Running tomcat on port 80 as non-root

• Use the Apache httpd server to “pass” requests to Tomcat.

• Use IPtables. This requires a kernel version of 2.4.x or higher. If you’re running an older version of the kernel take a look at IPChains and consider a command something like: ipchains -I input --proto TCP --dport 80 -j REDIRECT 8080

  The IPtables solution allows Tomcat to run as an independent server as a non-privileged user and listen on port 80. IPtables will redirect all requests coming in on port 80 to port 8080 or whatever port you have Tomcat running under.The first step for this solution is to make sure your firewall allows TCP requests on port 8080 (or whatever port your Tomcat configuration has specfied). Essentially you need to duplicate all the firewall rules you have configured for port 80 since you will be redirecting those requests to 8080. The second step is to use the iptables command (usually installed by default on linux distributions) to redirect all packets on port 80, to port 8080. Here is a an example of the command you would use to do this:
  
iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth0 -j REDIRECT --to-port 8080


  To redirect local requests use the following command:iptables -t nat -A OUTPUT -p tcp -d 127.0.0.1 --dport 80 -j REDIRECT --to-port 8080
  This is handy if you’re running Tomcat on your workstation and debugging an application that’s required to run on port 80.

• Use rinetd. rinetd is a dedicated port redirector program that receives a packet and redirects it to a different port or address. Since rinetd redirects packets after they’ve gone through IPtables, this solution can be used for local and non-local requests.There are two things you should consider when using rinetd. First, rinetd cannot be used to redirect FTP requests because FTP requires more than one socket. Secondly, rinetd makes all packets appear as though they originated from the local machine. This obviously will impact things like web server logs and setting permissions based on IP address.Although rinetd has these side effects, using a combination of iptables and rinetd may be another option but seems like a more complicated solution from a debugging and maintenance perspective.

Installing self-signed ssl certificate

1. Generate an RSA key for signing the certificate:
openssl genrsa -out mykey.pem 2048

2. Generate a certificate using the new key:
openssl req -new -x509 -key mykey.pem -out mycert.pem -days 365

Enter your name, organization name and address as prompted.
In this example, we've created a key file, mykey.pem, and a self-signed certificate. Normally, you want a certificate from a "certificate authority" or CA. 
3. Since the certificate is in PEM format, convert it to PKCS12 for Tomcat:
openssl pkcs12 -export -in mycert.pem -inkey mykey.pem -out mycert.p12 -name tomcat

You MUST specify an export password! Tomcat expects one.

4. Keep the “mycert.p12” file you will need it to configure in tomcat server.xml.

5. Edit $CATALINA_HOME/conf/server.xml and uncomment the SSL connector tag.
Connector port="8443" maxHttpHeaderSize="8192"
maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
enableLookups="false" disableUploadTimeout="false" proxyPort="443"
acceptCount="100" scheme="https" secure="true"
clientAuth="false" sslProtocol="TLS" keystoreType="PKCS12"
keystoreFile="/opt/openssl-0.9.8g/mycert.p12"
keystorePass="*****" />"

Google's Page Speed

Google has released a Firefox add-on called Page Speed. It integrates with another add-on, Firebug, and is aimed at web developers trying to make their pages faster. “Page Speed is a tool we’ve been using internally to improve the performance of our web pages,” 

Also see YSlow, another Firebug add-on (this time by Yahoo) that “analyzes web pages and suggests ways to improve their performance”.

Best Ajax Framework

There are lot of ajax frameworks out there, my pick is

• Dojo -  Provides more features and widgets but customization is harder
• YUI -  has well documented code and detailed tutorial.
• GWT - Google's framework :-)
• SweekDev Ria - Has more features and performance overheads

First Web Server

In a glass case at CERN is an unpreposessing little NeXT cube. It's hard to believe that this little workstation changed the world, but it did. It's Tim Berners Lee's original web server, the world's first.

Google Launches Search Options, Declares Real-Time Search Biggest Challenge

Google has just launched a new “search options” feature on its main search page. When you click on “Search options” you can filter your search by different types of results (videos, forums, and reviews), by time (recent, past 24 hours, past week, past year), as well as seeing related searches, a “wonder wheel” view, or a timeline view.

At Google’s Searchology event, which is going on right now, Marissa Mayer listed the following as the hardest unsolved problems in search:

- Finding the most recent information
- Expressing that you want just one type of result
- Assessing which results are best
- Knowing what you’re looking for
- Expressing your searches in keywords

Notice that real-time search is the No. 1 problem. (Twitter and a bunch of startups from OneRiot to Tweetmeme are also working on it, with the latter two launching their own real-time search efforts today). And it certainly is a problem for Google, even with the new recent results option. Try searching for any of teh top trending results on Twitter right now like Miss California (vs. Twitter search results) or Star Trek (vs. Twitter results), and you don’t even get any Twitter results on Google.

While real-time search is still a big problem, it is not the only problem. Some of the new options address the difficulty of searching back through time. The recent results get as real-time as Google can get, but you can also expand the timeframe. And you can look at an actual timeline of results, which looks for dates within results and then places them chronologically (this is sort of hit or miss—just because a date is mentioned in a text does not mean the entire result is about or from that period of time). Google now also lets you see related searches as an option. And the Wonder Wheel is more of a visual aid to see how different related topics are clustered together. When you click on any spoke of the wheel, it then causes that search term to be at the center. We’ve seen many of these techniques in the past, but Google is giving them a higher profile by putting them in its main search page..

Accessing Remote Database from MySQL Trigger

Recently, we were in need of accessing the remote machine database from the MySQL's trigger. We found the only way to get this done by using the FEDERATED storage engine.

The FEDERATED storage engine is available beginning with MySQL 5.0.3. It is a storage engine that accesses data in tables of remote databases rather than in local tables.

The FEDERATED storage engine is available beginning with MySQL 5.0.3. This storage engine enables data to be accessed from a remote MySQL database on a local server without using replication or cluster technology. When using a FEDERATED table, queries on the local server are automatically executed on the remote (federated) tables. No data is stored on the local tables.