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Open Source

This category contains 14 posts

Connect and query Cloudera Impala using PHP ODBC on CentOS 7

Cloudera Impala is a SQL query engine for Hadoop. Impala is supposed to be better suited for real-time SQL queries, compared to MapReduce-based, batch processing software like Hive or Pig. The former is not dependent on MapReduce. In one of the ongoing projects which is running Impala on Hadoop, I had to configure connecting to it via PHP – so that the web developers can start using it.

This blog post explains to query Impala using PHP and ODBC. What’s more, Cloudera (the company behind Impala) provides an RPM for ODBC drivers for Impala. Following is how to install, configure and use Impala ODBC drivers with PHP (version 5.4) on CentOS 7 (64bit) Linux distribution.  Read the rest of this entry »

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Use SSH Tunnel to access an Intranet Web Server behind a Firewall

You have SSH (Secure Shell) access to an intranet server running a web application in your office. Sitting remotely, you can modify the web scripts on the command line. Once done, to see the results, you cannot access the web application because it is meant to be accessed from within the intranet, within the office. Port 80 is blocked by a firewall. So should you wait to go to the office to see the result? Not really. You have SSH access and thanks to something called SSH Tunnel.

Let’s say you can access server.abc.com using SSH which is running the web application. After modifying the web scripts, you can see the results in your web browser (on your laptop) as follows:

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I am Mufflerman: Powered by OpenCV and PHP Facedetect

Sometime back I worked on a project which required face detection in the photos uploaded by the user. Yesterday I read about our honorable prime minister Modi ji and BJP are setting selfie booths. This led to the idea of “I am Mufflerman” 😉 Try the demo here.

I am Mufflerman

I am Mufflerman

On the demo page, click on the button on the top and upload a selfie (if on a desktop/laptop) or click a selfie if you are browsing the demo on a phone.

Upload a photo which is a selfie. Do not upload a groupfie (more than one person in the photo). The demo does a frontal face detection so look straight into the camera. Read the rest of this entry »

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Authenticate osTicket against Zimbra LDAP

osTicket is a free online helpdesk/support ticket system. Zimbra Open Source Edition is a free groupware product which offers E-mail, Calendar, Tasks and Chat. Recently for a client I had setup these two products.

Zimbra stores the E-mail users’ credentials in its built-in LDAP server. Hence it made sense to authenticate the login of other services or products like osTicket against Zimbra’s LDAP.

Following is a short tutorial on how I achieved it. Read the rest of this entry »

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MySQL GUI Tools (Query Browser, Administrator) for Fedora 13

In Fedora Linux, the mysql-gui-tools package provides the graphical (or GUI) clients to query and administer a MySQL database – useful alternatives to the command line client.

While I’m very comfortable with the mysql command line client, I do switch to the GUI query browser to add/edit stored procedures/functions.

“yum install mysql-gui-tools” was the simplest command to install the GUI tools for MySQL in Fedora Linux. But in Fedora 13, this results in “No package mysql-gui-tools available”.

So what happened here?

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Drupal Views: Hide or display alternate text for 0 (zero) comments

I have been playing with Drupal Views extensively for the last three months for a Website project. Whenever I overcome a hurdle with Views, I end up realizing how powerful and flexible is the Views module. It is just me who doesn’t know all the syntax to tap it’s power. Here is one such example. With about four lines of code, I was able to get rid of an annoyance in an otherwise neat-looking View.

For the Website project, I built a View to show the recent blog posts along with their title, author, post date and the number of comments. All looked fine expect the comments. It pinched me to see “0 comments”, in the View, against the posts, which did not have a comment. Read the rest of this entry »

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Firefox 3.5 (Final) on Fedora 11

Firefox 3.5, the final release, has made its debut and is ready for download from here. Typically (and unfortunately) it may take about a day or two for Firefox 3.5 final to appear in the Fedora 11 repositories and across all the mirrors. When it appears, upgrading from the current version (Beta 4) of FireFox to the final release would be a matter of issuing ‘yum install firefox’. But we may not have to wait! Read the rest of this entry »

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Fedora X

How things change while on the move! I had been hitting the Fedora site constantly for the Fedora 10 download – last at around 20:30 hrs IST from a client’s office. While driving back, about 30 mins away from home, I checked the site on my Windows Mobile (ironic?) and I spotted “Fedora 10” written all over the site. Rushed home at double speed.

Fired the torrent as well as direct download. The latter because, saw only one peer @ 98.7% download. Let’s see who, direct or the torrent download, wins the race on my 2 Mbps connection at home. The torrent download is not giving me more than 3KBps whereas the direct download is dicey and swinging – at times from about 260 KBps to 40 KBps

Once downloaded I have to start thinking about backing up my laptop running Fedora 9 and installing the 10. This may happen tonight, if sleep does not take over the X.

Will update this post as I sail to X from IX.

And now (Nov 27, 2008 @ 16:30 IST), my laptop runs Fedora 10 🙂 Continuing to write from Fedora 10, about it. Following is the first glimpse, with the noteworthy new wallpaper,  of Fedora 10’s desktop, after the installation:

Fedora 10 Desktop

Fedora 10 Desktop

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Chromified Firefox

In a half an hour attempt to make Firefox look like Google Chrome with some similar functionality, I achieved the following:

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Online storage for Linux

I was looking for an online storage:

  • Which can work on Linux (on my Fedora 9 laptop)
  • Using which backing up files is quick – as easy as drag-n-drop or copy-n-paste (else I will be lazy to back up)
  • Free
  • Atleast a GB of space (if not more)

Optionally:

  • To be able to access the files from anywhere
  • To be able access the files using my laptop, home desktop and office desktop running Windows/Linux
  • Offline access to files (for those rare occasions when I’m not connected to the Internet)

I checked out Xdrive, Adrive, Gmail Drive and Live Mesh but none of these fit my mandatory requirements. Xdrive and Live Mesh are Windows only. Adrive’s WebDav access is paid. Gmail Drive (tried using fuse-gmailfs on Fedora) was erratic.

The solution that worked for me was Dropbox – 2 GB free space, works on Linux and drag-n-drop online storage. Dropbox is also available for Windows and Mac OS, besides Linux Read the rest of this entry »

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