Make detail tuples typed-ish

spec/metadata_spec.cr

@@ -0,0 +1,87 @@
+require "./spec_helper"
+
+module LavinMQ
+  struct NamedTupleMetadata(T) < Metadata
+    describe Value do
+      describe "compare" do
+        {% begin %}
+          {%
+            testdata = {
+              {1, 2, -1},
+              {2, 1, 1},
+              {"a", "b", -1},
+              {"b", "a", 1},
+              {1, 1, 0},
+              {1, nil, 1},
+              {nil, 1, -1},
+              {nil, nil, 0},
+              {1, "a", -1},
+              {"a", 1, 1},
+              {1u8, 2i32, -1},
+            }
+          %}
+          {% for values in testdata %}
+            {% left, right, expected = values %}
+            it "{{left.id}} <=> {{right.id}} is {{expected}}" do
+              res = Value.new({{left}}) <=> Value.new({{right}})
+              res.should eq {{expected}}
+            end
+          {% end %}
+        {% end %}
+      end
+    end
+  end
+
+  describe Metadata do
+    data = Metadata.new({
+      foo: "bar",
+      baz: 1,
+      sub: {
+        bar:  "foo",
+        next: {
+          value: 2,
+        },
+      },
+    })
+
+    describe "#dig" do
+      it "can return first level value" do
+        data.dig("foo").should eq Metadata::Value.new("bar")
+      end
+
+      it "can return value from deep level" do
+        data.dig("sub.next.value").should eq Metadata::Value.new(2)
+      end
+
+      it "raises on invalid path" do
+        expect_raises(KeyError) do
+          data.dig("invalid.path")
+        end
+      end
+    end
+
+    describe "#dig?" do
+      it "returns Value(Nil) for invalid path" do
+        data.dig?("invalid.path").should be_a Metadata::Value(Nil)
+      end
+    end
+
+    describe "#[]" do
+      it "returns expected value" do
+        data.dig("foo").should eq Metadata::Value.new("bar")
+      end
+
+      it "raises on invalid key" do
+        expect_raises(KeyError) do
+          data.dig("invalid")
+        end
+      end
+    end
+
+    describe "#[]?" do
+      it "raises on invalid key" do
+        data["invalid"]?.should be_a Metadata::Value(Nil)
+      end
+    end
+  end
+end

src/lavinmq/http/controller.cr

@@ -22,16 +22,12 @@ module LavinMQ
         return iterator unless raw_name = params["name"]?
         term = URI.decode_www_form(raw_name)
         if params["use_regex"]?.try { |v| v == "true" }
-          iterator.select { |v| match_value(v).to_s =~ /#{term}/ }
+          iterator.select &.[:name].to_s.matches?(/#{term}/)
         else
-          iterator.select { |v| match_value(v).to_s.includes?(term) }
+          iterator.select &.[:name].to_s.includes?(term)
         end
       end
 
-      protected def match_value(value)
-        value[:name]? || value["name"]?
-      end
-
       MAX_PAGE_SIZE = 10_000
 
       private def page(context, iterator : Iterator(SortableJSON))
@@ -43,27 +39,13 @@ module LavinMQ
           {error: "payload_too_large", reason: "Max allowed page_size 10000"}.to_json(context.response)
           return context
         end
-        iterator = iterator.map do |i|
-          i.details_tuple
-        rescue e
-          {error: e.message}
-        end
+        iterator = iterator.map &.metadata
         all_items = filter_values(params, iterator)
-        if sort_by = params.fetch("sort", nil).try &.split(".")
+
+        if sort_by = params.fetch("sort", nil)
           sorted_items = all_items.to_a
           filtered_count = sorted_items.size
-          if first_element = sorted_items.first?
-            {% begin %}
-              case dig(first_element, sort_by)
-                {% for k in {Int32, UInt16, UInt32, UInt64, Float64} %}
-                when {{k.id}}
-                  sorted_items.sort_by! { |i| dig(i, sort_by).as({{k.id}}) }
-                {% end %}
-              else
-                sorted_items.sort_by! { |i| dig(i, sort_by).to_s.downcase }
-              end
-            {% end %}
-          end
+          sorted_items.sort_by! &.dig?(sort_by)
           sorted_items.reverse! if params["sort_reverse"]?.try { |s| !(s =~ /^false$/i) }
           all_items = sorted_items.each
         end
@@ -95,15 +77,6 @@ module LavinMQ
         context
       end
 
-      private def dig(i : NamedTuple, keys : Array(String))
-        if keys.size > 1
-          nt = i[keys.first].as?(NamedTuple) || return
-          dig(nt, keys[1..])
-        else
-          i[keys.first]? || 0
-        end
-      end
-
       private def array_iterator_to_json(json, iterator, columns : Array(String)?, start : Int, page_size : Int)
         size = 0
         total = 0

src/lavinmq/metadata.cr

@@ -0,0 +1,142 @@
+module LavinMQ
+  abstract struct Metadata
+    def self.new(data : NamedTuple)
+      NamedTupleMetadata.new(data)
+    end
+
+    # This is similar to JSON::Any..
+    struct Value(T) # , V)
+      include Comparable(Value)
+
+      def initialize(@value : T)
+        @type = T
+      end
+
+      def self.nil
+        new(nil)
+      end
+
+      def type
+        T
+      end
+
+      def value : T
+        @value
+      end
+
+      def <=>(other : Value)
+        return 0 if @value.nil? && [email protected]?
+        return -1 if @value.nil?
+        return 1 if [email protected]?
+
+        {% if T <= Number %}
+          if other_value = [email protected]?(Number)
+            return @value <=> other_value
+          end
+        {% end %}
+
+        if self.type != other.type
+          return @value.to_s <=> [email protected]_s
+        end
+
+        {% if T <= Comparable %}
+          if (value = @value) && (other_value = [email protected]?(T))
+            return value <=> other_value
+          end
+        {% end %}
+
+        0
+      end
+
+      delegate to_json, to_s, to: @value
+    end
+  end
+
+  # Wraps a generic NamedTuple to make it possible to add
+  # methods to it. Used in e.g. HTTP::Controller.
+  struct NamedTupleMetadata(T) < Metadata
+    def initialize(@data : T)
+    end
+
+    def self.empty
+      new NamedTuple.new
+    end
+
+    delegate to_json, to_s, to: @data
+
+    # Takes a dot separated path and returns the value at that path
+    # If T is `{a: {b: {c: 1} d: "foo"}` #dig("a.b.c") returns a Value(Int32)
+    # and #dig("a.d") returns a Value(String)
+    def dig(path : Symbol | String)
+      fetch(path) { raise KeyError.new "Invalid path: #{path.inspect}" }
+    end
+
+    def dig?(path : Symbol | String)
+      fetch(path) { Value.nil }
+    end
+
+    def [](key : Symbol | String)
+      fetch(key) { raise KeyError.new "Missing key: #{key.inspect}" }
+    end
+
+    def []?(key : Symbol | String)
+      fetch(key) { Value.nil }
+    end
+
+    private def fetch(path : Symbol | String, &default : -> Value)
+      # The macto will generate a case statement that matches "paths" to values in
+      # the wrapped namedtuple structure.
+      # For NamedTupleMetaData.new({a: {b: 1, c: "foo"}}) the generated
+      # statement will look like:
+      #
+      # case path
+      # when "a", :"a"
+      #   if value = @data[:a]
+      #     return Value.new(value)
+      #   end
+      #   return Value.nil
+      # when "a.b", :"a.b"
+      #   if value = @data[:a][:b]
+      #     return Value.new(value)
+      #   end
+      #   return Value.nil
+      # when "a.b.c", :"a.b.c"
+      #   if value = @data[:a][:b][:c]
+      #     return Value.new(value)
+      #   end
+      #   return Value.nil
+      # else
+      #   yield
+      # end
+      #
+      {% begin %}
+        {%
+          paths = [] of Array(String)
+          # This will walk the "namedtuple tree" and find all paths to values. It's not
+          # possible to do recursive macros, but ArrayLiteral#each will iterate over items
+          # added while currently iterating.
+          to_visit = T.keys.map { |k| {[k], T[k]} }
+          to_visit.each do |(path, type)|
+            if type <= NamedTuple
+              paths << path
+              type.keys.each { |k| to_visit << {path + [k], type[k]} }
+            else
+              paths << path
+            end
+          end
+        %}
+        case path
+          {% for path in paths %}
+            when {{path.join(".")}}, :{{path.join(".")}}
+              if value = @data[:"{{path.join("\"][:\"").id}}"]
+                return Value.new(value)
+              end
+              return Value.nil
+          {% end %}
+        else
+          yield
+        end
+      {% end %}
+    end
+  end
+end

src/lavinmq/sortable_json.cr

@@ -1,7 +1,13 @@
+require "./metadata"
+
 module LavinMQ
   module SortableJSON
     abstract def details_tuple
 
+    def metadata
+      Metadata.new details_tuple
+    end
+
     def to_json(json : JSON::Builder)
       details_tuple.to_json(json)
     end