oatpp/changelog/1.1.0.md

# Oat++ 1.1.0

Oat++ `1.1.0` is introducing breaking changes. 
Please read carefully to prepare for migration.

## No more explicit 'ObjectWrapper'

Do not explicitly write `ObjectWrapper`

DTO:

```cpp
class MyDto : oatpp::Object {

  DTO_INIT(MyDto, Object)
  
  DTO_FIELD(MyDto, nested);
  DTO_FIELD(List<Any>, listOfAny);
  DTO_FIELD(Fields<List<String>>, mapOfLists);

}
```

ApiController:

```cpp
ENDPOINT("POST", "body-dto", postWithBody,
         BODY_DTO(MyDto, body)) {
  ...    
}
```

## Object-Mapping type Any

The new Type Introduced - `oatpp::Any`.

Now it's possible to do like this:

```cpp
class MyDto : public oatpp::Object {

  DTO_INIT(MyDto, Object)
 
  DTO_FIELD(Any, any); // Put any oatpp::<Type> here
  DTO_FIELD(List<Any>, listOfAny)
  DTO_FIELD(Fields<Any>, mapOfAny);

};
```

### JSON Serializer

Will serialize Any depending on the value type it stores.

### JSON Deserializer

Will try to guess the type of the `Any`. 
Currently, `Any` is deserialized as follows:

- JSON objects are deserialized to `Any` holding `oatpp::Fields<Any>`.
- JSON lists are deserialized to `Any` holding `oatpp::List<Any>`.
- JSON `null` is deserialized to `Any` holding `nullptr`.
- JSON `true`/`false` is deserialized to `Any` holding `oatpp::Boolean`.
- JSON `number` is deserialized to `Any` holding `oatpp::Float64`.

### Example

```cpp
oatpp::Fields<oatpp::Any> map = {
  {"title", oatpp::String("Hello Any!")},
  {"listOfAny",
   oatpp::List<oatpp::Any>({
     oatpp::Int32(32),
     oatpp::Float32(0.32),
     oatpp::Boolean(true)
   })
  }
};

auto json = mapper->writeToString(map); 
```

**Output:**

```json
{
  "title": "Hello Any!",
  "listOfAny": [
    32,
    0.3199999928474426,
    true
  ]
}
```

## Object-Mapping Collections

Now `oatpp::<mapping-enabled-collections>` are based on `std::<collections>`

Example:

```cpp
oatpp::Vector<oatpp::String> vector = oatpp::Vector<oatpp::String>::createShared();
oatpp::List<oatpp::String> list = oatpp::List<oatpp::String>::createShared();
oatpp::Fields<oatpp::String> pairList= oatpp::Fields<oatpp::String>::createShared();
oatpp::UnorderedFields<oatpp::String> hashMap = oatpp::UnorderedFields<oatpp::String>::createShared();

oatpp::Vector<oatpp::String> vector = {"a", "b", "c"};
oatpp::List<oatpp::String> list = {"a", "b", "c"};
oatpp::Fields<oatpp::String> pairList = {{"k1", "v1"}, {"k2", "v2"}, {"k3", "v3"}};
oatpp::UnorderedFields<oatpp::String> hashMap = {{"k1", "v1"}, {"k2", "v2"}, {"k3", "v3"}};

vector[0] = "z"; // <--- Complexity = O(1);
vector->push_back("www");

list[0] = "z"; // <--- Complexity = O(n);
list->push_back("www");

pairList["k1"] = "z"; // <--- Complexity = O(n);
pairList->push_back({"key_z", "z"}); 

hashMap["k1"] = "z" // <--- Complexity = O(1);
hashMap->insert({"key_z", "z"});

for(auto& item : *vector) {
  ...
}

for(auto& item : *list) {
  ...
}

for(auto& pair : *pairList) {
  ...
}

for(auto& pair : *hashMap) {
  ...
}
```

## Object-Mapping Simplified Primitives

No more `<primitive>->getValue()`.

```cpp
oatpp::Int32 objV = 32;
v_int32 v = objV; // You may check for nullptr before doing this

bool equals = v == objV; // <--- NO NEED to check for nullptr here
bool isNull = objV == nullptr;
bool isNull = !objV;
```

## Object-Mapping Enum

Enum is added to DTO codegen.

### Declaration 

```cpp
#include OATPP_CODEGEN_BEGIN(DTO)

ENUM(Enum1, v_int32,            // <-- type is mandatory 
     VALUE(V_1, 1),             // <-- integral value is mandatory
     VALUE(V_2, 2, "name-2"),
     VALUE(V_3, 3, "name-3", "description_3")
)

#include OATPP_CODEGEN_END(DTO)
```

This will generate:

```cpp
enum class Enum1 : v_int32 {
  V_1 = 1,
  V_2 = 2,
  V_3 = 3
}

... // PLUS Meta here
```

Current limitation - `ENUM` can not be declared nested in the class :(.
This may be fixed later.

### Usage

#### DTO

```cpp
ENUM(MyEnum, v_int32,
  VALUE(V1, 10, "enum1-v1"),
  VALUE(V2, 20, "enum1-v2"),
  VALUE(V3, 30, "enum1-v3")
);

class MyDto : public oatpp::Object {

  DTO_INIT(MyDto, Object)

  DTO_FIELD(Enum<MyEnum>, enum1);            // Default interpretation - AsString
  DTO_FIELD(Enum<MyEnum>::NotNull, enum2);   // NOT_NULL constraint for Ser/De

  DTO_FIELD(Enum<MyEnum>::AsString, enum3);  // Ser/De as string name
  DTO_FIELD(Enum<MyEnum>::AsNumber, enum4);  // Ser/De as a corresponding integral value

  DTO_FIELD(Enum<MyEnum>::AsString::NotNull, enum5);
  DTO_FIELD(Enum<MyEnum>::AsNumber::NotNull, enum6);

};
```

#### ApiController

```cpp
  ENDPOINT("GET", "enum/as-string", testEnumString,
           HEADER(Enum<AllowedHeaderValues>::AsString, enumValue, "X-MyEnum"))
  {
    return createResponse(Status::CODE_200, "OK");
  }

  ENDPOINT("GET", "enum/as-number", testEnumNumber,
           HEADER(Enum<AllowedHeaderValues>::AsNumber, enumValue, "X-MyEnum"))
  {
    return createResponse(Status::CODE_200, "OK");
  }
```

#### ApiClient

```cpp
  API_CALL("GET", "enum/as-string", getWithEnumHeaderAsString, HEADER(Enum<AllowedHeaderValues>::AsString, enumValue, "X-MyEnum"))
  API_CALL("GET", "enum/as-number", getWithEnumHeaderAsNumber, HEADER(Enum<AllowedHeaderValues>::AsNumber, enumValue, "X-MyEnum"))
```

### Meta functions

```cpp
{
  auto entry = oatpp::Enum<MyEnum>::getEntryByName("<name>");
  auto entry = oatpp::Enum<MyEnum>::getEntryByValue(MyEnum::VALUE);
  auto entry = oatpp::Enum<MyEnum>::getEntryByUnderlyingValue(123);
  auto entry = oatpp::Enum<MyEnum>::getEntryByIndex(0);
  ...
  OATPP_LOGD("Entry", "%d, %s, %d, %d, %s", entry.index, entry.name, entry.value, entry.description);
}

{
 const auto& entries = oatpp::Enum<MyEnum>::getEntries();
 for(const auto& e : entries) {
  ...
 }
}
```