Category: PHP
Moving PHP sites to php 7.2 – undefined constants used as a string
PHP7.2 and above will no longer allow Undefined Constants
According to the “Promote the error level of undefined constants” section of the PHP 7.2 Backwards Incompatible Changes Document
Unqualified references to undefined constants will now generate anE_WARNING(instead of anE_NOTICE). In the next major version of PHP, they will generate Error exceptions.
There have been many changes to PHP over its many versions – For Matraex’s use of PHP, each version has been mostly compatible with the previous one with only minor changes, until a major decision affected one of the ways we deliberately used what we once called a “Feature” of PHP. (For a full list of incompatible changes look at the Backwards Incompatible Changes sections in the PHP Appendices )
On March 5th, 2017, Rowan Collins proposed to deprecate bareword strings. In PHP 7.2 the messages throw an E_WARNING message and in PHP 8.0 it will through an E_ERROR.
PHP has always been a loosely typed language which allows flexibility in many ways, And we had used this flexibility in order write code in a ways that we belive made it more legible, maintainable and supportable within our coding style. With this new change, hundreds of thousands of lines of code will need to be rewrittend before we can put it on a 7.2 or above server, keys may be difficult to search, we will have inconsistencies in usage of keys depending on whether they are inside or out side of quotes.
Take this one example where lines 1, 3 and 4 below would work, but line 2 would throw a warning in 7.2 and would through an error in 8.0.
- echo “Hello, $user[firstname],”;
- echo “Hello, “.$user[firstname].”,”;
- echo “Hello, “.$user[‘firstname’].”,”;
- echo “Hello, “.$user[“firstname”].”,”;
Matraex would have previously preferred to use methods 1 and then 2, as they require fewer quotes and a search in our IDE of ‘user[first’ would have highlighted both uses.
Mr Collins did evaluate both sides of the decision and wrote a bit about it. He described that “The value of keeping the current behaviour would be for programs written to deliberately take advantage of it”, however he really dismisses that value and gave a stronger argument undefined constants can “mask serious bugs”.
I agree with each of the arguments and our 7.2 scripts will all comply with this new syntax requirement. However, I disagree with the way the solution was indiscriminately executed. A more considerate solution would have been to create a configuration option in PHP to control the requirement and allow developers and system administrators to continue to ‘deliberately’ use ‘undefined constants’. This option would also allow existing stable programs to continue to take advantage of the other features of PHP >=7.2 without a significant refactor. Perhaps the Impact section of the article could attempted to get more feedback from users that had deliberately made heavy investment in this feature.
To be more direct here is my request: PHP developers, please create / allow a configuration option in PHP which will allow undefined constants to be used as strings.
Changing existing code across the 10 + years of PHP projects will take thousands of hours to modify and test, and that is just the projects that still exist. This is a barrier to upgrading to PHP 8.0.
Arguments for a configuration option
- Millions of lines of code which deliberately use undefined constants as string (more likely billions or trillions – I probably have close to one million myself overtime)
- My random belief: PHP should enforce “standards” on those that want or need them, and allow experience users to explicitly choose to ignore them.
- The configuration option would be disabled by default to address all of the problems mentioned in ‘the problem’ section of the article
Dealing with undefined constant warnings
Now we get to more technical area where I document some of the methods we have used to find code that needs to be updated for PHP 7.2 code.
1) Use grep to find all uses of the code
This code finds ALL uses of lower case strings without quotes – because our standards do require constants to be in upper case
grep -Rne ‘\$[A-Z\_a-z]*\[[A-Za-Z\_]\{1,\}\]’ *.php
2) Suppress E_WARNING messages
This is a bad idea, while it will certainly make it so that your code continues to work in 7.2, it will not fix it going into 8.0, and this WILL mask other issues that you do need to know about.
If you want to learn mroe about this, take a look at this discussion about it on Stack Overflow. Definitely read the comments about hiding warnings to get a better feel for it.
3) Create PHP configuration options to make provisions for undefined constants
These options would require the good work of a C developer that works on the PHP source. Some of these ideas may just work as described, they really are just a good start (or continuation) of a discussion for features which could be implemented. I don’t have a ‘bounty’ system but if you are interested in creating any of these options, or would like to group together to coordinate it, please contact me.
- undefined_constants_string_level – Have a PHP directive which declares what E_ level all undefined constant warnings should – default in 8.0 can be E_ERROR
- undefined_constants_string_lowercase – Allow users to configure options which would allow only lowercase (or mixed case) constants as strings – which would allow / reserve upper case for use as constants.
- undefined_constants_string_superglobal – Allow undefined constants to be used when attempting to reference any key to a super global array (such as $_POST[mykey] or S_SERVER[HTTP_HOST]);
Solution -> Fatal error: Allowed memory size exhausted wp-includes/class.wp-dependencies.php on line 339
Recently one of our Managed WordPress Services clients came to me to describe a problem with a WordPress site they were working on.
If you need in depth help debugging an erro on your WordPress of PHP site, contact us.
They were receiving an error: Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 71 bytes) in /***REDACTED_PATH***/wp-includes/class.wp-dependencies.php on line 339
The client described that they had not done any kind of upgrades or changes to cause the issue and asked about whether we did any upgrades as part of the weekly site reviews we do under the Managed WordPress Service. I found in the weekly email report sent by another person in our office, that we had done some upgrades, however the file that was throwing the error (class.wp-dependencies.php) had not been updated. So I had to dig in deeper to find the root cause.
I ended up writing some debugging code that I placed directly in class.wp-dependencies.php that helped me to identify some of the causes. Because I found lots of other sites when googling that had the same error, I decided I would post the debugging code, in the case that it helps other users debug their issue. The issue ended up being that site had an enqueued script jquery which dependency on jquery-migrate which in turn had a dependency on jquery. This circular reference looped in the WP code until the server ran out of memory. (in this case it was about 128MB).
The theme and plugins had two locations which enqueued jquery scripts, one was enqueud BEFORE a dependency existed, then a dependency was created and the script was queued again. The code I wrote is intended for debuggin purposes, because the the issue could easily come from other issues, and I wanted to see the backtrace for exactly where the problematic scripts (jquery, jquery-migrate) were queued from.
Here is the output from my code:
MATRAEX Debugging Code This WordPress project has circular dependencies
Aborting script execution at /***PATH_REDACTED***/wp-includes/class.wp-dependencies.php:400
Debugging tip look for theme code that calls ‘enqueue’ on for items which already have dependencies)
If this error did not show, your script would have likely errored on line 339 when it ran out of memory from the circular debugging.
Most likely this is a plugin error!!
jquery has a dependency on jquery-migrate which has a circular dependecy on jquery
Backtrace of when jquery was enqueued:
Instance 0:
#0 WP_Dependencies->enqueue(jquery) called at [/***PATH_REDACTED***/wp-includes/functions.wp-scripts.php:276] #1 wp_enqueue_script(jquery, http://dev.art4healing.org/wp-content/plugins/jquery-updater/js/jquery-3.1.1.min.js, , 3.1.1) called at [/***PATH_REDACTED***/wp-content/plugins/jquery-updater/jquery-updater.php:26] #2 rw_jquery_updater() #3 call_user_func_array(rw_jquery_updater, Array ([0] => )) called at [/***PATH_REDACTED***/wp-includes/plugin.php:524] #4 do_action(wp_enqueue_scripts) called at [/***PATH_REDACTED***/wp-includes/script-loader.php:1197] #5 wp_enqueue_scripts() #6 call_user_func_array(wp_enqueue_scripts, Array ([0] => )) called at [/***PATH_REDACTED***/wp-includes/plugin.php:524] #7 do_action(wp_head) called at [/***PATH_REDACTED***/wp-includes/general-template.php:2555] #8 wp_head() called at [/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php:19] #9 require_once(/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php) called at [/***PATH_REDACTED***/wp-includes/template.php:572] #10 load_template(/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php, 1) called at [/***PATH_REDACTED***/wp-includes/template.php:531] #11 locate_template(Array ([0] => header.php), 1) called at [/***PATH_REDACTED***/wp-includes/general-template.php:45] #12 get_header() called at [/***PATH_REDACTED***/wp-content/themes/Parallax-One/front-page.php:5] #13 include(/***PATH_REDACTED***/wp-content/themes/Parallax-One/front-page.php) called at [/***PATH_REDACTED***/wp-includes/template-loader.php:75] #14 require_once(/***PATH_REDACTED***/wp-includes/template-loader.php) called at [/***PATH_REDACTED***/wp-blog-header.php:19] #15 require(/***PATH_REDACTED***/wp-blog-header.php) called at [/***PATH_REDACTED***/index.php:17]
Instance 1:
#0 WP_Dependencies->enqueue(jquery) called at [/***PATH_REDACTED***/wp-includes/functions.wp-scripts.php:276] #1 wp_enqueue_script(jquery) called at [/***PATH_REDACTED***/wp-content/plugins/nextgen-gallery/nggallery.php:513] #2 C_NextGEN_Bootstrap->fix_jquery() #3 call_user_func_array(Array ([0] => C_NextGEN_Bootstrap Object ([_registry] => C_Component_Registry Object ([_searched_paths] => Array ( ....... #4 do_action(wp_enqueue_scripts) called at [/***PATH_REDACTED***/wp-includes/script-loader.php:1197] #5 wp_enqueue_scripts() #6 call_user_func_array(wp_enqueue_scripts, Array ([0] => )) called at [/***PATH_REDACTED***/wp-includes/plugin.php:524] #7 do_action(wp_head) called at [/***PATH_REDACTED***/wp-includes/general-template.php:2555] #8 wp_head() called at [/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php:19] #9 require_once(/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php) called at [/***PATH_REDACTED***/wp-includes/template.php:572] #10 load_template(/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php, 1) called at [/***PATH_REDACTED***/wp-includes/template.php:531] #11 locate_template(Array ([0] => header.php), 1) called at [/***PATH_REDACTED***/wp-includes/general-template.php:45] #12 get_header() called at [/***PATH_REDACTED***/wp-content/themes/Parallax-One/front-page.php:5] #13 include(/***PATH_REDACTED***/wp-content/themes/Parallax-One/front-page.php) called at [/***PATH_REDACTED***/wp-includes/template-loader.php:75] #14 require_once(/***PATH_REDACTED***/wp-includes/template-loader.php) called at [/***PATH_REDACTED***/wp-blog-header.php:19] #15 require(/***PATH_REDACTED***/wp-blog-header.php) called at [/***PATH_REDACTED***/index.php:17]
jquery-migrate has a dependency on jquery which has a circular dependecy on jquery-migrate
Backtrace of when jquery-migrate was enqueued:
Instance 0:
#0 WP_Dependencies->enqueue(jquery-migrate) called at [/***PATH_REDACTED***/wp-includes/functions.wp-scripts.php:276] #1 wp_enqueue_script(jquery-migrate, http://dev.art4healing.org/wp-content/plugins/jquery-updater/js/jquery-migrate-3.0.0.min.js, Array ([0] => jquery), 3.0.0) called at [/***PATH_REDACTED***/wp-content/plugins/jquery-updater/jquery-updater.php:32] #2 rw_jquery_updater() #3 call_user_func_array(rw_jquery_updater, Array ([0] => )) called at [/***PATH_REDACTED***/wp-includes/plugin.php:524] #4 do_action(wp_enqueue_scripts) called at [/***PATH_REDACTED***/wp-includes/script-loader.php:1197] #5 wp_enqueue_scripts() #6 call_user_func_array(wp_enqueue_scripts, Array ([0] => )) called at [/***PATH_REDACTED***/wp-includes/plugin.php:524] #7 do_action(wp_head) called at [/***PATH_REDACTED***/wp-includes/general-template.php:2555] #8 wp_head() called at [/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php:19] #9 require_once(/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php) called at [/***PATH_REDACTED***/wp-includes/template.php:572] #10 load_template(/***PATH_REDACTED***/wp-content/themes/Parallax-One/header.php, 1) called at [/***PATH_REDACTED***/wp-includes/template.php:531] #11 locate_template(Array ([0] => header.php), 1) called at [/***PATH_REDACTED***/wp-includes/general-template.php:45] #12 get_header() called at [/***PATH_REDACTED***/wp-content/themes/Parallax-One/front-page.php:5] #13 include(/***PATH_REDACTED***/wp-content/themes/Parallax-One/front-page.php) called at [/***PATH_REDACTED***/wp-includes/template-loader.php:75] #14 require_once(/***PATH_REDACTED***/wp-includes/template-loader.php) called at [/***PATH_REDACTED***/wp-blog-header.php:19] #15 require(/***PATH_REDACTED***/wp-blog-header.php) called at [/***PATH_REDACTED***/index.php:17]
Add this following code to the query() function, just before the return statement withing the the “case ‘queue’ :” line in the file wp-includes/class.wp-dependencies.php. (in the version current as of this writing it is about line 387)
//BEGIN NON WP CODE - MATRAEX foreach($this->queue as $queued) $check[$queued]=$this->registered[ $queued ]->deps; foreach($check as $queued => $deparr) foreach($deparr as $depqueued) if($check[$depqueued] && in_array($queued,$check[$depqueued])) $recursivedependencies[$queued]= $depqueued; if($recursivedependencies) { $_SERVER[DOCUMENT_ROOT] = str_replace("/home","/data",$_SERVER[DOCUMENT_ROOT]); ob_start(); echo "
MATRAEX Debugging Code
blog post
This WordPress project has circular dependencies
Aborting script execution at “.__FILE__.”:”.__LINE__.”
Debugging tip look for theme code that calls ‘enqueue’ on for items which already have dependencies)
If this error did not show, your script would have likely errored on line 339 when it ran out of memory from the circular debugging.
Most likely this is a plugin error!!
“; global $enqueue_backtrace; foreach($recursivedependencies as $queued =>$depqueued) { echo ”
$queued has a dependency on $depqueued which has a circular dependecy on $queued” ; echo ”
Backtrace of when $queued was enqueued: “; foreach($enqueue_backtrace[$queued] as $k=>$lines) { echo ”
Instance $k:"; foreach(explode("\n",$lines) as $line) if(strstr($line,'enqueue')) echo "$line\n"; echo "“;
}
}
$out=ob_get_clean();
$out = str_replace($_SERVER[DOCUMENT_ROOT],”/***PATH_REDACTED***/”,$out);
$out = str_replace(“/plugins/”,”/plugins/”,$out);
$out = str_replace(“/themes/”,”/themes/”,$out);
echo $out;
exit;
}
//END NON WP CODE – MATRAEX
The full function code should look like this
In Addition, add the following code to the enqueue function just below the line with public function enqueue () at the time of this writing, that wa about line 378 of wp-includes/class.wp-dependencies.php.
//BEGIN NON WP CODE - MATRAEX global $enqueue_backtrace; ob_start(); debug_print_backtrace(); $enqueue_backtrace[$handles][] = ob_get_clean(); //END NON WP CODE - MATRAEX
The full function code should look like this
Find all PHP Short Tag instances – COMMANDLINE
Occassionally we have run across web products which were developed using the PHP short open tag “<?” instead of “<?php”.
We could go into the php.ini file and update “short_open_tag” to “On”, however this ends up creating software which can not run on as many servers, and it is less transportable between servers.
The command below when run from the directory that houses all of your PHP files, will identify all of the files which use short open tags. You will then be able to make the changes to the files from <? to <?php
grep -rI '<?' -n . |grep -v '<?[(php)(xml)="]'
This command is running a first grep statement recursively in the current directory looking for any “<?”. The output of this is passed through another grep statement which then ignores any instances of “<?php”, “<?xml”, “<?=” and ‘<?”‘
Lets decompose:
- -r – means search the current (“.”) directory recursively
- -I means ignore binary files
- ‘<?’ search for all instances of ‘<?’
- -n – add the line number of the found code to help you find it faster
- -v – in the excludes anythign that matches in the second grep statement
- ‘ the regular expression then matches each of the items we want to ignore.
Note:
I have put in double quote(“) in the regular expression which ignores <?” because we have some php functions which loop through some XML code and tests for “<?”.
Website WordPress PHP Custom Application Development Boise
Website WordPress PHP Custom Application Development Boise
I was asked recently, what kinds of work do you do for your clients.
The short answer is “Matraex, Inc provides Website WordPress PHP Custom Application Development Boise to small businesses”
Below I describe our services in more depth.
Contact me to discuss what we can do for you – Michael Blood – 208.344.1115 x 250
Matraex, Inc – Nationwide Web Services
- We design online presence websites in WordPress.
- We custom build web applications for businesses, entrepreneurs and individuals with ideas.
- We create custom automation and time saving software using the web.
- We support, refresh, repair and enhance existing websites and custom applications.
- We provide Managed WordPress Hosting services.
- We build, host and support custom scale-able hosting environments.
Matraex, Inc – Basic consulting and technology list
- WordPress Website Development
- WordPress Plugin Development
- Custom Web Application Development
- Web Task Automation
- PHP Development
- MySQL and Postgres Database Administration
- Website Overhaul and Repair
Matraex Inc, – Boise, Idaho Web Services:
While we work for clients nationwide. A large percentage of our clients are from here in Boise, Idaho. When items become complex we are able to work directly with clients in our office onsite at our client’s office. We communicate via skype or just on the phone.
- Boise, Idaho WordPress Website Development
- Boise, Idaho WordPress Plugin Development
- Boise, Idaho Custom Web Application Development
- Boise, Idaho Web Task Automation
- Boise, Idaho PHP Development
- Boise, Idaho MySQL and PostgreSQL Database Administration
- Boise, Idaho Website Overhaul and Repair
WordPress Website Development
WordPress is an online, open source website creation tool written in PHP. WordPress allows Matraex, Inc to quickly create a beautiful online presence for your business and the give you the ability to login and make simple updates to your site. It is the easiest and most powerful blogging and website content management system (or CMS)
We offer WordPress Website Development solutions that are compatible with all business models and industry verticals. Our team of WordPress developers provides WordPress CMS development, plugin development. Also theme customization and maintenance services as well as ongoing security and update services through our Managed WordPress Hosting.
When you engage Matraex, Inc to build or enhance your online, unless you have another tool in place. We will likely recommend that we develop your marketing presence using the WordPress Content Management System. Depending on your vertical and your website needs we will either find existing WordPress plugins. We also build new plugins which add the needed custom touch to your website.
WordPress Plugin Development
A WordPress plugin is a piece of software that can be uploaded to extend and expand the functionality of your WordPress site. Matraex, Inc builds custom plugins such as this, any time that our client needs are not met with the base WordPress Package.
In each of these situations, Matraex, Inc relies on its deep knowledge of WordPress. Also the WordPress SDK and the PHP programming language to implement new and innovative website features.
Legacy WordPress Plugin Repair and Replacement
In many cases we have customers with existing WordPress websites with plugins which are out of date. Even some what wont work with newer versions of WordPress, in these cases we can:
- Find an up to date WordPress Plugin which replaces the functionality of the out of date plugin
- Make changes to the WordPress Plugin code to bring it up to date or
- Build a replacement plugin made for the current version of WordPress.
Custom Web Application Development
Matraex, Inc works with entreprenuers, business owners and individuals with ideas to define innovative Web based applications and solutions which solve real world problems. Our team takes stakeholders through a process to define problems and craft potential solutions. From this we build a project that our clients want and the Matraex team can commit to. We then work closely with the client to get constant feedback throughout the development process to implement a fabulous product. Each of our Custom Web Application projects are implemented into a production hosting environment, where we continue to support them as needed.
Web Task Automation
Most people that work within a small business recognize problems and issues within their industry that need to be fixed. Small tasks which take up more time, than the value they provide. They often know that if they had the software, the task could be automated. Matraex, Inc builds the custom software that provides this automation. We work with our clients, the industry professionals who understand the issues. We create software which reliably accomplishes and automates the tasks. We periodically followup on the process to confirm that the software continues to accomplishes what has been intended or whether it could be improved.
PHP Development
PHP Powers nearly 70% of websites and has emerged as the most preferred & widely used server-side language. Historically, 90% of our development projects have been done with PHP. All new development projects are done using PHP, whether it is within the WordPress CMS. The laravel Framework, uses other composer packages. Or a custom frameworkless PHP project using a homegrown library of functions.
Matraex builds PHP websites using MySQL, Linux and Apache which is popularly known as the LAMP platform. We are able to launch new LAMP shared or dedicated development and production environments in minutes at one of our two redundant Data Centers (Involta and Fiberpipe)
Our company’s PHP Development Services offer multipurpose solutions that encapsulate the following:
- PHP Web Development
- PHP Application Development
- Custom PHP Development
- PHP Software Customization and Integration
- PHP Porting and Migration
- Packaged PHP Applications
- PHP Professional Services
- PHP Outsourcing
MySQL and Postgres Database Administration
The custom applications that Matraex, Inc develops integrate with a database to store persistent application data. Some applications like WordPress automatically setup and manage all aspects of the MySQL database architecture. But our custom applications require database administration (DBA) services for setup and maintenance. Matraex, Inc has Oracle Certified MySQL Administration experts to address the Database needs of these custom applications.
Matraex, Inc internally follows very stringent Database Naming conventions which we have used for more than 10 years. These standards allow our development team to very quickly create custom relationships. We also area able to easily read and understand relationships in existing applications we have built.
Website Overhaul and Repair
Websites get old, designs get tired and software gets outdated. Matraex, Inc breathes new life into websites by either a small simple change. Or a complete website overhaul. Depending on the client need we address goals and budget to recreate websites which perform.
Matraex offers Website WordPress PHP Custom Application Development Boise.
Grep command to find all PHP shortcode entries
Grep command to find all PHP shortcode entries
As PHP files are moved from one server to the other, occassionally we find a situateion where PHP was developed on a server that allowed shortcodes “<?” which does not use the longer “<?php” if this happens, the PHP code does not execute and shows the code that would have executed, on the output of the page.
When this happens I have found that using a simple command I can identify all of the places that use the short code
grep -n '<?[^p=]' *.php
COMMANDDUMP – Upgrading from PHP 5.3 to 5.6 on Ubuntu 14.04
COMMANDDUMP – Upgrading from PHP 5.3 to 5.6 on Ubuntu 14.04
When upgrading from PHP version 5.3 to 5.6 there are several things to worry about. On a shared system with multiple sites which do not make use of a common unit testing or library, these tools and commands could be useful to find issues. (this would also work from 5.4 or from 5.5 to 5.6)
COMMAND DUMP of things I ran.
Create a file call 5.4.php.searchterms
#echo import_request_variables >> upgrade.php.searchterms
#echo session_is_registered >> upgrade.php.searchterms
#echo session_register >> upgrade.php.searchterms
#echo session_unregister >> upgrade.php.searchterms
#echo define_syslog_variables >> upgrade.php.searchterms
#echo register_globals >> upgrade.php.searchterms
#echo sqlite >> upgrade.php.searchterms
#echo php_logo_guid >> upgrade.php.searchterms
#echo php_egg_logo_guid >> upgrade.php.searchterms
#echo php_real_logo_guid >> upgrade.php.searchterms
#echo zend_logo_guid >> upgrade.php.searchterms
#echo register_long_arrays >> upgrade.php.searchterms
#find -type f -name ‘*.php’ -exec grep -f upgrade.php.searchterms {} \; -ls
Check the version of your server
#lsb_release -a
#dpkg -l |grep php|grep apache
#php -v
#apache2ctl -vV
To upgrade from ubuntu 14.04 LTS you have to get php 5.6 from another repository as it is not includedin the default repos
apt-get -y update
apt-get install -y software-properties-common
add-apt-repository ppa:ondrej/php5-5.6 -y
apt-get -y update
apt-get -y install php5 php5-cli php5-common php5-curl php5-gd php5-imap php5-json php5-mysql php5-readline
You will be prompted when installing the latest version of PHP5 whether you want to keep the old or new version of PHP5.ini I chosed to install the pakage maintainer’s version, then I compare the two and update the new one with the differences. The following command makes it easy to compare by removing all of the commented lines from the diff against the backed up file
cd /etc/php5/apache2 diff <(grep -v '^\s*;' php.ini|awk '$1 != ""') <(grep -v '^\s*;' php.ini.ucf-old|awk '$1 != ""')|more
I also updated the php.ini date.timezone setting to my area due to this php.net post
date.timezone = America/Boise /etc/init.d/apache2 reload
Preg_Match Visual Composer PHP Error
We started getting a preg_match Visual Composer PHP error that was: Warning: preg_match() expects parameter 2 to be string, array given in /wp-content/themes/bridge/vc_templates/vc_empty_space.php on line 12.
I was able to determine that when using the empty space feature for managing site contents in the design, if you saved “px” in the pixel value for the size of the empty space, WordPress results would throw this error. For example, if I saved 16px for the size, we would get this error message. However, if I went back in and just saved the value as 16 the system would work as expected.
This is only a slight fix, I have discovered that in a recent update to Visual Composer, the issue was resolved. So be sure you have updated to (at this time) v4.8
Here is a quick link to the Visual Composer plugin.
This webpage is not available ERR_CONTENT_DECODING_FAILED – PHP ob_start() ob_gzhandler – Trailing spaces after closing ?> in WordPress Plugin
This webpage is not available ERR_CONTENT_DECODING_FAILED – PHP ob_start() ob_gzhandler – Trailing spaces after closing ?> in WordPress Plugin
Recently we ran into an issue where a website would not load. We traced the problem to a line in the code which attempted to pass all content to ob_start(‘ob_gzhandler’).
This basically words to zip up all content and send it to the browser. However an error was being thrown ERR_CONTENT_DECODING_FAILED, which showed up in the browser window and in the browser console. After some detailed debugging in PHP using some die commands()
die("die: ".__FILE__.":".__LINE__);
I found that the issue came from an rogue blank character which displayed before the ob_start(“ob_gzhandler”) function could be called.
There were a couple of ways I could deal with this, first I could simply put an ob_start() at the top of the code, and then put an ob_get_clean(); just before the ob_start(‘ob_gzhandler’), however this felt a bit sloppy, so I went in search of the rogue character.
The application that this was in, was one that simply included the wordpress load file so that it could integrate with a WordPress installation, and I found that the characters was coming from the WordPress install. Using a hunch I decided d to look for a recently updated plugin and I quickly found a plugin that had an end php tag “?>” with an extra line after it.
I quickly fixed this and then decided I would figure out a way to quickly identify issues like this. While there are many ways to address this and figure out how to over come it, the issue seems to identify an need to figure out whether plugins conform to some best practices (such as omitting a closing ?> php sign)
If we identify this need, we will write a free plugin to put on the WordPress site, which will go through all plugins on sites to confirm that they use some best practices such as this.
Find out which PHP packages are installed on ubuntu / debian
Find out which PHP packages are installed on ubuntu / debian
As we have moved or upgraded sites from one server to another, sometimes we have needed to know which PHP5 dependencies were installed on one server servera, so that we could make sure those same dependencies were met on another server serverb
To do this we can run a simply command line tool on server a
servera# echo `dpkg -l|awk '$1 ~ /ii/ && $2 ~ /php5/{print $2}'`
libapache2-mod-php5 php5 php5-cli php5-common php5-curl php5-gd php5-mcrypt php5-mysql php5-pgsql
and then we copy the contents of the output and past it after the apt-get install command on serverb
serverb# apt-get install libapache2-mod-php5 php5 php5-cli php5-common php5-curl php5-gd php5-mcrypt php5-mysql php5-pgsql
Dont forget to reload apache as some packages do not reload it automatically
serverb# /etc/init.d/apache2 reload
PHP Solution to http to https ajax call: No ‘Access-Control-Allow-Origin’ header is present on the requested resource
PHP Solution to http to https ajax call: No ‘Access-Control-Allow-Origin’ header is present on the requested resource
When submitting a form from an http:// site to an https:// via ajax, you will run into the following error in the Chrome console
XMLHttpRequest cannot load https://www.example.com. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://www.example.com' is therefore not allowed access
This problem can come about if your current url is http://www.example.com/ and you are using an ajax POST or GET request to the https://www.example.com site.
For example on http://example.com/login.php you might have some JQuery such as
$('div#login').load('https://example.com/loginform.php')
Or
$.post({url:'https://example.com/loginform.php'
,data: 'username=bob&password=pass123'
,success: function(data){ $('div#login').html('You are logged in') }
})
To correct this, add the following PHP to the top of the loginform.php page. Note the HTTP_HOST variable which should make it so that if you are simply trying to access the https:// site using the exact same domain name you will not have to change the code
<?php
header("Access-Control-Allow-Origin: http://$_SERVER[HTTP_HOST]");
?>