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This a part two of the “RealURL made easy” series. In the first part we reviewed how url is constructed using RealURL and saw what are main configuration directives. This part will show practical steps to create a good RealURL configuration. The next (3rd) part will teach you some neat configuration tricks. But first we have to create the configuration.

From RealURL perspective all installations can be divided into to groups: single-domain tree and multi-domain tree. Single domain tree is the simplest and we already saw how to configure single domains for RealURL using _DEFAULT keyword.
Multi-domain configuration is more complex. Typically sites in a multi-domain setup share the same set of preVars and postVarSets. fixedPostVars (if used at all) are different because fixedPostVars should be specified for the specific page (this is covered in part 1). Therefore we will concentrate on this typical case here.
The steps for setting up multi-domain RealURL configuration are:

• create a prototype for configuration
• collect all domain names and root page id values
• configure main domains
• efficiently configure aliased domains 

Creating configuration prototype

Firsts, we create a common base for all domains. As shown in part 1, we do it in the separate file.

The prototype is created as variable, which contains all properties common for all domains. The variable should have tx_realurl_ prefix to avoid conflicts with any other variables in the system:

<?php
$tx_realurl_config = array(
    'init' => array(
        'enableCHashCache' => true,
        'appendMissingSlash' => 'ifNotFile',
        'enableUrlDecodeCache' => true,
        'enableUrlDecodeCache' => true,
        'emptyUrlReturnValue' => '/',
    ),
    'preVars' => array(
    ),
    'postVarSets' => array(
        '_DEFAULT' => array(
        ),
    ),
    'pagePath' => array(
        'type' => 'user',
        'userFunc' => 'EXT:realurl/class.tx_realurl_advanced.php:&tx_realurl_advanced->main',
        'spaceCharacter' => '-',
        'languageGetVar' => 'L',
        'expireDays' => 3,
    ),
);
?>

Let's see what we have here. init section enables cHash processing. This is necessary if you use extensions like tt_news, whose output depends on the URL parameters. For more details see “Linking properly in your TYPO3 code” article.

Next there is appendMissingSlash option. This will append slash to the end of generated URL if the last segment does not look like a file. It is not required but makes URL look better for users.

Next two options enable caches. This significally improves RealURL performance.
The last option in init section sets the value of “empty” URL. Usually URL is empty when it refers to home page.

Next two sections are empty in our ptototype but you can add something there as was described in part 1 of these series. We will also see some examples in part 3 of these series.

The last section (pagePath) seldomly change. Sometimes people change the value of spaceCharacter option to underscore character. Notice that value of languageGetVar should not be changed.

expireDays sets expiration value for cache entries if page is moved or renamed. RealURL will continue to accept old path to page for these amount of days and redirect to a new address. This is very useful for users who bookmarked pages. Search engines (like Google) will also notice a change and properly update their index.

Creating configuration for domains

Next we collect domain names and corresponding page id values. If one page shares more than one domain, we will voluntary choose one domain as main and we will treat others as aliased domains.

The following code goes before the closing PHP tag in the file:

$TYPO3_CONF_VARS['EXTCONF']['realurl'] = array(
    'www.domain1.tld' => $tx_realurl_config,
    'domain1.tld' => 'www.domain1.tld',
    'www.domain2.tld' => $tx_realurl_config,
    'domain1.tld' => 'www.domain2.tld',
);

Notice how main and aliased domains are configured. Main domains have full configuration and aliased just point to main domains. This has two advantages over separate configuration:

• saves PHP memory
• ensures that aliased domain always have the same configuration as main domain

You will be surprised but we are almost done! The only thing left is to specify proper root page id values.

Specifying rootpage id values

Specifying root page id values is necessary in multidomain setup. Otherwise RealURL will not be able to trace the path and resolve it to page id. We do it very easily. We add the following code after previous code:

$TYPO3_CONF_VARS['EXTCONF']['realurl']['www.domain1.tld']['pagePath']['rootpage_id'] = 123;
$TYPO3_CONF_VARS['EXTCONF']['realurl']['www.domain2.tld']['pagePath']['rootpage_id'] = 456;

Last final cosmetic step is to unset $tx_realurl_config because it is not longer needed:

unset($tx_realurl_config);

That's all. You now have proper multi-domain setup for RealURL.

What you did not know about _DEFAULT

There is one important issue with using _DEFAULT in multi-domain environment.
When RealURL searches for domains, it does walks domains in the configuration sequentally until the first match. _DEFAULT matches always. It means that if any domain is placed after _DEFAULT, it will never be reached. Remember that! But better avoid using _DEFAULT at all in multi-domain configuration.

Conclusion

In this part we saw how easy it is to create a working configuration for RealURL in multi-domain environment. In the next article we will talk more about preVars and postVarSets and see how to make them better.