# See the License for the specific language governing permissions and
# limitations under the License.
-# Services to read JSON: `from_json_string` and `JsonDeserializer`
+# Services to read JSON: `deserialize_json` and `JsonDeserializer`
module serialization_read
-import ::serialization::caching
-private import ::serialization::engine_tools
+import serialization::caching
+private import serialization::engine_tools
+import serialization::safe
+
private import static
-private import string_parser
import poset
# Deserializer from a Json string.
class JsonDeserializer
super CachingDeserializer
+ super SafeDeserializer
# Json text to deserialize from.
private var text: Text
- # Accepted parameterized classes to deserialize
- #
- # If `whitelist.empty`, all types are accepted.
- #
- # ~~~nitish
- # import json::serialization
- #
- # class MyClass
- # serialize
- # end
- #
- # var json_string = """
- # {"__class" = "MyClass"}
- # """
- #
- # var deserializer = new JsonDeserializer(json_string)
- # var obj = deserializer.deserialize
- # assert deserializer.errors.is_empty
- # assert obj isa MyClass
- #
- # deserializer = new JsonDeserializer(json_string)
- # deserializer.whitelist.add "Array[String]"
- # deserializer.whitelist.add "AnotherAcceptedClass"
- # obj = deserializer.deserialize
- # assert deserializer.errors.length == 1
- # assert obj == null
- # ~~~
- var whitelist = new Array[Text]
-
- # Should objects be checked if they a subtype of the static type before deserialization?
- #
- # Defaults to `true`, as it should always be activated.
- # It can be turned off to implement the subtype check itself.
- var check_subtypes = true is writable
-
# Root json object parsed from input text.
private var root: nullable Object is noinit
if class_name == null and static_type != null then
# Fallack to the static type, strip the `nullable` prefix
- var prefix = "nullable "
- if static_type.has_prefix(prefix) then
- class_name = static_type.substring_from(prefix.length)
- else class_name = static_type
+ class_name = static_type.strip_nullable
end
end
return object
end
- if whitelist.not_empty and not whitelist.has(class_name) then
- errors.add new Error("Deserialization Error: '{class_name}' not in whitelist")
- return null
- end
-
- if static_type != null and check_subtypes then
- var static_class = static_type.strip_nullable_and_params
- var dynamic_class = class_name.strip_nullable_and_params
- if not class_inheritance_metamodel.has_edge(dynamic_class, static_class) then
- errors.add new Error("Deserialization Error: `{class_name}` is not a subtype of the static type `{static_type}`")
- return null
- end
- end
+ if not accept(class_name, static_type) then return null
# advance on path
path.push object
if object isa Array[nullable Object] then
# Can we use the static type?
if static_type != null then
- var prefix = "nullable "
- var class_name = if static_type.has(prefix) then
- static_type.substring_from(prefix.length)
- else static_type
-
opened_array = object
- var value = deserialize_class(class_name)
+ var value = deserialize_class(static_type.strip_nullable)
opened_array = null
return value
end
# Deserialize a `nullable Object` from this JSON formatted string
#
+ # If a `static_type` is given, only subtypes of the `static_type` are accepted.
+ #
# Warning: Deserialization errors are reported with `print_error` and
# may be returned as a partial object or as `null`.
#
# This method is not appropriate when errors need to be handled programmatically,
# manually use a `JsonDeserializer` in such cases.
- fun from_json_string: nullable Object
+ fun deserialize_json(static_type: nullable String): nullable Object
do
var deserializer = new JsonDeserializer(self)
- var res = deserializer.deserialize
+ var res = deserializer.deserialize(static_type)
if deserializer.errors.not_empty then
print_error "Deserialization Errors: {deserializer.errors.join(", ")}"
end
return res
end
-
- # Strip the `nullable` prefix and the params from the class name `self`
- #
- # ~~~nitish
- # assert "String".strip_nullable_and_params == "String"
- # assert "Array[Int]".strip_nullable_and_params == "Array"
- # assert "Map[Set[String], Set[Int]]".strip_nullable_and_params == "Map"
- # ~~~
- private fun strip_nullable_and_params: String
- do
- var class_name = to_s
-
- var prefix = "nullable "
- if class_name.has_prefix(prefix) then class_name = class_name.substring_from(prefix.length)
-
- var bracket_index = class_name.index_of('[')
- if bracket_index == -1 then return class_name
- return class_name.substring(0, bracket_index)
- end
end
redef class SimpleCollection[E]
private fun class_inheritance_metamodel_json: CString is intern
redef class Sys
- # Class inheritance graph
- #
- # ~~~
- # var hierarchy = class_inheritance_metamodel
- # assert hierarchy.has_edge("String", "Object")
- # assert not hierarchy.has_edge("Object", "String")
- # ~~~
- var class_inheritance_metamodel: POSet[String] is lazy do
+ redef var class_inheritance_metamodel is lazy do
var engine = new JsonDeserializer(class_inheritance_metamodel_json.to_s)
engine.check_subtypes = false
engine.whitelist.add_all(
- ["String", "POSet[String]", "POSetElement[String]", "HashSet[String]", "HashMap[String, POSetElement[String]]"])
+ ["String", "POSet[String]", "POSetElement[String]",
+ "HashSet[String]", "HashMap[String, POSetElement[String]]"])
+
var poset = engine.deserialize
if engine.errors.not_empty then
- print_error engine.errors.join("\n")
+ print_error "Deserialization errors in class_inheritance_metamodel:"
+ print_error engine.errors.join("\n* ")
return new POSet[String]
end
+
if poset isa POSet[String] then return poset
return new POSet[String]
end
end
-
-redef class Deserializer
- redef fun deserialize_class(name)
- do
- if name == "POSet[String]" then return new POSet[String].from_deserializer(self)
- if name == "POSetElement[String]" then return new POSetElement[String].from_deserializer(self)
- if name == "HashSet[String]" then return new HashSet[String].from_deserializer(self)
- if name == "HashMap[String, POSetElement[String]]" then return new HashMap[String, POSetElement[String]].from_deserializer(self)
-
- return super
- end
-end
nitlanguage / nit.git / blobdiff