gnu-social/vendor/zendframework/zend-config/doc/book/reader.md

Zend\Config\Reader

Zend\Config\Reader gives you the ability to read a config file. It works with concrete implementations for different file formats. Zend\Config\Reader itself is only an interface, defining the methods fromFile() and fromString(). The concrete implementations of this interface are:

• Zend\Config\Reader\Ini
• Zend\Config\Reader\Xml
• Zend\Config\Reader\Json
• Zend\Config\Reader\Yaml
• Zend\Config\Reader\JavaProperties

fromFile() and fromString() are expected to return a PHP array containing the data from the specified configuration.

Differences from ZF1

The Zend\Config\Reader component no longer supports the following features:

• Inheritance of sections.
• Reading of specific sections.

Zend\Config\Reader\Ini

Zend\Config\Reader\Ini enables developers to store configuration data in a familiar INI format, and then to read them in the application by using an array syntax.

Zend\Config\Reader\Ini utilizes the parse_ini_file() PHP function. Please review this documentation to be aware of its specific behaviors, which propagate to Zend\Config\Reader\Ini, such as how the special values of TRUE, FALSE, "yes", "no", and NULL are handled.

Key Separator

By default, the key separator character is the period character (.). This can be changed, however, using the setNestSeparator() method. For example:

$reader = new Zend\Config\Reader\Ini();
$reader-setNestSeparator('-');

The following example illustrates basic usage of Zend\Config\Reader\Ini for loading configuration data from an INI file. In this example, configuration data for both a production system and for a staging system exists.

webhost                  = 'www.example.com'
database.adapter         = 'pdo_mysql'
database.params.host     = 'db.example.com'
database.params.username = 'dbuser'
database.params.password = 'secret'
database.params.dbname   = 'dbproduction'

We can use Zend\Config\Reader\Ini to read this INI file:

$reader = new Zend\Config\Reader\Ini();
$data   = $reader->fromFile('/path/to/config.ini');

echo $data['webhost'];  // prints "www.example.com"
echo $data['database']['params']['dbname'];  // prints "dbproduction"

Zend\Config\Reader\Ini supports a feature to include the content of a INI file in a specific section of another INI file. For instance, suppose we have an INI file with the database configuration:

database.adapter         = 'pdo_mysql'
database.params.host     = 'db.example.com'
database.params.username = 'dbuser'
database.params.password = 'secret'
database.params.dbname   = 'dbproduction'

We can include this configuration in another INI file by using the @include notation:

webhost  = 'www.example.com'
@include = 'database.ini'

If we read this file using the component Zend\Config\Reader\Ini, we will obtain the same configuration data structure as in the previous example.

The @include = 'file-to-include.ini' notation can be used also in a subelement of a value. For instance we can have an INI file like the following:

adapter         = 'pdo_mysql'
params.host     = 'db.example.com'
params.username = 'dbuser'
params.password = 'secret'
params.dbname   = 'dbproduction'

And assign the @include as a subelement of the database value:

webhost           = 'www.example.com'
database.@include = 'database.ini'

Zend\Config\Reader\Xml

Zend\Config\Reader\Xml enables developers to provide configuration data in a familiar XML format and consume it in the application using an array syntax. The root element of the XML file or string is irrelevant and may be named arbitrarily.

The following example illustrates basic usage of Zend\Config\Reader\Xml for loading configuration data from an XML file. First, our XML configuration in the file config.xml:

<?xml version="1.0" encoding="utf-8"?>
<config>
    <webhost>www.example.com</webhost>
    <database>
        <adapter value="pdo_mysql"/>
        <params>
            <host value="db.example.com"/>
            <username value="dbuser"/>
            <password value="secret"/>
            <dbname value="dbproduction"/>
        </params>
    </database>
</config>

We can use the Zend\Config\Reader\Xml to read the XML configuration:

$reader = new Zend\Config\Reader\Xml();
$data   = $reader->fromFile('/path/to/config.xml');

echo $data['webhost'];  // prints "www.example.com"
echo $data['database']['params']['dbname']['value'];  // prints "dbproduction"

Zend\Config\Reader\Xml utilizes PHP's XMLReader class. Please review its documentation to be aware of its specific behaviors, which propagate to Zend\Config\Reader\Xml.

Using Zend\Config\Reader\Xml, we can include the content of XML files in a specific XML element. This is provided using the standard XInclude functionality of XML. To use this functionality, you must add the namespace xmlns:xi="http://www.w3.org/2001/XInclude" to the XML file.

Suppose we have an XML file that contains only the database configuration:

<?xml version="1.0" encoding="utf-8"?>
<config>
    <database>
        <adapter>pdo_mysql</adapter>
        <params>
            <host>db.example.com</host>
            <username>dbuser</username>
            <password>secret</password>
            <dbname>dbproduction</dbname>
        </params>
    </database>
</config>

We can include this configuration in another XML file using an xinclude:

<?xml version="1.0" encoding="utf-8"?>
<config xmlns:xi="http://www.w3.org/2001/XInclude">
    <webhost>www.example.com</webhost>
    <xi:include href="database.xml"/>
</config>

The syntax to include an XML file in a specific element is <xi:include href="file-to-include.xml"/>

Zend\Config\Reader\Json

Zend\Config\Reader\Json enables developers to consume configuration data in JSON, and read it in the application by using an array syntax.

The following example illustrates a basic use of Zend\Config\Reader\Json for loading configuration data from a JSON file.

Consider the following JSON configuration file:

{
  "webhost"  : "www.example.com",
  "database" : {
    "adapter" : "pdo_mysql",
    "params"  : {
      "host"     : "db.example.com",
      "username" : "dbuser",
      "password" : "secret",
      "dbname"   : "dbproduction"
    }
  }
}

We can use Zend\Config\Reader\Json to read the file:

$reader = new Zend\Config\Reader\Json();
$data   = $reader->fromFile('/path/to/config.json');

echo $data['webhost'];  // prints "www.example.com"
echo $data['database']['params']['dbname'];  // prints "dbproduction"

Zend\Config\Reader\Json utilizes zend-json.

Using Zend\Config\Reader\Json, we can include the content of a JSON file in a specific JSON section or element. This is provided using the special syntax @include. Suppose we have a JSON file that contains only the database configuration:

{
  "database" : {
    "adapter" : "pdo_mysql",
    "params"  : {
      "host"     : "db.example.com",
      "username" : "dbuser",
      "password" : "secret",
      "dbname"   : "dbproduction"
    }
  }
}

Now let's include it via another configuration file:

{
    "webhost"  : "www.example.com",
    "@include" : "database.json"
}

Zend\Config\Reader\Yaml

Zend\Config\Reader\Yaml enables developers to consume configuration data in a YAML format, and read them in the application by using an array syntax. In order to use the YAML reader, we need to pass a callback to an external PHP library or use the YAML PECL extension.

The following example illustrates basic usage of Zend\Config\Reader\Yaml, using the YAML PECL extension.

Consider the following YAML file:

webhost: www.example.com
database:
    adapter: pdo_mysql
    params:
      host:     db.example.com
      username: dbuser
      password: secret
      dbname:   dbproduction

We can use Zend\Config\Reader\Yaml to read this YAML file:

$reader = new Zend\Config\Reader\Yaml();
$data   = $reader->fromFile('/path/to/config.yaml');

echo $data['webhost'];  // prints "www.example.com"
echo $data['database']['params']['dbname'];  // prints "dbproduction"

If you want to use an external YAML reader, you must pass a callback function to the class constructor. For instance, if you want to use the Spyc library:

// include the Spyc library
require_once 'path/to/spyc.php';

$reader = new Zend\Config\Reader\Yaml(['Spyc', 'YAMLLoadString']);
$data   = $reader->fromFile('/path/to/config.yaml');

echo $data['webhost'];  // prints "www.example.com"
echo $data['database']['params']['dbname'];  // prints "dbproduction"

You can also instantiate Zend\Config\Reader\Yaml without any parameters, and specify the YAML reader using the setYamlDecoder() method.

Using Zend\Config\ReaderYaml, we can include the content of another YAML file in a specific YAML section or element. This is provided using the special syntax @include.

Consider the following YAML file containing only database configuration:

database:
    adapter: pdo_mysql
    params:
      host:     db.example.com
      username: dbuser
      password: secret
      dbname:   dbproduction

We can include this configuration in another YAML file:

webhost:  www.example.com
@include: database.yaml

Zend\Config\Reader\JavaProperties

Zend\Config\Reader\JavaProperties enables developers to provide configuration data in the popular JavaProperties format, and read it in the application by using array syntax.

The following example illustrates basic usage of Zend\Config\Reader\JavaProperties for loading configuration data from a JavaProperties file.

Suppose we have the following JavaProperties configuration file:

#comment
!comment
webhost:www.example.com
database.adapter:pdo_mysql
database.params.host:db.example.com
database.params.username:dbuser
database.params.password:secret
database.params.dbname:dbproduction

We can use Zend\Config\Reader\JavaProperties to read it:

$reader = new Zend\Config\Reader\JavaProperties();
$data   = $reader->fromFile('/path/to/config.properties');

echo $data['webhost'];  // prints "www.example.com"
echo $data['database.params.dbname'];  // prints "dbproduction"