`std.web`

A router over http.serve.

import std.http
import std.web

routes = [
    { method: "GET",  path: "/",           handler: fn(req) http.html(home()) },
    { method: "GET",  path: "/posts/:id",  handler: fn(req) show(req.params.id) },
    { method: "POST", path: "/posts",      handler: create },
    web.static("/assets", "public/assets"),
]

http.serve(8080, web.router(routes, middleware))

Path parameters

:name segments arrive in req.params:

fn show(req) {
    id = req.params.id
    http.json(find(id))
}

`GET` routes answer `HEAD`

A GET route responds to HEAD automatically, with the headers and no body.

This exists because it is what every client expects - health checks, link checkers, proxies and curl -I all send HEAD - and a router that 404s them looks broken while working perfectly for browsers.

Middleware

A middleware is fn(req, next). It can inspect the request, call next(req), and modify the response:

fn timing(req, next) {
    start = time.monotonic()
    resp = next(req)
    log.info("request", { path: req.path, ms: time.monotonic() - start })
    resp
}

They run outermost-first in the order given. Not calling next short-circuits, which is how authentication and a preflight response work.

Static files

web.static("/assets", "public/assets")

Traversal-safe: .. in a request cannot escape the directory. Use this rather than reading a request-supplied path with std.fs, which will happily serve /etc/passwd if you ask it to.

Errors

An unmatched route gives 404. A handler that raises gives 500 and logs. For designed error pages, per-route middleware, signed cookies, sessions, form validation and blueprints, use the webkit package, which is a full framework over this module.

Order

Routes match in order, so put specific paths before general ones. A static mount at / will shadow everything after it.

std.web