Pattern Placeholders

Alphanumeric Placeholders

In your URL pattern you can also use the : syntax to denote a variable placeholder. These position holders are alphanumeric by default:

route( "blog/:year/:month?/:day?", "blog.index" );

Once a URL is matched to the route above, the placeholders (:year/:month?/:day?) will become request collection (RC) variables:

http://localhost/blog/2012/12/22 -> rc.year=2012, rc.month=12, rc.day=22
http://localhost/blog/2012/12-> rc.year=2012, rc.month=12
http://localhost/blog/2012-> rc.year=2012

Optional Placeholders

Sometimes we will want to declare routes that are very similar in nature and since order matters, they need to be declared in the right order. Like this one:

route( "/blog/:year-numeric/:month-numeric/:day-numeric" );
route( "/blog/:year-numeric/:month-numeric" );
route( "/blog/:year-numeric/" );
route( "/blog/" );

However, we just wrote 4 routes for this approach when we can just use optional variables by using the ? symbol at the end of the placeholder. This tells the processor to create the routes for you in the most detailed manner first instead of you doing it manually.

route( "/blog/:year-numeric?/:month-numeric?/:day-numeric?" );

Caution Just remember that an optional placeholder cannot be followed by a non-optional one. It doesn't make sense.

Numeric Placeholders

ColdBox gives you also the ability to declare numerical only routes by appending -numeric to the variable placeholder so the route will only match if the placeholder is numeric. Let's modify the route from above.

route( "blog/:year-numeric/:month-numeric?/:day-numeric?", "blog.index" );

This route will only accept years, months and days as numbers.

Alpha Placeholders

ColdBox gives you also the ability to declare alpha only routes by appending -alpha to the variable placeholder so the route will only match if the placeholder is alpha only.

route( "wiki/:page-alpha", "wiki.show" );

This route will only accept page names that are alpha only.

There are two ways to place a regex constraint on a placeholder, using the -regex: placeholder or adding a constraints structure to the route declaration.

Regular Expression Placeholders

You can also have the ability to declare a placeholder that must match a regular expression by using the -regex( {regex_here} ) placeholder.

// route with regex placeholders
route(
    pattern="/api/:format-regex:(xml|json)/",
    target="api.execute"
);

The rc variable format must match the regex supplied: (xml|json)

Regular Expression Constraints

You can also apply a structure of regular expressions to a route instead of inlining the regular expressions in the placeholder location. You will do this using the constraints() method of the router.

The key in the structure must match the name of the placeholder and the value is a regex expression that must be enclosed by parenthesis ().

// route with custom constraints
route(
    pattern = "/api/:format/:entryID",
    target  = "api.execute"
).constraints( {
    format  = "(xml|json)",
    entryID = "([0-9]{4})" 
} );