Recovering Lost Data In Safari

While trying to recover lost data typed into a web page on Safari, I stumbled across this forum and one response was worth remembering for later:

"If you wish to open cache.db you'd use the sqlite3 command.
It comes with your mac and it's easy to use if you know SQL.
Open Terminal an type in:
"cd ~/Library/Caches/com.apple.Safari;sqlite3 cache.db".
it'll open up the database and you can type ".tables" to show
the table names  then ".output FILENAME" 
then "select * from TABLENAME;" and it'll output to the
desired file you could do "foo.txt" as the file name. I have
3 tables, cfurl_cache_blob_data, cfurl_cache_schema_version,
cfurl_cache_response, in it so i did the steps three times
starting with the .output command for three separate files..."

This is a handy way to search through your old safari data by dumping everything in a file and then grepping the contents. The exact commands I used to accomplish this were:

cd ~/Library/Caches/com.apple.Safari
sqlite3 cache.db
.output temp.txt
select * from cfurl_cache_blob_data;

It's kind of surprising to see what's actually in your cache! I had no idea that the pages I surf were being stored to this extent. Turned out to be very handy.

But scary.

Other useful commands:

.help
.schema cfurl_cache_blob_data
.exit

Clients and Servers on the Terminal: Simple File Transfers

I just stumbled across an interesting shell command: nc

It's used for simple client/server interactions from the shell. With it, you can do interesting things like take output from one machine, send it over the network to another machine that pipes this input into other commands. Here's an example:

# On the destination machine
nc -l -p 2345 | tar xv
# On the source machine
tar c PATH_TO_FILES > /dev/tcp/IP.OF.DESTINATION/2345

Which will tar PATH_TO_FILES, on the source machine and transmit it over the network on port 2345. The destination will receive the data and pipe it into a command that will extract the tar.

This is so useful, I had to jot it down!

Subclipse / SVN Working copy locked - Solution

Problem

I could not update or commit a certain folder in my subversion project using subclipse in eclipse.

Symptoms

Both commit and update failed with the error:

svn: Working copy 'path/to/folder/that/was/not/working' locked; try performing 'cleanup'

I also got warnings that the directory was not under version control.

To get this problem, I had copied files from one project to another (in the file system not in subclipse). Although I deleted the .svn directory after copying, I still ran into this issue.

Solution

On the command line, cd to the project directory and run svn cleanup as in:

cd path/to/folder/that/was/not/working
svn cleanup

The problem should go away!

Maven - Sun JAR Issues (javamail, jms, jmx, jdmk, persistence)

Problem

Compiling fails because of dependencies related to Sun, such as javamail, jms, jmx. These failures have some of the symptoms listed below.

Background. Many of Sun's Java projects do not have licenses that allow for redistribution. Basically, their stuff is somewhat "locked down." To get it, you have to click through a Software License Agreement; meaning, their libraries can, at times, be a pain to download. Historically, their JARs have not been in public Maven Repositories. As such, Maven tends not to automatically download Sun dependencies. Nowadays, they are available in the default repository . . . supposedly. However, over here IN REALITY, that doesn't really work.

If you have "Maven: The Definitive Guide," read page 73 under the section "Adding J2EE Dependencies" for related information.

Symptoms

Some symptoms of this problem I saw while trying to solve it include:

Failed to resolve artifact

Missing:
----------
1) javax.persistence:ejb:jar:3.0-public_review

[INFO] Unable to find resource 'javax.persistence:ejb:jar:3.0-public_review' in repository JBoss Repository (https://repository.jboss.org/nexus/content/groups/public/)

error: error reading /Users/keving/.m2/repository/com/sun/jdmk/jmxtools/1.2.1/jmxtools-1.2.1.jar; cannot read zip file

error: error reading /Users/keving/.m2/repository/javax/mail/mail/1.4.1/mail-1.4.1.jar; cannot read zip file

error: error reading /Users/keving/.m2/repository/com/sun/jmx/jmxri/1.2.1/jmxri-1.2.1.jar; cannot read zip file

[INFO] Unable to find resource 'javax.jms:jms:jar:1.1' in repository central (http://repo1.maven.org/maven2)

[INFO] Unable to find resource 'javax.persistence:ejb:jar:3.0-public_review' in repository maven.springframework.org (http://maven.springframework.org/snapshot)

[INFO] Unable to find resource 'javax.persistence:ejb:jar:3.0-public_review' in repository central (http://repo1.maven.org/maven2)

Failed to resolve artifact. com.sun.jmx:jmxri:jar:1.2.1

Failed to resolve artifact. com.sun.jdmk:jmxtools:jar:1.2.1

Solutions

I recommend solution 4, below. After an hour or two of Googling, reading and learning, my final course of action (Solution 4) was to first delete all the troubled Sun dependencies, then painstakingly download the right JARs directly from Sun/Oracle and install them in the local repository. Below, I have listed all the useful solutions I found and tried during my journey to finding a complete repair.

Solution 1 - Fastest, Easiest Fix

Simplest solution: change just one character in the POM fille... use version 1.2.14 instead of 1.2.15. So the log4j dependency section
changes FROM:

<dependency>
<groupid>log4j</groupid>
<artifactid>log4j</artifactid>
<version>1.2.15</version>
</dependency>

TO:

<dependency>
<groupid>log4j</groupid>
<artifactid>log4j</artifactid>
<version>1.2.14</version>
</dependency>

Solution 2 - Quick Fix

Next simplest solution: exclude Sun jars by adding the following exclusions to the Log4j dependency within the pom.xml file:

Solution 3 - Ideal Fix (didn't work for me)

Best Solution (but doesn't work...or at least I can't get it to work): Use the special repositories provided by Sun: add to POM.xml

Supposedly, this repository is provided by Sun and contains the missing jars. Each one has a "Reference Implementation" of the underlying API. Somehow, this allows for a looser license so the code can be redistributed without clicking through an SLA. When I tried this, it only successfully installed 1 of the JARs--javamail.

Solution 4 - Thorough Repair (my choice)

This is the longer, yet more complete solution--get the actual jars from Sun/Oracle. I kept track of all the little things I did and listed them below, keeping as many things "cut and pasteable" as possible. These are the steps I took and the commands I happened to run along the way:

Delete the jars from the local repository:

  rm -rf ~/.m2/repository/javax/persistence/ejb/
  rm -rf ~/.m2/repository/javax/jms
  rm -rf ~/.m2/repository/javax/mail
  rm -rf ~/.m2/repository/com/sun/jdmk
  rm -rf ~/.m2/repository/com/sun/jmx

run maven again (at least to the compile phase) to see exactly which jars fail.

cd [top-level project directory with pom.xml]
mvn assembly:directory -Dmaven.test.failure.ignore=true

then download any remaining, missing JARs directly from SUN. Here are the detailed steps I took, grouped by each type of jar. The exact links may change over time but the basic steps should be the same. Note that the jdmk and jmx jars both come in one download.

JMS

1. click here to download the JMS jar from Sun/Oracle, accept the Software License Agreement and download the jar
2. unpack the zip archive (automatic on my machine to directory ~/Downloads)
3. cd to the lib directory

cd ~/Downloads/jms1.1/lib/

4. install the jms jar into the local maven repository, using the following command

JDMK - JMX Tools and/or JMXRI

1. click here to download the JDMK jar from Sun/Oracle, accept the Software License Agreement and download the jar
(Found on Sun's Java SE page for the JDMK/JMX project by choosing Download" under the "BINARY DOWNLOAD" section under "JMX 1.2.1 Reference Implementation")
2. This zip will include jars for both jmxtools and jmxri. Unpack the archive(automatic on my machine to directory ~/Downloads)
3. cd to the lib directory

cd ~/Downloads/jmx-1_2_1-bin/lib/

4. install both jars into the local repository, using the following commands

Persistence

1. click here to access the javax.persistence jar from sourceforge
2. unpack the archive (automatic on my machine to directory ~/Downloads)
3. cd to the lib directory

cd ~/Downloads/hibernate-annotations-3.1beta5/lib/

4. install the javax persistence jar into the local maven repository, using the following command

JavaMail

Java mail is now open source so you shold be able to pull it from the default Maven repository. If not, try adding Sun's repository (Solution 3) and seeing if that will pull down the javamail jar. Be sure to completely delete the javamail directory (~/.m2/repository/javax/mail) before running this.

Summary / Tradeoffs

Each solution I found, I didn't quite like for different reasons. Solution 4 was the first satisfying choice. Each of the previous approaches involved tradeoffs. The first one downgrades to an earlier version of Log4j and, clearly, they moved to 1.2.15 for a reason.. Maybe there are security patches. Maybe the difference is negligable. Either way, I don't want to deal with figuring it out. So, Solution 1 would be the quick and dirty fix I'd use a coworker who needed to get their environment working in a hurry but it's not something I'd choose as a long-term fix. Solution falls into a similar boat. I like that it doesn't downgrade, but it cuts out dependences that are probably there for a reason. Most of what I read indicated that those libraries are virtually unused. Still, to me, there their for a reason so although I'd prefer solution 2 over solution 1, I wouldn't use it long-term, either. Solution 3 didn't work for me. The claim was that this repository had all the magic jars required but it didn't turn out that way. Upon download, two of them failed the checksum--I couldn't figure out why--and the other two jars didn't appear to be in the repository at all. In fact, it seemed that the only thing I could get, error-free, was the javamail jar. Not good enough.

Finally, the fourth solution allowed Log4j to remain at the latest version and keep all it's dependencies. Admittedly, it was far more tedious and took me about 20 minutes to complete. Hopefully, this detailed post will greatly reduce that time for at least one person out there. If that person is you, I hope you can have your cake (a complete solution) and eat it too (a quick solution)! Celebrate.

Linux Equivalent of ipconfig renew and ipconfig release on Windows

I've looked this up 3 times so I finally decided to jot it down so I don't forget it.

Problem

Can't remember the Linux commands equivalent to:

ipconfig renew
ipconfig release

Symptoms

• Your IP is assigned via DHCP on a Linux box
• You've unplugged from one network and plugged into another and the old IP address hasn't cleared out
• Don't want to shutdown/restart the interface you just want to refresh the DHCP settings

Solution

sudo /sbin/dhclient -r is equivalent to ipconfig release
sudo /sbin/dhclient is equivalent to ipconfig renew
sudo /sbin/ifconfig is equivalent to ipconfig

The dhclient command broadcasts a DHCP message to your DHCP server, resulting in a new lease. A slower way to achieve the same result is to shutdown the interface and bring it back up via (assuming your target interface is eth0):

sudo /sbin/ifdown eth0
sudo /sbin/ifup eth0

This same, slower approach can also be done graphically on RedHat by clicking System > Administration > Network, choosing your interface (eth0) and clicking deactivate followed by activate.

Rollback Subclipse - Revert Subversion Changes

Problem

You need to rollback/revert subversion to a previous version and you're using the Subclipse plugin for Eclipse (or Flash Builder 4, etc.) to do it.

Symptoms

• There have been many changes to your project. You want to "undo" all those changes, restoring your project to its former glory.
• Choosing "Revert" only blew away your local changes. That's not good enough.
• There's a particular point in the past where everything "worked" and you need to reset everything back to that revision.

Solution

1. Right click your top level project folder and choose "Team" > "Show History"
2. Find the point in the past where things worked
TIP: click the play button on the top left to "show the next 25" revisions
3. Highlight all revisions AFTER the target revision
4. Right click and choose "Revert changes from revision # to revision #"
5. That's it. Commit your changes

For me, the revision that worked was revision 3690. The revision I was on was 3765. So, I highlighted revisions 3691 to 3765, right clicked and chose "Revert changes from revision 3765 to 3691."

From there, I wanted to keep certain changes so I right clicked my project folder and chose "Compare With..." > "Latest From Repository". This opened a view of every single file in the project that was altered. I double-clicked the files with useful changes, copied the changes I wanted over and saved the compare editor.

After everything looked correct, I committed. Worked great.

Debug BlazeDS Tomcat Server in Eclipse!!!

Warning: this post is dripping with awesome. Once you're able to get this working, you might go dancing in the street (I know I did!). Consider yourself warned.

Problem

You need to debug java code running on Tomcat as part of BlazeDS. You want to do this in Eclipse.

Symptoms

• You're tired of using logs, system outs, or other tom-foolery to debug the server-side code for your Flex application!
• You tried to set this up but received the following error:
java.lang.NoSuchMethodError: org.eclipse.wst.common.componentcore.internal.resources.VirtualComponent.clearCache()V
• You'd like to set a breakpoint and have server execution stop and jump to your breakpoint, even while executing RemoteObject code from Flex
• Once you hit such a breakpoint, you want to be able to inspect variables and expressions and enjoy similar debugging pleasures

Solution

Note: In this process, I encountered the very common error:

java.lang.NoSuchMethodError:

org.eclipse.wst.common.componentcore.internal.resources
.VirtualComponent.clearCache()V

Fixing it simply required updating eclipse.

I'll summarize the steps to getting debugging tomcat in eclipse to work as follows:

1. Open the Server View, right click and create a New Server
2. Point it to your /blazeds/tomcat folder (do not add any projects yet)
3. Right Click the new server and choose "Open"
4. Make sure your settings match this screenshot


NOTE: if the "Sever Location" section is disabled, that means you added a project in step 2. Delete this sever and start over without adding any projects.

---

Better yet, just follow this excellent and detailed blog titled Setting up your BlazeDS (tomcat) server on Eclipse ( local ). It worked flawlessly.

I credit the FlashBandit blog with opening my eyes to the fact that Setting Up a Basic BlazeDS Server with Debugging was even possible.

Uninstall MySQL on Mac OS X (Leopard 10.5 or Snow Leopard 10.6)

Problem

You need to completely remove mysql from your system as easily as possible.

Symptoms

You want to do a clean delete and a fresh install because you don't want to deal with errors such as:

• MySQL [your version] for Mac OS X can't be installed in this disk. A newer version of this software already exists on this disk.
• [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
• [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist

Solution

Execute the following commands that I found here and here:

sudo rm /usr/local/mysql
sudo rm -rf /usr/local/mysql*
sudo rm -rf /Library/StartupItems/MySQLCOM
sudo rm -rf /Library/PreferencePanes/My*
edit /etc/hostconfig and remove the line MYSQLCOM=-YES-
sudo rm -rf /Library/Receipts/mysql*
sudo rm -rf /Library/Receipts/MySQL*
sudo rm -rf /var/db/receipts/com.mysql.*

Maybe one day, if I'm feeling frisky, I'll come back and write a bash script to remove the MYSQLCOM line auto-magically. Maybe some magic involving sid or awk or something.