Configuration File Processing with PHP - A Grouped Configuration File
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A type of configuration file that closely resembles the one we just examined is like that used for the Windows transparency layer for Linux machines, WINE.
;; MS-DOS drives configuration
;;
;; Each section has the following format:
;; [Drive X]
;; "Path"="xxx" (Unix path for drive root)
;; "Type"="xxx" (supported types are 'floppy', 'hd', 'cdrom'
;; and 'network')
;; "Label"="xxx" (drive label, at most 11 characters)
;; "Serial"="xxx" (serial number, 8 characters hexadecimal)
;; "Filesystem"="xxx" (supported types are 'msdos'/'dos'/'fat',
;; 'win95'/'vfat', 'unix')
;; This is the FS Wine is supposed to emulate on a certain
;; directory structure.
;;
[Drive C]
"Path" = "/pack/Work/windows/c"
"Type" = "hd"
"Label" = "MS-DOS"
"Filesystem" = "win95"
[Drive D]
"Path" = "/mnt/cdrom"
"Type" = "cdrom"
"Label" = "CD-Rom"
"Filesystem" = "win95"
; make sure that device is correct and has proper permissions ! |
As we examine the sample from the configuration file we notice that it has been organized into related sections. We also see that the semi-colon is being used to denote comment lines and that we'll also want to treat the double quotes as white space.
PHP code designed to read such a configuration file might look like this:
<?php
$config_file = "my_config.conf";
$comment = ";";
$group = "NONE";
$fp = fopen($config_file, "r");
while (!feof($fp)) {
$line = trim(fgets($fp));
if ($line && !ereg("^$comment", $line)) {
if (ereg("^\[", $line) && ereg("\]$", $line)) {
$line = trim($line,"[");
$line = trim($line, "]");
$group = trim($line);
} else {
$pieces = explode("=", $line);
$pieces[0] = trim($pieces[0]) , "\"");
$pieces[1] = trim($pieces[1]) , "\"");
$option = trim($pieces[0]);
$value = trim($pieces[1]);
$config_values[$group][$option] = $value;
}
}
}
fclose($fp);
if ($config_values['Drive D']['Type'] == "cdrom")
echo "Drive D is configured as a CD-Rom device<br />";
else
echo "Drive D is not configured as a CD-Rom device<br />"; |
Here we've expanded the code from the previous scenario to allow blocked configuration values.
The $config_file variable still holds the name of the configuration file and $comment has been changed to reflect the use of the semi-colon as a comment delimiter.
After we obtain a line from the configuration file and have determined it to be something worthwhile, we need to evaluate whether it is a grouping element or a directive. Another comparison to check for an opening and closing brackets at the beginning and end accomplishes this.
The grouping element is stripped of its brackets and any remaining white space. It's stored as $group and is used as the first branch of our multi-dimensional array so that all related directives can are kept together.
If the line is a directive then it is split, stripped and stored. The information from the configuration file can be used throughout the script by referencing the array by its group and directive.
Next: Conclusion >>
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