Serves maps from signed URLs, for browsers and CDNs to cache.

Compiled only when :plug is a dependency. Mount it where no session or CSRF plug touches its responses, since a response that sets a cookie is not cached by a CDN:

forward "/maps", StaticMaps.Plug,
  secret: {MyApp.Config, :map_secret, []},
  source: StaticMaps.Source.OSM,
  icons: %{office: File.read!("priv/office.svg")}

and build URLs with path/3, using the same secret:

StaticMaps.Plug.path("/maps", [center: {14.5547, 121.0244}, zoom: 15], secret: secret)

Options

• :secret — at least 32 bytes, or {module, function, args} returning them, to read runtime configuration. Required.
• :cache — :max_age (86 400), :s_maxage (2 592 000), :stale_while_revalidate (86 400) and :immutable (false) for successful responses; false sends no-store instead.
• :max_size ({1280, 1280}), :max_scale (2), :max_markers (100) — limits on every request, signed or not.
• :max_concurrency — renders in progress at once; defaults to the number of schedulers.
• :source, :attribution — passed to StaticMaps.render/1, and never read from a request.
• :background — the default background; a URL built with :background overrides it.
• :icons — named marker icons, %{name => svg_or_image_bytes}, for markers given icon: :name. A URL names an icon; it never carries one.

Responses

A 304 is answered straight after the signature check, without rendering or fetching a tile. Identical requests that arrive during a render wait for it rather than starting their own.