Handle conditional access tags for time ranges

Author: ivarbrek

profiles/lib/access_conditional.lua

@@ -0,0 +1,79 @@
+-- Handle conditional access tags as described in the OSM wiki:
+-- https://wiki.openstreetmap.org/wiki/Conditional_restrictions
+
+-- Note that we only handle conditional tags for a date range,
+-- meant to be used for temporary restrictions, typically due to
+-- construction. We also require the date range to be at least a
+-- week long
+
+
+
+ConditionalAccess = {}
+
+
+local function parse_conditional_access(way, key)
+    local conditional = way:get_value_by_key(key .. ':conditional')
+    if not conditional then
+      return nil
+    end
+
+    -- Examples of conditional tags: "no @ (2018 May 22-2018 Oct 7)
+    -- or  "no @ 2018 Jun 01-2018 Jul 23"
+    local condition, time_range = conditional:match("([^@]+)@(.+)")
+    if not condition or not time_range then
+      return nil
+    end
+
+    local start_date_str, end_date_str = time_range:match("([^-]+)-(.+)")
+    if not start_date_str or not end_date_str then
+      return nil
+    end
+
+    local function parse_date(date_str)
+      local year, month, day = date_str:match("(%d+)%s+(%a+)%s+(%d+)")
+
+      local month_names = {
+        Jan = 1, Feb = 2, Mar = 3, Apr = 4, May = 5, Jun = 6,
+        Jul = 7, Aug = 8, Sep = 9, Oct = 10, Nov = 11, Dec = 12
+      }
+      month = month_names[month]
+      if not year or not month or not day then
+        return nil
+      end
+
+      local numericYear = tonumber(year)
+      local numericDay = tonumber(day)
+      if numericYear and numericDay then
+          return os.time({ year = numericYear, month = month, day = numericDay })
+      else
+          return nil
+      end
+    end
+
+    local start_date = parse_date(start_date_str)
+    local end_date = parse_date(end_date_str)
+    local current_date = os.time()
+
+    -- Require start and end date to be more than a week apart
+    if not start_date or not end_date or end_date - start_date < 60 * 60 * 24 * 7 then
+      return nil
+    end
+
+    if current_date >= start_date and current_date <= end_date then
+      return condition:match("%S+")
+    else
+      return nil
+    end
+  end
+
+function ConditionalAccess.parse_by_set(way, keys)
+    for i, key in ipairs(keys) do
+        local conditional = parse_conditional_access(way, key)
+        if conditional then
+            return conditional
+        end
+    end
+    return nil
+end
+
+return ConditionalAccess

profiles/lib/way_handlers.lua

@@ -9,6 +9,7 @@ local set_classification = require("lib/guidance").set_classification
 local get_destination = require("lib/destination").get_destination
 local Tags = require('lib/tags')
 local Measure = require("lib/measure")
+local ConditionalAccess = require("lib/access_conditional")
 
 WayHandlers = {}
 
@@ -243,6 +244,13 @@ function WayHandlers.access(profile,way,result,data)
   data.forward_access, data.backward_access =
     Tags.get_forward_backward_by_set(way,data,profile.access_tags_hierarchy)
 
+  -- check for conditional access (roads that are temporarily closed, etc.)
+  local conditional = ConditionalAccess.parse_by_set(way,profile.access_tags_hierarchy)
+  if conditional then
+    data.forward_access = conditional
+    data.backward_access = conditional
+  end
+
   -- only allow a subset of roads to be treated as restricted
   if profile.restricted_highway_whitelist[data.highway] then
       if profile.restricted_access_tag_list[data.forward_access] then