diff options
Diffstat (limited to 'doc/src/guide')
| -rw-r--r-- | doc/src/guide/routing.ezdoc | 26 |
1 files changed, 8 insertions, 18 deletions
diff --git a/doc/src/guide/routing.ezdoc b/doc/src/guide/routing.ezdoc index e7b43f2..2482c12 100644 --- a/doc/src/guide/routing.ezdoc +++ b/doc/src/guide/routing.ezdoc @@ -191,26 +191,16 @@ HostMatch = "*". After the matching has completed, the resulting bindings can be tested against a set of constraints. Constraints are only tested when the binding is defined. They run in the order you defined them. The match -will succeed only if they all succeed. +will succeed only if they all succeed. If the match fails, then Cowboy +tries the next route in the list. -They are always given as a two or three elements tuple, where the first -element is the name of the binding, the second element is the constraint's -name, and the optional third element is the constraint's arguments. +The format used for constraints is the same as match functions in +`cowboy_req`: they are provided as a list of fields which may have +one or more constraints. While the router accepts the same format, +it will skip fields with no constraints and will also ignore default +values, if any. -The following constraints are currently defined: - -* {Name, int} -* {Name, function, fun ((Value) -> true | {true, NewValue} | false)} - -The `int` constraint will check if the binding is a binary string -representing an integer, and if it is, will convert the value to integer. - -The `function` constraint will pass the binding value to a user specified -function that receives the binary value as its only argument and must -return whether it fulfills the constraint, optionally modifying the value. -The value thus returned can be of any type. - -Note that constraint functions SHOULD be pure and MUST NOT crash. +Read more about ^constraints^. :: Compilation |