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doc/src/manual/cowboy_router.ezdoc

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+::: cowboy_router
+
+The `cowboy_router` middleware maps the requested host and
+path to the handler to be used for processing the request.
+It uses the dispatch rules compiled from the routes given
+to the `compile/1` function for this purpose. It adds the
+handler name and options to the environment as the values
+`handler` and `handler_opts` respectively.
+
+Environment input:
+
+* dispatch = dispatch_rules()
+
+Environment output:
+
+* handler = module()
+* handler_opts = any()
+
+:: Types
+
+: bindings() = [{atom(), binary()}]
+
+List of bindings found during routing.
+
+: constraints() = [IntConstraint | FunConstraint]
+
+Types:
+
+* IntConstraint = {atom(), int}
+* FunConstraint = {atom(), function, Fun}
+* Fun = fun((binary()) -> true | {true, any()} | false)
+
+List of constraints to apply to the bindings.
+
+The int constraint will convert the binding to an integer.
+The fun constraint allows writing custom code for checking
+the bindings. Returning a new value from that fun allows
+replacing the current binding with a new value.
+
+: dispatch_rules() - opaque to the user
+
+Rules for dispatching request used by Cowboy.
+
+: routes() = [{Host, Paths} | {Host, constraints(), Paths}]
+
+Types:
+
+* Host = Path = '_' | iodata()
+* Paths = [{Path, Handler, Opts} | {Path, constraints(), Handler, Opts}]
+* Handler = module()
+* Opts = any()
+
+Human readable list of routes mapping hosts and paths to handlers.
+
+The syntax for routes is defined in the user guide.
+
+: tokens() = [binary()]
+
+List of host_info and path_info tokens found during routing.
+
+:: Exports
+
+: compile(Routes) -> Dispatch
+
+Types:
+
+* Routes = routes()
+* Dispatch = dispatch_rules()
+
+Compile the routes for use by Cowboy.