April 2010 Archives

April 2010
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Wed Apr 21 15:55:50 EDT 2010

Web interface for NanoBlogger: Add entries.

Please bare in mind that this is a proof of concept (that works) but here it is a web interface that allows you to submit entries to NanoBlogger through a BASH CGI. The script is rather simple, it just takes the fields title, description and body then writes it to a text file, you can latter process it through a cronjob or just leave it there for then you get a chance parse it by nb.

For this we will be using 3 code segments, the first would be the HTML form that will allow us to enter the content and pass those values to the CGI besides those two we have a javascript segment that allow us to preview the actual article that we are submitting.

The Form.
In other to have a bit of eye-candy i decided to use the heather and cascade style sheet from the actual style i am using for NanoBlogger. I found that the easiest way was to create a file by running `nb -b /path/of/the/blog/ make-file nb_send_entry.txt`. This will create a template that we can use to add the form HTML inside the 'BODY' section.

<form name="nb_entrada_send" method="post" ACTION="http://orvtech.com/send_nb_entry.cgi"><table border="0" width="600">
<tr>
<td width="100px">Titulo:</td>
<td width="500px"><input type="text" size="60" maxlength="50" id="title" name="entrada_title" value="Enter Title Here"></td>
</tr>
<tr>
<td width="100px">Descripcion:</td>
<td width="500px"><input type="text" size="60" maxlength="100" id="description" name="entrada_description" value="Enter Description Here"></td>
</tr>
<tr>
<td colspan="2">Contenido:<br />
< textarea cols="75" rows="30" id="body" name="entrada_body">
HTML esta permitido.
</ textarea>
</td>
</tr>
<tr>
<td width="600" colspan="2">
<div align="center "style="margin: auto; align: center; width: 600px;">
<input type="button" name="preview" value="Vista Previa" onclick="return openPreview();" />
  <input type=submit value="Enviar" />  
<input type="reset" value="Cancelar" />
</div>
</td>
</tr>
</table></form>

The product of this code is a web page with the same look and feel that the blog has. Here is a sample from our Spanish site:

The JavaScript.
If you take a look at above source code we have a 'preview' button; this button calls the function openPreview. The idea of this function is to show how would the HTML that we are codding look using the current style. You can get a good idea on how would this entry look before you submit it. Here is the code:

<script language="JavaScript">
function openPreview()
{
features = 'width=800, height=600, toolbar=no, menubar=no, resizable=no, location=no, directories=no, status=no';
var popWin = window.open ('','Preview_Entry', features);

var popTitleText = popWin.document.getElementById("title");
var titleText = document.getElementById("title");
var popBodyText = popWin.document.getElementById("body");
var bodyText = document.getElementById("body");

popWin.document.writeln('<head><title>Submit an Entry | Linux y el NSLU2</title><link rel="stylesheet" href="/styles/nb_default.css" type="text/css" media="all" /><link rel="shortcut icon" href="/favicon.ico" /></head><body> <div class="border"> <div class="container">  <div id="topmenu">  <ul>  <li><a href="/index.html" title="Inicio"><span>Inicio</span></a></li>  <li><a href="/gallery.html" title="Galería"><span>Galería</span></a></li>  <li><a href="/archives/scripts/index.html" title="BASH Scripts"><span>Scripts</span></a></li>  <li><a href="/articles/el_nslu2/" title="El NSLU2"><span>El NSLU2</span></a></li> <li><a href="/archives/scripts/index.html" title="Linux"><span>Linux</span></a></li> <li><a href="http://orvtech.com/index.html" title="orvtech.com in english"><span>In English</span></a></li>  </ul>  </div> <div id="header"></div><div class="container"><div class="archives"><div class="blogbody"> <h3 class="title">' + titleText.value + '</h3>' + bodyText.value + '</div></div></div></div></div></body>');

popTitleText.value = titleText.value;
popWin.document.close();
}
</script>

As you can see we are defining a new window and opening it with the content we entered on the form, it uses the nb_default.css. Most of the customizations can be done on in popWin.document.writeln in case you want to adapt it to your blog. Remember that this is a proof of concept and that it can still be improved, perhaps we can latter make it to read the blog.conf file. Here is a screenshot of how it looks.

All you need is BASH.
A CGI codded in bash to create the new entry for the blog. Here is the source code of send_nb_entry.cgi


#!/bin/bash

echo "Content-type: text/html"
echo -e "Status: 200 \n"
echo -e "<html><head><meta http-equiv=\"refresh\" content=\"2;url=http://orvtech.com\"></head><body><p>ENTRY ACCEPTED IN FOR QUEUE</p></body></html>"

DRAFT_ENTRY_DIRECTORY="/tmp"
POST_DATA=$(</dev/stdin)
TEMP_FILE="/tmp/nb_cgi_send_nb_entry.tmp"

nb_entrada_title=`echo $POST_DATA | sed -n 's/^.*entrada_title=\([^&]*\).*$/\1/p' | sed -e 's/%20/ /g'| sed 's/+/ /g'| sed 's/\%0[dD]//g' | awk '/%/{while(match($0,/\%[0-9a-fA-F][0-9a-fA-F]/)) {$0=substr($0,1,RSTART-1)sprintf("%c",0+("0x"substr($0,RSTART+1,2)))substr($0,RSTART+3);}}{print}'`
nb_entrada_description=`echo $POST_DATA | sed -n 's/^.*entrada_description=\([^&]*\).*$/\1/p' | sed -e 's/%20/ /g'| sed 's/+/ /g'| sed 's/\%0[dD]//g' | awk '/%/{while(match($0,/\%[0-9a-fA-F][0-9a-fA-F]/)) {$0=substr($0,1,RSTART-1)sprintf("%c",0+("0x"substr($0,RSTART+1,2)))substr($0,RSTART+3);}}{print}'`
name_entrada_tmp=`date +%Y-%m-%dT%H_%M_%S.tmp`
echo "TITLE: $nb_entrada_title" > $TEMP_FILE
echo "AUTHOR:" >> $TEMP_FILE
echo "DATE:" >> $TEMP_FILE
echo "DESC: $nb_entrada_description" >> $TEMP_FILE
echo "FORMAT: raw" >> $TEMP_FILE
echo "-----" >> $TEMP_FILE
echo "BODY:" >> $TEMP_FILE

echo $POST_DATA | sed -n 's/^.*entrada_body=\([^&]*\).*$/\1/p' | sed -e 's/%20/ /g'| sed 's/+/ /g'| sed 's/\%0[dD]//g' |\
   awk '/%/{while(match($0,/\%[0-9a-fA-F][0-9a-fA-F]/))\
       {$0=substr($0,1,RSTART-1)sprintf("%c",0+("0x"substr(\
       	      $0,RSTART+1,2)))substr($0,RSTART+3);}}{print}' >> $TEMP_FILE

	      echo "END-----" >> $TEMP_FILE
	      mv `echo -e $TEMP_FILE` `echo -e $DRAFT_ENTRY_DIRECTORY/$name_entrada_tmp`

We can latter import the file defined by $DRAFT_ENTRY_DIRECTORY/$name_entrada_tmp issuing the command:

nb -b /path/to/your/blog import entry /tmp/2010-03-02T15_02_01.tmp

This will add the entry to our blog. I though about automating this in the CGI but at this point i prefer to create a central control panel and keep things separated.

Spanish version: Interfaz web para agregar entradas a NanoBlogger.

Posted by orvtech | Permanent link | File under: Scripts, NSLU2, nanoblogger

Wed Apr 21 12:52:16 EDT 2010

ZNC IRC Bouncer start up script.

A few weeks a go I published an article about how to have push notifications to your iPhone from an IRC channel events. After installing and configuring ZNC I was a bit disappointed that it didn't had a start up script so I decided to write one.

This script allows you to start, stop, reload the configuration and restart the service. lets take a look at /etc/init.d/zncd

 
#!/bin/bash
 
 ZNC_FOLDER="/usr/bin"
 ZNC_OWNR="your_user_here"
 
 if [ ! -f $ZNC_FOLDER/znc -o ! -d $ZNC_FOLDER ]
 then
 echo "ZNC startup: cannot start, it appears that it is not installed"
 exit 1
 fi
 
 case "$1" in
 start)
 echo -n "Starting ZNC: "
 su - $ZNC_OWNR -c "$ZNC_FOLDER/znc"
 touch /var/lock/subsys/ZNC
 echo "OK"
 ;;
 stop)
 echo -n "Shutdown ZNC: "
 kill -9 `ps -C znc | awk '{print $1}' | grep ^[0-9]`
 rm -f /var/lock/subsys/ZNC
 echo "OK"
 ;;
 reload)
 echo -n "Reloading ZNC:"
 kill -HUP `ps -C znc | awk '{print $1}' | grep ^[0-9]`
 echo "OK"
 ;;
 status)
 if ps -C znc > /dev/null
 then 
 echo "ZNC Bouncer is running"
 else 
 echo "ZNC Bouncer is not running"
 fi
 ;;
 restart)
 $0 stop
 sleep 2
 $0 start
 ;;
 *)
 echo "Usage: $0 start|stop|restart|reload|status"
 exit 1
 esac
 exit 0

If your NSLU2 is running gentoo you could add it to the default run level like this:

 
rc-update add zncd default

The output should be something like this:

 * zncd added to runlevel default

Spanish version: script de arranque para ZNC bouncer.

Posted by orvtech | Permanent link | File under: Scripts, IRC, NSLU2, Linux

Sun Apr 11 19:11:00 EDT 2010

Bluetooh Audio Through the NSLU2.

@POTUSCamacho has an interesting article about how to use the NSLU2 in combination with a USB bluetooth adapter as an audio server. POTUSCamacho explains how to do it with a mono audio adapter but clarifies that it should be possible to do it using a stereo adapter.

Lets take a look at this interesting howto:

Once you have installed Ubuntu, log in and update your packages:
sudo -i apt-get update
Then install the following packages:
sudo -i apt-get install linux-sound-base bluetooth bluez bluez-alsa bluez-btsco bluez-compat bluez-utils python python-bluez vlc
Note: I do alot of other development stuff on my unit. I may have left off something, and if so let me know if you try it and it doesn't work.
Now that the needed packages are installed, an .asoundrc needs to be created in your user home directory. An example:
pcm.bluetooth { type bluetooth device 00:00:00:00:00:00 }
Edit the device section with the MAC address of your bluetooth headset. To find this, issue a reset of the bluetooth adapter by issuing the command:
hciconfig hci0 reset
Then place your headset in pairing mode and issue the following command:
sdptool browse
Now copy the following python script into a file named pair.py:
#!/usr/bin/python import gobject import sys import dbus import dbus.service import dbus.mainloop.glib class Rejected(dbus.DBusException): _dbus_error_name = "org.bluez.Error.Rejected" class Agent(dbus.service.Object): exit_on_release = True def set_exit_on_release(self, exit_on_release): self.exit_on_release = exit_on_release @dbus.service.method("org.bluez.Agent", in_signature="", out_signature="") def Release(self): print "Release" if self.exit_on_release: mainloop.quit() @dbus.service.method("org.bluez.Agent", in_signature="os", out_signature="") def Authorize(self, device, uuid): print "Authorize (%s, %s)" % (device, uuid) authorize = raw_input("Authorize connection (yes/no): ") if (authorize == "yes"): return raise Rejected("Connection rejected by user") @dbus.service.method("org.bluez.Agent", in_signature="o", out_signature="s") def RequestPinCode(self, device): print "RequestPinCode (%s)" % (device) return raw_input("Enter PIN Code: ") @dbus.service.method("org.bluez.Agent", in_signature="o", out_signature="u") def RequestPasskey(self, device): print "RequestPasskey (%s)" % (device) passkey = raw_input("Enter passkey: ") return dbus.UInt32(passkey) @dbus.service.method("org.bluez.Agent", in_signature="ou", out_signature="") def DisplayPasskey(self, device, passkey): print "DisplayPasskey (%s, %d)" % (device, passkey) @dbus.service.method("org.bluez.Agent", in_signature="ou", out_signature="") def RequestConfirmation(self, device, passkey): print "RequestConfirmation (%s, %d)" % (device, passkey) confirm = raw_input("Confirm passkey (yes/no): ") if (confirm == "yes"): return raise Rejected("Passkey doesn't match") @dbus.service.method("org.bluez.Agent", in_signature="s", out_signature="") def ConfirmModeChange(self, mode): print "ConfirmModeChange (%s)" % (mode) @dbus.service.method("org.bluez.Agent", in_signature="", out_signature="") def Cancel(self): print "Cancel" def create_device_reply(device): print "New device (%s)" % (device) mainloop.quit() def create_device_error(error): print "Creating device failed: %s" % (error) mainloop.quit() if __name__ == '__main__': dbus.mainloop.glib.DBusGMainLoop(set_as_default=True) bus = dbus.SystemBus() manager = dbus.Interface(bus.get_object("org.bluez", "/"), "org.bluez.Manager") if len(sys.argv) > 1: path = manager.FindAdapter(sys.argv[1]) else: path = manager.DefaultAdapter() adapter = dbus.Interface(bus.get_object("org.bluez", path), "org.bluez.Adapter") path = "/test/agent" agent = Agent(bus, path) mainloop = gobject.MainLoop() if len(sys.argv) > 2: if len(sys.argv) > 3: device = adapter.FindDevice(sys.argv[2]) adapter.RemoveDevice(device) agent.set_exit_on_release(False) adapter.CreatePairedDevice(sys.argv[2], path, "DisplayYesNo", reply_handler=create_device_reply, error_handler=create_device_error) else: adapter.RegisterAgent(path, "DisplayYesNo") print "Agent registered" mainloop.run() #adapter.UnregisterAgent(path) #print "Agent unregistered"
Now place your headset into pairing mode again and issue the follow command:
sudo -i python pair.py hci0 00:00:00:00:00:00
Once again replacing the address above with your headsets MAC. The last step involves editing the vlcrc. To do this, issue the command:
pico .vlc/vlcrc
Scroll down and replace:
alsadev=(default soundcard)
To:
alsadev=bluetooth
If it does not exist then create it.

Now you should be ready to listen to audio. To listen to the audio from NASA TV's online video stream, issue the command:
cvlc --aout-rate 8000 --novideo http://www.nasa.gov/55644main_NASATV_Windows.asx
If everything is working you should hear audio. Keep in mind that the sample rate needs to be 8000Hz since that is the sample rate the headset can handle.

To pair another headset, or to re-pair the current, the /var/lib/bluetooth/(your MAC)/linkkeys file must be deleted. It will regenerate once you have paired the devices. Also remember that the .asoundrc file must be edited to match a different headset as the MAC will be different.

To find out more info about this article, please visit POTUSCamacho Industries blog.

Spanish version: Audio vía bluetooh desde el NSLU2.

Posted by orvtech | Permanent link | File under: Scripts, NSLU2, Linux