Posts on jimueller

ExtJS Learning Resources

Fri, 03 Mar 2017 08:02:21 -0600

Learning ExtJS can be a bit of a challange since, although it is well documented, there seems to be less “real world” examples available. Since ExtJS has become more focused on the enterprise, there is less activity on typical Q&A platforms like Stack Overflow. Finally, ExtJS has made major changes in its last few releases which leaves many of the examples available badly outdated.

The good news is that there some great resources available for learning ExtJS, in addition to Sencha’s documentation. Some are free, but those that aren’t free are still pretty cheap for what you get.

Books

Sencha Ext JS 6 Bootcamp in a Book: Classic Toolkit Edition Amazon by Steve Drucker of Fig Leaf is in my opinion the best, most cost-effective resource available for learning ExtJS. The book is about $60 and is basically the student guide for a weeklong course on ExtJS. The previous version of the book, covering ExtJS 5 is still available for on $25, and for learning ExtJS fundamentals there is no major differences. I consider this book to be the equivelent of classes provided by Sencha, which can cost more than a $1000.

The book covers everything you need to build ExtJS applications if you have no ExtJS experience. There are no gaps for a beginner and even if you have ExtJS experience it is a great way to get the complete picture of building and app and filling in any gaps you may have. The book does have some examples of creating custom components, but it does not go in depth on more advanced ExtJS topics. If you are strictly looking for advanced ExtJS, this is not the best book for you.

ExtJS Documentation

The Sencha ExtJS documentation is really good but in many cases you really have to know what you are looking for. Like most SDK/API documentation, it is not going always tell you how to accomplish your goal. I’ve used the following practices to get the most out of the ExtJS docs.

Skim through all of the docs files to get an idea of what is available
Use the search functionality and look for synonyms when trying to find specific events, methods, or properties
View the source to view JSDuck comments that may be missing from the new docs site

To learn ExtJS, I spend a significant amount of time reading the docs to understand what classes were available and their purpose. I try to take a “when in Rome” approach when using frameworks, so in an ExtJS project, I will try to find the ExtJS way of doing things. By browsing the docs, I was able to have an idea of what framework classes could be used to accomplish a goal without resorting to using another framework like jQuery or writing my own function. Ext has many utility classes and methods on the Ext object that can do just about anything jQuery can do, and has functions for formatting or manipulating text. ExtJS is a large framework and there are no shortcuts for understanding what it provides.

When looking for a specific method, event, or property, it’s useful to use the search/filter tool. Ext is pretty consistent on naming, but often it’s necessary to search for synonyms. For example, if you are looking for the control of a component’s visibility, try searching for “visible, hidden, hide, show” so that you don’t overlook one of the class’s members.

When Sencha switched the docs site in late 2016, the new version has had trouble parsing out the JSDuck comments used in ExtJS source code. This seems to be expecially true for inherited docs. To

extjs utility classes

Sun, 19 Feb 2017 11:22:18 -0600

extjs currency number field

Sun, 19 Feb 2017 11:21:20 -0600

Switch to Hugo

Sat, 18 Feb 2017 12:52:10 -0600

Switching over the ol’ blog from Jekyll to Hugo. Hugo doesn’t suck. Jekyll was well, a pain that always seem to break every time some gem updated.

saving nested associated date with extjs

Thu, 18 Aug 2016 12:56:54 -0600

allowing sencha cmd to serve on port 80 on linux

Sat, 06 Aug 2016 11:20:50 -0600

If you’ve tried to serve files with Sencha Cmd on port 80, you’ll probably see an error like this.

user@localhost ~/dev/extjs/extjsapp $ sencha web -p 80 start
Sencha Cmd v6.1.3.42
[INF] Starting server on port : 80
[INF] Mapping http://localhost:80/ to ....
[WRN] FAILED SelectChannelConnector@0.0.0.0:80: java.net.SocketException: Permission denied
[WRN] FAILED org.eclipse.jetty.server.Server@5d25ad3: java.net.SocketException: Permission denied
Exception in thread "Thread-5" com.sencha.exceptions.BasicException: Permission denied
	at com.sencha.exceptions.BasicException.wrap(BasicException.java:54)
	at com.sencha.exceptions.BasicException.stealthify(BasicException.java:43)
	at com.sencha.exceptions.BasicException.raise(BasicException.java:35)
	at com.sencha.util.http.Server.start(Server.java:265)
	at com.sencha.util.JettyServer.start(JettyServer.java:102)
	at com.sencha.command.filesystem.StartCommand$1.run(StartCommand.java:72)
	at com.sencha.util.ThreadUtil$1.run(ThreadUtil.java:65)
	at com.sencha.util.ThreadUtil$2.run(ThreadUtil.java:162)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.SocketException: Permission denied
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:433)
	at sun.nio.ch.Net.bind(Net.java:425)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:288)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at com.sencha.util.http.Server.start(Server.java:263)
	... 5 more

Sencha Cmd defaults to serving files port 1841, but sometimes there is a need to serve on port 80. One reason is if you are setting ‘localhost’ as an allowed cross-origin domain.

On Linux, only root is allowed to bind processes to reserved ports - those up to 1023. There are a few methods to get around this, such as configuring port routing or authbind. I prefer allowing java processes to bind to port 80 by granting the CAP_NET_BIND_SERVICE permission permenantly to java. Authbind can be used for one time access, and may be more appropriate if there are security concerns.

The following steps will demonstrate how to use setcap to allow java to bind on port 80. I would prefer to only grant Sencha Cmd with the permission, but was unable to determine how to do this.

First, determine where java is installed, by following the symbolic links.

> whereis java

The output will be similar to: java: /usr/bin/java /usr/share/java /usr/share/man/man1/java.1.gz and we see that java is in /usr/bin/java.

Let’s take a look at that.

> ls -l /usr/bin/java lrwxrwxrwx 1 root root 22 Jul 24 19:41 /usr/bin/java -> /etc/alternatives/java

We can see that /usr/bin/java is a symbolic link to /etc/alternatives/java, let’s take a look at that.

> ls -l /etc/alternatives/java lrwxrwxrwx 1 root root 46 Jul 24 19:41 /etc/alternatives/java -> /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java

We can now see that the actual location of java is /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java. Now that we know where java is, we can grant permission to bind to low-numbered ports.

sudo setcap CAP_NET_BIND_SERVICE=+eip /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java

Here we are granting with the following permissions.

e:Effictive activates the capability
p:Permitted allows the capability
i:Inherites the capability is inherited by child processes.

Now that the CAP_NET_BIND_SERVICE capability has been granted, let’s try serving on port 80.

user@localhost ~/dev/extjs/extjsapp $ sencha web -p 80 start
Sencha Cmd v6.1.3.42
[INF] Starting server on port : 80
[INF] Mapping http://localhost:80/ to ....

That looks much better.

easily install and update visual studio code on ubuntu

Sun, 22 Nov 2015 11:22:05 -0600

Visual Studio Code, my current go-to editor on Windows and Linux. I prefer Xubuntu for it’s combination of speed, configurability, and Git integration. It’s just a really nice editor.

As a relativly new product in Beta status, it’s getting fairly frequent updates. This isn’t really a problem on Windows since it has an installer to take care of updates. This is probably true for Mac as well, but on Linux VSCode is provided as a .zip archive.

The official installation instructions for Linux are to extract this .zip file to a directory and open the code executable. Honestly, as a relativly novice Linux user, this method for installation isn’t very hard. However, there is an arguably easier way, by using Ubuntu Make, which I came across on from an answer to a question about this topic on AskUbuntu.

I wasn’t previously aware of Ubuntu Make, here’s the definition from the Ubuntu Wiki.

Ubuntu Make is a command line tool which allows you to download the latest version of popular developer tools on your installation, installing it longside all the required dependencies (which will only ask for root access if you don’t have all the required dependencies installed already), enable multi-arch on your system if you are on a 64 bit machine, integrate it with the Unity launcher… Basically, one command to get your system ready to develop with!

Sounds great, and it is. Installing with Ubuntu Make gives the added benefits of making upgrading a one step process and making the Code icon available in menus and launchers.

Installation

Install Ubuntu Make

{% highlight shell %} sudo add-apt-repository ppa:ubuntu-desktop/ubuntu-make sudo apt-get update sudo apt-get install ubuntu-make {% endhighlight %}

Install Visual Studio Code with Make

umake web visual-studio-code

When you’re done, a Visual Studio Code icon will be automatically added to your launcher, and will now be available in the Applications menu, likely under the Develeopment folder.

Upgrade

When Visual Studio Code notifies me that a newer version is available, I just run the umake command again and VS Code is updated seamlessly.

umake web visual-studio-code

References:

How to install Visual Studio Code on Ubuntu?

clean websphere portal temp directories

Sun, 22 Nov 2015 11:21:41 -0600

WebSphere and WebSphere Portal create temporary directories for managing publish state, session state, and other data that can accumulate, degrading performance and causing publishing synchronization issues, especially on a development machine. If you begin to experience slow startup times or have publishing errors from RAD, cleaning temp folders can often resolve these issues.

On Windows, use Robocopy to delete long file paths

Note: On Windows, long directory paths can sometimes cause problems when trying to delete files in the WebSphere directory. Robocopy.exe is a bundled utility that has support for long file paths. Robocopy can be used to all files in a directory by mirroring an empty directory.

Create an empty directory. C:\>mkdir temp/empty
Using the empty directory as the source directory, you can use Robocopy’s /MIR switch to mirror the empty directory, effectivly deleteing all files in the destination directory.
>robocopy.exe C:\temp\empty C:\folder\to\delete\ /MIR
Stop the server.

profile_root/wstemp profile_root/temp profile_root/logs profile_root/tranlog

howto install fme dqman without documentum client

Fri, 06 Sep 2013 11:22:46 -0600

During a development project, I needed to run fme’s dqMan to query Documentum, but didn’t want to install the Documentum client as well. The following procedure shows how to get the required Documentum files off of an existing install so dqMan can run.

The following procedure is for Documentum 6.5, it may be applicable for other versions

Download dqMan from the fme website. You will receive the license file in an email.
Extract and install dqMan
From the content server, copy the dmcl.dll file from the Documentum\product\6.5\bin directory to a location on your system Path.
Create a dmcl.ini file and place the following section.
[DOCBROKER_PRIMARY] host=yourContentServer #IP or Hostname
Create and Environmental Variable named DCML_CONFIG that points to the dmcl.ini file. E.g. C:\dmcl.ini

use putty with console2

Sat, 18 Aug 2012 20:49:34 -0600

Console2 is a great frontend on Windows for cmd.exe and PowerShell. It provides re-sizable windows, a tabbed interface, and transparent windows.

It can also be used with PuTTY, but it takes a little bit of work. The issue is apparently with ANSI escape codes. Thankfully David A. Sjøen (@dasjoen) commented on Scott Hanselman’s Console2 article with the solution using ANSICON.

From the ANSICON ReadMe

ANSICON provides ANSI escape sequences for Windows console programs. It provides much the same functionality as `ANSI.SYS’ does for MS-DOS.

Instructions

Download ANSICON (Github) and extract the contents from the x86 or x64 folders to your Console2 installation folder.

I now have the following files in my C:\Program Files\Console2\ directory:
- ANSI32.dll
- ANSI64.dll
- ansicon.exe
- ANSI-LLW.exe
Open Console2 and create a new tab with the command line, replacing aPuttyProfileName with the name of a saved PuTTY profile:
C:\Program Files\Console2\ansicon.exe "C:\Program Files (x86)\PuTTY\plink.exe" -load aPuttyProfileName