget:
   http://github.com/sh1mmer/dotnet-yql-tutorial/blob/master/yql_js_widget.js
   This is a pre-made Javascript widget. If you check out the links on the end of this article, you can check out other implementations as well. (Such as Dojo-YQL or JQuery YQL).
   For this article, we will use vanilla Javascript.
5. Create the Mash-up.
   The only think what you’ll need now is the logic to implement the previous made YQL query, to have the YQL results in your Document Object Model (DOM).
   With the Firebug plug-in, you can check the “Net” tab, to see if the correct object is retrieved. You can walk through the results, and implement it in your Javascript to do fancy things with it.

<html>
<head>
<title>YQL - Game Release</title>
</head>
<body>
<script type="text/javascript" src="yql-js-widget.js" ></script>
<script type="text/javascript">
var config = {};
var format = '<li class="{td[0].img.alt}">{td[1].p} - <a href="http://games.fok.nl/{td[2].a.href}" target="_blank">{td[2].a.content}</a> - <a href="http://www.youtube.com/results?search_query={td[2].a.content}" target="_blank">Watch on YouTube</a></li>';
var gameQuery = "select * from html where url = 'http://games.fok.nl/overzicht.php?action=release' and xpath = '/html/body/div[4]/table/tr/td[2]/div[2]/div/table/tr'";
yqlWidget.push(gameQuery, config, format, "widgetContainer");
yqlWidget.render();
</script><ul id="widgetContainer"></ul>
</body>
</html>

Well that’s it. See how easy it is to create a nice Mash-up? As long as you can reach the DOM, you can mash-up everything. Below my article, I’ve written some nice links. If you liked my article or you would like to discuss with me about YQL or Mash-up technologies; feel free to add me on LinkedIn or Twitter.

• YQL Community: http://github.com/yql/
• YQL video by Jonathan LeBlanc: http://developer.yahoo.com/yui/theater/video.php?v=leblanc-yql

* In webdevelopment, a mashup is a web page or application that combines
data or functionality from two or more external sources to create a new
service. An example of a Mash-up is a Google Map combined with Wikipedia
town information and a (accuweather.com) Weather indicator.

One of my websites is build on the CMS Joomla. These days I’m much more comfortable with Wordpress.
Today I will guide you, how to easy migrate from Joomla/Mambo to Wordpress.

Migrating Articles from Mambo/Joomla to Wordpress
With this wizzard from Rodney Blevins you can migrate Mambo/Joomla articles and links very easy to Wordpress.
Unfortunately migrating the links didn’t really work for my Wordpress 2.7.

Notice that for this wizzard, both installations of Mambo/Joomla and Wordpress need to be on the same webserver installed.

1. Download the wizzard from the above link.
2. Create a new folder “export” in the root of your Wordpress installation.
3. Edit the config.php file, with the database name, username, password of Mambo/Joomla and Wordpress database settings.
4. Incase you have Joomla installed, or you changed the database prefix; you’ll have to edit the var: “$dbprefix” to your prefix. For example: “mos_” to: “jos_”.
5. Incase the database prefix for the Wordpress DB is different then “wp_”; open up the index.php file, and search / replace all: “wp_” and change it manually to your prefix. For example: “wp_” to “lee_”.
6. Now save and upload the index.php and config.php files to the export folder
7. Surf to http://your-wp-installation/export and follow the steps to import your articles or links into Wordpress.

Removing Mambo/Joomla tags from Wordpress posts
Now when your done, it could be that your Wordpress post message contain Joomla tags in the post.
Tags like: “{mosimage}” or plugin based tags like: “{rokaccess}”.
You can easily remove these tags from all your post with some database queries.
Open phpMyAdmin and within your Wordpress database, press the SQL tab.

To see how many post I have with Mambo/Joomla tags, I used this query:

SELECT * FROM wp_posts WHERE post_content LIKE "%{%"

I noticed by the retrieved list, that some of my posts contain the {mosimage} tag.
To remove (replace to empty string) these tags and update my posts, I used the following query:

UPDATE wp_posts SET post_content = replace(post_content, "{mosimage}", "");

Just another check, to see if 0 posts return, if I search in my Wordpress database for the {mosimage} tag:

SELECT * FROM wp_posts WHERE post_content LIKE "{mosimage}"

Migrating users
The next important thing to migrate, will be the user database.
Let’s compare both XML exports from phpMyAdmin, to see the table structures:

Joomla Export:

<jos_users>
    <id>64</id>
    <name>Lee</name>
    <username>Lee</username>
    <email>my@email.nl</email>
    <password>###</password>
    <usertype>Super Administrator</usertype>
    <block>0</block>
    <sendEmail>0</sendEmail>
    <gid>25</gid>
    <registerDate>2007-07-25 21:57:51</registerDate>
    <lastvisitDate>2009-05-01 18:01:52</lastvisitDate>
    <activation></activation>
    <params>editor=none</params>
</jos_users>

Same Export in Wordpress would be:

<wp_users>
    <user_login>Lee</user_login>
    <user_pass></user_pass>
    <user_nicename>Lee</user_nicename>
    <user_email>my@email.nl</user_email>
    <user_url>http://www.ladysign.nl</user_url>
    <user_registered>2007-07-25 21:57:51<</user_registered>
    <user_activation_key></user_activation_key>
    <user_status>0</user_status>
    <display_name>Lee</display_name>
</wp_users>

Be replacing the table names in the export, or writing a nice script which creates a INSERT INTO query,
you can prefill the Wordpress database with the users from the Mambo/Joomla user table.
However, there will be one problem.

Password encryption
And that problem is setting over the passwords.
Joomla! 1.5 uses MD5 to hash the passwords. When the passwords are created, they are hashed with a 32 character salt that is appended to the end of the password string.
The password is stored as {TOTAL HASH}:{ORIGINAL SALT}.
That’s diffrent then the MD5 encryption of Wordpress.
For now I’ll solve this, by removing all the Wordpress passwords, and let the user recreate a new one via ‘lost password’.
This is ofcourse not a nice solution. Does anyone has an idea?

There are 4 main checks for diagnosing remote database connection problems:

• tnsnames.ora
• Oracle class path
• ping
• tnsping

tnsnames.ora

First check if the tnsnames.ora file has the correct database information/credentials.
The tnsnames.ora file can be found in: \ORACLE\ora92\network\ADMIN
These credentials should look like:

MYDATABSENAME =
	(DESCRIPTION=
		(ADDRESS_LIST=
			(ADDRESS=(PROTOCOL=TCP)(HOST=ladysign)(PORT=<port 1111>))
		)
		(CONNECT_DATA=
			(SERVICE_NAME=myServiceName)
		)
	)

Oracle Class path

Make sure oracle is in your class path.
Press Windows Key + Break key; Advanced Tab > Environment Variables
Make sure there is a ORACLE_HOME system variable. For example:
ORACLE_HOME = C:\\ORACLE\ora92

Ping

The ping utility is used to test the connectivity to a remote machine. ping will indicate whether a remote server is accessible and responding. If the ping command indicates that a machine cannot be accessed, the other connectivity tests will also fail.
U can use the ping command via the (DOS) command line; ping . For example:

C:\>ping ladysign
Pinging ladysign [198.64.245.67] with 32 bytes of data:

Reply from 198.64.245.67: bytes=32 time<10ms TTL=254
Reply from 198.64.245.67: bytes=32 time<10ms TTL=254
Reply from 198.64.245.67: bytes=32 time<10ms TTL=254
Reply from 198.64.245.67: bytes=32 time<10ms TTL=254

TNSPing

When the connectivity to the host is confirmed with the ping command, the next connection to check is the listener.
You can do this with the tnsping utility, which determines wheter or not an Oracle service can be succesfully reached.
However, tnssping will only report if the listener process is up and provides no indication of the state of the database:
For example:

C:\>tnsping MYDATABASENAME

TNS Ping Utility for 32-bit Windows: Version 9.2.0.1.0 - Production on 06-APR-2009 11:02:32

Copyright (c) 1997 Oracle Corporation.  All rights reserved.

Used parameter files:
C:\ORACLE\ora92\network\admin\sqlnet.ora

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION= (ADDRESS_LIST= (ADDRESS=(PROTOCOL=TCP)(HOST=ladysign)(PORT=1111))) (CONNECT_DATA= (SERVICE_NAME=myDatabaseService)))
OK (80 msec)
OK (10 msec)
OK (10 msec)
OK (0 msec)
OK (10 msec)

Ever wanted to query a resultset and received a whole bunch of results with empty values?
Just query on select no empty values.
The query can look like this:

SELECT * FROM MY_TABLE WHERE CD_VAL = 'something' AND CD_VAL IS NOT NULL;

Say you want to query all the fields after a specific date.
You’ll just write a sql with a value > then the filled in date.
But how do you specify a date? You need the to_Date function for doing this.

TIMESTAMP >= to_Date('20081203','yyyymmdd')