Random Web Tools http://www.randomtools.net Advice and tools from a young web developer Fri, 13 Jan 2012 01:08:01 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 How to install PHP Memcache on Windows WAMP, Linux for any operating system (without really installing) http://www.randomtools.net/how-to-install-php-memcache-on-windows-wamp-linux-for-any-operating-system-without-really-installing-231.html http://www.randomtools.net/how-to-install-php-memcache-on-windows-wamp-linux-for-any-operating-system-without-really-installing-231.html#comments Wed, 11 Jan 2012 18:30:50 +0000 Dan http://www.randomtools.net/?p=231 I have a site that runs on Linux in production that uses Memcache. Installing Memcache on Linux is a cinch. I was setting this site up in my development environment however (Windows 7 64-bit, with WAMP, specifically Apache 2 and PHP 5.3) and I quickly discovered it’s not so easy. For the life of me, I could not find the correct php_memcache.dll file.

After spending a ton of time unsuccessfully install Memcache on my local machine, I realized that I don’t even need the memory caching functionality of Memcache, I just need the functions to work.

After some thought, I decided to just implement the class and functions that Memcache provides. Following is what I came up with. It just uses a specified directory to store cache in serialized files on the hard drive. Obviously it doesn’t exactly simulate real production Memcache, but it allows you to work from any box without having to install it.

Here’s what I came up with:

<?php
/*
Fake PHP Memcache class
Use Memcache functions without installing. Useful in development environments.
 
Dan Barnett
http://www.randomtools.net/
*/
class Memcache {
	private $cache_dir = 'C:/path/to/directory/';
 
	public function close() {}
 
	public function connect() {
		return true;
	}
 
	public function pconnect() {
		return $this->connect();
	}
 
	public function getVersion() {
		return -1;
	}
 
	public function get($key) {
		return unserialize(file_get_contents($this->cache_dir . md5($key) . ".txt"));
	}
 
	public function set($key, $value) {
		return file_put_contents($this->cache_dir . md5($key) . ".txt", serialize($value));
	}
 
	public function flush() {
		foreach (glob($this->cache_dir . '*.txt') as $file) {
			unlink($file);
		}
		return true;
	}
}
 
function memcache_close() {}
 
function memcache_connect() {
	global $memcache;
	$memcache = new Memcache();
}
 
function memcache_pconnect() {
	return memcache_connect();
}
 
function memcache_set($key, $value) {
	global $memcache;
	return $memcache->set($key, $value);
}
 
function memcache_get($key) {
	global $memcache;
	return $memcache->get($key);
}
 
function memcache_get_version() {
	global $memcache;
	return $memcache->getVersion();
}
 
function memcache_flush() {
	global $memcache;
	return $memcache->flush();
}
?>

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/how-to-install-php-memcache-on-windows-wamp-linux-for-any-operating-system-without-really-installing-231.html/feed 0 How to Install PHP APC on Fedora & CentOS http://www.randomtools.net/how-to-install-php-apc-on-fedora-centos-225.html http://www.randomtools.net/how-to-install-php-apc-on-fedora-centos-225.html#comments Sat, 10 Dec 2011 04:08:55 +0000 Dan http://www.randomtools.net/?p=225 APC (or Alternate PHP Cache) is a popular PHP PECL extension that can be used for PHP op-code caching. It is very stable and can significantly reduce page rendering times. It works by caching the PHP binaries, so that PHP doesn’t have to compile them on every request.

Installation is simple:

1. Use yum to install necessary packages.

# yum install php-pear php-devel httpd-devel pcre-devel

2. Use pecl to install the PECL apc package.

# pecl install apc

3. Create a config file that will be included in the PHP ini settings, which will load the APC binary. The default settings should be sufficient for most.

# echo "extension=apc.so" > /etc/php.d/apc.ini

4. Restart Apache:

# service httpd restart

5. Make sure it works by creating a phpinfo.php with the following code and then accessing it in your browser. If it works correctly, there will be a new APC section.

<?php phpinfo(); ?>

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/how-to-install-php-apc-on-fedora-centos-225.html/feed 0 How to insert a tab character into Putty for Linux http://www.randomtools.net/how-to-insert-a-tab-character-into-putty-for-linux-218.html http://www.randomtools.net/how-to-insert-a-tab-character-into-putty-for-linux-218.html#comments Thu, 20 Oct 2011 19:18:14 +0000 Dan http://www.randomtools.net/?p=218 If you’re like me, you’ve noticed that if you’re trying to grep for a tab character, the following won’t work:

grep "\t" file.txt

The solution is to use a literal tab character, but it’s not quite so simple. You can’t insert a tab character just by hitting the tab button or by pasting one in. You need to hit Ctrl+V first:

So to type a tab in the putty console:

  • Ctrl+V
  • [TAB] character

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/how-to-insert-a-tab-character-into-putty-for-linux-218.html/feed 0 How to loop through days (dates) in bash and force two digits (zerofill) http://www.randomtools.net/how-to-loop-through-days-dates-in-bash-and-force-two-digits-zerofill-213.html http://www.randomtools.net/how-to-loop-through-days-dates-in-bash-and-force-two-digits-zerofill-213.html#comments Fri, 20 May 2011 21:30:16 +0000 Dan http://www.randomtools.net/?p=213 Often with bash, I need to run a script and pass in a date. It helps to be able to use a bash loop to do it all at once. Here’s how you do it, and make sure the day is two digits. Note the use of the println command.

for day in {1..31}; do php some_script.php 2011-05-`printf "%02d" $day`; done

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/how-to-loop-through-days-dates-in-bash-and-force-two-digits-zerofill-213.html/feed 0 How to have htop save configuration on exit http://www.randomtools.net/how-to-have-htop-save-configuration-on-exit-206.html http://www.randomtools.net/how-to-have-htop-save-configuration-on-exit-206.html#comments Sun, 03 Apr 2011 22:55:26 +0000 Dan http://www.randomtools.net/?p=206 htop is awesome. I use it all the time to monitor all the servers I use. It was only until recently that I noticed it has some great configuration options, namely the "Tree View." This allows you to see a hierarchy of processes, which can be really helpful in finding out why certain processes are running.

I quickly realized it would be a pain to have to constantly hit F5 every time I opened the program, until I realized there was a way to make htop remember your last configuration.

What you want to do is make sure you close out of htop with F10 instead of Ctrl+C, which I normally use. You only need to use F10 when you want to save the settings, and can subsequently close out how you normally do!

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/how-to-have-htop-save-configuration-on-exit-206.html/feed 0 How to Hide Digsby Ads http://www.randomtools.net/how-to-hide-digsby-ads-195.html http://www.randomtools.net/how-to-hide-digsby-ads-195.html#comments Mon, 13 Dec 2010 21:15:13 +0000 Dan http://www.randomtools.net/?p=195 I use Digsby as my instant messenger client. A couple minutes ago, I received an update which set ads to display in the conversation windows by default. I immediately decided I'd try to figure out how to remove the ads, or switch back to Pidgin, the free open source client. Turns out it was simple to turn off the ads. When you're done, you'll need to reopen your conversation windows to see the changes.

From the Buddy List window:

  1. Tools -> Preferences
  2. Conversations
  3. Uncheck "Support Digsby development by showing an ad in the IM window"

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/how-to-hide-digsby-ads-195.html/feed 1 How to Fix Linux SSH: Permission denied (publickey). http://www.randomtools.net/linux-ssh-permission-denied-publickey-190.html http://www.randomtools.net/linux-ssh-permission-denied-publickey-190.html#comments Thu, 09 Dec 2010 07:01:24 +0000 Dan http://www.randomtools.net/?p=190 I just got done setting up a user in my new developer environment on multiple boxes. I made sure to copy over the authorized_keys file exactly, including the correct 0600 permissions, but kept getting the "Permission denied (publickey)" error when trying to ssh into one box, even though all the others worked.

What finally solved it for me was to make sure the user's password is set:

# passwd <user>

If that doesn't work, make sure the user's .ssh directory is chmod 0700 and the user's authorized_keys file is chmod 0600.

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/linux-ssh-permission-denied-publickey-190.html/feed 0 Android ANR keyDispatchingTimedOut http://www.randomtools.net/android-anr-keydispatchingtimedout-178.html http://www.randomtools.net/android-anr-keydispatchingtimedout-178.html#comments Fri, 17 Sep 2010 02:49:21 +0000 Dan http://www.randomtools.net/?p=178

I recently had some issues with my Mancala app where some users were experiencing frequent force closes and I could not figure out the reason for this behavior. Fortunately, with the help of Android's relatively new force close reporting features, I was able to get some insight into the issue. The big issue seemed to be an ANR keyDispatchingTimedOut error, which was something I had no idea about, and Google wasn't super helpful.

Here's an example of the "Dalvik threads" that were reported to me in the Android Developer Console. My understanding is that this is a list of threads and their stack traces at the time of the force close.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79

DALVIK THREADS:
&quot;main&quot; prio=5 tid=1 NATIVE
  | group=&quot;main&quot; sCount=1 dsCount=0 s=N obj=0x4001d8c8 self=0xccc8
  | sysTid=9498 nice=0 sched=0/0 cgrp=default handle=-1345013672
  | schedstat=( 103942869 246185301 151 )
  at java.net.InetAddress.getaddrinfo(Native Method)
  at java.net.InetAddress.lookupHostByName(InetAddress.java:508)
  at java.net.InetAddress.getAllByNameImpl(InetAddress.java:280)
  at java.net.InetAddress.getByName(InetAddress.java:310)
  at java.net.InetSocketAddress.<init>(InetSocketAddress.java:110)
  at java.net.InetSocketAddress.<init>(InetSocketAddress.java:89)
  at org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.<init>(HttpConnection.java:62)
  at org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnectionPool.get(HttpConnectionPool.java:88)
  at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getHTTPConnection(HttpURLConnectionImpl.java:927)
  at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:909)
  at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:1152)
  at com.xoise.mancala.Mancala.checkUpdate(Mancala.java:203)
  at com.xoise.mancala.Mancala.onCreate(Mancala.java:45)
  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
  at android.os.Handler.dispatchMessage(Handler.java:99)
  at android.os.Looper.loop(Looper.java:123)
  at android.app.ActivityThread.main(ActivityThread.java:4627)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:521)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
  at dalvik.system.NativeStart.main(Native Method)
 
&quot;SoundPoolThread&quot; prio=5 tid=8 NATIVE
  | group=&quot;main&quot; sCount=1 dsCount=0 s=N obj=0x43ee6dc8 self=0x22b020
  | sysTid=9506 nice=0 sched=0/0 cgrp=default handle=1204184
  | schedstat=( 854492 25299072 9 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;SoundPool&quot; prio=5 tid=9 NATIVE
  | group=&quot;main&quot; sCount=1 dsCount=0 s=N obj=0x43ee6e88 self=0x22b430
  | sysTid=9505 nice=0 sched=0/0 cgrp=default handle=1203920
  | schedstat=( 122071 25207520 2 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;Binder Thread #2&quot; prio=5 tid=7 NATIVE
  | group=&quot;main&quot; sCount=1 dsCount=0 s=N obj=0x43ecfa48 self=0x13f1f8
  | sysTid=9504 nice=0 sched=0/0 cgrp=default handle=1189136
  | schedstat=( 3265379 22705078 15 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;Binder Thread #1&quot; prio=5 tid=6 NATIVE
  | group=&quot;main&quot; sCount=1 dsCount=0 s=N obj=0x43ecf988 self=0x125a90
  | sysTid=9503 nice=0 sched=0/0 cgrp=default handle=1202768
  | schedstat=( 4425047 132843018 15 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;Compiler&quot; daemon prio=5 tid=5 VMWAIT
  | group=&quot;system&quot; sCount=1 dsCount=0 s=N obj=0x43ecd348 self=0x121228
  | sysTid=9502 nice=0 sched=0/0 cgrp=default handle=1184232
  | schedstat=( 1708986 15808104 6 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;JDWP&quot; daemon prio=5 tid=4 VMWAIT
  | group=&quot;system&quot; sCount=1 dsCount=0 s=N obj=0x43ecd2a0 self=0x120b08
  | sysTid=9501 nice=0 sched=0/0 cgrp=default handle=1184152
  | schedstat=( 2685545 5004884 22 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;Signal Catcher&quot; daemon prio=5 tid=3 RUNNABLE
  | group=&quot;system&quot; sCount=0 dsCount=0 s=N obj=0x43ecd1e8 self=0x120fa8
  | sysTid=9500 nice=0 sched=0/0 cgrp=default handle=1196024
  | schedstat=( 3875733 5920410 15 )
  at dalvik.system.NativeStart.run(Native Method)
 
&quot;HeapWorker&quot; daemon prio=5 tid=2 VMWAIT
  | group=&quot;system&quot; sCount=1 dsCount=0 s=N obj=0x43111d58 self=0x129518
  | sysTid=9499 nice=0 sched=0/0 cgrp=default handle=1185056
  | schedstat=( 27954104 52368162 15 )
  at dalvik.system.NativeStart.run(Native Method)</init></init></init>

This ANR, or Application Not Responding, error occurs when a process on the main thread takes too long (something like 5 seconds). Android kills that process and any related by design to spare the device's resources.

The solution is to run resource-expensive tasks on another thread, and then post, or update the main thread accordingly. A common use for this is network calls (and this was what my problem was). The following is an example of how to implement this logic, in my case to check if an update is needed:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

private void checkUpdate() {
	SharedPreferences prefs = getPreferences(0);
	SharedPreferences.Editor editor = prefs.edit();
 
	long lastUpdateTime = prefs.getLong(&quot;lastUpdateTime&quot;, 0);
	long time = System.currentTimeMillis() / 1000;
 
	if (lastUpdateTime + 3600 * 24 &lt; time) {
		checkNetworkUpdate();
		editor.putLong(&quot;lastUpdateTime&quot;, time);
		editor.commit();
	}
}
 
protected void checkNetworkUpdate() {
	Thread t = new Thread() {
		public void run() {
			try {
				URL updateURL = new URL(&quot;http://www.updateurl.com/&quot;);       
				URLConnection conn = updateURL.openConnection();
				conn.setConnectTimeout(3000);
				Scanner scanner = new Scanner(conn.getInputStream()); 
				scanner.useDelimiter(&quot;\\n&quot;);
 
				int curVersion = getPackageManager().getPackageInfo(&quot;your.package.name&quot;, 0).versionCode;
				int newVersion = 0;
				if (scanner.hasNext())
					newVersion = Integer.valueOf(scanner.next());
 
				final boolean displayUpdate = newVersion &gt; curVersion;
 
				runOnUiThread(new Runnable() {
					public void run() {
						handleNetworkReply(displayUpdate);
					}
				});
			} catch (Exception e) {}
		}
	};
	t.start();
}
 
private void handleNetworkReply(boolean displayUpdate) {
	if (displayUpdate) {
		(new AlertDialog.Builder(this)).setMessage(&quot;An update is available!\n\nOpen Android Market to see the details?&quot;)
			.setTitle(&quot;Update Available&quot;)
			.setPositiveButton(&quot;Yes&quot;, new DialogInterface.OnClickListener() {
				public void onClick(DialogInterface dialog, int whichButton) {
					Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(&quot;market://details?id=your.package.name&quot;));
					startActivity(intent);
				}
			})
			.setNegativeButton(&quot;No&quot;, null)
			.create()
			.show();
	}
}

Then just call checkUpdate() to perform the task. Note the major points of importance here being the Thread object with a run() method and the runOnUiThread() method of the Activity, which allows you to post data to the main UI thread.

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/android-anr-keydispatchingtimedout-178.html/feed 0 Automatically convert to and from Base64 http://www.randomtools.net/automatically-convert-to-and-from-base64-170.html http://www.randomtools.net/automatically-convert-to-and-from-base64-170.html#comments Mon, 16 Aug 2010 06:16:11 +0000 Dan http://www.randomtools.net/?p=170 I just finished a small, simple, yet interesting script for detecting whether code is base64 and encoding or decoding it based on the result. Let's be honest, PHP made it super easy for me with the base64_encode() and base64_decode() functions. I just wrapped it up in what I think is a pretty handy little tool that I know at least one person will get some use out of!

Try it out: Base64 Converter

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/automatically-convert-to-and-from-base64-170.html/feed 0 View HTTP Response Headers http://www.randomtools.net/view-http-response-headers-175.html http://www.randomtools.net/view-http-response-headers-175.html#comments Mon, 16 Aug 2010 06:15:44 +0000 Dan http://www.randomtools.net/?p=175 Just a quick note to share a site I found that comes in handy when needing to debug web troubles. You can use the site to handily view HTTP request and HTTP response headers to see exactly what's going on behind the scenes.

Web Sniffer

To be totally honest, I’ll probably end up creating my own site for this because I like to build things out for the fun of it.

Bookmark this page
[del.icio.us] [Digg] [Facebook] [Google] [Reddit] [Slashdot] [StumbleUpon]
]]> http://www.randomtools.net/view-http-response-headers-175.html/feed 0