Category: middleware

the fade anything technique

Problem

You want to add something flash to your site.
A color loads, which you then want to change



Solution

Well cool “Fade Anything Technique”!

Really simple implementation, just copy fade anything and then any divs, etc with an id
of fade-xxx will fade from that color. Many more options, check out these highly recommended articles.



Example



<head>
...
<script type="text/javascript" src="/fat.js">
</head>
...
<div style="width: 600px; border:1px dashed #23932B; padding: 10px;" id="fade-23932B" class="fade-23932B">
...
</div>



Reference

Check out the article hosted by axentric, written by Adam Michela

It was inspired by 37 signals



Troubleshoot Apache Startup

Problem

Here are a few tips, if you are having problems starting apache.

1. A common problem is trying to start Apache on a restricted port. This is where you configure apache to listen on port 80, changing the default 8080.

2. Another problem can be defining logging into directories that don’t exist.

3. If you get an error like User not allowed, or Group not recognized, etc – this is the User and Group statements within your apache configs.



Solution

1. On UNIX this is considered restricted and generally only available to the root user. On windows it is also commonly restricted, so requires an admin account.

2. This will generally output an error along those lines, into apache’s top level error log. Failing that you can try running apache with truss (search my site to find syntax) on Solaris, strace on Linux and trace on AIX.

3. You need to change to match the user running the command – or if root, the delegated user and group user is in.

Another tip is to run /etc/init.d/httpd configtest – which will effectively run httpd -t to syntax check the config. You can also perform a -S which checks and prints your virtual hosts.

If you getting compliants about modules, try running httpd -l to see compile in mods.



Example


Nothing here – please see Solution 🙂



Reference

[tags]apache, Unix Coding School[/tags]



epoch generation and converting

Problem

You want to generate the current epoch offset for UNIX. The count forward since 8am on 1st Jan 1970.

Or conversely you want to see the date and time, for a given epoch offset.



Solution

You can use perl’s mktime or localtime – or just use my tools below.



Example


Either enter epoch:

Or enter the date (plus time)

daymonthyear
hrminssecs

epoch offset or date will appear here



Reference

[tags]epoch, unix, 2038[/tags]

  1. techno park epoch year 2038 problem


Vertical label creation

Problem

You want to generate a vertical image, with text over the top.



Solution

Here is some code I wrote, which is used extensively on my sites:



Example




Reference

Give it a blast on this site, like this: http://coding-school.com/common/label-up.php?label=your+text+here

Automatically calculates size required. You can also add font=# – where # is 1 to 5, like this:

http://coding-school.com/common/label-up.php?label=your+text+here&font=3

I’ve now created an online tool, using this code



libcurl lookup taking long time

Problem

You notice for some hosts curl and/or libcurl are taking 7 or so secs to lookup the host. But nslookup or dig respond almost immediately.



Solution

Try doing curl -4 -w “time_namelookup: %{time_namelookup}n” …. and try without the -4. If you see drastic differences, you could be falling foul of the IPV6 bug. To work around this, you can either just use -4 with curl or set CURLOPT_IPRESOLVE with libcurl.



Example


I spents hours and hours and hours, trying to get this working with libcurl and perl. It turned out I need to upgrade to WWW::Curl::Easy version 3.0 – as opposed to version 2. Do a search on search.cpan.org for Curl and it will tell you how to check your version.

Then if you like me upgrade, you need to also modify all your code from: Curl::easy::setopt($curl, … to $curl->setopt( …



Reference



10 simple techie tips for lazy people

Problem

Don’t know about you, but I’m generally quite lazy. Why roll the mouse and click the screen,
when with a quick control c I can copy some text. 🙂



Solution

Learn 10 simple short cuts, which can save you hours.



Example


1.

Copy some text – select it then control c
Now it is in the clipboard.

2.

Click where you want to paste it and control v to paste it. 😉

You can also right click with your mouse to cut and paste.

3.

Minimise all windows, by holding down the windows key and press m

4.

Kick off explorer, by holding down windows key and press e

5.

Do a find by holding down windows key and press f

6.

Switch between windows by holding down alt and pressing tab

7.

Reverse tab through a HTML form, by holding down the shift key.

8.

Open a web link in a new window, by holding down shift and clicking it

9.

To type in a new web address, hold down alt and press d

10.

Save a document with control s, print it with control p, undo a change with control z – sorry got carry away. 🙂



Reference



HTTP Basic Auth with HTTP headers and libcurl

Problem

Came across an interesting problem with curl.

For curl to perform HTTP Basic Authentication, it is easy to pass –user to the curl command, but harder with libcurl.

Suspect there is an attribute that can be set, but I monitor a multitude of web sites through some perl scripts and libcurl. I did n’t want to have to modify my wrapper scripts, which mesh perl hashes with the code that drives curl (via libcurl).

I do allow for headers though, having needed to pass different things through, like HTTP_REFERER, LAST_MODIFIED, etc.

Therefore I just needed to pass the HTTP BASIC Authentication through as a header.



Solution

First off you need to base64 encode the user and password.

Use Google’s tool



Example


We then strip out the equals and pass following through to curl or libcurl:

@myheaders=('Authorization: Basic YWRtaW46YWRtaW4');Curl::easy::setopt($curl, Curl::easy::CURLOPT_HTTPHEADER, @myheaders);

Or from the command line:

curl ... -H'Authorization: Basic YWRtaW46YWRtaW4'

Obviously you need to put your user, followed by a colon and your password – to obtain the correct base64 encoding back – strip the equals out and away you go.



Reference



Simple Basic Encryption – Main differences between algorithms

Problem



Solution



Example




Reference

Symmetric Algo – one key to encrypt and decrypt.

Asymmetric Algo – separate key to encrypt and decrypt.

Stream ciphers – encrypt each bit in sequence.

Block ciphers – encrypt specific blocks of bits.

Hash/Message Digests – one way ciphers, create fingerprints of data.