{"id":1073,"date":"2014-07-01T21:31:58","date_gmt":"2014-07-02T01:31:58","guid":{"rendered":"http:\/\/cfdbplugin.com\/?page_id=1073"},"modified":"2016-08-22T19:41:03","modified_gmt":"2016-08-22T23:41:03","slug":"filter-functions","status":"publish","type":"page","link":"https:\/\/cfdbplugin.com\/?page_id=1073","title":{"rendered":"Filter Functions"},"content":{"rendered":"

Situation<\/h3>\n

In a short code or export link you want to have a filter expression that calls a PHP function on a field value. Example: You want to check for a value in a case-insensitive way: [cfdb-table form=”form1″ show=”first_name” filter=”strtoupper(first_name)=MIKE”<\/span>] Output looks like:<\/p>\n\n\n\n\n
first_name<\/td>\n<\/tr>\n
Mike<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Here we use the PHP function strtoupper<\/a> to upper-case the value in the first_name<\/strong> field and compare it with “MIKE<\/strong>“. This does not upper case first_name when it is displayed. It only upper cases it for the purpose of doing the comparison. So if the actual value for first_name is “Mike” the filter would pass but you would still see “Mike” displayed by the short code output. Alternatively, a filter does not need to be compared to a value if it just returns true or false. For example, the following short code filters for all “your-email” fields that have “@gmail.com” in them. [cfdb-table form=”myform” filter=”strpos(your-email,@gmail.com)>1″<\/span>]<\/p>\n

Filter\u00a0Functions vs.\u00a0Transforms Functions<\/h3>\n

Instead of upper-casing first_name in the filter, we can upper-case it before it gets to the filter. Using a transform, we change the actual value of the first_name field. Then when it gets to the filter, it is already upper-cased. Furthermore, it is displayed by the short code as upper-cased. [cfdb-table form=”form1″ show=”first_name”\u00a0trans=”first_name=strtoupper(first_name)” filter=”first_name=MIKE”<\/span>] Output looks like:<\/p>\n\n\n\n\n
first_name<\/td>\n<\/tr>\n
MIKE<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

See more about Transform Functions<\/a>. The rest of this page focuses on Filter Functions<\/p>\n

What Functions Can Be Used?<\/h3>\n

Potentially any PHP function can be used, including those you create. But there are only a small set that you can use with default settings. These include most string-related PHP functions.<\/p>\n

Function Security<\/h3>\n

A user who can create a short code (or export link) could potentially run a PHP function that might harm your installation or data. Therefore security restrictions are in place by default. This security can be turned off entirely in the administration page Contact Form DB<\/strong> -> Options<\/strong>\u00a0->\u00a0Allow Any Function in Short Codes<\/strong>. If that is set to true<\/strong> then users which role for\u00a0Can See Submission when using shortcodes<\/strong> can write a short code or compose a URL that can run any PHP function. It is best to keep this option to false<\/strong>. Alternatively, individual functions that the administrator deems as safe can be registered as being permissible to use.<\/p>\n

Permitting a Function and Creating Custom Functions<\/h3>\n

To permit individual functions, you will need to be able to add PHP code to register function names. First, install the\u00a0Shortcodes Actions and Filters plugin<\/a>\u00a0and activate it. From the administration page, go to the\u00a0Tools<\/strong>\u00a0menu ->\u00a0Shortcodes Actions and Filters<\/strong>. Put your code there and save. Syntax errors will be displayed when you save. Example: to register a custom function “cfdb_reverse” define the function the call cfdb_register_function.<\/p>\n

require_once(ABSPATH . 'wp-content\/plugins\/contact-form-7-to-database-extension\/CFDBPermittedFunctions.php');\r\n\r\nfunction cfdb_reverse($text) {\r\n  return strrev($text);\r\n}\r\n\r\ncfdb_register_function('cfdb_reverse');<\/pre>\n
You can then use the function in a filter, e.g. [cfdb-table form=”myform” filter=”cfdb_reverse(first_name)=ekim”<\/span>] Existing PHP and WordPress functions can be added using cfdb_register_function(function_name<\/em>).<\/p>\n
Function Parameters<\/h3>\n
Your custom function can take zero or more parameters. Parameters can be:<\/p>\n