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  • Help updating cron entry using regular expressions

    - by Uday
    hi I am trying to update a cron entry NOT by using crontab -e but by shell commands. For example the cron entry is like this: 10 * * * * /home/localuser/foo.sh -b 1 -h 4 > foo_output.sh 2>&1 No i need edit the command line parameters part ONLY i.e -b 1 -h 4 to something else which will be coming in from the user. First thing would be to write the crontab to a tmp file and then manipulate that temp file. Now, is there an easy way to edit that line using SED or something? The crude way wud be to delete that entire line, write a new line with the entire expression and then load that into the cron. I am not very good with regular expressions. My system supports sed -i so was thinking this could be done in a single line command. Thanks in advance

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  • split a textfile after each n matches to a new file using sed or awk

    - by ozz
    i tried to split a file in parts of n matches each. The file is just one line and the seperator is '<br>' foo<br>bar<br>.....<br> I just want to split the file in parts, where each file has 100 datasets (text plus <br>)( normaly 100 datasets, but at the end maybe less) I already played around with this ... split-file-in-2-with-sed and this split-one-file-into-multiple-files-based-on-pattern sed.exe -e "^.*.<br>{0,100}/g" < original.txt > first_half.txt The split do not work an the result is only 1 file instead of many.

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  • Right solution for /etc/hosts file reset on reboot

    - by user846226
    i've just installed funtoo and after setting the FQDN on /etc/conf.d/hostname i noticed when setting a list of aliases in /etc/hosts file it get overwtiten on each reboot. Someone points to set the aliases to 127.0.0.2 ip address but that's not a valid solution for me. Could someone point me to the file where i should place entries like 127.0.0.1 local.foo 127.0.0.1 local.bar in order to make them persist in /etc/hosts after rebooting? Thanks! PD: I think openresolv could be the one who is overwritting the file.

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  • How to change the setting for a network device reported by ethtool, specifically Speed, on VM?

    - by Ramadheer Singh
    This is related to these two questions, although they don't answer my question. The machines are RHEL6. 1.ethtool not showing all the properties 2.changing network speed to 1000Mb/s Output on VM: [root@foo ~]# ethtool eth0 Settings for eth0: Current message level: 0x00000007 (7) Link detected: yes Output on Real Hardware: (interested in Speed) # ethtool eth0 Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised auto-negotiation: Yes ***Speed: 1000Mb/s*** Duplex: Full Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation: on Supports Wake-on: d Wake-on: d Link detected: yes if there's anyway I can set this in VM, please suggest.

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  • Is there a way for one SSH config file to include another one?

    - by Joe Casadonte
    In case it matters: OS: Ubuntu 10.04 SSH: OpenSSH_5.3p1 Debian-3ubuntu5 I'd like one SSH config file to include another one. The use case would be to define whatever I want in my default .ssh/config file and then pre-pend a couple of extra things in a separate file (e.g. ~/.ssh/foo.config). I want the second file to incorporate the first one, though, so I don't have to duplicate everything in the first one. Is that doable? Thanks!

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  • Highlighting subroutines in Notepad++

    - by predatflaps
    I would like to highlight the contents of IF statements in a slightly different colour from the background, so that I can see them more easily. Is it possible in Notepad++? it would be amazing to highlight all the nested subroutines in a function in slightly different light/dark colours depending on the scheme so that you can straightaway see the commands at a glance without spying out the curly brackets. not psychedelic colours, just slightly visible background colour difference. wouldn't it be great? Function Foo(){ highlight one color if(){highlight color2 for(){highlight color3 if (){hilghlight color4 } } } } }

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  • Open file without specifying exact location

    - by person
    Say I have a file in some obscure directory that I want to open and edit. I don't want to do something like this... vim ~/foo/bar/blah/doh/ugh.txt I'd rather be able to say find this file and open it. I know there are commands like locate and find to find a file or directory, but I'm not sure whether these can (or even should) be utilized in what I'm trying to do. Basically, what is the simplest way to open a file with a program w/o specifying its exact location? (In cases where there isn't another file with the same name in the entire system, and cases where there are multiple).

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  • Viewing zip archive contents using 'less' on OS X.

    - by multihead
    I couldn't help but notice that the 'less' program on all of the recent distributions of Linux that I've used (Ubuntu and Gentoo in this case) allow me to view the contents of ZIP and TAR archives, while the install of 'less' that I have on OS X (and Solaris) instead produce a "foo.zip may be a binary file. See it anyway?", which proceeds to spit out the raw binary data instead of a nice file structure listing. Google has not produced much in the way of helpful results -- it's tricky to search for 'less' in this context. I downloaded and built the latest version from greenwoodsoftware.com, but even it refuses to show the contents of these archives. I didn't come across any related configure/build options either. Any ideas? Thanks!

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  • How to choose NoSQL database engine?

    - by Poma
    We have a database with following specs: 30k records, 7mb in size 20 inserts/second 1000 updates/second 1000 range selects/second, by secondary index, approx 10 rows each needs at least one secondary index needs some mechanism to expire keys if they are not updated for 75 secs (can be done via programmatic garbage collector but will require additional 'last_update' index and will add some load) consistency is not required durability is not required db should be stored in memory For now we use Redis, but it does not have secondary index and it's keys index:foo:* is too slow. Membase also does not have secondary index (as far as I know). MongoDB and MySQL memory engine have table-level locks. What engine will fit our use case?

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  • is there a linux equivalent of iTerm(mac) sending command to multiple tabs functionality?

    - by jabbertalker
    in iTerm, you can send a command to execute simultaneously on a set of already opened tabs. Is there a way to do this in linux (with gnome-terminal preferably)? for instance, supposed that I had 10 tabs already ssh'd into [email protected] and sudoed to root and wanted to send a command to run on all 10 tabs. The goal of this is to be able to stay within a set of tabs and command them, rather than having to use expect scripts to ssh and elevate and run commands. Basically, like how you could do in iTerm.

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  • why run a Linux shell command with &?

    - by George2
    I am using Red Hat Linux Enterprise version 5. Sometimes I notice people run command with a couple of & options. For example, in the below command, there are two &-signs. What are the function of them? Are they always used together with nohup? nohup foo.sh <parameters to specific the scripe> >& <log_file_name> & thanks in advance, George

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  • List files recursively and sort by modification time

    - by Problemaniac
    How do I list all files under a directory recursively and sort the output by modification time? I normally use ls -lhtc but it doesn't find all files recursively. I am using Linux and Mac. ls -l on Mac OS X can give -rw-r--r-- 1 fsr user 1928 Mar 1 2011 foo.c -rwx------ 1 fsr user 3509 Feb 25 14:34 bar.c where the date part isn't consistent or aligned, so a solution have to take this into account. Partial solution stat -f "%m%t%Sm %N" ./* | sort -rn | head -3 | cut -f2- works, but not recursively.

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  • Creating video with audio and still image for YouTube

    - by scottlabs
    I'm running the following command: ffmpeg -i audio.mp3 -ar 44100 -f image2 -i logo.jpg -r 15 -b 1800 -s 640x480 foo.mov Which successfully outputs a video with my recorded audio and an image on it. When I try and upload this to YouTube it fails to process, regardless of the formats I try: .mov, .avi, .flv, .mp4 Is there some setting I'm missing in the above that would generate a format Youtube will accept? I've tried looking through the ffmpeg documentation but I'm in over my head. I did an experiment by putting a 2 second video with a 30 second mp3. When I uploaded to youtube, the resulting video was only 2 seconds long. So it may be that YouTube looks only to the video track for the length, and since a picture is only a frame long or whatever, maybe that borks it.

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  • Open Source or Low Cost Layer 7 ("Content") Switch?

    - by Rob
    I have several web servers that host a number of different applications and web sites. I want to make it easy to host apps or parts of web sites on different servers (e.g. example.com/foo might be on one physical server and example.com/bar might be on another). We do this Apache redirects right now, but that gets messy fast and in any case we have other problems we want to solve, such as throttling requests from individual clients, and reducing dependency on specific physical hosts. Is there an open source or low cost layer 7 switch that would be suitable for this sort of task? I was hoping to find something like a stripped down Linux VMware guest/appliance built for this purpose, but haven't seen anything suitable out there so far.

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  • Java Logger API

    - by Koppar
    This is a more like a tip rather than technical write up and serves as a quick intro for newbies. The logger API helps to diagnose application level or JDK level issues at runtime. There are 7 levels which decide the detailing in logging (SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST). Its best to start with highest level and as we narrow down, use more detailed logging for a specific area. SEVERE is the highest and FINEST is the lowest. This may not make sense until we understand some jargon. The Logger class provides the ability to stream messages to an output stream in a format that can be controlled by the user. What this translates to is, I can create a logger with this simple invocation and use it add debug messages in my class: import java.util.logging.*; private static final Logger focusLog = Logger.getLogger("java.awt.focus.KeyboardFocusManager"); if (focusLog.isLoggable(Level.FINEST)) { focusLog.log(Level.FINEST, "Calling peer setCurrentFocusOwner}); LogManager acts like a book keeper and all the getLogger calls are forwarded to LogManager. The LogManager itself is a singleton class object which gets statically initialized on JVM start up. More on this later. If there is no existing logger with the given name, a new one is created. If there is one (and not yet GC’ed), then the existing Logger object is returned. By default, a root logger is created on JVM start up. All anonymous loggers are made as the children of the root logger. Named loggers have the hierarchy as per their name resolutions. Eg: java.awt.focus is the parent logger for java.awt.focus.KeyboardFocusManager etc. Before logging any message, the logger checks for the log level specified. If null is specified, the log level of the parent logger will be set. However, if the log level is off, no log messages would be written, irrespective of the parent’s log level. All the messages that are posted to the Logger are handled as a LogRecord object.i.e. FocusLog.log would create a new LogRecord object with the log level and message as its data members). The level of logging and thread number are also tracked. LogRecord is passed on to all the registered Handlers. Handler is basically a means to output the messages. The output may be redirected to either a log file or console or a network logging service. The Handler classes use the LogManager properties to set filters and formatters. During initialization or JVM start up, LogManager looks for logging.properties file in jre/lib and sets the properties if the file is provided. An alternate location for properties file can also be specified by setting java.util.logging.config.file system property. This can be set in Java Control Panel ? Java ? Runtime parameters as -Djava.util.logging.config.file = <mylogfile> or passed as a command line parameter java -Djava.util.logging.config.file = C:/Sunita/myLog The redirection of logging depends on what is specified rather registered as a handler with JVM in the properties file. java.util.logging.ConsoleHandler sends the output to system.err and java.util.logging.FileHandler sends the output to file. File name of the log file can also be specified. If you prefer XML format output, in the configuration file, set java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter and if you prefer simple text, set set java.util.logging.FileHandler.formatter =java.util.logging.SimpleFormatter Below is the default logging Configuration file: ############################################################ # Default Logging Configuration File # You can use a different file by specifying a filename # with the java.util.logging.config.file system property. # For example java -Djava.util.logging.config.file=myfile ############################################################ ############################################################ # Global properties ############################################################ # "handlers" specifies a comma separated list of log Handler # classes. These handlers will be installed during VM startup. # Note that these classes must be on the system classpath. # By default we only configure a ConsoleHandler, which will only # show messages at the INFO and above levels. handlers= java.util.logging.ConsoleHandler # To also add the FileHandler, use the following line instead. #handlers= java.util.logging.FileHandler, java.util.logging.ConsoleHandler # Default global logging level. # This specifies which kinds of events are logged across # all loggers. For any given facility this global level # can be overriden by a facility specific level # Note that the ConsoleHandler also has a separate level # setting to limit messages printed to the console. .level= INFO ############################################################ # Handler specific properties. # Describes specific configuration info for Handlers. ############################################################ # default file output is in user's home directory. java.util.logging.FileHandler.pattern = %h/java%u.log java.util.logging.FileHandler.limit = 50000 java.util.logging.FileHandler.count = 1 java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter # Limit the message that are printed on the console to INFO and above. java.util.logging.ConsoleHandler.level = INFO java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter ############################################################ # Facility specific properties. # Provides extra control for each logger. ############################################################ # For example, set the com.xyz.foo logger to only log SEVERE # messages: com.xyz.foo.level = SEVERE Since I primarily use this method to track focus issues, here is how I get detailed awt focus related logging. Just set the logger name to java.awt.focus.level=FINEST and change the default log level to FINEST. Below is a basic sample program. The sample programs are from http://www2.cs.uic.edu/~sloan/CLASSES/java/ and have been modified to illustrate the logging API. By changing the .level property in the logging.properties file, one can control the output written to the logs. To play around with the example, try changing the levels in the logging.properties file and notice the difference in messages going to the log file. Example --------KeyboardReader.java------------------------------------------------------------------------------------- import java.io.*; import java.util.*; import java.util.logging.*; public class KeyboardReader { private static final Logger mylog = Logger.getLogger("samples.input"); public static void main (String[] args) throws java.io.IOException { String s1; String s2; double num1, num2, product; // set up the buffered reader to read from the keyboard BufferedReader br = new BufferedReader (new InputStreamReader (System.in)); System.out.println ("Enter a line of input"); s1 = br.readLine(); if (mylog.isLoggable(Level.SEVERE)) { mylog.log (Level.SEVERE,"The line entered is " + s1); } if (mylog.isLoggable(Level.INFO)) { mylog.log (Level.INFO,"The line has " + s1.length() + " characters"); } if (mylog.isLoggable(Level.FINE)) { mylog.log (Level.FINE,"Breaking the line into tokens we get:"); } int numTokens = 0; StringTokenizer st = new StringTokenizer (s1); while (st.hasMoreTokens()) { s2 = st.nextToken(); numTokens++; if (mylog.isLoggable(Level.FINEST)) { mylog.log (Level.FINEST, " Token " + numTokens + " is: " + s2); } } } } ----------MyFileReader.java---------------------------------------------------------------------------------------- import java.io.*; import java.util.*; import java.util.logging.*; public class MyFileReader extends KeyboardReader { private static final Logger mylog = Logger.getLogger("samples.input.file"); public static void main (String[] args) throws java.io.IOException { String s1; String s2; // set up the buffered reader to read from the keyboard BufferedReader br = new BufferedReader (new FileReader ("MyFileReader.txt")); s1 = br.readLine(); if (mylog.isLoggable(Level.SEVERE)) { mylog.log (Level.SEVERE,"ATTN The line is " + s1); } if (mylog.isLoggable(Level.INFO)) { mylog.log (Level.INFO, "The line has " + s1.length() + " characters"); } if (mylog.isLoggable(Level.FINE)) { mylog.log (Level.FINE,"Breaking the line into tokens we get:"); } int numTokens = 0; StringTokenizer st = new StringTokenizer (s1); while (st.hasMoreTokens()) { s2 = st.nextToken(); numTokens++; if (mylog.isLoggable(Level.FINEST)) { mylog.log (Level.FINEST,"Breaking the line into tokens we get:"); mylog.log (Level.FINEST," Token " + numTokens + " is: " + s2); } } //end of while } // end of main } // end of class ----------MyFileReader.txt------------------------------------------------------------------------------------------ My first logging example -------logging.properties------------------------------------------------------------------------------------------- handlers= java.util.logging.ConsoleHandler, java.util.logging.FileHandler .level= FINEST java.util.logging.FileHandler.pattern = java%u.log java.util.logging.FileHandler.limit = 50000 java.util.logging.FileHandler.count = 1 java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter java.util.logging.ConsoleHandler.level = FINEST java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter java.awt.focus.level=ALL ------Output log------------------------------------------------------------------------------------------- May 21, 2012 11:44:55 AM MyFileReader main SEVERE: ATTN The line is My first logging example May 21, 2012 11:44:55 AM MyFileReader main INFO: The line has 24 characters May 21, 2012 11:44:55 AM MyFileReader main FINE: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 1 is: My May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 2 is: first May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 3 is: logging May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 4 is: example Invocation command: "C:\Program Files (x86)\Java\jdk1.6.0_29\bin\java.exe" -Djava.util.logging.config.file=logging.properties MyFileReader References Further technical details are available here: http://docs.oracle.com/javase/1.4.2/docs/guide/util/logging/overview.html#1.0 http://docs.oracle.com/javase/1.4.2/docs/api/java/util/logging/package-summary.html http://www2.cs.uic.edu/~sloan/CLASSES/java/

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  • Can't run init script on boot after another init script

    - by Colin McQueen
    I have three init scripts and the Broker init script runs fine, but when I try to run the Consumer init script and then the Data Collector init script, the only process that is running is the Broker. I added the symbolic links to the run levels using update-rc.d for each script and I also changed the number prefixes in the symbolic links to try and run the scripts in the proper order but that did not work. I am able to run the scripts from the terminal and they work fine but they need to all be started on boot. Any ideas as to why my other scripts are not running? Also inside my Consumer and Data Collector I am running: su user1 -c 'java -jar foo.jar' to start the services. Also the Consumer Java class sits and waits for a message from the queue, so the Java code does not stop until I specify the stop argument for the init script. The Broker has to start first, then the Consumer, then the Data Collector. Adding the symbolic links for the runlevels: sudo update-rc.d Broker defaults 10 90 sudo update-rc.d Consumer defaults 15 85 sudo update-rc.d DataCollector defaults 20 80

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  • VSNewFile: A Visual Studio Addin to More Easily Add New Items to a Project

    - by InfinitiesLoop
    My first Visual Studio Add-in! Creating add-ins is pretty simple, once you get used to the CommandBar model it is using, which is apparently a general Office suite extensibility mechanism. Anyway, let me first explain my motivation for this. It started out as an academic exercise, as I have always wanted to dip my feet in a little VS extensibility. But I thought of a legitimate need for an add-in, at least in my personal experience, so it took on new life. But I figured I can’t be the only one who has felt this way, so I decided to publish the add-in, and host it on GitHub (VSNewFile on GitHub) hoping to spur contributions. Adding Files the Built-in Way Here’s the problem I wanted to solve. You’re working on a project, and it’s time to add a new file to the project. Whatever it is – a class, script, html page, aspx page, or what-have-you, you go through a menu or keyboard shortcut to get to the “Add New Item” dialog. Typically, you do it by right-clicking the location where you want the file (the project or a folder of it): This brings up a dialog the contains, well, every conceivable type of item you might want to add. It’s all the available item templates, which can result in anywhere from a ton to a veritable sea of choices. To be fair, this dialog has been revamped in Visual Studio 2010, which organizes it a little better than Visual Studio 2008, and adds a search box. It also loads noticeably faster.   To me, this dialog is just getting in my way. If I want to add a JavaScript script to my project, I don’t want to have to hunt for the script template item in this dialog. Yes, it is categorized, and yes, it now has a search box. But still, all this UI to swim through when all I need is a new file in the project. I will name it. I will provide the content, I don’t even need a ‘template’. VS kind of realizes this. In the add menu in a class library project, for example, there is a “Add Class…” choice. But all this really does is select that project item from the dialog by default. You still must wait for the dialog, see it, and type in a name for the file. How is that really any different than hitting F2 on an existing item? It isn’t. Adding Files the Hack Way What I often find myself doing, just to avoid going through this dialog, is to copy and paste an existing file, rename it, then “CTRL-A, DEL” the content. In a few short keystrokes I’ve got my new file. Even if the original file wasn’t the right type, it doesn’t matter – I will rename it anyway, including the extension. It works well enough if the place I am adding the file to doesn’t have much in it already. But if there are a lot of files at that level, it sucks, because the new file will have the name “Copy of xyz”, causing it to be moved into the ‘C’ section of the alphabetically sorted items, which might be far, far away from the original file (and so I tend to try and copy a file that starts with ‘C’ *evil grin*). Using ‘Export Template’ To be completely fair I should at least mention this feature. I’m not even sure if this is new in VS 2010 or not (I think so). But it allows you to export a project item or items, including potential project references required by it. Then it becomes a new item in the available ‘installed templates’. No doubt this is useful to help bootstrap new projects. But that still requires you to go through the ‘New Item’ dialog. Adding Files with VSNewFile So hopefully I have sufficiently defined the problem and got a few of you to think, “Yeah, me too!”… What VSNewFile does is let you skip the dialog entirely by adding project items directly to the context menu. But it does a bit more than that, so do read on. For example, to add a new class, you can right-click the location and pick that option. A new .cs file is instantly added to the project, and the new item is selected and put into the ‘rename’ mode immediately. The default items available are shown here. But you can customize them. You can also customize the content of each template. To do so, you create a directory in your documents folder, ‘VSNewFile Templates’. In there, you drop the templates you want to use, but you name them in a particular way. For example, here’s a template that will add a new item named “Add TITLE”. It will add a project item named “SOMEFILE.foo” (or ‘SOMEFILE1.foo’ if that exists, etc). The format of the file name is: <ORDER>_<KEY>_<BASE FILENAME>_<ICON ID>_<TITLE>.<EXTENTION> Where: <ORDER> is a number that lets you determine the order of the items in the menu (relative to each other). <KEY> is a case sensitive identifier different for each template item. More on that later. <BASE FILENAME> is the default name of the file, which doesn’t matter that much, since they will be renaming it anyway. <ICON ID> is a number the dictates the icon used for the menu item. There are a huge number of built-in choices. More on that later. <TITLE> is the string that will appear in the menu. And, the contents of the file are the default content for the item (the ‘template’). The content of the file can contain anything you want, of course. But it also supports two tokens: %NAMESPACE% and %FILENAME%, which will be replaced with the corresponding values. Here is the content of this sample: testing Namespace = %NAMESPACE% Filename = %FILENAME% I kind went back and forth on this. I could have made it so there’d be an XML or JSON file that defines the templates, instead of cramming all this data into the filename itself. I like the simplicity of this better. It makes it easy to customize since you can literally just throw these files around, copy them from someone else, etc, without worrying about merge data into a central description file, in whatever format. Here’s our new item showing up: Practical Use One immediate thing I am using this for is to make it easier to add very commonly used scripts to my web projects. For example, uh, say, jQuery? :) All I need to do is drop jQuery-1.4.2.js and jQuery-1.4.2.min.js into the templates folder, provide the order, title, etc, and then instantly, I can now add jQuery to any project I have without even thinking about “where is jQuery? Can I copy it from that other project?”   Using the KEY There are two reasons for the ‘key’ portion of the item. First, it allows you to turn off the built-in, default templates, which are: FILE = Add File (generic, empty file) VB = Add VB Class CS = Add C# Class (includes some basic usings) HTML = Add HTML page (includes basic structure, doctype, etc) JS = Add Script (includes an immediately-invoking function closure) To turn one off, just include a file with the name “_<KEY>”. For example, to turn off all the items except our custom one, you do this: The other reason for the key is that there are new Visual Studio Commands created for each one. This makes it possible to bind a keyboard shortcut to one of them. So you could, for example, have a keyboard combination that adds a new web page to your website, or a new CS class to your class library, etc. Here is our sample item showing up in the keyboard bindings option. Even though the contents of the template directory may change from one launch of Visual Studio to the next, the bindings will remain attached to any item with a particular key, thanks to it taking care not to lose keyboard bindings even though the commands are completely recreated each time. The Icon Face ID Visual Studio uses a Microsoft Office style add-in mechanism, I gather. There are a predetermined set of built-in icons available. You can use your own icons when developing add-ins, of course, but I’m no designer. I just wanted to find appropriate-ish icons for the built-in templates, and allow you to choose from an existing built-in icon for your own. Unfortunately, there isn’t a lot out there on the interwebs that helps you figure out what the built-in types are. There’s an MSDN article that describes at length a way to create a program that lists all the icons. But I don’t want to write a program to figure them out! Just show them to me! Sheesh :) Thankfully, someone out there felt the same way, and uses a novel hack to get the icons to show up in an outlook toolbar. He then painstakingly took screenshots of them, one group at a time. It isn’t complete though – there are tens of thousands of icons. But it’s good enough. If anyone has an exhaustive list, please let me, and the rest of the add-in community know. Icon Face ID Reference Installing the Add-in It will work with Visual Studio 2008 and Visual Studio 2010. Just unzip the release into your Documents\Visual Studio 20xx\Addins folder. It contains the binary and the Visual Studio “.addin” file. For example, the path to mine is: C:\Users\InfinitiesLoop\Documents\Visual Studio 2010\Addins Conclusion So that’s it! I hope you find it as useful as I have. It’s on GitHub, so if you’re into this kind of thing, please do fork it and improve it! Reference: VSNewFile on GitHub VSNewFile release on GitHub Icon Face ID Reference

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  • Integrating NetBeans for Raspberry Pi Java Development

    - by speakjava
    Raspberry Pi IDE Java Development The Raspberry Pi is an incredible device for building embedded Java applications but, despite being able to run an IDE on the Pi it really pushes things to the limit.  It's much better to use a PC or laptop to develop the code and then deploy and test on the Pi.  What I thought I'd do in this blog entry was to run through the steps necessary to set up NetBeans on a PC for Java code development, with automatic deployment to the Raspberry Pi as part of the build process. I will assume that your starting point is a Raspberry Pi with an SD card that has one of the latest Raspbian images on it.  This is good because this now includes the JDK 7 as part of the distro, so no need to download and install a separate JDK.  I will also assume that you have installed the JDK and NetBeans on your PC.  These can be downloaded here. There are numerous approaches you can take to this including mounting the file system from the Raspberry Pi remotely on your development machine.  I tried this and I found that NetBeans got rather upset if the file system disappeared either through network interruption or the Raspberry Pi being turned off.  The following method uses copying over SSH, which will fail more gracefully if the Pi is not responding. Step 1: Enable SSH on the Raspberry Pi To run the Java applications you create you will need to start Java on the Raspberry Pi with the appropriate class name, classpath and parameters.  For non-JavaFX applications you can either do this from the Raspberry Pi desktop or, if you do not have a monitor connected through a remote command line.  To execute the remote command line you need to enable SSH (a secure shell login over the network) and connect using an application like PuTTY. You can enable SSH when you first boot the Raspberry Pi, as the raspi-config program runs automatically.  You can also run it at any time afterwards by running the command: sudo raspi-config This will bring up a menu of options.  Select '8 Advanced Options' and on the next screen select 'A$ SSH'.  Select 'Enable' and the task is complete. Step 2: Configure Raspberry Pi Networking By default, the Raspbian distribution configures the ethernet connection to use DHCP rather than a static IP address.  You can continue to use DHCP if you want, but to avoid having to potentially change settings whenever you reboot the Pi using a static IP address is simpler. To configure this on the Pi you need to edit the /etc/network/interfaces file.  You will need to do this as root using the sudo command, so something like sudo vi /etc/network/interfaces.  In this file you will see this line: iface eth0 inet dhcp This needs to be changed to the following: iface eth0 inet static     address 10.0.0.2     gateway 10.0.0.254     netmask 255.255.255.0 You will need to change the values in red to an appropriate IP address and to match the address of your gateway. Step 3: Create a Public-Private Key Pair On Your Development Machine How you do this will depend on which Operating system you are using: Mac OSX or Linux Run the command: ssh-keygen -t rsa Press ENTER/RETURN to accept the default destination for saving the key.  We do not need a passphrase so simply press ENTER/RETURN for an empty one and once more to confirm. The key will be created in the file .ssh/id_rsa.pub in your home directory.  Display the contents of this file using the cat command: cat ~/.ssh/id_rsa.pub Open a window, SSH to the Raspberry Pi and login.  Change directory to .ssh and edit the authorized_keys file (don't worry if the file does not exist).  Copy and paste the contents of the id_rsa.pub file to the authorized_keys file and save it. Windows Since Windows is not a UNIX derivative operating system it does not include the necessary key generating software by default.  To generate the key I used puttygen.exe which is available from the same site that provides the PuTTY application, here. Download this and run it on your Windows machine.  Follow the instructions to generate a key.  I remove the key comment, but you can leave that if you want. Click "Save private key", confirm that you don't want to use a passphrase and select a filename and location for the key. Copy the public key from the part of the window marked, "Public key for pasting into OpenSSH authorized_keys file".  Use PuTTY to connect to the Raspberry Pi and login.  Change directory to .ssh and edit the authorized_keys file (don't worry if this does not exist).  Paste the key information at the end of this file and save it. Logout and then start PuTTY again.  This time we need to create a saved session using the private key.  Type in the IP address of the Raspberry Pi in the "Hostname (or IP address)" field and expand "SSH" under the "Connection" category.  Select "Auth" (see the screen shot below). Click the "Browse" button under "Private key file for authentication" and select the file you saved from puttygen. Go back to the "Session" category and enter a short name in the saved sessions field, as shown below.  Click "Save" to save the session. Step 4: Test The Configuration You should now have the ability to use scp (Mac/Linux) or pscp.exe (Windows) to copy files from your development machine to the Raspberry Pi without needing to authenticate by typing in a password (so we can automate the process in NetBeans).  It's a good idea to test this using something like: scp /tmp/foo [email protected]:/tmp on Linux or Mac or pscp.exe foo pi@raspi:/tmp on Windows (Note that we use the saved configuration name instead of the IP address or hostname so the public key is picked up). pscp.exe is another tool available from the creators of PuTTY. Step 5: Configure the NetBeans Build Script Start NetBeans and create a new project (or open an existing one that you want to deploy automatically to the Raspberry Pi). Select the Files tab in the explorer window and expand your project.  You will see a build.xml file.  Double click this to edit it. This file will mostly be comments.  At the end (but within the </project> tag) add the XML for <target name="-post-jar">, shown below Here's the code again in case you want to use cut-and-paste: <target name="-post-jar">   <echo level="info" message="Copying dist directory to remote Pi"/>   <exec executable="scp" dir="${basedir}">     <arg line="-r"/>     <arg value="dist"/>     <arg value="[email protected]:NetBeans/CopyTest"/>   </exec>  </target> For Windows it will be slightly different: <target name="-post-jar">   <echo level="info" message="Copying dist directory to remote Pi"/>   <exec executable="C:\pi\putty\pscp.exe" dir="${basedir}">     <arg line="-r"/>     <arg value="dist"/>     <arg value="pi@raspi:NetBeans/CopyTest"/>   </exec> </target> You will also need to ensure that pscp.exe is in your PATH (or specify a fully qualified pathname). From now on when you clean and build the project the dist directory will automatically be copied to the Raspberry Pi ready for testing.

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  • JavaScript local alias pattern

    - by Bertrand Le Roy
    Here’s a little pattern that is fairly common from JavaScript developers but that is not very well known from C# developers or people doing only occasional JavaScript development. In C#, you can use a “using” directive to create aliases of namespaces or bring them to the global scope: namespace Fluent.IO { using System; using System.Collections; using SystemIO = System.IO; In JavaScript, the only scoping construct there is is the function, but it can also be used as a local aliasing device, just like the above using directive: (function($, dv) { $("#foo").doSomething(); var a = new dv("#bar"); })(jQuery, Sys.UI.DataView); This piece of code is making the jQuery object accessible using the $ alias throughout the code that lives inside of the function, without polluting the global scope with another variable. The benefit is even bigger for the dv alias which stands here for Sys.UI.DataView: think of the reduction in file size if you use that one a lot or about how much less you’ll have to type… I’ve taken the habit of putting almost all of my code, even page-specific code, inside one of those closures, not just because it keeps the global scope clean but mostly because of that handy aliasing capability.

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  • What groupware/project-management apps (preferably self-hosted webapp) do you recommend for a small dev shop?

    - by HedgeMage
    I run a small Drupal consulting shop and we've been trying different groupware solutions for what seems like ages, yet nothing we've found seems to be a good fit. We don't need CRM-overkill such as SugarCRM offers -- it's just too much for our small size. We do need git integration (at a minimum, an easy way to associate commits with issues) Time tracking on configurable or 15m increments per-project issue tracking billing (incl. recurring billing for support contracts, etc) some sort of per-project notes/wiki for things like login credentials, client contact info, etc. Contact logging (Client foo called at 2:20pm and asked to add bar to the spec, signed addendum with pricing due to client NLT CoB today, to be returned by CoB tomorrow) Open source solutions are greatly preferred to closed ones Most of all, it should be very efficient to use. Several solutions just fell out of use here because they required too many clicks for simple, frequent tasks like logging time spent on an issue or noting a call from a client. It shouldn't take 20 minutes to make a note. Edit: I almost forgot to mention: we're a mixed Linux/Mac shop with no Windows users.

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  • Building Simple Workflows in Oozie

    - by dan.mcclary
    Introduction More often than not, data doesn't come packaged exactly as we'd like it for analysis. Transformation, match-merge operations, and a host of data munging tasks are usually needed before we can extract insights from our Big Data sources. Few people find data munging exciting, but it has to be done. Once we've suffered that boredom, we should take steps to automate the process. We want codify our work into repeatable units and create workflows which we can leverage over and over again without having to write new code. In this article, we'll look at how to use Oozie to create a workflow for the parallel machine learning task I described on Cloudera's site. Hive Actions: Prepping for Pig In my parallel machine learning article, I use data from the National Climatic Data Center to build weather models on a state-by-state basis. NCDC makes the data freely available as gzipped files of day-over-day observations stretching from the 1930s to today. In reading that post, one might get the impression that the data came in a handy, ready-to-model files with convenient delimiters. The truth of it is that I need to perform some parsing and projection on the dataset before it can be modeled. If I get more observations, I'll want to retrain and test those models, which will require more parsing and projection. This is a good opportunity to start building up a workflow with Oozie. I store the data from the NCDC in HDFS and create an external Hive table partitioned by year. This gives me flexibility of Hive's query language when I want it, but let's me put the dataset in a directory of my choosing in case I want to treat the same data with Pig or MapReduce code. CREATE EXTERNAL TABLE IF NOT EXISTS historic_weather(column 1, column2) PARTITIONED BY (yr string) STORED AS ... LOCATION '/user/oracle/weather/historic'; As new weather data comes in from NCDC, I'll need to add partitions to my table. That's an action I should put in the workflow. Similarly, the weather data requires parsing in order to be useful as a set of columns. Because of their long history, the weather data is broken up into fields of specific byte lengths: x bytes for the station ID, y bytes for the dew point, and so on. The delimiting is consistent from year to year, so writing SerDe or a parser for transformation is simple. Once that's done, I want to select columns on which to train, classify certain features, and place the training data in an HDFS directory for my Pig script to access. ALTER TABLE historic_weather ADD IF NOT EXISTS PARTITION (yr='2010') LOCATION '/user/oracle/weather/historic/yr=2011'; INSERT OVERWRITE DIRECTORY '/user/oracle/weather/cleaned_history' SELECT w.stn, w.wban, w.weather_year, w.weather_month, w.weather_day, w.temp, w.dewp, w.weather FROM ( FROM historic_weather SELECT TRANSFORM(...) USING '/path/to/hive/filters/ncdc_parser.py' as stn, wban, weather_year, weather_month, weather_day, temp, dewp, weather ) w; Since I'm going to prepare training directories with at least the same frequency that I add partitions, I should also add that to my workflow. Oozie is going to invoke these Hive actions using what's somewhat obviously referred to as a Hive action. Hive actions amount to Oozie running a script file containing our query language statements, so we can place them in a file called weather_train.hql. Starting Our Workflow Oozie offers two types of jobs: workflows and coordinator jobs. Workflows are straightforward: they define a set of actions to perform as a sequence or directed acyclic graph. Coordinator jobs can take all the same actions of Workflow jobs, but they can be automatically started either periodically or when new data arrives in a specified location. To keep things simple we'll make a workflow job; coordinator jobs simply require another XML file for scheduling. The bare minimum for workflow XML defines a name, a starting point, and an end point: <workflow-app name="WeatherMan" xmlns="uri:oozie:workflow:0.1"> <start to="ParseNCDCData"/> <end name="end"/> </workflow-app> To this we need to add an action, and within that we'll specify the hive parameters Also, keep in mind that actions require <ok> and <error> tags to direct the next action on success or failure. <action name="ParseNCDCData"> <hive xmlns="uri:oozie:hive-action:0.2"> <job-tracker>localhost:8021</job-tracker> <name-node>localhost:8020</name-node> <configuration> <property> <name>oozie.hive.defaults</name> <value>/user/oracle/weather_ooze/hive-default.xml</value> </property> </configuration> <script>ncdc_parse.hql</script> </hive> <ok to="WeatherMan"/> <error to="end"/> </action> There are a couple of things to note here: I have to give the FQDN (or IP) and port of my JobTracker and NameNode. I have to include a hive-default.xml file. I have to include a script file. The hive-default.xml and script file must be stored in HDFS That last point is particularly important. Oozie doesn't make assumptions about where a given workflow is being run. You might submit workflows against different clusters, or have different hive-defaults.xml on different clusters (e.g. MySQL or Postgres-backed metastores). A quick way to ensure that all the assets end up in the right place in HDFS is just to make a working directory locally, build your workflow.xml in it, and copy the assets you'll need to it as you add actions to workflow.xml. At this point, our local directory should contain: workflow.xml hive-defaults.xml (make sure this file contains your metastore connection data) ncdc_parse.hql Adding Pig to the Ooze Adding our Pig script as an action is slightly simpler from an XML standpoint. All we do is add an action to workflow.xml as follows: <action name="WeatherMan"> <pig> <job-tracker>localhost:8021</job-tracker> <name-node>localhost:8020</name-node> <script>weather_train.pig</script> </pig> <ok to="end"/> <error to="end"/> </action> Once we've done this, we'll copy weather_train.pig to our working directory. However, there's a bit of a "gotcha" here. My pig script registers the Weka Jar and a chunk of jython. If those aren't also in HDFS, our action will fail from the outset -- but where do we put them? The Jython script goes into the working directory at the same level as the pig script, because pig attempts to load Jython files in the directory from which the script executes. However, that's not where our Weka jar goes. While Oozie doesn't assume much, it does make an assumption about the Pig classpath. Anything under working_directory/lib gets automatically added to the Pig classpath and no longer requires a REGISTER statement in the script. Anything that uses a REGISTER statement cannot be in the working_directory/lib directory. Instead, it needs to be in a different HDFS directory and attached to the pig action with an <archive> tag. Yes, that's as confusing as you think it is. You can get the exact rules for adding Jars to the distributed cache from Oozie's Pig Cookbook. Making the Workflow Work We've got a workflow defined and have collected all the components we'll need to run. But we can't run anything yet, because we still have to define some properties about the job and submit it to Oozie. We need to start with the job properties, as this is essentially the "request" we'll submit to the Oozie server. In the same working directory, we'll make a file called job.properties as follows: nameNode=hdfs://localhost:8020 jobTracker=localhost:8021 queueName=default weatherRoot=weather_ooze mapreduce.jobtracker.kerberos.principal=foo dfs.namenode.kerberos.principal=foo oozie.libpath=${nameNode}/user/oozie/share/lib oozie.wf.application.path=${nameNode}/user/${user.name}/${weatherRoot} outputDir=weather-ooze While some of the pieces of the properties file are familiar (e.g., JobTracker address), others take a bit of explaining. The first is weatherRoot: this is essentially an environment variable for the script (as are jobTracker and queueName). We're simply using them to simplify the directives for the Oozie job. The oozie.libpath pieces is extremely important. This is a directory in HDFS which holds Oozie's shared libraries: a collection of Jars necessary for invoking Hive, Pig, and other actions. It's a good idea to make sure this has been installed and copied up to HDFS. The last two lines are straightforward: run the application defined by workflow.xml at the application path listed and write the output to the output directory. We're finally ready to submit our job! After all that work we only need to do a few more things: Validate our workflow.xml Copy our working directory to HDFS Submit our job to the Oozie server Run our workflow Let's do them in order. First validate the workflow: oozie validate workflow.xml Next, copy the working directory up to HDFS: hadoop fs -put working_dir /user/oracle/working_dir Now we submit the job to the Oozie server. We need to ensure that we've got the correct URL for the Oozie server, and we need to specify our job.properties file as an argument. oozie job -oozie http://url.to.oozie.server:port_number/ -config /path/to/working_dir/job.properties -submit We've submitted the job, but we don't see any activity on the JobTracker? All I got was this funny bit of output: 14-20120525161321-oozie-oracle This is because submitting a job to Oozie creates an entry for the job and places it in PREP status. What we got back, in essence, is a ticket for our workflow to ride the Oozie train. We're responsible for redeeming our ticket and running the job. oozie -oozie http://url.to.oozie.server:port_number/ -start 14-20120525161321-oozie-oracle Of course, if we really want to run the job from the outset, we can change the "-submit" argument above to "-run." This will prep and run the workflow immediately. Takeaway So, there you have it: the somewhat laborious process of building an Oozie workflow. It's a bit tedious the first time out, but it does present a pair of real benefits to those of us who spend a great deal of time data munging. First, when new data arrives that requires the same processing, we already have the workflow defined and ready to run. Second, as we build up a set of useful action definitions over time, creating new workflows becomes quicker and quicker.

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  • Evil DRY

    - by StefanSteinegger
    DRY (Don't Repeat Yourself) is a basic software design and coding principle. But there is just no silver bullet. While DRY should increase maintainability by avoiding common design mistakes, it could lead to huge maintenance problems when misunderstood. The root of the problem is most probably that many developers believe that DRY means that any piece of code that is written more then once should be made reusable. But the principle is stated as "Every piece of knowledge must have a single, unambiguous, authoritative representation within a system." So the important thing here is "knowledge". Nobody ever said "every piece of code". I try to give some examples of misusing the DRY principle. Code Repetitions by Coincidence There is code that is repeated by pure coincidence. It is not the same code because it is based on the same piece of knowledge, it is just the same by coincidence. It's hard to give an example of such a case. Just think about some lines of code the developer thinks "I already wrote something similar". Then he takes the original code, puts it into a public method, even worse into a base class where none had been there before, puts some weird arguments and some if or switch statements into it to support all special cases and calls this "increasing maintainability based on the DRY principle". The resulting "reusable method" is usually something the developer not even can give a meaningful name, because its contents isn't anything specific, it is just a bunch of code. For the same reason, nobody will really understand this piece of code. Typically this method only makes sense to call after some other method had been called. All the symptoms of really bad design is evident. Fact is, writing this kind of "reusable methods" is worse then copy pasting! Believe me. What will happen when you change this weird piece of code? You can't say what'll happen, because you can't understand what the code is actually doing. So better don't touch it anymore. Maintainability just died. Of course this problem is with any badly designed code. But because the developer tried to make this method as reusable as possible, large parts of the system get dependent on it. Completely independent parts get tightly coupled by this common piece of code. Changing on the single common place will have effects anywhere in the system, a typical symptom of too tight coupling. Without trying to dogmatically (and wrongly) apply the DRY principle, you just had a system with a weak design. Now you get a system which just can't be maintained anymore. So what can you do against it? When making code reusable, always identify the generally reusable parts of it. Find the reason why the code is repeated, find the common "piece of knowledge". If you have to search too far, it's probably not really there. Explain it to a colleague, if you can't explain or the explanation is to complicated, it's probably not worth to reuse. If you identify the piece of knowledge, don't forget to carefully find the place where it should be implemented. Reusing code is never worth giving up a clean design. Methods always need to do something specific. If you can't give it a simple and explanatory name, you did probably something weird. If you can't find the common piece of knowledge, try to make the code simpler. For instance, if you have some complicated string or collection operations within this code, write some general-purpose operations into a helper class. If your code gets simple enough, its not so bad if it can't be reused. If you are not able to find anything simple and reasonable, copy paste it. Put a comment into the code to reference the other copies. You may find a solution later. Requirements Repetitions by Coincidence Let's assume that you need to implement complex tax calculations for many countries. It's possible that some countries have very similar tax rules. These rules are still completely independent from each other, since every country can change it of its own. (Assumed that this similarity is actually by coincidence and not by political membership. There might be basic rules applying to all European countries. etc.) Let's assume that there are similarities between an Asian country and an African country. Moving the common part to a central place will cause problems. What happens if one of the countries changes its rules? Or - more likely - what happens if users of one country complain about an error in the calculation? If there is shared code, it is very risky to change it, even for a bugfix. It is hard to find requirements to be repeated by coincidence. Then there is not much you can do against the repetition of the code. What you really should consider is to make coding of the rules as simple as possible. So this independent knowledge "Tax Rules in Timbuktu" or wherever should be as pure as possible, without much overhead and stuff that does not belong to it. So you can write every independent requirement short and clean. DRYing try-catch and using Blocks This is a technical issue. Blocks like try-catch or using (e.g. in C#) are very hard to DRY. Imagine a complex exception handling, including several catch blocks. When the contents of the try block as well as the contents of the individual catch block are trivial, but the whole structure is repeated on many places in the code, there is almost no reasonable way to DRY it. try { // trivial code here using (Thingy thing = new thingy) { //trivial, but always different line of code } } catch(FooException foo) { // trivial foo handling } catch (BarException bar) { // trivial bar handling } catch { // trivial common handling } finally { // trivial finally block } The key here is that every block is trivial, so there is nothing to just move into a separate method. The only part that differs from case to case is the line of code in the body of the using block (or any other block). The situation is especially interesting if the many occurrences of this structure are completely independent: they appear in classes with no common base class, they don't aggregate each other and so on. Let's assume that this is a common pattern in service methods within the whole system. Examples of Evil DRYing in this situation: Put a if or switch statement into the method to choose the line of code to execute. There are several reasons why this is not a good idea: The close coupling of the formerly independent implementation is the strongest. Also the readability of the code and the use of a parameter to control the logic. Put everything into a method which takes a delegate as argument to call. The caller just passes his "specific line of code" to this method. The code will be very unreadable. The same maintainability problems apply as for any "Code Repetition by Coincidence" situations. Enforce a base class to all the classes where this pattern appears and use the template method pattern. It's the same readability and maintainability problem as above, but additionally complex and tightly coupled because of the base class. I would call this "Inheritance by Coincidence" which will not lead to great software design. What can you do against it: Ideally, the individual line of code is a call to a class or interface, which could be made individual by inheritance. If this would be the case, it wouldn't be a problem at all. I assume that it is no such a trivial case. Consider to refactor the error concept to make error handling easier. The last but not worst option is to keep the replications. Some pattern of code must be maintained in consistency, there is nothing we can do against it. And no reason to make it unreadable. Conclusion The DRY-principle is an important and basic principle every software developer should master. The key is to identify the "pieces of knowledge". There is code which can't be reused easily because of technical reasons. This requires quite a bit flexibility and creativity to make code simple and maintainable. It's not the problem of the principle, it is the problem of blindly applying a principle without understanding the problem it should solve. The result is mostly much worse then ignoring the principle.

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  • Web API, JavaScript, Chrome &amp; Cross-Origin Resource Sharing

    - by Brian Lanham
    The team spent much of the week working through this issues related to Chrome running on Windows 8 consuming cross-origin resources using Web API.  We thought it was resolved on day 2 but it resurfaced the next day.  We definitely resolved it today though.  I believe I do not fully understand the situation but I am going to explain what I know in an effort to help you avoid and/or resolve a similar issue. References We referenced many sources during our trial-and-error troubleshooting.  These are the links we reference in order of applicability to the solution: Zoiner Tejada JavaScript and other material from -> http://www.devproconnections.com/content1/topic/microsoft-azure-cors-141869/catpath/windows-azure-platform2/page/3 WebDAV Where I learned about “Accept” –>  http://www-jo.se/f.pfleger/cors-and-iis? IT Hit Tells about NOT using ‘*’ –> http://www.webdavsystem.com/ajax/programming/cross_origin_requests Carlos Figueira Sample back-end code (newer) –> http://code.msdn.microsoft.com/windowsdesktop/Implementing-CORS-support-a677ab5d (older version) –> http://code.msdn.microsoft.com/CORS-support-in-ASPNET-Web-01e9980a   Background As a measure of protection, Web designers (W3C) and implementers (Google, Microsoft, Mozilla) made it so that a request, especially a JSON request (but really any URL), sent from one domain to another will only work if the requestee “knows” about the requester and allows requests from it. So, for example, if you write a ASP.NET MVC Web API service and try to consume it from multiple apps, the browsers used may (will?) indicate that you are not allowed by showing an “Access-Control-Allow-Origin” error indicating the requester is not allowed to make requests. Internet Explorer (big surprise) is the odd-hair-colored step-child in this mix. It seems that running locally at least IE allows this for development purposes.  Chrome and Firefox do not.  In fact, Chrome is quite restrictive.  Notice the images below. IE shows data (a tabular view with one row for each day of a week) while Chrome does not (trust me, neither does Firefox).  Further, the Chrome developer console shows an XmlHttpRequest (XHR) error. Screen captures from IE (left) and Chrome (right). Note that Chrome does not display data and the console shows an XHR error. Why does this happen? The Web browser submits these requests and processes the responses and each browser is different. Okay, so, IE is probably the only one that’s truly different.  However, Chrome has a specific process of performing a “pre-flight” check to make sure the service can respond to an “Access-Control-Allow-Origin” or Cross-Origin Resource Sharing (CORS) request.  So basically, the sequence is, if I understand correctly:  1)Page Loads –> 2)JavaScript Request Processed by Browser –> 3)Browsers Prepares to Submit Request –> 4)[Chrome] Browser Submits Pre-Flight Request –> 5)Server Responds with HTTP 200 –> 6)Browser Submits Request –> 7)Server Responds with Data –> 8)Page Shows Data This situation occurs for both GET and POST methods.  Typically, GET methods are called with query string parameters so there is no data posted.  Instead, the requesting domain needs to be permitted to request data but generally nothing more is required.  POSTs on the other hand send form data.  Therefore, more configuration is required (you’ll see the configuration below).  AJAX requests are not friendly with this (POSTs) either because they don’t post in a form. How to fix it. The team went through many iterations of self-hair removal and we think we finally have a working solution.  The trial-and-error approach eventually worked and we referenced many sources for the information.  I indicate those references above.  There are basically three (3) tasks needed to make this work. Assumptions: You are using Visual Studio, Web API, JavaScript, and have Cross-Origin Resource Sharing, and several browsers. 1. Configure the client Joel Cochran centralized our “cors-oriented” JavaScript (from here). There are two calls including one for GET and one for POST function(url, data, callback) {             console.log(data);             $.support.cors = true;             var jqxhr = $.post(url, data, callback, "json")                 .error(function(jqXhHR, status, errorThrown) {                     if ($.browser.msie && window.XDomainRequest) {                         var xdr = new XDomainRequest();                         xdr.open("post", url);                         xdr.onload = function () {                             if (callback) {                                 callback(JSON.parse(this.responseText), 'success');                             }                         };                         xdr.send(data);                     } else {                         console.log(">" + jqXhHR.status);                         alert("corsAjax.post error: " + status + ", " + errorThrown);                     }                 });         }; The GET CORS JavaScript function (credit to Zoiner Tejada) function(url, callback) {             $.support.cors = true;             var jqxhr = $.get(url, null, callback, "json")                 .error(function(jqXhHR, status, errorThrown) {                     if ($.browser.msie && window.XDomainRequest) {                         var xdr = new XDomainRequest();                         xdr.open("get", url);                         xdr.onload = function () {                             if (callback) {                                 callback(JSON.parse(this.responseText), 'success');                             }                         };                         xdr.send();                     } else {                         alert("CORS is not supported in this browser or from this origin.");                     }                 });         }; The POST CORS JavaScript function (credit to Zoiner Tejada) Now you need to call these functions to get and post your data (instead of, say, using $.Ajax). Here is a GET example: corsAjax.get(url, function(data) { if (data !== null && data.length !== undefined) { // do something with data } }); And here is a POST example: corsAjax.post(url, item); Simple…except…you’re not done yet. 2. Change Web API Controllers to Allow CORS There are actually two steps here.  Do you remember above when we mentioned the “pre-flight” check?  Chrome actually asks the server if it is allowed to ask it for cross-origin resource sharing access.  So you need to let the server know it’s okay.  This is a two-part activity.  a) Add the appropriate response header Access-Control-Allow-Origin, and b) permit the API functions to respond to various methods including GET, POST, and OPTIONS.  OPTIONS is the method that Chrome and other browsers use to ask the server if it can ask about permissions.  Here is an example of a Web API controller thus decorated: NOTE: You’ll see a lot of references to using “*” in the header value.  For security reasons, Chrome does NOT recognize this is valid. [HttpHeader("Access-Control-Allow-Origin", "http://localhost:51234")] [HttpHeader("Access-Control-Allow-Credentials", "true")] [HttpHeader("Access-Control-Allow-Methods", "ACCEPT, PROPFIND, PROPPATCH, COPY, MOVE, DELETE, MKCOL, LOCK, UNLOCK, PUT, GETLIB, VERSION-CONTROL, CHECKIN, CHECKOUT, UNCHECKOUT, REPORT, UPDATE, CANCELUPLOAD, HEAD, OPTIONS, GET, POST")] [HttpHeader("Access-Control-Allow-Headers", "Accept, Overwrite, Destination, Content-Type, Depth, User-Agent, X-File-Size, X-Requested-With, If-Modified-Since, X-File-Name, Cache-Control")] [HttpHeader("Access-Control-Max-Age", "3600")] public abstract class BaseApiController : ApiController {     [HttpGet]     [HttpOptions]     public IEnumerable<foo> GetFooItems(int id)     {         return foo.AsEnumerable();     }     [HttpPost]     [HttpOptions]     public void UpdateFooItem(FooItem fooItem)     {         // NOTE: The fooItem object may or may not         // (probably NOT) be set with actual data.         // If not, you need to extract the data from         // the posted form manually.         if (fooItem.Id == 0) // However you check for default...         {             // We use NewtonSoft.Json.             string jsonString = context.Request.Form.GetValues(0)[0].ToString();             Newtonsoft.Json.JsonSerializer js = new Newtonsoft.Json.JsonSerializer();             fooItem = js.Deserialize<FooItem>(new Newtonsoft.Json.JsonTextReader(new System.IO.StringReader(jsonString)));         }         // Update the set fooItem object.     } } Please note a few specific additions here: * The header attributes at the class level are required.  Note all of those methods and headers need to be specified but we find it works this way so we aren’t touching it. * Web API will actually deserialize the posted data into the object parameter of the called method on occasion but so far we don’t know why it does and doesn’t. * [HttpOptions] is, again, required for the pre-flight check. * The “Access-Control-Allow-Origin” response header should NOT NOT NOT contain an ‘*’. 3. Headers and Methods and Such We had most of this code in place but found that Chrome and Firefox still did not render the data.  Interestingly enough, Fiddler showed that the GET calls succeeded and the JSON data is returned properly.  We learned that among the headers set at the class level, we needed to add “ACCEPT”.  Note that I accidentally added it to methods and to headers.  Adding it to methods worked but I don’t know why.  We added it to headers also for good measure. [HttpHeader("Access-Control-Allow-Methods", "ACCEPT, PROPFIND, PROPPA... [HttpHeader("Access-Control-Allow-Headers", "Accept, Overwrite, Destin... Next Steps That should do it.  If it doesn’t let us know.  What to do next?  * Don’t hardcode the allowed domains.  Note that port numbers and other domain name specifics will cause problems and must be specified.  If this changes do you really want to deploy updated software?  Consider Miguel Figueira’s approach in the following link to writing a custom HttpHeaderAttribute class that allows you to specify the domain names and then you can do it dynamically.  There are, of course, other ways to do it dynamically but this is a clean approach. http://code.msdn.microsoft.com/windowsdesktop/Implementing-CORS-support-a677ab5d

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  • Naming conventions: camelCase versus underscore_case ? what are your thoughts about it? [closed]

    - by poelinca
    I've been using underscore_case for about 2 years and I recently switched to camelCase because of the new job (been using the later one for about 2 months and I still think underscore_case is better suited for large projects where there are alot of programmers involved, mainly because the code is easier to read). Now everybody at work uses camelCase because (so they say) the code looks more elegant . What are you're thoughts about camelCase or underscore_case p.s. please excuse my bad english Edit Some update first: platform used is PHP (but I'm not expecting strict PHP platform related answers , anybody can share their thoughts on which would be the best to use , that's why I came here in the first place) I use camelCase just as everibody else in the team (just as most of you recomend) we use Zend Framework which also recommends camelCase Some examples (related to PHP) : Codeigniter framework recommends underscore_case , and honestly the code is easier to read . ZF recomends camelCase and I'm not the only one who thinks ZF code is a tad harder to follow through. So my question would be rephrased: Let's take a case where you have the platform Foo which doesn't recommend any naming conventions and it's the team leader's choice to pick one. You are that team leader, why would you pick camelCase or why underscore_case? p.s. thanks everybody for the prompt answers so far

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  • Highly scalable and dynamic "rule-based" applications?

    - by Prof Plum
    For a large enterprise app, everyone knows that being able to adjust to change is one of the most important aspects of design. I use a rule-based approach a lot of the time to deal with changing business logic, with each rule being stored in a DB. This allows for easy changes to be made without diving into nasty details. Now since C# cannot Eval("foo(bar);") this is accomplished by using formatted strings stored in rows that are then processed in JavaScript at runtime. This works fine, however, it is less than elegant, and would not be the most enjoyable for anyone else to pick up on once it becomes legacy. Is there a more elegant solution to this? When you get into thousands of rules that change fairly frequently it becomes a real bear, but this cannot be that uncommon of a problem that someone has not thought of a better way to do this. Any suggestions? Is this current method defensible? What are the alternatives? Edit: Just to clarify, this is a large enterprise app, so no matter which solution works, there will be plenty of people constantly maintaining its rules and data (around 10). Also, The data changes frequently enough to say that some sort of centralized server system is basically a must.

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