A slightly more general HTTP routing library than LFE's lfest
The lanes project aims to offer some of the YAWS-specific features of the lfest project to a wider selection of BEAM-based web servers. This is done with the understanding that the original design of lfest (and thus the design inherited in the lanes project) is not optimal.
For now, though, we are focused on the immediate and practical needs of LFE application developers.
- Erlang 21+
Create your application/service routes with the
(defroutes ...) form.
Here is an example that is compatible with Elli:
(include-lib "lanes_elli/include/macros.lfe") (defroutes ;; top-level ('GET #"/" (lanes.elli:ok "Welcome to the Volvo Store!")) ;; single order operations ('POST #"/order" (progn (lanes-elli-data:create-order (lanes.elli:get-data req)) (lanes.elli:accepted))) ('GET #"/order/:id" (lanes.elli:ok (lanes-elli-data:get-order id))) ('PUT #"/order/:id" (progn (lanes-elli-data:update-order id (lanes.elli:get-data req)) (lanes.elli:no-content))) ('DELETE #"/order/:id" (progn (lanes-elli-data:delete-order id) (lanes.elli:no-content))) ;; order collection operations ('GET #"/orders" (lanes.elli:ok (lanes-elli-data:get-orders))) ;; payment operations ('PUT #"/payment/order/:id" (progn (lanes-elli-data:make-payment id (lanes.elli:get-data req)) (lanes.elli:no-content))) ('GET #"/payment/order/:id" (lanes.elli:ok (lanes-elli-data:get-payment-status id))) ;; error conditions ('ALLOWONLY ('GET 'POST 'PUT 'DELETE) (lanes.elli:method-not-allowed)) ('NOTFOUND (lanes.elli:not-found "Bad path: invalid operation.")))
For full context, be sure to see the code in
lanes plugin supports a
defroutes macro that generates a
hanlder/3 function typically used in Elli handler modules. One still
needs to provide the
handle_event/3 functions in the
defroutes is called.
A few important things to note here:)
- Each route is composed of an HTTP verb, a path, and a function to execute should both the verb and path match.
- The function call in the route has access to the
arg-datapassed from YAWS; this contains all the data you could conceivably need to process a request. (You may need to import the
yaws_api.hrlin your module to parse the data of your choice, though.)
- If a path has a segment preceded by a colon, this will be converted to a
variable by the
(defroutes ...)macro; the variable will then be accessible from the function you provide in that route.
(defroutes ...)macro generates the
routes/3function; it's three arguments are the HTTP verb (method name), the path info (a list of path segments, with the
":varname"segments converted to
varname/ variable segments), and then the
arg-datavariable from YAWS.
lanes needs to provide YAWS with an
out/1 function. The location of this
function is configured in your
etc/yaws.conf file in the
<appmods ...> directives (it can be repeated for supporting multiple
YAWS will call this function with one argument: the YAWS
data. Since this function is the entry point for applications running under
YAWS, it is responsible for determining how to process all requests.
out/1 function in lane+YAWS-based apps calls the
generated by the
(defroutes ...) lanes/YAWS mamcro.
When a lanes-based project is compiled, the
routes/3 function is available for use via
whatever modules have defined routes with
Apache Version 2 License
Copyright © 2014-2021, Duncan McGreggor email@example.com