Saturday, June 2, 2012

XML Response in Python

Writing an XML response doc in python is pretty easy.
While working on one of the projects i wrote some
methods thats make it even easy to use:

import xml.dom.minidom

class MyXml:
    def __init__(self):
        self.doc = xml.dom.minidom.Document()

    def add_root(self, node_str):
        """creates and returns root node"""
        root = self.doc.createElementNS("", node_str)
        return root       

    def add_node(self, node, node_str):
        """creates and returns a child node"""
        ch_node = self.doc.createElementNS("", node_str)
        return root
    def add_txt_value(self, node, value):
        """creates a text node and appends to existing node"""
        txt_node = self.doc.createTextNode(str(value))

# example to create a xml response document you can simply add nodes and text
#as given below
#<?xml version="1.0" encoding="utf-8"?>
# <response>
#       <success> Hey i got your msg</success>
# </response>

if __name__ == '__main__':
    xmlObj = MyXml()
    #to create root node
    root = xmlObj.add_root("response")
    #to add child node arg1 parent node, arg2 child node
    node1 = xmlObj.add_node(root, "success")
    #to add success string to success node
    xmlObj.add_txt_value(node1, "Hey i got your msg")

Wednesday, January 4, 2012

Mahout Recommendation Engine

Apache mahout implements scalable data mining algorithms over apache hadoop. Classification , clustering and collaborative filtering algorithms are implemented in mahout that can be used for analyzing large scale data and predicting user behavior.

Mahout implements collaborative filtering based on :
1. User Preferences
2. Item similarity (product similarity)

Here i am giving a sample code for item similarity based recommendation building.
1. For building mahout project one needs maven.
2. InputFile : content of the file will be like :
userid, itemid, preference
note: both userid and item id are supposed to be long type and preference is supposed to be of float type.
string is not supported by mahout recommendation API so you need to resolve your data in IDs before feeding into mahout recommender.

Output: Given code takes input in above given format and write output in given file as :
Note: Recommendations will be arranged in descending order of recommendation strength. If customer preference is not known and then in that case there will be no ordering and given below recommender will be converted to binary recommender , that means either you like some product (1) or you don't like that product (0).

import java.util.List;
import org.apache.mahout.common.*;

public class HiveLog {
    public static void main(String... args) throws Exception
        // create data source (model) - from the csv file          

        File inputFile= new File("/home/test/test_input.csv");

        final DataModel model = new FileDataModel( inputFile );
        FileWriter fstream=new FileWriter("/home/test/recommendation.csv",true);
        BufferedWriter out=new BufferedWriter(fstream);      

RecommenderBuilder recommenderBuilder=new RecommenderBuilder(){
public Recommender buildRecommender(DataModel model) throws TasteException {

DiffStorage diffStorage = new MemoryDiffStorage( model, Weighting.WEIGHTED, Long.MAX_VALUE);
return new SlopeOneRecommender(model,Weighting.WEIGHTED, Weighting.WEIGHTED, diffStorage);

Recommender recommender=recommenderBuilder.buildRecommender(model);
      // for all users
        for (LongPrimitiveIterator it = model.getUserIDs(); it.hasNext();)
          long userId = it.nextLong();
            // get the recommendations for the user
            List<RecommendedItem> recommendations = recommender.recommend(userId,8);
            int i=0;
            for (RecommendedItem recommendedItem : recommendations)
if (i==0)


For more details and mahout algorithms implementation  please write.


Thursday, February 17, 2011

Cron Configuration of "crontab" on prior Installation of Cygwin (Tested with Windows XP Only)

You want to configure crontab on prior installation of cygwin and getting error like :
Error starting service: 1060

You can get rid of the problem by removing the old version cygwin dll (cygwin1.dll) file that can be found in root windows installation directory like C:\WINDOWS\system32 or if  Open ssh is installed then it would be in : C:\Program Files\OpenSSH\bin directory.

To remove this file you need to change permissions of the file :

chmod 777 /cygdrive/c/WINDOWS/system32/cygwin1.dll
don't worry it will change the permission of your cygwin1.dll file only.
Once file permission have updated you can remove this file like :
rm -f /cygdrive/c/WINDOWS/system32/cygwin1.dll
now follow the given below steps and your cron is ready to use. 

pawan.singh@pawanksingh ~
$ cron-config
Cron is already installed as a service under account LocalSystem.
Do you want to remove or reinstall it? (yes/no) yes
OK. The cron service was removed.

Do you want to install the cron daemon as a service? (yes/no) yes
Enter the value of CYGWIN for the daemon: [ ] ntsec

You must decide under what account the cron daemon will run.
If you are the only user on this machine, the daemon can run as yourself.
   This gives access to all network drives but only allows you as user.
Otherwise cron should run under the local system account.
  It will be capable of changing to other users without requiring a
  password, using one of the three methods detailed in
Do you want the cron daemon to run as yourself? (yes/no) no

Running cron_diagnose ...
WARNING: Your computer does not appear to have a cron table for pawan.singh.
Please generate a cron table for pawan.singh using 'crontab -e'

... no problem found.

Do you want to start the cron daemon as a service now? (yes/no) yes
OK. The cron daemon is now running.

In case of problem, examine the log file for cron,
/var/log/cron.log, and the Windows event log (using /usr/bin/cronevents)
for information about the problem cron is having.

Examine also any cron.log file in the HOME directory
(or the file specified in MAILTO) and cron related files in /tmp.

If you cannot fix the problem, then report it to
Please run the script /usr/bin/cronbug and ATTACH its output
(the file cronbug.txt) to your e-mail.

WARNING: PATH may be set differently under cron than in interactive shells.
         Names such as "find" and "date" may refer to Windows programs. 

Wednesday, February 9, 2011

Manage ssh sessions

Hi All,

There is a small script that manages idle ssh connections on the basis of idle hour diff and idle minute difference . Script is very simple and self explanatory. Even though if there is any confusion you  can write me back.

## Written By :
## last Updated: 0000-00-00

###### get Command line input ########
# arg1: idle connection hour diff                 #
# arg2: idle connection minute diff              #

if [ $# == 2 ]; then
elif [ $# == 1 ]; then
echo "please enter at least one command line argument as idle time hour diff"

list=`ps -W | grep 'sh.exe' | awk '{print $1":"$7}'`;
month=`date | awk '{print $2}'`;
prevmonth=`date -d 'last month' '+%b'`;
#echo $month
hr=`date | awk '{print $4}' | cut -d ':' -f 1`;
mt=`date | awk '{print $4}' | cut -d ':' -f 2`;
#echo $list
for p in $list
pid=`echo $p| cut -d ':' -f 1`;
hour=`echo $p| cut -d ':' -f 2`;
#echo $hour
minute=`echo $p| cut -d ':' -f 3`;
#echo $minute
#echo $hr
#echo $mt
    if [[ "$month" == "$hour" ]]; then
#        echo 1
        echo "Killing ssh session with pid :"$pid;
        /usr/bin/kill -f $pid;
    elif [[ "$prevmonth" == "$hour" ]]; then
#        echo 11
        let hour_diff=$hr-$hour
        if [[ "$hour_diff" -gt "$idl_hr_diff" ]] ;then
            echo "Killing ssh session with pid :"$pid;
            /usr/bin/kill -f $pid;
    let hour_diff=$hr-$hour
    let mid_night_hour_diff=$hour-$hr
#    echo "hello "$hour_diff
    let min_diff=$mt-$minute
#    echo "hi "$min_diff

        if [[ "$hour_diff" -ge "$idl_hr_diff" ]];then
            if [[ "$min_diff" -ge "$idl_mt_diff" ]]; then
#            echo 2
            echo "Killing ssh session with pid :"$pid
            /usr/bin/kill -f $pid;
#            echo 3
            echo "Ideal time less then threshold value. Skipping process with pid: "$pid
#            echo 4
            echo "Ideal time less then threshold value. Skipping process with pid: "$pid

Sunday, January 23, 2011

how to get python pexpect module on windows?

From quite a long time i was looking for a python module like "pexpect" for windows OS. I have wasted so many hours of mine to get some work around, finally what i got might help you all.

1. We can install pexpect module of python on windows . :) :)  But it requires cygwin installation.

2. Download Cygwin and install from any official site. Eg:

3. Once cygwin installation has completed, start cygwin session. (execute: cygwin.bat from installation directory or double click shortcut  of cygwin on your desktop.)

4. All windows directories will be referenced with respect to /cygdrive . Eg: D: directory will be referenced as /cygdrive/d/

5. execute following given below commands: Make sure python is installed on your system if not please install before executing given below commands.

#### assuming your python installation directory is C:/python25 ####
$ alias pythonpath=/cygdrive/c/python25/python
$ export pythonpath

6. Now check all well or not :

$ which python

#### if every thing will be ok It will return "/usr/local/python"  other wise go through steps given above and check u did all as mentioned there #############

7. Now get your pexpect.tar.gz file.

$ tar -xvzf pexpect.tar.gz
$ cd pexpect

$ python build
$ python install

8. Now you can use pexpect in your python script:

Note: you can use pexpect module on python from cygwin prompt only (For: Windows OS).

For Any Other Assistance Please write me on :