support http.path.segments.* field

comments clean

test cases

support http.path.segments.*

changelog

http.path.segments.rev.*

changelog

remove segments.rev.*

support range segments definition

lint fix

clean

string.buffer

clean

clean

cache segment result

remove #only tag

re_split ctx.pos=2

dont use re.match

clean

test cases

clean

more tests

apply suggestions

fix rebase issue

changelog/unreleased/kong/support_http_path_segments_field.yml

@@ -0,0 +1,4 @@
+message: |
+  support `http.path.segments.*` field in expressions router flavor.
+type: feature
+scope: Core

kong/router/atc.lua

@@ -62,6 +62,7 @@ do
     ["String"] = {"net.protocol", "tls.sni",
                   "http.method", "http.host",
                   "http.path",
+                  "http.path.segments.*",
                   "http.headers.*",
                   "http.queries.*",
                  },

kong/router/fields.lua

@@ -167,6 +167,15 @@ end -- is_http
 if is_http then
 
   local fmt = string.format
+  local ngx_null = ngx.null
+  local re_split = require("ngx.re").split
+
+
+  local HTTP_SEGMENTS_PREFIX = "http.path.segments."
+  local HTTP_SEGMENTS_PREFIX_LEN = #HTTP_SEGMENTS_PREFIX
+  local HTTP_SEGMENTS_REG_CTX = { pos = 2, }  -- skip first '/'
+  local HTTP_SEGMENTS_OFFSET = 1
+
 
   -- func => get_headers or get_uri_args
   -- name => "headers" or "queries"
@@ -209,7 +218,67 @@ if is_http then
 
         return params.queries[field:sub(PREFIX_LEN + 1)]
       end
-    end
+
+    elseif field:sub(1, HTTP_SEGMENTS_PREFIX_LEN) == HTTP_SEGMENTS_PREFIX then
+      return function(params)
+        if not params.segments then
+          HTTP_SEGMENTS_REG_CTX.pos = 2 -- reset ctx, skip first '/'
+          params.segments = re_split(params.uri, "/", "jo", HTTP_SEGMENTS_REG_CTX)
+        end
+
+        local segments = params.segments
+
+        local name = field:sub(HTTP_SEGMENTS_PREFIX_LEN + 1)
+        local value = segments[name]
+
+        if value then
+          return value ~= ngx_null and value or nil
+        end
+
+        -- "/a/b/c" => 1="a", 2="b", 3="c"
+        -- http.path.segments.0 => params.segments[1 + 0] => a
+        -- http.path.segments.1_2 => b/c
+
+        local p = name:find("_", 1, true)
+
+        -- only one segment
+
+        if not p then
+          local pos = tonumber(name)
+
+          value = pos and segments[HTTP_SEGMENTS_OFFSET + pos] or nil
+          segments[name] = value or ngx_null
+
+          return value
+        end
+
+        -- (pos1, pos2) defines a segment range
+
+        local pos1 = tonumber(name:sub(1, p - 1))
+        local pos2 = tonumber(name:sub(p + 1))
+        local segs_count = #segments - HTTP_SEGMENTS_OFFSET
+
+        if not pos1 or not pos2 or
+           pos1 >= pos2 or pos1 > segs_count or pos2 > segs_count
+        then
+          segments[name] = ngx_null
+          return nil
+        end
+
+        local buf = buffer.new()
+
+        for p = pos1, pos2 - 1 do
+          buf:put(segments[HTTP_SEGMENTS_OFFSET + p], "/")
+        end
+        buf:put(segments[HTTP_SEGMENTS_OFFSET + pos2])
+
+        value = buf:get()
+        segments[name] = value
+
+        return value
+      end
+
+    end -- if prefix
 
     -- others return nil
   end

spec/01-unit/08-router_spec.lua

@@ -5393,5 +5393,171 @@ do
       assert.same(ctx.route_match_cached, "pos")
     end)
   end)
+
+  describe("Router (flavor = " .. flavor .. ") [http]", function()
+    reload_router(flavor)
+
+    it("select() should match single http.segments.*", function()
+      local use_case = {
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8101",
+            expression = [[http.path.segments.0 == "foo" && http.path.segments.1 == "bar"]],
+            priority = 100,
+          },
+        },
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8102",
+            expression = [[http.path.segments.0 == "foo" && http.path.segments.2 ^= "baz"]],
+            priority = 200,
+          },
+        },
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8103",
+            expression = [[http.path.segments.0 == "foo" && http.path.segments.3 ~ r#"\d+"#]],
+            priority = 300,
+          },
+        },
+      }
+
+      local router = assert(new_router(use_case))
+
+      local match_t = router:select("GET", "/foo/bar")
+      assert.truthy(match_t)
+      assert.same(use_case[1].route, match_t.route)
+
+      local match_t = router:select("GET", "/foo/bar/bazxxx")
+      assert.truthy(match_t)
+      assert.same(use_case[2].route, match_t.route)
+
+      local match_t = router:select("GET", "/foo/bar/baz/12345")
+      assert.truthy(match_t)
+      assert.same(use_case[3].route, match_t.route)
+
+      local match_t = router:select("GET", "/foo/xxx")
+      assert.falsy(match_t)
+    end)
+
+    it("select() should match range http.segments.*", function()
+      local use_case = {
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8101",
+            expression = [[http.path.segments.0_1 ~ r#"\d+/\w+"#]],
+            priority = 100,
+          },
+        },
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8102",
+            expression = [[http.path.segments.1_3 == r#"xxx/yyy/zzz"#]],
+            priority = 100,
+          },
+        },
+      }
+
+      local router = assert(new_router(use_case))
+
+      local match_t = router:select("GET", "/123/foo/bar")
+      assert.truthy(match_t)
+      assert.same(use_case[1].route, match_t.route)
+
+      local match_t = router:select("GET", "/123/hello-world/bar")
+      assert.truthy(match_t)
+      assert.same(use_case[1].route, match_t.route)
+
+      local match_t = router:select("GET", "/foo/xxx/yyy/zzz/bar")
+      assert.truthy(match_t)
+      assert.same(use_case[2].route, match_t.route)
+    end)
+
+    it("select() accepts but does not match invalid http.segments.*", function()
+      local use_case = {
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8101",
+            expression = [[http.path.segments.a == r#"foo"#]],
+            priority = 100,
+          },
+        },
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8102",
+            expression = [[http.path.segments.10_11 == r#"foo/bar"#]],
+            priority = 100,
+          },
+        },
+      }
+
+      local router = assert(new_router(use_case))
+
+      local match_t = router:select("GET", "/foo/bar")
+      assert.falsy(match_t)
+    end)
+
+    it("exec() should hit cache with http.segments.*", function()
+      local use_case = {
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8101",
+            expression = [[http.path.segments.0 == "foo" && http.path.segments.1 == "bar"]],
+            priority = 100,
+          },
+        },
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8102",
+            expression = [[http.path.segments.1_3 == r#"xxx/yyy/zzz"#]],
+            priority = 100,
+          },
+        },
+      }
+
+      local router = assert(new_router(use_case))
+
+      local ctx = {}
+      local _ngx = mock_ngx("GET", "/foo/bar", { a = "1", })
+      router._set_ngx(_ngx)
+
+      -- first match
+      local match_t = router:exec(ctx)
+      assert.truthy(match_t)
+      assert.same(use_case[1].route, match_t.route)
+      assert.falsy(ctx.route_match_cached)
+
+      -- cache hit pos
+      local match_t = router:exec(ctx)
+      assert.truthy(match_t)
+      assert.same(use_case[1].route, match_t.route)
+      assert.same(ctx.route_match_cached, "pos")
+
+      local ctx = {}
+      local _ngx = mock_ngx("GET", "/foo/xxx/yyy/zzz/bar", { a = "1", })
+      router._set_ngx(_ngx)
+
+      -- first match
+      local match_t = router:exec(ctx)
+      assert.truthy(match_t)
+      assert.same(use_case[2].route, match_t.route)
+      assert.falsy(ctx.route_match_cached)
+
+      -- cache hit pos
+      local match_t = router:exec(ctx)
+      assert.truthy(match_t)
+      assert.same(use_case[2].route, match_t.route)
+      assert.same(ctx.route_match_cached, "pos")
+    end)
+  end)
 end   -- local flavor = "expressions"