PHP Error Handling and Debugging – Part 1

This article describes the process of testing PHP code.  Using the tips that I will explain can help to decrease the code/test cycle time.

The first thing that you must know in order to plan your code/test process is the environment in which your code will run.

If you have full control of the system, less configuration is required. In this case you can rely on the default settings, and simply need to know where the logs are kept by default. On a typical LAMP (apache) system you can find the log files in /var/log/httpd. Check the documentation for the operating system that you use as some operating systems use a different directory (i.e. one version of Ubuntu uses /var/log/apache2). By default error messages from php will be kept in this directory.

If you are developing on a server where you don’t have access to the default logs, you can configure where your log messages are sent by putting a php.ini file containing the directive

error_log: path_to_log

in the root of the domain.

With this information in mind, we can begin to find code errors.

There are two error types to look for:

  1. parse
  2. runtime

A parse error is the first thing to look for when testing new or modified code. This can be something like a missing semicolon or other grammatical mistake. If a parse error occurs, it will be sent to PHP’s error_log. A simple way to find this kind of error is to load the file directly in a browser (i.e. an AJAX script that would not normally run in a browser could be tested this way for parse errors). With a default PHP installation the parse error will shown on the screen.

Most errors that are encountered are runtime errors. There are two kinds of runtime errors:

  1. exception
  2. functional

The first kind of runtime error happens when a statement or function call that is grammatically correct encounters a unexpected circumstance such as an invalid parameter (i.e. fopen(file_that_doesnt_exist,’r’)). This kind of error can only be seen during an actual run of the code with valid inputs. Opening the file in the browser directly usually will not find it as the inputs will not be those that would typically be encountered. For example opening an AJAX script that relys on the _POST variable for its input will typically not run many of the branches because of the missing _POST variables. To find this error, run the script as it would typically be run and check the error log for errors.

A functional runtime error is when the code runs, doesn’t generate an error, but doesn’t produce the expected outputs. To find this error use one or more of the following techniques:

  • echo/printf
  • error_log
  • try/catch

The simplest way to find errors is by adding echo statements to the code. This method can be somewhat tedious and slower to use than others, but a few well placed echo statements that use print_r to show the value of key return data structures can sometimes quickly illuminate the source of the malfunctioning code. The problem with this method is that because it outputs directly to stdout (the web browser) it is only available if the script can be run in the web browser directly with typical inputs. Many times this is not possible (i.e. for AJAX or cron code).

A more general way of debugging is to use the error_log function instead of echo. With the error_log function you can direct the messages to a file of your choosing with

error_log($message,3,"path/filename")

or to the configured error_log mentioned earlier via

error_log($message)

A bonus when using the error_log() function is that you also get a timestamp for each error logged.

If a runtime error is expected, a try/catch statement should be placed to ignore it or otherwise handle it in a way that doesn’t cause the script to stop abruptly.  This way the script will continue to run and an error will be logged.  This is better because you will know at what section of code the error occurred.  If the blocking error had gone uncaught (in the case of AJAX responder script errors), the calling application might have received a malformed response (parse error).  A try/catch statement is only helpful when a blocking exception occurs, and will not help to debug functional runtime errors.  The structure of this type of code testing is as follows:

try {
 //your new code
 } catch(Exception $E) {
 error_log(E.getMessage());
 }

In this article we have discussed simple code/test cycle techniques for PHP.  Tune in next time for part 2 where we will review using a debugger such as XDebug.

Javascript Compression — Tools and Process

This article is a review of the tools and processes that I have tested and gives plusses and minuses of each.

Software Uncompressed Compressed Percent Comment
Closure Compiler 39K 16K 59% with ADVANCED_OPTIMIZATIONS
YUI Compressor 39K 22K 44%
perl-Javascript-Minifier 39K 25K 36%

 

perl-Javascript-Minifier
Since CPAN library’s Javascript-Minifier and CSS-Minifier are immediately available linux tools they are a good starting point. The Javascript-Minifier is simple to use. Here is a script that you can try to see how it works:

#!/usr/bin/perl
 use JavaScript::Minifier qw(minify);
 my($iFile)=$ARGV[0];
 my($oFile)=$iFile;
 $oFile=~ s/[.]js//;
 $oFile="${oFile}_perl_min.js";
 open(INFILE, "$iFile") or die;
 open(OUTFILE, ">$oFile") or die;
 minify(input => *INFILE, outfile => *OUTFILE);
 close(INFILE);
 close(OUTFILE);

In my tests, it didn’t break my code, but did generate errors because of incorrectnesses in my code. I used the google chrome jslint plugin to find the errors. jslint only works on pure javascript, but strings are not parsed. Thus you can use php to initialize variables by putting the php code inside of quotes, and still check it with jslint.

 

YUI Compressor
The YUI Compressor is Yahoo’s library, and works better than perl-Javascript-Minifier. Here is an example command for using YUI Compressor:

java -jar yuicompressor-2.4.7.jar --type js -o filename_yui_min.js filename.js

A nice feature of the yuicompressor is that it can accept javascript strings from the command line. This makes it simple to script. It’s goal is to not break code, and in my tests this was observed to be true.

 

Closure Compiler
The google closure compiler is the most advanced of the ones that I tested. It has a simple mode that doesn’t break code and an option for ADVANCED_OPTIMIZATIONS that produces very compressed code. Here is an example command for using the closure compiler in simple mode:

java -jar compiler.jar --js filename.js --js_output_file filename_closure_min.js --externs externs.js

And similarly for advanced mode:

java -jar compiler.jar --compilation_level ADVANCED_OPTIMIZATIONS --js filename.js --js_output_file filename_closure_min.js --externs exterms.js

Similar to perl-Javascript-Minifier, closure compiler only works on pure javascript files. Because of the effectiveness of the optimizations that it does, it can break code. To effectively use it, you need to design your javascript with minification in mind. Typically you want to use your javascript as a library (i.e. as handers for events such as mouse clicks) to do this, you need to add a small amount of code that preserves the function names that will be available to external scripts. Similarly if you want to use external libraries in your library, you need to add extern declarations that will preserve the external symbols. There are less modifications required if you use the simple mode than for the advanced mode. I wanted to use advanced mode for some script that contains jQuery calls (including jQuery Mobile), but wasn’t able to find a way to preserve the jQuery and $ symbols. I tried using –externs with the externs file available as an addon from google svn, but this didn’t solve the problem. Therefore I recommend using simple mode for files containing jQuery and advanced mode for files that do not.

 

In summary of the tools reviewed google closure compiler is the most effective, perl-Javascript-Minifier is the least likely to break code, and yuicompressor is a compromise between these extremes. Additionally each of these tools can be run locally on your machine.

TWiki for a dynamic Company Operations Manual

This article is an overview of the TWiki system with an emphasis on usage as an intranet and Company Operations Manual. A small business can benefit by having such a system in several ways :

  • share knowledge and overlap responsibilities
  • document experience and improve processes
  • identify and facilitate process automation

A Company Operations Manual seeks to codify the processes that the company’s operation depends upon. It must

  • be simple to use/extend
  • be easy to navigate
  • have properties that facilitate improvement and revision
  • allow compartmentalization

TWiki fits each of these needs abundantly. It is by nature a system designed for ease of input. Concepts such as WikiWords and WebNotify allow for quick navigation by facilitating linkages among the various processes and automatically prompting personnel when processes of interest are updated. There are plugins that can keep statistics on how frequently topics are used. This allows identification of processes that would be good candidates for automation (high usage) and those that could be improved or deleted (low usage). TWiki also has built-in support for access control via group membership. This coupled with good design can simply the process of restricting auditors, contractors, and guests to areas of their focus, expertise, or clearance.

In small business there are fewer hands, and the processes and policys must be correspondingly light-weight. A dynamic, intranet-based Company Operations Manual is one way to achieve this necessary business requirement.

Interesting facts about media consumption

I’ve been doing some research lately about media consumption by age group and I found a couple graphical representations of the data on this subject.  We’ve been working on a project that utilizes the data shown, but it’s top secret right now so I’ve got to keep it hush hush 😉

The first chart is from adage.com and lists the types of media consumption by generation.  It’s a tough read but the information you’ll get is well worth the effort.

Media Consumption - 2011
Created by: MBA Online

The second chart is much more easy to read :)  It shows the change in internet consumption over the last several years.  As you can see mobile web usage is doubling yearly now while desktop usage is on the decline.  People will be doing what they do online all the time in the near future and internet media consumption will be a continuous thing that never stops.

 

Source: StatCounter Global Stats – Mobile vs. Desktop Market Share

Good luck guessing what we are up to.  I can’t wait to explain it in a blog post.  For now… We’ll see you online.

 

Process Automation: Customer Relationship Management Software – CRM

One of the modern tools of business automation is customer relationship management software commonly known as CRM software. CRM software provides process automation and a centralized data storage point for all things pertaining to suspects, prospects, and customers.

Services offered by the CRM help businesses to organize, synchronize, and manage business processes with the goal of finding, attracting, and winning new clients and then nurturing and retaining those relationships by providing a system that facilitates communication between the client and various departments such as sales, marketing, and support.  The software often serves as the digital hub of a company wide marketing strategy that places a high value on customers relationships and ties financial data to every step involved with acquiring and servicing a customer.

At Catontech we’ve been working with the open source solution Vtiger CRM and evaluating it for future usage and integration with web presence packages allowing leads generated by online marketing efforts to be stored in the system for future marketing efforts.  You can view the video below to get an idea of how the system looks and feels.


What we like about Vtiger is that it is open source and runs on linux, appache, mysql, and php and can be implemented at a very low cost with a low learning curve and integrates nicely with WordPress.  Vtiger CRM is relatively easy to learn and you can get up to speed in about 1/2 an hour.

We have began testing the use of Vtiger Customer Relationship Management Software on three different projects and we will be reporting on the outcome of those ventures in the near future.

– Joel

Protect our Internet Freedom


Those of you that keep up with me know about my book a month program that I use to keep pace with business and technology trends.  Last months book was The Laws of Disruption: Harnessing the New Forces that Govern Life and Business in the Digital Age by Larry Downes.  In it Larry discusses how technologies change society and how law makers oftentimes clash with technology in an effort to appear to be legislating issues that are identified by elements of the society.  Most of the time lawmakers just throw a monkey wrench into markets that are created by innovation.

The following video portrays the latest government intrusion into a market built on technology that it does not understand.  Please watch this video and take action.  We must stand up and protect our internet freedom or we will lose it.  Increased governmental regulation of the internet could change the internet environment and make web applications as we know them a thing of the past.  I didn’t have any part in creating this video but I agree with it 100%.

PROTECT IP Act Breaks The Internet from Fight for the Future on Vimeo.

Tell Congress not to censor the internet NOW! – http://www.fightforthefuture.org/pipa

PROTECT-IP is a bill that has been introduced in the Senate and the House and is moving quickly through Congress. It gives the government and corporations the ability to censor the net, in the name of protecting “creativity”. The law would let the government or corporations censor entire sites– they just have to convince a judge that the site is “dedicated to copyright infringement.”

The government has already wrongly shut down sites without any recourse to the site owner. Under this bill, sharing a video with anything copyrighted in it, or what sites like Youtube and Twitter do, would be considered illegal behavior according to this bill.

According to the Congressional Budget Office, this bill would cost us $47 million tax dollars a year — that’s for a fix that won’t work, disrupts the internet, stifles innovation, shuts out diverse voices, and censors the internet. This bill is bad for creativity and does not protect your rights.

Protect our internet freedom.  Express your concern here!!!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The basic weekly web awareness task list

Building web awareness of your business takes time and consistent effort.  Here is a list of tasks that I work on weekly to insure that people can find Catontech.com. Used consistently these methods will build awareness and cause your website to improve in search engine ranking.

  • Write a blog post about a topic relevant to your business.  I recommend using the WordPress blogging platform.
  • Use an rss reader to read other bloggers articles that are relevant to your business and leave comments with a link to your site.  Try to do a minimum of five comments per week.  I recommend using Google Reader to subscribe to other bloggers RSS feed.
  • Use twitter to comment about things you are doing that are relevant to your business.  I recommend using tweet deck and twaitter to organize and automate some of these tasks.
  • Post updates to Google+ and Facebook
  • Answer questions on Yahoo Answers or Linkedin Answers
Over time performing the tasks in this basic to do list will improve your websites ranking in search engines and drive traffic to your site.  It takes about six months to see a return on investment from this investment of time but it is well worth the effort.
What do you do to promote web awareness of your business online?
– Joel

 

How to know when: comments should be deleted

Tips for quickly determining if comments should be deleted.

Your blog or online publication is a serious investment and the centerpiece of a good inbound marketing program.  You work hard creating content and the payoff occurs when visitors leave their comments.  However there is an insidious element at work on the internet. Spammers are hard at work trying to find ways to trick search engines into thinking that their sites are linked to reputable sites such as yours across the internet. You’ll receive bogus comments on your blog from people trying to create links to sites that they represent.  Serious spammers devise scripts that look for blogs to post generic garbage type comments on that are filled with links to an advertising sites and you can end up getting several of these a day.  This can either give you a false sense of optimism about your readership if you are naive and allow this to take place or it can make your job as content provider tedious when weeding the garbage comments out.  There are several good plugins for handling comments such as Asikmet but they cost money when being used on a business site.  If your on a budget you won’t want to waste your time dealing with these type comments so here’s several quick indicators you can use to quickly and easily determine when comments should be deleted.

When comments should be deleted:

  1. The person leaving the comment didn’t leave their name.  Sometimes you’ll get legitimate commentors that don’t leave their names but if they don’t consider it a strike against them.
  2. The uri in their post (their website) links to a specific product page on a commercial site.
  3. The email address that they posted looks phony.  
  4. The comment isn’t coherent.  
  5. Their comment wasn’t about your article. 
  6. They posted multiple links to advertising sites.
Look for combinations of the things we’ve listed above when reading the comments you receive.  A comment with two or more issues such as the ones we’ve discussed here probably isn’t fit to appear on your site.  With a little practice you’ll become good at skimming comments for these issues and with very little time and effort you’ll know when comments should be deleted.
I’m sure as you continue working on your blog or online publication that you’ll notice more patterns that could be added to this list so feel free to leave comments here on the tips you find.
Legitimate comments are welcome here!!
Joel Caton
Meridian, MS

Catontech Web Presence Package

Introducing the Catontech Web Presence Package

Do you need a web presence for your organization?  Would you like to save money by doing it yourself but you don’t feel you have the time to study all the new technology and gain the required technical expertise?  There is a solution that fits your needs:  The Catontech Web Presence Package.  Let us provide you the tools to give your business an online presence in a cost effective way.  Here’s what the Catontech Web Presence Package offers:

Features:

  • Your own domain .com, .net. .us etc.  Example: yourbusiness.com
  • A cost effective upfront price that will pay for your service for a year!!
  • An easy to use content management system so you can update your site without the hassle of contracting programmers or developers.
  • Guides for do it yourself search engine submission at no cost to you.
  • Coaching on how to promote your site without spending money.
  • Access to free tools you can use to update and maintain your site.
  • Free design of your initial banner and icon.
  • Integration with social media sites such as Twitter and Facebook.
  • Catontech discount club membership.
  • Referral rewards.
– Joel
Meridian, MS

Guidelines for writing great articles

Part of my efforts with the Mississippi Magic Magazine involve setting up guidelines for writing great articles.  If you are wondering why a technologies consultant is posting guidelines on writing great articles then let me explain.  We are in the business of creating success in our constituents that we partner with through consulting and development.  That being said… Mississippi Magic Magazine provides an outlet of expression for people and businesses in Mississippi but it does not employ writers to produce magazine content.  Therefore, all the writing done on the Mississippi Magic Magazine is done by volunteer writers that have a vested interest in the community.  From business owners to pastors of churches, people active in leadership in the community provide all of the content found in magazine.  To make this a profitable venture for each of them, we’ve found it necessary to publish a guidelines for writing great articles.

Benefits:

  • People like to do business with those they are familiar with.   Through connecting with our community through your articles, you’ll lower the barriers that people have to traditional broadcast style advertising communications.  .
  • Articles will be broadcasted to the RSS subscription readership.
  • Articles will be indexed by search engines so that anyone looking the information you provided will find it and you on the internet.
  • Articles will spread in a viral method through through social media sites such as twitter, facebook, and linked in.
  • Unlike traditional media, articles written will be available online well into the indefinite future.
  • Articles will link your thoughts, expertise, and methods to your perceived value as a solutions provider and allow people to reach you.
  • Articles always make the front page when they are published.
Good practices:
  • Offering needed information to make an informed decisions.
  • Offering solutions by showing how to solve a problem.
  • Providing lists of methods or resources.
  • Expounding upon a subject.
  • Offering information about events by featuring information, pictures, and video covering people in the community.
  • Praising and pointing out the good about others.
  • Simplifying complex information, instructions, or events.
Avoid:
  • Slandering others.
  • Defaming others.
  • Advertising your products or services.
  • Soliciting business.
Using these methods, community leaders can provide invaluable content that leads people in the community to them as a provider of services and goods.  Through the relationship formed between the reader and author in the magazine articles these leaders have an inroad to the reader when the reader seeks to find a provider for a need or want that the author can fulfill.
This style of marketing defined in these guidelines for writing great articles are known today as inbound marketing.  By using them you’ll get found on the internet and connect with your customer.
– Joel