To enable transformations, you have to setup the column_info
table and the proper directives. Please see the Configuration on how to do so.
You can apply different transformations to the contents of each
column. The transformation will take the content of each column and
transform it with certain rules defined in the selected
transformation.
Say you have a column ‘filename’ which contains a filename. Normally
you would see in phpMyAdmin only this filename. Using transformations
you can transform that filename into a HTML link, so you can click
inside of the phpMyAdmin structure on the column’s link and will see
the file displayed in a new browser window. Using transformation
options you can also specify strings to append/prepend to a string or
the format you want the output stored in.
For a general overview of all available transformations and their
options, you can consult your <www.your-host.com>/<your-install-
dir>/transformation_overview.php installation.
For a tutorial on how to effectively use transformations, see our
Link section on the
official phpMyAdmin homepage.
Go to your tbl_structure.php page (i.e. reached through clicking on
the ‘Structure’ link for a table). There click on “Change” (or change
icon) and there you will see three new fields at the end of the line.
They are called ‘MIME-type’, ‘Browser transformation’ and
‘Transformation options’.
All specific transformations for mimetypes are defined through class
files in the directory ‘libraries/plugins/transformations/’. Each of
them extends a certain transformation abstract class declared in
libraries/plugins/transformations/abstract.
They are stored in files to ease up customization and easy adding of
new transformations.
Because the user cannot enter own mimetypes, it is kept sure that
transformations always work. It makes no sense to apply a
transformation to a mimetype the transform-function doesn’t know to
handle.
There is a file called ‘transformations.lib.php‘ that provides some
basic functions which can be included by any other transform function.
The file name convention is [Mimetype]_[Subtype]_[Transformation, while the abtract class that it extends has the
Name].class.php
name [Transformation Name]TransformationsPlugin. All of the
methods that have to be implemented by a transformations plug-in are:
The getMIMEType(), getMIMESubtype() and getName() methods return the
name of the MIME type, MIME Subtype and transformation accordingly.
getInfo() returns the transformation’s description and possible
options it may receive and applyTransformation() is the method that
does the actual work of the transformation plug-in.
Please see the libraries/plugins/transformations/TEMPLATE and
libraries/plugins/transformations/TEMPLATE_ABSTRACT files for adding
your own transformation plug-in. You can also generate a new
transformation plug-in (with or without the abstract transformation
class), by using
scripts/transformations_generator_plugin.sh or
scripts/transformations_generator_main_class.sh.
The applyTransformation() method always gets passed three variables:
Transformations¶
Introduction¶
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- The field ‘MIME-type’ is a drop-down field. Select the MIME-type that
corresponds to the column’s contents. Please note that transformations
are inactive as long as no MIME-type is selected. - The field ‘Browser transformation’ is a drop-down field. You can
choose from a hopefully growing amount of pre-defined transformations.
See below for information on how to build your own transformation.
There are global transformations and mimetype-bound transformations.
Global transformations can be used for any mimetype. They will take
the mimetype, if necessary, into regard. Mimetype-bound
transformations usually only operate on a certain mimetype. There are
transformations which operate on the main mimetype (like ‘image’),
which will most likely take the subtype into regard, and those who
only operate on a specific subtype (like ‘image/jpeg’). You can use
transformations on mimetypes for which the function was not defined
for. There is no security check for you selected the right
transformation, so take care of what the output will be like. - The field ‘Transformation options’ is a free-type textfield. You have
to enter transform-function specific options here. Usually the
transforms can operate with default options, but it is generally a
good idea to look up the overview to see which options are necessary.
Much like the ENUM/SET-Fields, you have to split up several options
using the format ‘a’,’b’,’c’,…(NOTE THE MISSING BLANKS). This is
because internally the options will be parsed as an array, leaving the
first value the first element in the array, and so forth. If you want
to specify a MIME character set you can define it in the
transformation_options. You have to put that outside of the pre-
defined options of the specific mime-transform, as the last value of
the set. Use the format “’; charset=XXX’”. If you use a transform, for
which you can specify 2 options and you want to append a character
set, enter “‘first parameter’,’second parameter’,’charset=us-ascii’”.
You can, however use the defaults for the parameters: “’‘,’‘,’charset
=us-ascii’”.
- getMIMEType() and getMIMESubtype() in the main class;
- getName(), getInfo() and applyTransformation() in the abstract class
it extends.
- $buffer – Contains the text inside of the column. This is the
text, you want to transform. - $options – Contains any user-passed options to a transform
function as an array. - $meta – Contains an object with information about your column. The
data is drawn from the output of the mysql_fetch_field() function. This means, all
object properties described on the manual page are available in this
variable and can be used to transform a column accordingly to
unsigned/zerofill/not_null/… properties. The $meta->mimetype
variable contains the original MIME-type of the column (i.e.
‘text/plain’, ‘image/jpeg’ etc.)