Open

The only way a mod starts something outside Perch. Every path is validated: https URLs only, Steam app ids only, and app references that must exist in the live installed-apps scan. Every launch is written to the log.

None of the three returns anything.

perch.open.url(url: string): ()      -- must start with https://
perch.open.steam(appid: string): ()  -- a string of digits, what a settings.game row stores
perch.open.app(ref: string): ()      -- the reference a settings.launch row stored

A refused call is logged: open.url refused (not https), open.steam refused (not an appid), open.app refused (not an installed app).

Launching what the user picked

A settings.launch row stores a launch_target_t, and its type picks the verb. A dock of such rows launches from the tap’s ctx.index:

--!strict
type tile_refs_t = { icon: field_ref_t<string>, label: field_ref_t<string> }
type fields_t = { tiles: list_ref_t<tile_refs_t> }

local tiles: { launch_target_t } = {}   -- refreshed in perch.on_configure

local function open_tile(ctx: input_context_t)
  local t = tiles[ctx.index or 1]
  if not t then return end
  if t.type == "url" then perch.open.url(t.ref)
  elseif t.type == "steam" then perch.open.steam(t.ref)
  else perch.open.app(t.ref) end
end

dock:place(surface.page, function(f: fields_t): node_t
  return ui.list { items = f.tiles, max = 5, gap = 8,
    item = function(it: tile_refs_t): node_t
      return ui.column { w = 66, gap = 6, align = ui.align.center, on_click = open_tile,
        ui.image { src = it.icon, w = 42, h = 42, hover = ui.hover.lift },
        ui.text { text = it.label, size = 12, color = ui.color.half },
      }
    end }
end)

Types

export type launch_target_t = { type: "steam" | "url" | "app", ref: string, label: string, icon: string }

Every field is "" when nothing is picked.