Merge branch 'release/0.17'

crystal-lang · May 25, 2016 · fb22a89 · fb22a89
2 parents 3d13b18 + 463d301
commit fb22a89
Showing 5 changed files with 104 additions and 1 deletion.
diff --git a/spec/std/json/mapping_spec.cr b/spec/std/json/mapping_spec.cr
@@ -118,6 +118,24 @@ class JSONWithRaw
   })
 end
 
+class JSONWithRoot
+  JSON.mapping({
+    result: {type: Array(JSONPerson), root: "heroes"},
+  })
+end
+
+class JSONWithNilableRoot
+  JSON.mapping({
+    result: {type: Array(JSONPerson), root: "heroes", nilable: true},
+  })
+end
+
+class JSONWithNilableRootEmitNull
+  JSON.mapping({
+    result: {type: Array(JSONPerson), root: "heroes", nilable: true, emit_null: true},
+  })
+end
+
 describe "JSON mapping" do
   it "parses person" do
     person = JSONPerson.from_json(%({"name": "John", "age": 30}))
@@ -349,4 +367,26 @@ describe "JSON mapping" do
     json.value.should eq(%([null,true,false,{"x":[1,1.5]}]))
     json.to_json.should eq(string)
   end
+
+  it "parses with root" do
+    json = %({"result":{"heroes":[{"name":"Batman"}]}})
+    result = JSONWithRoot.from_json(json)
+    result.result.should be_a(Array(JSONPerson))
+    result.result.first.name.should eq "Batman"
+    result.to_json.should eq(json)
+  end
+
+  it "parses with nilable root" do
+    json = %({"result":null})
+    result = JSONWithNilableRoot.from_json(json)
+    result.result.should be_nil
+    result.to_json.should eq("{}")
+  end
+
+  it "parses with nilable root and emit null" do
+    json = %({"result":null})
+    result = JSONWithNilableRootEmitNull.from_json(json)
+    result.result.should be_nil
+    result.to_json.should eq(json)
+  end
 end
diff --git a/spec/std/json/serialization_spec.cr b/spec/std/json/serialization_spec.cr
@@ -106,6 +106,11 @@ describe "JSON serialization" do
         JSONSpecEnum.from_json(%("Three"))
       end
     end
+
+    it "deserializes with root" do
+      Int32.from_json(%({"foo": 1}), root: "foo").should eq(1)
+      Array(Int32).from_json(%({"foo": [1, 2]}), root: "foo").should eq([1, 2])
+    end
   end
 
   describe "to_json" do

diff --git a/src/json/from_json.cr b/src/json/from_json.cr
@@ -1,8 +1,33 @@
+# Deserializes the given JSON in *string_or_io* into
+# an instance of `self`. This simply creates a `parser = JSON::PullParser`
+# and invokes `new(parser)`: classes that want to provide JSON
+# deserialization must provide an `def initialize(parser : JSON::PullParser`
+# method.
+#
+# ```
+# Int32.from_json("1")                # => 1
+# Array(Int32).from_json("[1, 2, 3]") # => [1, 2, 3]
+# ```
 def Object.from_json(string_or_io) : self
   parser = JSON::PullParser.new(string_or_io)
   new parser
 end
 
+# Deserializes the given JSON in *string_or_io* into
+# an instance of `self`, assuming the JSON consists
+# of an JSON object with key *root*, and whose value is
+# the value to deserialize.
+#
+# ```
+# Int32.from_json(%({"main": 1}), root: "main").should eq(1)
+# ```
+def Object.from_json(string_or_io, root : String) : self
+  parser = JSON::PullParser.new(string_or_io)
+  parser.on_key!(root) do
+    new parser
+  end
+end
+
 # Parses a String or IO denoting a JSON array, yielding
 # each of its elements to the given block. This is useful
 # for decoding an array and processing its elements without

diff --git a/src/json/mapping.cr b/src/json/mapping.cr
@@ -41,6 +41,7 @@ module JSON
   # * **default**: value to use if the property is missing in the JSON document, or if it's `null` and `nilable` was not set to `true`. If the default value creates a new instance of an object (for example `[1, 2, 3]` or `SomeObject.new`), a different instance will be used each time a JSON document is parsed.
   # * **emit_null**: if true, emits a `null` value for nilable properties (by default nulls are not emitted)
   # * **converter**: specify an alternate type for parsing and generation. The converter must define `from_json(JSON::PullParser)` and `to_json(value, IO)` as class methods. Examples of converters are `Time::Format` and `Time::EpochConverter` for `Time`.
+  # * **root**: assume the value is inside a JSON object with a given key (see `Object.from_json(string_or_io, root)`)
   #
   # The mapping also automatically defines Crystal properties (getters and setters) for each
   # of the keys. It doesn't define a constructor accepting those arguments, but you can provide
@@ -84,16 +85,26 @@ module JSON
         {% for key, value in properties %}
           when {{value[:key] || key.id.stringify}}
             %found{key.id} = true
+
             %var{key.id} =
               {% if value[:nilable] || value[:default] != nil %} %pull.read_null_or { {% end %}
 
+              {% if value[:root] %}
+                %pull.on_key!({{value[:root]}}) do
+              {% end %}
+
               {% if value[:converter] %}
                 {{value[:converter]}}.from_json(%pull)
               {% else %}
                 {{value[:type]}}.new(%pull)
               {% end %}
 
+              {% if value[:root] %}
+                end
+              {% end %}
+
             {% if value[:nilable] || value[:default] != nil %} } {% end %}
+
         {% end %}
         else
           {% if strict %}
@@ -137,6 +148,17 @@ module JSON
           {% end %}
 
             json.field({{value[:key] || key.id.stringify}}) do
+              {% if value[:root] %}
+                {% if value[:emit_null] %}
+                  if _{{key.id}}.is_a?(Nil)
+                    nil.to_json(io)
+                  else
+                {% end %}
+
+                io.json_object do |json|
+                  json.field({{value[:root]}}) do
+              {% end %}
+
               {% if value[:converter] %}
                 if _{{key.id}}
                   {{ value[:converter] }}.to_json(_{{key.id}}, io)
@@ -146,6 +168,14 @@ module JSON
               {% else %}
                 _{{key.id}}.to_json(io)
               {% end %}
+
+              {% if value[:root] %}
+                {% if value[:emit_null] %}
+                  end
+                {% end %}
+                  end
+                end
+              {% end %}
             end
 
           {% unless value[:emit_null] %}

diff --git a/src/json/pull_parser.cr b/src/json/pull_parser.cr
@@ -226,11 +226,12 @@ class JSON::PullParser
 
   def on_key!(key)
     found = false
+    value = uninitialized typeof(yield)
 
     read_object do |some_key|
       if some_key == key
         found = true
-        yield
+        value = yield
       else
         skip
       end
@@ -239,6 +240,8 @@ class JSON::PullParser
     unless found
       raise "json key not found: #{key}"
     end
+
+    value
   end
 
   def read_next