Parsing INI Strings and Files

Reading configuration files

In your PHP applications, it is recommended to separate the configuration information (database host, username, password, etc.) from your code to a separate file so the configuration can be swapped without changing the code itself.

A very well-known file format is the INI file format which drives the configuration of complex software products like PHP. For example, take a look at php.ini. Here are some chunks from the default php.ini file that shows very well the structure of INI files:

[mail function]
; For Win32 only.
; https://php.net/smtp
SMTP=localhost
; https://php.net/smtp-port
smtp_port=25

[Date]
date.timezone=Europe/Berlin
[MySQL]
mysql.allow_local_infile=On
mysql.allow_persistent=On
mysql.cache_size=2000

So, there are sections that start with a section headline in square brackets, comments that start with a semicolon, and settings in the format name=value.

The PHP function parse_ini_file() reads a configuration file and creates an array out of it.

parse_ini_file()

<?php
 //Syntax
 parse_ini_file(string $filename,
     bool $process_sections = false,
     int $scanner_mode = INI_SCANNER_NORMAL
  ): array|false

The parse_ini_file() function greatly simplifies the creation of our settings parser, it takes three parameters:

1. $filename
   The filename of the ini configuration file being parsed.
2. $process_sections
   The default value is false which returns all settings at once in a simple array. By setting this parameter to true, you can parse the ini file by sections which returns a multidimensional array with the section names and settings included as subarrays. See process_sections example.
3. $scanner_mode
   The default value is INI_SCANNER_NORMAL. The value INI_SCANNER_RAW indicates that the function should not parse option values.

Example: Reading/parsing an ini configuration file:

We created a config file config.ini for our PHP application:

[Emails]
admin=admin@brainbell.com
team=info@brainbell.com
[DB]
host=localhost
name=dbname
user=dbuser
pass=passwordx
port=3306
[Cache]
html.file=On

The parse_ini_file() function converts the contents of the config file into an associative array:

<?php
 $ini = parse_ini_file('config.ini');
 echo '<pre>';
 print_r($ini);

The above code prints the following result on the web browser:

Array
(
    [admin] => admin@brainbell.com
    [team] => info@brainbell.com
    [host] => localhost
    [name] => dbname
    [user] => dbuser
    [pass] => passwordx
    [port] => 3306
    [html.file] => 1
)

Example: Reading configuration of a specific section

If you want to group INI file sections, just set the second parameter to true in parse_ini_file(); then, you get each section in a subarray, and within those subarrays, you find the names and the values of directives in the INI file:

<?php
 $ini = parse_ini_file('config.ini', true);
 echo '<pre>';
 print_r($ini);

The contents of config.ini as a multidimensional array:

Array
(
    [Emails] => Array
        (
            [admin] => admin@brainbell.com
            [team] => info@brainbell.com
        )

    [DB] => Array
        (
            [host] => localhost
            [name] => dbname
            [user] => dbuser
            [pass] => passwordx
            [port] => 3306
        )

    [Cache] => Array
        (
            [html.file] => 1
        )
)

Reading/parsing specific section:

<?php
 $ini = parse_ini_file('config.ini', true);
 $emails = $ini['Emails'];
 
 echo $emails['admin'] . '<br>';
 echo $emails['team'];
 
 /* Prints:
 admin@brainbell.com
 info@brainbell.com
 */

Parsing INI Strings

<?php
 //Syntax
 parse_ini_string(
    string $ini_string,
    bool $process_sections = false,
    int $scanner_mode = INI_SCANNER_NORMAL
  ): array|false

The parse_ini_string() function works similarly to the parse_ini_file() function with one difference, it parses a string. This function takes three parameters:

1. $ini_string
The contents of the ini file being parsed.
2. $process_sections
If it is set to true, a multidimensional array with values for the sections in the file is returned.
3. $scanner_mode
This parameter is either INI_SCANNER_NORMAL, the default, or INI_SCANNER_RAW, indicating that the function should not parse option values.

Example: using parse_ini_string()

<?php
 $str = '[Emails]
admin=admin@brainbell.com
team=info@brainbell.com
[DB]
host=localhost
name=dbname
user=dbuser
pass=passwordx
port=3306
[Cache]
html.file=On';

 $ini = parse_ini_string($str, true);
 $emails = $ini['Emails'];
 
 echo $emails['admin'] . '<br>';
 echo $emails['team'];
 
 /* Prints:
 admin@brainbell.com
 info@brainbell.com
 */

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Working with Files in PHP: