Devin's Thought Stream

Thrift vs. Protocol Buffers - Digital Digressions by Stuart Sierra

Fri, 03 Sep 2010 21:05:05 +0000

Python web services with SoapLib � El blog de Carlos Ble

Tue, 31 Aug 2010 18:53:19 +0000

Django snippets: SOAP views with on-demand WSDL generation

Tue, 31 Aug 2010 18:42:43 +0000

Python SOAP client with suds

Sun, 29 Aug 2010 23:25:53 +0000

Help me find David Max Lee

2010-08-25T13:08:14.482-07:00

So I've got this old bandmate from twenty years ago that I'd like to locate. As the title of this blog post suggests, his name is David Max Lee. It's a full name constructed from rather common names and so it's been tricky hunting him down. I finally gave in and paid one of the people finder sites a few bucks to help me track him down. Here are some of the clues I have to his whereabouts:

* He should be about 43 years old
* He has lived in both Dallas and Arlington, TX
* He is a hacker in the sense that he likes to toy with computers and electronics
* He was once a member of the Dallas based band SPY

Speaking of SPY, I just recently found a copy of a low-budget video we made back in the 80's. It's posted on youtube:

http://www.youtube.com/user/jhwhitaker#p/a/u/0/llj1prdX6lc

David is the tallest one, most often standing on the far right in the group shots.

The people finder site helped me locate records belonging to a David Max Lee born on 08/24/1967. This might be him. These were the given addresses and phone numbers:

ADDRESS 1:
4220 SILVERWOOD TRL,
KELLER, TX 76248

ADDRESS 2:
8728 SARANAC TRL,
FORT WORTH, TX 76118

ADDRESS 3:
1364 SHADY LN #1105,
BEDFORD, TX 76021

ADDRESS 4:
9364 BRIARHURST DR,
DALLAS, TX 75243

ADDRESS 5:
7225 FAIR OAKS AVE #301,
DALLAS, TX 75231

(817) 284-3834
(817) 355-9464
(817) 846-9077
868-7653
(817) 868-7653

Following these leads, I found an amateur radio license issued to David M Lee. This makes me think I'm on to the right David Lee, as amateur radio sounds like just the kind of thing David would be into.

Call Sign: KD5YGM, Licensee ID: L00633781
Grant Date: 06/26/2003, Expiration Date: 06/26/2013, Certifier: David M Lee
Registrant: David M Lee, 8728 Saranac Trail, Fort Worth, TX 76118

Read more: http://www.city-data.com/aradio/lic-Fort-Worth-Texas2.html#ixzz0xeMRm87v

I found a second license issued to someone with the same name from 1996, but not sure that the two are related.

Call Sign: KF4LAB
Grant Date: 07/25/1996, Expiration Date: 07/25/2006, Cancellation Date: 07/26/2008
Registrant: David M Lee, 3222 Lee Rd 56, Auburn, AL 36830

Read more: http://www.city-data.com/aradio/lic-Auburn-Alabama.html#ixzz0xeN14UBW

Unfortunately the trail went cold from there. I heard a rumor a few years back that David is dead and I am hoping this is untrue.

Anderson Santos - Finally cx_Oracle, Debian and Python 2.5

Tue, 24 Aug 2010 14:19:04 +0000

Dynamic upload paths in Django

Wed, 11 Aug 2010 15:06:40 +0000

Ubuntu 10.04 with full cluster stack support � Florian’s blog

Wed, 04 Aug 2010 14:08:42 +0000

Linux-Helps: How to install and configure Linux-HA high avaliability heartbeat - 3.0 cluster on redhat rhel5

Wed, 04 Aug 2010 13:36:01 +0000

OpenGL Intellivision Man

2010-07-30T12:33:42.350-07:00

Not long ago I set out to turn an animated gif I found of the Intellivision Running Man into an OpenGL generated video clip. My goal was to shrink the images into tiny bitmaps, a.k.a. 8-bit, and then use the resulting bitmap data as positioning information within a 3D space. Another way of saying it: I wanted to render each pixel from the original images as a 3D block. Jump to the video to get a better idea about what I mean:

http://www.youtube.com/watch?v=E1rXt0l2pxY

Along the way I took a few turns. I never did reduce the image data to its smallest possible representation. I did reduce the image size for each image to 24x24 pixels and I converted the image data to grayscale. Using the handy PIL library, I was able to pull in the bitmap file data as a tuple of pixel values. I used each "pixel" to offset the drawing position in pyglet's on_draw handler.

The code I used to render the animation is a hack of an example found here:

http://code.google.com/p/pyglet-hene/source/browse/trunk/

This is a fairly ugly hack, meaning I didn't work to make the code beautiful. It's just the original code, chopped, altered and enhanced as needed to accomplish what I wanted to see rendered on the screen.

Though not provided here, to run this code an image directory needs to be provided named "data" containing a series of bitmaps. My directory contains this:


ls -ltr
total 32
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 9.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 8.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 6.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 5.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 4.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 3.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 2.bmp
-rw-r--r-- 1 dvenable dvenable 1654 2010-07-20 14:06 1.bmp

If you are so inclined to try your own little experiment, find a favorite animated gif on the web, extract each frame, reduce size, convert to grayscale and drop your own images in a directory similar to the one I created here. Your animation result should be similar to what I've produced here.

And here's the complete source:


from pyglet.gl import *
import pyglet
from pyglet.window import *
from pyglet import image
import os
from PIL import Image
import glob
from math import sin, cos

window = pyglet.window.Window(width=640, height=480, resizable=True)

y=0.0
x=-10.0     
z=10.0    
xspeed = 0.5
yspeed = 0.0
lx=ly=0
lz=-2
angle=ratio=0.0

boxcol = [ [1.0, 0.0, 0.0], # bright: red
           [1.0, 0.5, 0.0],        # orange
           [1.0, 1.0, 0.0],        # yellow
           [0.0, 1.0, 0.0],        # green
           [0.0, 1.0, 1.0],        # blue
                        ]

# Dark: red, orange, yellow, green ,blue
topcol =[ [0.6, 0.0, 0.0],
          [0.6, 0.25, 0.0],
          [0.6, 0.6, 0.0],
          [0.0, 0.6 ,0.0],
          [0.0, 0.6, 0.6]]
                        


box = None # display list storage
top = None #display list storage

yloop = None # loop for y axis
xloop = None # loop for x axies

bmpdata = None 
nextimg = 0
files = None

def load_image_data():
    global bmpdata, bmpdatalen, files 

    files = glob.glob('data/*.bmp')
    files.sort()
    bmpdata = map(lambda x: Image.open(x).getdata(), files.__iter__())
    bmpdatalen = len(bmpdata)


def build_lists():
  global box, top
  box = glGenLists(2)

  glNewList(box, GL_COMPILE)    # new compiled box display list

  # draw the box without the top (it will be store in display list
  # and will not appear on the screen)
  glBegin(GL_QUADS)
  
  # front face
  glTexCoord2f(0.0, 0.0);       glVertex3f(-1.0, -1.0, 1.0)
  glTexCoord2f(1.0, 0.0);       glVertex3f(1.0, -1.0, 1.0)
  glTexCoord2f(1.0, 1.0);       glVertex3f(1.0, 1.0, 1.0)
  glTexCoord2f(0.0, 1.0);       glVertex3f(-1.0, 1.0, 1.0)
  # back face
  glTexCoord2f(1.0, 0.0);       glVertex3f(-1.0, -1.0, -1.0)
  glTexCoord2f(1.0, 1.0);       glVertex3f(-1.0, 1.0, -1.0)
  glTexCoord2f(0.0, 1.0);       glVertex3f(1.0, 1.0, -1.0)
  glTexCoord2f(0.0, 0.0);       glVertex3f(1.0, -1.0, -1.0)
  # right face
  glTexCoord2f(1.0, 0.0);       glVertex3f(1.0, -1.0, -1.0)
  glTexCoord2f(1.0, 1.0);       glVertex3f(1.0, 1.0, -1.0)
  glTexCoord2f(0.0, 1.0);       glVertex3f(1.0, 1.0, 1.0)
  glTexCoord2f(0.0, 0.0);       glVertex3f(1.0, -1.0, 1.0)
  # left face
  glTexCoord2f(0.0, 0.0);       glVertex3f(-1.0, -1.0, -1.0)
  glTexCoord2f(1.0, 0.0);       glVertex3f(-1.0, -1.0, 1.0)
  glTexCoord2f(1.0, 1.0);       glVertex3f(-1.0, 1.0, 1.0)
  glTexCoord2f(0.0, 1.0);       glVertex3f(-1.0, 1.0, -1.0)
  glEnd()

  glEndList()   # Done building the list

  top=box+1

  glNewList(top, GL_COMPILE)    # new compiled top display list
  # Top face
  glBegin(GL_QUADS)
  glTexCoord2f(0.0, 1.0); glVertex3f(-1.0, 1.0, -1.0)
  glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, 1.0, 1.0)
  glTexCoord2f(1.0, 0.0); glVertex3f(1.0, 1.0, 1.0)
  glTexCoord2f(1.0, 1.0); glVertex3f(1.0, 1.0, -1.0)
  
  glTexCoord2f(1.0, 1.0);       glVertex3f(-1.0, -1.0, -1.0)
  glTexCoord2f(0.0, 1.0);       glVertex3f(1.0, -1.0, -1.0)
  glTexCoord2f(0.0, 0.0);       glVertex3f(1.0, -1.0, 1.0)
  glTexCoord2f(1.0, 0.0);       glVertex3f(-1.0, -1.0, 1.0)
  glEnd()
  glEndList()


     
def load_gl_textures():
        # load bitmaps and convert to textures
        global texture, texture_file, texture_surf
        #texture_file = os.path.join('data', 'cube.bmp')
        texture_file = files[nextimg]
        texture_surf = image.load(texture_file)
        texture = texture_surf.get_texture()
        glBindTexture(GL_TEXTURE_2D, texture.id)

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)


        
def init():
    """
    Pyglet oftentimes calls this setup()    
    """
    glEnable(GL_TEXTURE_2D)

    load_image_data()
    load_gl_textures()
    build_lists()

    glShadeModel(GL_SMOOTH) # Enables smooth shading
    glClearColor(0.0, 0.0, 0.0, 0.0) #Black background
    
    glClearDepth(1.0)               # Depth buffer setup
    glEnable(GL_DEPTH_TEST)         # Enables depth testing
    glDepthFunc(GL_LEQUAL)          # The type of depth test to do

    glEnable(GL_LIGHT0) # quick and dirty lighting 
    
    #glEnable(GL_LIGHTING)  # enable lighting
    glEnable(GL_COLOR_MATERIAL)     # enable coloring

    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)       # Really nice perspective calculations
       
    
     
@window.event
def on_draw():
    global nextimg, bmpdata, x, y, z, lx, ly, lz

    # Here we do all the drawing
    glClear(GL_COLOR_BUFFER_BIT |GL_DEPTH_BUFFER_BIT)

    # Select the texture
    load_gl_textures()
    #glBindTexture(GL_TEXTURE_2D, texture.id)

    xloop = 1
    yloop = 1
    
    mandata = bmpdata[nextimg]
    for idx in range (0, len(mandata)):
        if (idx+1) % 24 == 0:
            yloop += 1
            xloop = 1
        else:
            xloop += 1
        if mandata[idx] < 100:

            glLoadIdentity()        # reset our view
            gluLookAt(x,y,z, x+lx , y+ly, z+lz, 0.0, 1.0, 0.0)

            glTranslatef( xloop*1.8 - 30 ,
                                      28 - yloop*2.4 ,
                                      -60.0)
            glColor3f(*boxcol[xloop % 4]) # select a box color
            glCallList(box) # draw the box

            glColor3f(*topcol[1])
            glCallList(top)  # draw the top


    return pyglet.event.EVENT_HANDLED
      
def moveMeFlat(direction):
    global x, z, y, lx, lz, ly 
    x = x - direction*(lx)*0.75;
    y = y + direction*(ly)*0.5;
    z = z + direction*(lz)*0.5;
 
def orientMe(ang):
    global lx, lz
    lx = sin(ang)
    lz = -cos(ang)
  

def update(dt):
    global z, angle
    angle +=0.005
    orientMe(angle)
    moveMeFlat(0.5)

def update2(dt):
    global nextimg
    if nextimg < bmpdatalen-1:
        nextimg += 1
    else:
        nextimg = 0 


pyglet.clock.schedule_interval(update2, .1)
pyglet.clock.schedule(update)
        
@window.event
def on_resize(width, height):
        if height==0:
            height = 1
        glViewport(0, 0, width, height)
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()

        # Calculate the aspect ratio of the window
        gluPerspective(45.0, 1.0*width/height, 0.1, 100.0)

        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()
        return pyglet.event.EVENT_HANDLED
        
init()  

pyglet.app.run()

Cross-compile ActiveMQ-cpp on Centos 5

2010-07-20T07:31:04.675-07:00

To date an RPM for activemq-cpp is not available for Centos 5. I found RPMs in Fedora 13 and 14 repositories, but due to dependencies on fresher libs, they won't install.

Building for 32 bit architecture on 64 bit Centos 5 was a bit tricky. Here's the recipe I came up with that worked for me:

Install dependencies:


yum install expat-devel zlib-devel uuid-c++-devel openssl-devel

Download sources from here or other mirrors:


wget http://www.carfab.com/apachesoftware/activemq/activemq-cpp/source/activemq-cpp-library-3.2.1-src.tar.gz
wget http://mirror.candidhosting.com/pub/apache/apr/apr-1.4.2.tar.gz

Extract archives and build APR first. Note PKG_CONFIG_PATH, as this is one of the keys to ensuring that lib64 libraries are not found during link step.


[root@myserver] cd apr-1.4.2
[root@myserver] ./configure --prefix=/usr --libdir=/usr/lib CXXFLAGS="-m32" LDFLAGS="-m32" CFLAGS="-m32" --build=i686-redhat-linux-gnu PKG_CONFIG_PATH=/usr/lib/pkgconfig 
[root@myserver] ./make
[root@myserver] ./make install

Next build and install ActiveMQ-cpp:


[root@myserver] cd ../activemq-cpp-library-3.2.1
[root@myserver] ./configure --prefix=/usr --libdir=/usr/lib CXXFLAGS="-m32" LDFLAGS="-m32" CFLAGS="-m32" --build=i686-redhat-linux-gnu PKG_CONFIG_PATH=/usr/lib/pkgconfig --with-apr=../apr-1.4.2/apr-1-config
[root@myserver] ./make
[root@myserver] ./make install

devinvenable: A bunch of year old tweats are showing up with recent dates in my RSS feed. Must figure out why...

Tue, 13 Jul 2010 13:48:02 +0000

devinvenable: A bunch of year old tweats are showing up with recent dates in my RSS feed. Must figure out why...

qemu-img

2010-07-13T07:18:18.228-07:00

qemu-img is a handy tool for converting one virtual machine image format into another.


qemu-img convert windowsxp.img -O vdi windowsxp.vdi

I had need for its use after running into errors creating a virtual machine with virt-manager. KVM managed by virt-manager has been my recent virtualization solution of choice, that is, until last Friday when I hit a snag creating a new virtual machine for WindowsXP. The installation process got stuck and I wasn't able to recover. Following advice from somewhere it the net-realm, I opted to create the image using this easy command line two-liner.


 dd if=/dev/zero of=vm8.img bs=2048k count=12000
 kvm -m 512 -cdrom winxp.iso -boot d v8.img

The installation was successful and running the image from the command line using kvm was a snap, but what I really wanted was to place this image under the control of virt-manager.

I couldn't find a nice option to import an existing image, so if it exists it is not very intuitive. Apparently to place it under virt-manager's control I would need to create an xml file under /etc/libvirt/qemu/ and in addition I would probably need to convert the image from raw format to qcow2. But after messing around with this for too long, a colleague recommended I use virtualbox.

I used virtualbox in the past, so I figured a different approach might be worthwhile and should get me beyond the headache in the short term. But what about the work I did creating the original image? Installing WindowsXP is a hassle, not to mention the effort I'd put into installing subsequent software on the image.

And that's where qemu-img came in. virtualbox only reads vmi formatted images, thus I converted my raw image to vmi.

Updated: FAIL

Importing the new vmi was easy enough, but once I created the new virtual machine and started it...I got this error from virtualbox-osi:

"Failed to start the virtual machine windowsxp. VirtualBox can't operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot."

Okay...but I will silently resent you.

Updated: Original image hung after removing KVM. At this point I'm going to throw up my hands and create a new image and fresh install. I'm at the point of diminishing returns...

5. Built-in Types — Python v2.7 documentation

Sat, 10 Jul 2010 00:23:47 +0000

devinvenable: Lots of great opengl via pyglet information at http://tartley.com/.

Fri, 09 Jul 2010 01:52:45 +0000

devinvenable: Lots of great opengl via pyglet information at http://tartley.com/.

tartley.com : A website dedicated to oneself has been described as the greatest act of hubris. Welcome aboard.

Fri, 09 Jul 2010 00:34:27 +0000

Tutorial

Wed, 07 Jul 2010 16:59:56 +0000

WorkingWithImages - wxPyWiki

Wed, 07 Jul 2010 16:57:20 +0000

[SOLVED] PIL convert 16bit grayscale to 8 bit - Ubuntu Forums

Wed, 07 Jul 2010 16:57:06 +0000

Going really 8-bit

2010-07-07T15:28:29.793-07:00

Back when I was a kid, my nerd friends and I would create graphics for our Commodore computers by filling filling in squares on graph paper and calculating the bitmaps. A single character on the Commodore 64 and Vic 20 was an 8x8 grid.

I recently found an 8-bit image fondly remembered from my youth, the Intellivision Running Man, in animated GIF format. I converted the GIF to a short video, which I embedded in a video project.

Some of my video conversion notes were covered in another post and some are on my wiki.

I want to extract the Intellivision Running Man bitmaps for use in an opengl project that I'm thinking about doing. Though it would probably be simpler for me to just sit down with pen and paper to graph and calculate the bitmaps, I'm hoping to find tools that will allow me to extract the data directly from raw video.

I first needed to reduce the screen resolution as much as possible by shrinking the video and dropping frames. Here I shrank the video output to 24x24 and reduced the frame rate to 4 frames per second.

ffmpeg -i intel.avi -r 4 -s 24x24 intel8bit.avi

Next I extracted individual bitmap images:

ffmpeg -i intel8bit.avi -f image2 foo_%5d.bmp

I initially took one image into Gimp and used Desaturate to convert it to grayscale, and then I used Levels to reduce image to pure Black or White. But I didn't want to repeat this again and again. So I wrote a small Python script which achieved the same goal and along the way got to play with the PIL library, which I've not used before.


from PIL import Image
import sys, os

def bw(pt):
    if pt>126:
        return 255
    else:
        return 0

for infile in sys.argv[1:]:
    f, e = os.path.splitext(infile)
    outfile = f + "_mod" + e

    im = Image.open(infile)

    im = im.convert('L')
    out = im.point(bw)

    out.save(outfile)
    print outfile

This little script loads a bitmap then uses convert() with the 'L' option to make it grayscale. (I couldn't find a comprehensive list of options for convert---the documentation could use some work.)

Finally, I used the point method that passes each pixel in the bitmap data to a custom function. Your function can do anything, but mine just looks at the value, makes higher level grays absolute black and lower level grays absolute white. point() returns a copy of the bitmap file (headers updated and intact) with the transformed result, which is then saved.

At this point I have true black and white bitmaps.

I wanted to quickly visualize my bitmap, to get a feel for how much more I want to reduce the size of my bitmaps. This little script renders my images to screen as a series of X's.


from PIL import Image
import sys, os


for infile in sys.argv[1:]:

    im = Image.open(infile)
    data = im.getdata()
    for idx in range (0, len(data)):
        i = data[idx]
        if i == 255:
            print 'X',
        else:
            print ' ',

        if (idx+1) % 24 == 0:
            print ''

The output looks like this:


devin@studio:~/src/py$ python showdata.py /home/devin/Video/bitmaps/foo_00041_mod.bmp 

X X X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X       X X X X X X X X X 
X X X X X X X X X X X X     X X X X X X X X X X 
X X X X X X X X                   X X X X X X X 
X X X X X                   X X X X X X X X X X 
X X X X X                   X X X X X X X X X X 
X X X X X                   X X X X X X X X X X 
X X X X X                     X X X X X X X X X 
X X X X X X                       X X X X X X X 
X X X X X X X X         X X X X X X X X X X X X 
X X X X X X X X             X X X X X X X X X X 
X X X X X                         X X X X X X X 
X X X X X     X X X X X X X X     X X X X X X X 
X X X X X     X X X X X X X X     X X X X X X X 
X X X X X     X X X             X X X X X X X X 
X X X X X     X X X     X X X X X X X X X X X X 
X X X X X     X X X X X X X X X X X X X X X X X 
X X X X X     X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X

Google Answers: Converting C++ DES code snippet to Java

Thu, 01 Jul 2010 14:24:14 +0000

RSA Laboratories - 2.1.7 What are Message Authentication Codes?

Wed, 30 Jun 2010 21:05:15 +0000

Animated gif to video

2010-06-25T07:08:56.212-07:00

This little recipe worked for the basic job of converting the giv to an avi.


mplayer animated.gif -vo yuv4mpeg
ffmpeg -i stream.yuv -an -r 24 -b 640 -s vga -aspect 4:3 test.avi

However I wanted to loop the gif, but ffmpeg's -loop_input and -loop_ouput had no affect. Decided to make a copy and cat a few times...but this didn't work as expected. (Save yourself time and don't copy this section!)


mencoder -oac copy -ovc copy -forceidx test.avi test2.avi -o test.avi
mencoder -oac copy -ovc copy -forceidx test.avi test2.avi -o test.avi
mencoder -oac copy -ovc copy -forceidx test.avi test2.avi -o test.avi

Tried this with no luck:


 mplayer -loop 10 test.avi -vo yuv4mpeg

Finally found a good way:


avimerge -i test.avi test2.avi test3.avi - o mergedfile.avi

Sweet!

Logitech webcam issues with Ubuntu 10.04 LTS

2010-06-24T18:49:21.591-07:00

Update:

Fixed (well, a workaround): Setting environment variable LD_PRELOAD prior to running video problem solves issues on my box.

$ LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so cheese

---Original Text follows---

cheese and other video programs have been working rather poorly on my AMD64 bit Ubuntu Studio install.

Errors like the following show up:


libv4lconvert: Error decompressing JPEG: unknown huffman code: 0000ffd9
libv4lconvert: Error decompressing JPEG: unknown huffman code: 0000ffff
libv4lconvert: Error decompressing JPEG: unknown huffman code: 0000ffec
libv4lconvert: Error decompressing JPEG: unknown huffman code: 0000ffff
libv4lconvert: Error decompressing JPEG: unknown huffman code: 0000ffd9
libv4lconvert: Error decompressing JPEG: unknown huffman code: 0000fffd

Rebuilding the latest drivers from linuxtv.org didn't help. I'm still looking for a solution.

Note: Same camera produces same error on a second computer running same version of Ubuntu.

lsusb

Bus 005 Device 004: ID 046d:089d Logitech, Inc. QuickCam E2500 series

gstreamer-properties is a great test tool for this kind of thing.

I'm going to log a bug on this one.

New RSS feed

2010-06-20T20:22:26.472-07:00

If you are feeding this blog into Google Reader, update your settings and pull from here instead:

http://www.devinvenable.com/rss/feed.xml

I pull my activity from several sources (including blogger.com) to display a nicely formatted aggregate of my online activity on my home page. But it hasn't been possible to subscribe to the aggregate until now. I use Universal Feed Parser to combine my various feeds and had hoped that there would be a nice method to easily turn the parsed values back into serialized ATOM. Poking around, I didn't find any such method, so I used PyRSS2Gen to pack the parsed dictionary back into RSS. It probably would have been just as easy to load an XML library and just write out XML, but I didn't want to have to read specifications or, really, do much work on this. Still took me at least an hour of my life, but that's not so bad. If it wasn't kind of fun I wouldn't be monkeying with it on my day off!

Algebra Review in Ten Lessons

Wed, 16 Jun 2010 15:01:53 +0000

devinvenable: SOMEDAY I will remember that when code changes fail to work when deployed that I should blame SELinux FIRST instead of hours later.

Sat, 12 Jun 2010 15:14:21 +0000

devinvenable: SOMEDAY I will remember that when code changes fail to work when deployed that I should blame SELinux FIRST instead of hours later.

devinvenable: Corporate gmail switch not as easy as I hoped. Internal DNS and many other factors complicate the situation.

Thu, 10 Jun 2010 03:19:41 +0000

devinvenable: Corporate gmail switch not as easy as I hoped. Internal DNS and many other factors complicate the situation.

devinvenable: Just switched the company over to corporate gmail. So far...nothing has blown up.

Mon, 07 Jun 2010 19:15:53 +0000

devinvenable: Just switched the company over to corporate gmail. So far...nothing has blown up.

Allow Sendmail on Centos to accept connections on port 25

2010-06-04T13:46:18.962-07:00

Need to use sendmail as an MTA? It's running but your box is not accepting incoming connections on port 25?

Perhaps you need to do this:

The default sendmail.cf file does not allow Sendmail to accept network connections from any host other than the local computer. To configure Sendmail as a server for other clients, edit the /etc/mail/sendmail.mc file, and either change the address specified in the Addr= option of the DAEMON_OPTIONS directive from 127.0.0.1 to the IP address of an active network device or comment out the DAEMON_OPTIONS directive all together by placing dnl at the beginning of the line. When finished, regenerate /etc/mail/sendmail.cf by executing the following command:


    m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

Then restart the service.

Introduction to Using Visualizations - Google Chart Tools / Interactive Charts (aka Visualization API) - Google Code

Thu, 03 Jun 2010 01:51:29 +0000

A little something I need to remember...

2010-06-02T11:15:05.287-07:00

To turn off expandtab for editing makefiles, put the following in your vimrc:


autocmd FileType make setlocal noexpandtab

Shrink PDF linux (command line)

2010-05-31T03:48:24.216-07:00

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -sPAPERSIZE=a4 -dBATCH -sOutputFile=output.pdf input.pdf

Check Browser Compatibility, Cross Platform Browser Test - Browsershots

Fri, 28 May 2010 19:54:45 +0000

19 ffmpeg commands for all needs

Wed, 26 May 2010 14:14:02 +0000

Electric Duncan: A Sinfonia on Messaging with txAMQP, Part III

Sat, 22 May 2010 05:50:03 +0000

Just for fun

2010-05-20T14:04:42.359-07:00


 .file "tiny.cpp"
 .local _ZStL8__ioinit
 .comm _ZStL8__ioinit,1,1
 .section .rodata
.LC0:
 .string "Hello World"
 .text
.globl main
 .type main, @function
main:
.LFB957:
 .cfi_startproc
 .cfi_personality 0x0,__gxx_personality_v0
 pushl %ebp
 .cfi_def_cfa_offset 8
 movl %esp, %ebp
 .cfi_offset 5, -8
 .cfi_def_cfa_register 5
 andl $-16, %esp
 subl $16, %esp
 movl $.LC0, 4(%esp)
 movl $_ZSt4cout, (%esp)
 call _ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc
 movl $_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_, 4(%esp)
 movl %eax, (%esp)
 call _ZNSolsEPFRSoS_E
 movl $0, %eax
 leave
 ret
 .cfi_endproc
.LFE957:
 .size main, .-main
 .type _Z41__static_initialization_and_destruction_0ii, @function
_Z41__static_initialization_and_destruction_0ii:
.LFB966:
 .cfi_startproc
 .cfi_personality 0x0,__gxx_personality_v0
 pushl %ebp
 .cfi_def_cfa_offset 8
 movl %esp, %ebp
 .cfi_offset 5, -8
 .cfi_def_cfa_register 5
 subl $24, %esp
 cmpl $1, 8(%ebp)
 jne .L5
 cmpl $65535, 12(%ebp)
 jne .L5
 movl $_ZStL8__ioinit, (%esp)
 call _ZNSt8ios_base4InitC1Ev
 movl $_ZNSt8ios_base4InitD1Ev, %eax
 movl $__dso_handle, 8(%esp)
 movl $_ZStL8__ioinit, 4(%esp)
 movl %eax, (%esp)
 call __cxa_atexit
.L5:
 leave
 ret
 .cfi_endproc
.LFE966:
 .size _Z41__static_initialization_and_destruction_0ii, .-_Z41__static_initialization_and_destruction_0ii
 .type _GLOBAL__I_main, @function
_GLOBAL__I_main:
.LFB967:
 .cfi_startproc
 .cfi_personality 0x0,__gxx_personality_v0
 pushl %ebp
 .cfi_def_cfa_offset 8
 movl %esp, %ebp
 .cfi_offset 5, -8
 .cfi_def_cfa_register 5
 subl $24, %esp
 movl $65535, 4(%esp)
 movl $1, (%esp)
 call _Z41__static_initialization_and_destruction_0ii
 leave
 ret
 .cfi_endproc
.LFE967:
 .size _GLOBAL__I_main, .-_GLOBAL__I_main
 .section .ctors,"aw",@progbits
 .align 4
 .long _GLOBAL__I_main
 .weakref _ZL20__gthrw_pthread_oncePiPFvvE,pthread_once
 .weakref _ZL27__gthrw_pthread_getspecificj,pthread_getspecific
 .weakref _ZL27__gthrw_pthread_setspecificjPKv,pthread_setspecific
 .weakref _ZL22__gthrw_pthread_createPmPK14pthread_attr_tPFPvS3_ES3_,pthread_create
 .weakref _ZL20__gthrw_pthread_joinmPPv,pthread_join
 .weakref _ZL21__gthrw_pthread_equalmm,pthread_equal
 .weakref _ZL20__gthrw_pthread_selfv,pthread_self
 .weakref _ZL22__gthrw_pthread_detachm,pthread_detach
 .weakref _ZL22__gthrw_pthread_cancelm,pthread_cancel
 .weakref _ZL19__gthrw_sched_yieldv,sched_yield
 .weakref _ZL26__gthrw_pthread_mutex_lockP15pthread_mutex_t,pthread_mutex_lock
 .weakref _ZL29__gthrw_pthread_mutex_trylockP15pthread_mutex_t,pthread_mutex_trylock
 .weakref _ZL31__gthrw_pthread_mutex_timedlockP15pthread_mutex_tPK8timespec,pthread_mutex_timedlock
 .weakref _ZL28__gthrw_pthread_mutex_unlockP15pthread_mutex_t,pthread_mutex_unlock
 .weakref _ZL26__gthrw_pthread_mutex_initP15pthread_mutex_tPK19pthread_mutexattr_t,pthread_mutex_init
 .weakref _ZL29__gthrw_pthread_mutex_destroyP15pthread_mutex_t,pthread_mutex_destroy
 .weakref _ZL30__gthrw_pthread_cond_broadcastP14pthread_cond_t,pthread_cond_broadcast
 .weakref _ZL27__gthrw_pthread_cond_signalP14pthread_cond_t,pthread_cond_signal
 .weakref _ZL25__gthrw_pthread_cond_waitP14pthread_cond_tP15pthread_mutex_t,pthread_cond_wait
 .weakref _ZL30__gthrw_pthread_cond_timedwaitP14pthread_cond_tP15pthread_mutex_tPK8timespec,pthread_cond_timedwait
 .weakref _ZL28__gthrw_pthread_cond_destroyP14pthread_cond_t,pthread_cond_destroy
 .weakref _ZL26__gthrw_pthread_key_createPjPFvPvE,pthread_key_create
 .weakref _ZL26__gthrw_pthread_key_deletej,pthread_key_delete
 .weakref _ZL30__gthrw_pthread_mutexattr_initP19pthread_mutexattr_t,pthread_mutexattr_init
 .weakref _ZL33__gthrw_pthread_mutexattr_settypeP19pthread_mutexattr_ti,pthread_mutexattr_settype
 .weakref _ZL33__gthrw_pthread_mutexattr_destroyP19pthread_mutexattr_t,pthread_mutexattr_destroy
 .ident "GCC: (Ubuntu 4.4.3-4ubuntu5) 4.4.3"
 .section .note.GNU-stack,"",@progbits

Mesa Home Page

Wed, 19 May 2010 01:16:47 +0000

7 Lessons Learned While Building Reddit to 270 Million Page Views A Month via reddit.com

Tue, 18 May 2010 02:11:32 +0000

Improving Anti-spam system - Zimbra :: Wiki

Wed, 12 May 2010 22:58:18 +0000

• View topic - Exclusion by email address

Wed, 12 May 2010 22:52:28 +0000

Railing against JAVA Application Servers

2010-05-05T08:52:14.927-07:00

I'm not sure I'm being fair nor objective, but each time I get saddled with a project which involves a JAVA Application Server, I just feel unhappy.

Why? Because I don't like the so-called Inversion of Control pattern---at least all of my experiences with it have been unpleasant. One blogger at theburningmonk.com writes, "You have Macaroni code when your application is chopped up into many little pieces and it's difficult to see the big picture which may exist only in your (or some one else's!) head."

Another blogger says, "In software design, you can often end up with Macaroni code when you overuse/misuse/abuse abstractions, and it's one of the main dangers of using Inversion of Control."

This is my principal complaint as well. It's all well and good to have code reuse, and encapsulation is a worthy goal. Frankly the DRY principal is probably more important than either. Many ills of poor software design can be cured simply by keeping the code compact, elegant and devoid of redundancy regardless of whether or not the code is procedural, object-oriented, or tiny atomic classes bound together by an XML configuration file.

Procedural code gets a bad rap. There is something beautiful about examining code that has a well defined entry and exit point. It's beautiful when the debugger can be used to examine a code path from end to end. It's beautiful because you can see the whole picture. No diagrams needed to comprehend...no scrolling through hundreds of lines of XML to find the relationships. It's all right there in the code, where IMHFO it belongs.

devinvenable: Macaroni code: 1) When you overuse/misuse/abuse abstractions, 2) One of the main dangers of using Inversion of Control.

Tue, 04 May 2010 20:22:09 +0000

devinvenable: Macaroni code: 1) When you overuse/misuse/abuse abstractions, 2) One of the main dangers of using Inversion of Control.

devinvenable: Ha! Logged into facebook and got this: The File /var/www/lib/third-party/mobile-wurfl/wurfl-php-1.r2/WURFL/memcache does not exist!!!

Sat, 01 May 2010 01:33:39 +0000

devinvenable: Ha! Logged into facebook and got this: The File /var/www/lib/third-party/mobile-wurfl/wurfl-php-1.r2/WURFL/memcache does not exist!!!

Modes matter for password-less login

2010-04-28T11:04:30.940-07:00

I typically setup keys to allow myself password-less access to remote development servers that I use all the time. Today the typical ssh-keygen/deploy public-key routine didn't work as expected. After deploying my public-key to the remote's authorized_keys, I still was getting prompted for a login.

Found this in /var/log/secure.


Apr 28 12:51:35 theserver sshd[16285]: Authentication refused: bad ownership or modes for directory /home/theuser

It turns out the the failure was due to the user's group permissions on the remote machine for two important folders. Both the home folder and the .ssh folder had the following permissions:


drwxrwx--- 36 theuser thegroup 4096 Apr 28 11:56 ..

chmod 700 for both /home/theuser and /home/theuser/.ssh fixed the problem.

Tulsa Developers tied to vendor technology

2010-04-26T18:37:49.114-07:00

From time to time I take a look around to see what kind of programming talent is available in the Tulsa area. Most of what I find is tied to Oracle/Sun (Java) or Microsoft.

It's no secret that Tulsa has been heavy into Microsoft technology for years now. The community colleges and trade schools teach it, the recruiters can get their heads around it, and many conservative businesses would rather go with a name they know.

I remember a Williams employee steering me away from my Borland c++ compiler many moons ago, assuring me that Visual c++ was the future.

Well it was and it wasn't. I embraced Visual c++ and talked my first (serious) employer into letting me use it to write an application for a Phillips petroleum project. That work experience propelled me to my next development job, one I kept for almost a decade.

I wrote a heck of a lot of code using Visual c++ and the MFC framework, until it became my job to port the code to Unix flavors. For days, weeks, months I chased the not-quite-regular constants, the libraries that were similar but rarely identical to the standards. It was then that I started going cold on Microsoft.

I moved away from Microsoft development tools for a lot of reasons including a strong preference for open-source. There's so much free and truly open support on the web. When combined with Linux, open-source makes it possible to examine every nook and cranny of source code down to the kernel level.

Why would new developers gravitate to vendor tools when

they can't examine what is going on under the covers,

they can't control how long the technology will be supported before the vendor deprecates (or abandons) it in favor of new vendor tools,

they can't really have any substantial influence over the evolution of the technology?

I was thinking about these questions as I reviewed search results for "tulsa developers". It turns up these sites and not much more.

www.tulsadnug.org

tulsajava.com

Tulsa seems to have a flourishing Microsoft and Java community. Who is representing everything else that's happening in computer science?

According to Tiobe.com, the most popular programming language is JAVA. Microsoft-based technology doesn't rank until the fifth position, and then it falls off except for position eight. In Tulsa, I'm sure Visual Basic and C# would contend for two of the first three slots.

1. Java - 19.1%
2. C - 15.2%
3. C++ - 10.1%
4. PHP - 8.7%
5. Visual Basic - 8.4%
6. Perl - 6.2%
7. Python - 3.8%
8. C# - 3.7%
9. JavaScript - 3.1%
10. Ruby - 2.6%
11. Delphi - 2.1%

We all know that Tulsa, Oklahoma is a conservative city and not well known for risk taking. And perhaps there is more to the story that a simple web query immediately reveals. Ping.fm is Tulsa-based. Python-friendly Vidoop was founded here, though they relocated and then folded. Perhaps they should have stuck around.

Switch Primary Monitor in Ubuntu 10.4

2010-04-21T16:14:39.490-07:00

The default Monitor Preferences dialog, while sweet, does not allow you to make your secondary monitor your primary. This is a problem if you want the top and bottom Ubuntu Panels displayed on the secondary monitor. Thankfully I found this sweet little script.


#!/bin/sh
#
# Change Primary Monitor for Gnome
# ver 1.0
# 
# Copyright (c) 2010 michal@post.pl
# 
# This file is free software. You can redistribute it 
# and/or modify it under the terms of the GNU
# General Public License (GPL) as published by
# the Free Software Foundation, in version 3.
# It works for me. I hope it works for you as well.
# NO WARRANTY of any kind. 
#


# get list of top-level gnome panels
getTopPanels() {
 gconftool-2 --all-dirs /apps/panel/toplevels
}

# get monitor number for this panel
getMonitor() {
 local PANEL=$1
 gconftool-2 --get $PANEL/monitor
}

# set monitor to display on for given top-level panel
setMonitor() {
 local PANEL=$1
 local NEW=$2
 gconftool-2 --set --type int $PANEL/monitor $NEW
}

# return number of connected monitors
getConnectedMonitors() {
 xrandr --query | grep -c '^.* connected'
}

# compute next monitor
nextMonitor() {
 # number of monitors
 local CURRENT=$1
 local MONITORS=$2
 awk 'BEGIN{ print ('$CURRENT' + 1) % '$MONITORS'; }'
}

# logging finction
log() {
 echo $@ 1>&2
}

# main logic below #############

MONITORS=`getConnectedMonitors`
log "Detected $MONITORS connected monitors"

getTopPanels | while read PANEL
do
 MONITOR=`getMonitor $PANEL`
 NEW=`nextMonitor $MONITOR $MONITORS`
 log "Panel $PANEL is displayed on $MONITOR. Switching to monitor $NEW."
 setMonitor $PANEL $NEW
done

mod_security setup on Centos 5.4

2010-04-15T07:41:45.928-07:00

Enable the EPEL repository.


 rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm

Install via yum.


 yum install mod_security

This will load your basic mod_security configuration including the core rules.

Next I had to set SecDataDir in the config. This was not initially set and errors in the following form appeared in the log file.


ModSecurity: Unable to retrieve collection (name "", key ""). Use SecDataDir to define data directory first.

Fixed this up by creating SecDataDir and creating a directory for this purpose, making sure to give apache permission to use it.


vim /etc/httpd/modsecurity.d/modsecurity_crs_10_config.conf 
( Added SecDataDir /usr/local/apache/modsec_data )
mkdir /usr/local/apache
mkdir /usr/local/apache/modsec_data
chown apache:apache /usr/local/apache/modsec_data
chown apache:apache /usr/local/apache

After a restart modsecurity successfully began applying rules, but rather than blocking problem requests (my intention) it merely logged warnings. I changed the SecDefaultAction in vim /etc/httpd/modsecurity.d/modsecurity_crs_10_config.conf from


SecDefaultAction "phase:2,pass"


SecDefaultAction "phase:2,deny,log,status:403"

vim /etc/httpd/modsecurity.d/modsecurity_crs_10_config.conf

devinvenable: mod_security2.so easier to build from src for Centos 5.4 than monkey with 3rd-party RPM.

Wed, 14 Apr 2010 19:39:10 +0000

devinvenable: mod_security2.so easier to build from src for Centos 5.4 than monkey with 3rd-party RPM.

devinvenable: I wish I was as organized in the real world as I am in the virtual world.

Wed, 14 Apr 2010 17:55:23 +0000

devinvenable: I wish I was as organized in the real world as I am in the virtual world.

Gmail Tip: How To Browse Only the Unread Messages

Wed, 07 Apr 2010 13:20:23 +0000

Trouble using sockets in Django view

2010-03-30T12:15:10.721-07:00

I ran into an issue while writing socket communication in code that was called by a Django view handler. After a Twisted-based and socket-based solution failed mysteriously, I discovered a telnet-based solution that worked.

Read more about it the details here:

http://wiki.devinvenable.com/mediawiki/index.php/Interesting_socket_behavior_exhibited_while_processing_Django_view

Comments or insights as to the cause of the problem behavior would be helpful.

Everything You Always Wanted to Know about Twisted

Mon, 29 Mar 2010 19:48:01 +0000

Amazon S3 Firefox Organizer(S3Fox) :: Add-ons for Firefox

Fri, 26 Mar 2010 18:59:26 +0000

git merge

2010-03-25T13:17:12.959-07:00

I used to work with a guy named Jay who, when encountering a particularly complex or difficult programming challenge, would state aloud, "Now that's powerful."

git is a powerful tool. And it really is but, my God, it sure has a way with obscure error messages.

At some point you'll not be able to pull changes from the master (I want to call it the HEAD via cvs, svn concepts) because you are in the middle of a conflicted merge. You'll know this because you'll see this message:


You are in the middle of a conflicted merge.

Unlike svn update, which will pull the latest changes and automatically merge what can be merged and insert diffs where it can't, you need to manually merge the changes. You can open the diff tool with this command:


git mergetool

mergetool doesn't actually work out the diffs---you do. It opens a default diff editor for each file in need of merging, which may be vimdiff if nothing else is installed on your system. You compare the differences, edit to make any changes, and save the file. mergetool then asks you if the diff is complete, and if so, opens the next file. This continues until you have resolved all conflicts.

By the way, mergetool works with a number of different diff tools. See the man page for a complete list. I went with meld, the gnome diff editor. Once installed via apt-get, mergetool opened meld without any additional configuration. Not quite sure how it knew which one I wanted, but it guessed and got it right.

So now you can pull the latest changes, right? Not so fast. You might see an error like this:


fatal: You have not concluded your merge. (MERGE_HEAD exists)

Ah, what does it all mean? I find this to be common thought when using git. Clemens Buchacher had the answer:


The following is an easy mistake to make for users coming from version 
control systems with an "update and commit"-style workflow. 

        1. git merge 
        2. resolve conflicts 
        3. git pull, instead of commit

Yes, that would be me: a fellow used to the "update and commit" style workflow.

For my case, I just had to commit once and then I could, finally, pull changes I had committed on another server.

JSON API

2010-03-16T15:51:21Z

devinvenable posted a photo:

XML API

2010-03-16T15:51:20Z

devinvenable posted a photo:

Mashup Editor

2010-03-16T15:51:20Z

devinvenable posted a photo:

Object with links to Related Records

2010-03-16T15:51:19Z

devinvenable posted a photo:

Search Result Page

2010-03-16T15:51:19Z

devinvenable posted a photo:

devinvenable: JAVA week! Today I'm writing a Postilion simulator using jPos.

Mon, 15 Mar 2010 14:36:07 +0000

devinvenable: JAVA week! Today I'm writing a Postilion simulator using jPos.

Sitting Under Canvas (8-bit)

2010-03-12T21:28:26Z

devinvenable posted a photo:

Something for a WIKI I'm setting up.

Create your own udev rules to control removable devices - Ubuntu Forums

Mon, 08 Mar 2010 20:23:05 +0000

Mono Community - mod_mono permissions error.

Mon, 08 Mar 2010 20:22:59 +0000

Automounting removable eSata drive on Centos 5.4

2010-03-08T14:03:40.304-08:00

So my boss says, "I don't get it. When I have a gnome desktop open on the Centos box, my new eSata II removable mounts. But if I don't have a desktop open it doesn't get mounted when I reboot the box."

I ask The Google about it, and it tells me:

http://wiki.centos.org/TipsAndTricks/HAL

But try as I might, gnome-volume-manager fails to detect and mount the eSata drive. The idea of running gnome daemons when in fact I'm working with a server in which gnome is rarely utilized (except for when my boss runs a remote desktop) gives me pause. Hmmm, I think, wouldn't this be a good job for udev rules?

Running dmesg tells me that the device is present and that it's getting mounted as /dev/sdb1. (Or you can tail /var/log/messages) Running the following gives me a list of attributes that are visible to udev on my device.


# udevinfo -a -p $(udevinfo -q path -n /dev/sdb)

With this is see several attributes which can be used for matching when the udev rules are applied. I take the following two:


    SYSFS{rev}=="ST6O"
    SYSFS{model}=="Hitachi HDT72101"

I want to mount the block device as /media/removable each time the device is plugged. I also want to unmount when the device is removed. The following worked for me.


ACTION=="add",SYSFS{rev}=="ST6O",SYSFS{model}=="Hitachi HDT72101",KERNEL=="sd?1",NAME="REMOVABLE", RUN+="/bin/mount /dev/REMOVABLE /media/removable"
ACTION=="remove",SYSFS{rev}=="ST6O",SYSFS{model}=="Hitachi HDT72101",RUN+="/bin/umount /media/removable"

For more information, refer to this helpful page.

http://reactivated.net/writing_udev_rules.html

devinvenable: Heavy into refactoring c++ code today. Reminds me of the golden olden days at Visionael.

Thu, 04 Mar 2010 20:32:57 +0000

devinvenable: Heavy into refactoring c++ code today. Reminds me of the golden olden days at Visionael.

devinvenable: I couldn't make it to #pycon this year. Where can I find video?

Tue, 23 Feb 2010 19:25:13 +0000

devinvenable: I couldn't make it to #pycon this year. Where can I find video?

strptime

2010-02-22T07:22:18.759-08:00

Can't find strptime in datetime because you're working in a Python 2.4 environment?


Python 2.4.3 (#1, Jul 27 2009, 17:56:30) 
[GCC 4.1.2 20080704 (Red Hat 4.1.2-44)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> d = datetime.strptime("21-JAN-08", "%d-%b-%y")
Traceback (most recent call last):
  File "", line 1, in ?
AttributeError: type object 'datetime.datetime' has no attribute 'strptime'

strptime was added to datetime in 2.5. Prior to 2.5 you pull it from the typically lower-level library 'time'.


>>> import time
>>> time.strptime("21-JAN-08", "%d-%b-%y")
(2008, 1, 21, 0, 0, 0, 0, 21, -1)

Ah, there it is. Of course, you wanted a datetime, didn't you?


>>> t = time.strptime("21-JAN-08", "%d-%b-%y")
>>> datetime(*t[0:6])
>>> datetime.datetime(2008, 1, 21, 0, 0)

devinvenable: Or DON'T use toSource(). Forget it; that's a mozilla only extension. Better off using JSON.stringify(), available in most modern browsers.

Thu, 18 Feb 2010 17:57:42 +0000

devinvenable: Or DON'T use toSource(). Forget it; that's a mozilla only extension. Better off using JSON.stringify(), available in most modern browsers.

devinvenable: Need to convert a javascript object to string? Don't download a special library or function; just use the javascript 1.3 toSource() method.

Wed, 17 Feb 2010 16:50:12 +0000

devinvenable: Need to convert a javascript object to string? Don't download a special library or function; just use the javascript 1.3 toSource() method.

I love my retro layout.

2010-02-11T19:24:07Z

devinvenable posted a photo:

mod_mono, Centos 5 64 bit, and SELinux Part 2

2010-02-09T10:52:25.942-08:00

The trick to creating a SELinux policy is setting the mode to be permissive, which prevents nothing but logs all of the infractions to audit.log, and then using the log to generate the policy. After running my mod_mono based application for a bit in permissive mode, I used this command to generate a local policy.


egrep 'http|mono' /var/log/audit/audit.log | audit2allow -M myhttp

Here is the result:


module myhttp 1.0;

require {
 type httpd_tmp_t;
 type device_t;
 type initrc_t;
 type httpd_t;
 type httpd_sys_script_t;
 type http_port_t;
 type port_t;
 type inotifyfs_t;
 class process { execstack execmem getsched ptrace };
 class unix_stream_socket connectto;
 class chr_file { read write ioctl };
 class tcp_socket name_connect;
 class file execute;
 class sem { unix_read write unix_write associate read destroy };
 class shm { unix_read read write unix_write associate };
 class dir read;
}

#============= httpd_sys_script_t ==============
allow httpd_sys_script_t http_port_t:tcp_socket name_connect;
allow httpd_sys_script_t httpd_tmp_t:file execute;
allow httpd_sys_script_t inotifyfs_t:dir read;
allow httpd_sys_script_t self:process { execmem getsched ptrace };
allow httpd_sys_script_t self:sem { unix_read write unix_write associate read destroy };

#============= httpd_t ==============
allow httpd_t device_t:chr_file { read write ioctl };
allow httpd_t httpd_sys_script_t:unix_stream_socket connectto;
allow httpd_t initrc_t:shm { unix_read read write unix_write associate };
allow httpd_t port_t:tcp_socket name_connect;
allow httpd_t self:process { execstack execmem };

mod_mono, Centos 5 64 bit, and SELinux

2010-02-08T11:07:21.199-08:00

Getting mod_mono up and running on Ubuntu 9.10 is relatively simple. Install the packages, drop in a test asmx file, browse to the URL and you are done.

 
apt-get install libapache2-mod-mono mono-apache-server2

My experience getting the same demo file with Centos 5 running SELinux was a bit more involved. First off, here's the complete simple web service. You should be able to drop it into your document root and browse to the appropriate URL, once mod_mono is properly installed.


<%@ WebService Language="c#" Codebehind="TestService.asmx.cs" Class="WebServiceTests.TestService" %>

using System;
using System.Web.Services;
using System.Web.Services.Protocols;

namespace WebServiceTests
{
    public class TestService : System.Web.Services.WebService
    {
        [WebMethod]
        public string Echo (string a)
        {
            return a;
        }

        [WebMethod]
        public int Add (int a, int b)
        {
            return a + b;
        }
    }
}

On Centos 5, install these packages:


yum install mod_mono xsp mono-web

To enable mod_mono for Apache and run the xsp demo programs, add something like the following to the tail end of your http.conf file. Be sure to check that the paths used here are the same on your machine. (Note that I'm using a 64 bit Centos installation.)



AddType application/x-asp-net .aspx
AddType application/x-asp-net .asmx
AddType application/x-asp-net .ashx
AddType application/x-asp-net .asax
AddType application/x-asp-net .ascx
AddType application/x-asp-net .soap
AddType application/x-asp-net .rem
AddType application/x-asp-net .axd
AddType application/x-asp-net .cs
AddType application/x-asp-net .config
AddType application/x-asp-net .Config
AddType application/x-asp-net .dll
AddType application/x-asp-net .asp
DirectoryIndex index.aspx
DirectoryIndex Default.aspx
DirectoryIndex default.aspx


Alias /demo /usr/lib64/xsp/test
MonoApplications "/demo:/usr/lib64/xsp/test"
MonoServerPath /usr/bin/mod-mono-server

You are likely to run into myriad problems if using SELinux. Start with giving permissions to run mono to httpd.


chcon -t httpd_sys_content_t '/usr/bin/mono'

Each time you hit your URL you will likely encounter another SELinux error. You can repeat this process again and again until you come up with a final policy that will allow apache access to mono, its directories, and dependencies. My final policy looked like this.


module mymono 1.0;

require {
        type lib_t;
        type tmp_t;
        type mono_exec_t;
        type httpd_t;
        type httpd_sys_script_t;
        class process ptrace;
        class sock_file { write create };
        class sem create;
        class file { read execute_no_trans };
}

#============= httpd_sys_script_t ==============
allow httpd_sys_script_t self:sem create;

#============= httpd_t ==============
allow httpd_t lib_t:file execute_no_trans;
allow httpd_t mono_exec_t:file { read execute_no_trans };
allow httpd_t self:process ptrace;
allow httpd_t tmp_t:sock_file { write create };

Mono makes extensive use of a temp directory known as the wapi directory. It is possible for you to specify your own temp directory in your http.conf file or else the default will be used: /tmp/.wapi.

It took awhile to discover that /tmp/.wapi needed different permissions. The best clue I could get from messages was:


Feb  8 08:43:32 carbon setroubleshoot: SELinux is preventing the mono from using potentially mislabeled files (mod_mono_server_global). For complete SELinux messages. run sealert -l a00a5946-cec1-4291-a410-e74c5f96edfd

This was corrected by running...


restorecon -R -v /tmp/.wapi

...as suggested by sealert.

Just as I thought I was finished, as the mono test application was finally working, I found additional errors in the /var/log/audit/audit.log. This policy was the fix:


module mynotify 1.0;

require {
        type httpd_t;
        type inotifyfs_t;
        class dir read;
}

#============= httpd_t ==============
allow httpd_t inotifyfs_t:dir read;

Are we done yet? I sure hope so. I read elsewhere on the web that there is a plan to get the proper SELinux configuration into the mod_mono RPMs. Until that happens, I hope that this info will help you to get your mod_mono setup working.

Note: After rebooting, I had to relabel the temp and bin directory with these two commands:


restorecon -R -v /tmp/.wapi
chcon -t httpd_sys_content_t '/usr/bin/mono'

I'm currently looking for a better, permanent solution.

mod_mono - LinuxQuestions.org

Fri, 05 Feb 2010 14:44:44 +0000

mod_mono

Writing a WebService - Mono

Mon, 01 Feb 2010 21:30:04 +0000

ISO 9797 algorithm 3

2010-01-26T08:04:53.443-08:00

Last Friday I set out to implement ISO 9797 algorithm 3 using the OpenSSL library. I did not have the specification handy, so I decided to to the best I could with what I could find by way of examples on the net.

I came across a description of the algorithm in this 2005 thread (http://www.derkeiler.com/Newsgroups/sci.crypt/2005-02/0374.html). This was posted in a query by someone named Christian. He also posted his keys, data and the expected answer.


H0 = 0
stages 1 to n: Hj = Enc(K, Dj XOR H{j-1})
MAC = Enc(K, Dec(K', Hn))

Francois Grieu replied with, "This is very likely ISO/IEC 9797-1, using DES as the block cipher,
padding method 2, MAC algorithm 3." He provided an answer by sharing sample code in "some near-extinct dialect".


set m0 72C29C2371CC9BDB #message
set m1 65B779B8E8D37B29
set m2 ECC154AA56A8799F
set m3 AE2F498F76ED92F2

set pd 8000000000000000 #padding

set iv 0000000000000000 #initialisation vector

set k0 7962D9ECE03D1ACD #key
set k1 4C76089DCE131543

set xx {iv} # setup
for mj in {m0} {m1} {m2} {m3} {pd} # for each block including padding
 set xx `xor {xx} {mj}` # chain
 set xx `des -k {k0} -c {xx}` #encrypt
end
set xx `des -k {k1} -d {xx}` #decrypt
set xx `des -k {k0} -c {xx}` #encrypt
echo {xx} #show result

5F1448EEA8AD90A7

I've implemented the same in c for the purpose of research.


#include openssl/des.h
#include memory
#include string.h

//message + padding
const unsigned char msg[40] = { 0x72, 0xC2, 0x9C, 0x23, 0x71, 0xCC, 0x9B, 0xDB,
                              0x65, 0xB7, 0x79, 0xB8, 0xE8, 0xD3, 0x7B, 0x29,
                              0xEC, 0xC1, 0x54, 0xAA, 0x56, 0xA8, 0x79, 0x9F,
                              0xAE, 0x2F, 0x49, 0x8F, 0x76, 0xED, 0x92, 0xF2,
                              0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

//initialization vector
unsigned char iv[8] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

unsigned char k0[8] = { 0x79, 0x62, 0xD9, 0xEC, 0xE0, 0x3D, 0x1A, 0xCD };
unsigned char k1[8] = { 0x4C, 0x76, 0x08, 0x9D, 0xCE, 0x13, 0x15, 0x43 };


void print_hex(const unsigned char *bs, int n) {

    for (int i = 0; i < n; i++)
        printf("%02x", bs[i]);
    printf("\n");
}

void des_ecb_crypt(unsigned char* input, unsigned char* output, int encrypt, unsigned char* key) {

    des_key_schedule sched;
    des_set_key((des_cblock *) key, sched);

    DES_ecb_encrypt((const_DES_cblock *)input,
                     (const_DES_cblock *)output,
                     &sched;,
                     encrypt);
}

void xor_block(unsigned char* src, unsigned char* dest) {

    for (int x = 0; x < 8; x++) {
       src[x] =  src[x] ^ dest[x];
    }
}

int main(int argc, char* argv[]) {

    unsigned char output[8];
    unsigned char xx[8];
    unsigned char block[8];
    int offset = 0;

    memcpy(xx, iv, 8);

    // Chain and encrypt 5 8-bit blocks
    for (int x = 0; x < 5; x++) {

        memcpy(block, &msg;[offset] , 8);
        offset+=8;

        //set xx `xor {xx} {mj}` # chain
        xor_block(xx, block);

        //set xx `des -k {k0} -c {xx}` #encrypt
        des_ecb_crypt(xx, output, DES_ENCRYPT, k0);
        memcpy(xx, output, 8);
    }


    des_ecb_crypt(xx, output, DES_DECRYPT, k1);
    memcpy(xx, output, 8);

    des_ecb_crypt(xx, output, DES_ENCRYPT, k0);
    memcpy(xx, output, 8);

    print_hex(xx, 8);
    return 1;
}

1.1 DES in CBC Mode (DES-CBC)

Mon, 25 Jan 2010 19:59:35 +0000

CBC-MAC on the command line � Clinically Awesome

Fri, 22 Jan 2010 18:43:30 +0000

Finding hidden characters in file using Vim

2010-01-15T09:02:34.979-08:00

Show newlines and tab location:


:set list

Back to normal:


:set nolist

View open file as hex:


:%!xxd

internet transfer speeds & file sizes - how fast? how much storage? -

Fri, 08 Jan 2010 19:54:15 +0000

Linux – Iftop - …Details…

Fri, 08 Jan 2010 16:42:07 +0000

Download time calculator

Fri, 08 Jan 2010 15:47:43 +0000

etbe: creating a new SE Linux policy module

Fri, 08 Jan 2010 15:47:33 +0000

45.2.�Building a Local Policy Module

Fri, 08 Jan 2010 15:47:33 +0000

$ cheat git

Fri, 08 Jan 2010 15:47:33 +0000

What ports need to be open for Samba to communicate with other windows/linux systems?

Tue, 29 Dec 2009 15:50:02 +0000

Free Translation Online

Tue, 29 Dec 2009 15:49:52 +0000

ZynAddSubFX Packaged

2009-12-28T15:24:03Z

devinvenable posted a photo:

The apt package of SynAddSubFX has always looked like crap on my computers.

ZynAddSubFX Compiled

2009-12-28T15:24:02Z

devinvenable posted a photo:

If you compile from source, the mysterious font size problems go away. Does the geometry of the monitor on the computer the package is compiled on effect the outcome?

HowToSeq24Introduction - Community Ubuntu Documentation

Sun, 27 Dec 2009 16:45:28 +0000

Ubuntu Forums - View Single Post - [ubuntu] Ubuntustudio interface question

Fri, 25 Dec 2009 03:35:12 +0000

UbuntuStudioPreparation - Community Ubuntu Documentation

Thu, 24 Dec 2009 23:35:44 +0000

Writing New Policy for a Daemon

Mon, 14 Dec 2009 19:54:17 +0000

Software Synthesis

Wed, 02 Dec 2009 21:42:46 +0000

Ed Hellen's Python notes and examples

Wed, 02 Dec 2009 20:07:36 +0000

DSP tutorial

Wed, 02 Dec 2009 20:00:16 +0000

Free Guitar Lesson - SC-002 - The Minor Pentatonic Scale

Fri, 27 Nov 2009 15:07:21 +0000

How to fix your Windows MBR with an Ubuntu liveCD�|�ArsGeek

Fri, 27 Nov 2009 03:31:47 +0000

lolas

2009-11-20T19:54:23Z

devinvenable posted a photo:

Crypto Nerd's Imagination

2009-11-19T19:13:45Z

devinvenable posted a photo:

devinvenable: Since taking on a full time job, I tweet less. Am I just less worried about networking? Tired of twitter? Less narcissistic? Out of words?

Wed, 17 Jun 2009 17:58:49 +0000

devinvenable: Since taking on a full time job, I tweet less. Am I just less worried about networking? Tired of twitter? Less narcissistic? Out of words?

devinvenable: @adriap my influence?

Tue, 09 Jun 2009 16:59:52 +0000

devinvenable: @adriap my influence?

devinvenable: Fb app won't open. Guess it's twitter time.

Sat, 06 Jun 2009 01:44:40 +0000

devinvenable: Fb app won't open. Guess it's twitter time.

devinvenable: @ambersa42 wii fit? You are such a nerd!

Tue, 02 Jun 2009 21:52:17 +0000

devinvenable: @ambersa42 wii fit? You are such a nerd!

devinvenable: @geoffreysimpson thanks!

Thu, 28 May 2009 16:48:55 +0000

devinvenable: @geoffreysimpson thanks!

devinvenable: Best thing in the Android update: decent video recorder and viewer.

Thu, 28 May 2009 16:47:51 +0000

devinvenable: Best thing in the Android update: decent video recorder and viewer.