DSN parser

Parse DSN strings into value objects to make them easier to use, pass around and manipulate.

Install

Via Composer

composer require nyholm/dsn

Quick usage

use Nyholm\Dsn\DsnParser;

$dsn = DsnParser::parse('http://127.0.0.1/foo/bar?key=value');
echo get_class($dsn); // "Nyholm\Dsn\Configuration\Url"
echo $dsn->getHost(); // "127.0.0.1"
echo $dsn->getPath(); // "/foo/bar"
echo $dsn->getPort(); // null

The DSN string format

A DSN is a string used to configure many services. A common DSN may look like a URL, other look like a file path.

memcached://127.0.0.1
mysql://user:[email protected]:3306/my_table
memcached:///var/local/run/memcached.socket?weight=25

Both types can have parameters, user, password. The exact definition we are using is found at the bottom of the page.

DSN Functions

A DSN may contain zero or more functions. The DSN parser supports a function syntax but not functionality itself. The function arguments must be separated with space or comma. Here are some example functions.

failover(dummy://a dummy://a)
failover(dummy://a,dummy://a)
failover:(dummy://a,dummy://a)
roundrobin(dummy://a failover(dummy://b dummy://a) dummy://b)

Parsing

There are two methods for parsing; DsnParser::parse() and DsnParser::parseFunc(). The latter is for situations where DSN functions are supported.

use Nyholm\Dsn\DsnParser;

$dsn = DsnParser::parse('scheme://127.0.0.1/foo/bar?key=value');
echo get_class($dsn); // "Nyholm\Dsn\Configuration\Url"
echo $dsn->getHost(); // "127.0.0.1"
echo $dsn->getPath(); // "/foo/bar"
echo $dsn->getPort(); // null

If functions are supported (like in the Symfony Mailer component) we can use DsnParser::parseFunc():

use Nyholm\Dsn\DsnParser;

$func = DsnParser::parseFunc('failover(sendgrid://KEY@default smtp://127.0.0.1)');
echo $func->getName(); // "failover"
echo get_class($func->first()); // "Nyholm\Dsn\Configuration\Url"
echo $func->first()->getHost(); // "default"
echo $func->first()->getUser(); // "KEY"

use Nyholm\Dsn\DsnParser;

$func = DsnParser::parseFunc('foo(udp://localhost failover:(tcp://localhost:61616,tcp://remotehost:61616)?initialReconnectDelay=100)?start=now');
echo $func->getName(); // "foo"
echo $func->getParameters()['start']; // "now"

$args = $func->getArguments();
echo get_class($args[0]); // "Nyholm\Dsn\Configuration\Url"
echo $args[0]->getScheme(); // "udp"
echo $args[0]->getHost(); // "localhost"

echo get_class($args[1]); // "Nyholm\Dsn\Configuration\DsnFunction"

When using DsnParser::parseFunc() on a string that does not contain any DSN functions, the parser will automatically add a default "dsn" function. This is added to provide a consistent return type of the method.

The string redis://127.0.0.1 will automatically be converted to dsn(redis://127.0.0.1) when using DsnParser::parseFunc().

use Nyholm\Dsn\DsnParser;

$func = DsnParser::parseFunc('smtp://127.0.0.1');
echo $func->getName(); // "dsn"
echo get_class($func->first()); // "Nyholm\Dsn\Configuration\Url"
echo $func->first()->getHost(); // "127.0.0.1"


$func = DsnParser::parseFunc('dsn(smtp://127.0.0.1)');
echo $func->getName(); // "dsn"
echo get_class($func->first()); // "Nyholm\Dsn\Configuration\Url"
echo $func->first()->getHost(); // "127.0.0.1"

Parsing invalid DSN

If you try to parse an invalid DSN string a InvalidDsnException will be thrown.

use Nyholm\Dsn\DsnParser;
use Nyholm\Dsn\Exception\InvalidDsnException;

try {
  DsnParser::parse('foobar');
} catch (InvalidDsnException $e) {
  echo $e->getMessage();
}

Consuming

The result of parsing a DSN string is a DsnFunction or Dsn. A DsnFunction has a name, argument and may have parameters. An argument is either a DsnFunction or a Dsn.

A Dsn could be a Path or Url. All 3 objects has methods for getting parts of the DSN string.

• getScheme()
• getUser()
• getPassword()
• getHost()
• getPort()
• getPath()
• getParameters()

You may also replace parts of the DSN with the with* methods. A DSN is immutable and you will get a new object back.

use Nyholm\Dsn\DsnParser;

$dsn = DsnParser::parse('scheme://127.0.0.1/foo/bar?key=value');

echo $dsn->getHost(); // "127.0.0.1"
$new = $dsn->withHost('nyholm.tech');

echo $dsn->getHost(); // "127.0.0.1"
echo $new->getHost(); // "nyholm.tech"

Not supported

Smart merging of options

The current DSN is valid, but it is up to the consumer to make sure both host1 and host2 has global_option.

redis://(host1:1234,host2:1234?node2_option=a)?global_option=b

Special DSN

The following DSN syntax are not supported.

// Rust
pgsql://user:pass@tcp(localhost:5555)/dbname

// Java
jdbc:informix-sqli://<server>[:<port>]/<databaseName>:informixserver=<dbservername>

We do not support DSN strings for ODBC connections like:

Driver={ODBC Driver 13 for SQL Server};server=localhost;database=WideWorldImporters;trusted_connection=Yes;

However, we do support "only parameters":

ocdb://?Driver=ODBC+Driver+13+for+SQL+Server&server=localhost&database=WideWorldImporters&trusted_connection=Yes

Definition

There is no official DSN RFC. We have defined a DSN configuration string as using the following definition. The "URL looking" parts of a DSN is based from RFC 3986.

configuration:
  { function | dsn }

function:
  function_name[:](configuration[,configuration])[?query]

function_name:
  REGEX: [a-zA-Z0-9\+-]+

dsn:
  { scheme:[//]authority[path][?query] | scheme:[//][userinfo]path[?query] | host:port[path][?query] }

scheme:
  REGEX: [a-zA-Z0-9\+-\.]+

authority:
  [userinfo@]host[:port]

userinfo:
  { user[:password] | :password }

path:
  "Normal" URL path according to RFC3986 section 3.3.
  REGEX: (/? | (/[a-zA-Z0-9-\._~%!\$&'\(\}\*\+,;=:@]+)+)

query:
  "Normal" URL query according to RFC3986 section 3.4.
  REGEX: [a-zA-Z0-9-\._~%!\$&'\(\}\*\+,;=:@]+

user:
  This value can be URL encoded.
  REGEX: [a-zA-Z0-9-\._~%!\$&'\(\}\*\+,;=]+

password:
  This value can be URL encoded.
  REGEX: [a-zA-Z0-9-\._~%!\$&'\(\}\*\+,;=]+

host:
  REGEX: [a-zA-Z0-9-\._~%!\$&'\(\}\*\+,;=]+

post:
  REGEX: [0-9]+

Example of formats that are supported:

• scheme://127.0.0.1/foo/bar?key=value
• scheme://user:[email protected]/foo/bar?key=value
• scheme:///var/local/run/memcached.socket?weight=25
• scheme://user:pass@/var/local/run/memcached.socket?weight=25
• scheme:?host[localhost]&host[localhost:12345]=3
• scheme://a
• scheme://
• server:80