Cocos2d-xのHttpClientでCookieを有効にする方法

# はじめに
`cocos2d-x::network::HttpClient`を使ってログインし、サーバー側でsessionに保持したログイン情報を使う際にちょっとハマったので、その説明になります。

# HttpClientのenableCookiesを設定する

実はたったこれだけで有効になります。

```cpp
HttpClient::getInstance()->enableCookies(nullptr);
```

![スクリーンショット 2014-10-26 15.13.01.png](https://qiita-image-store.s3.amazonaws.com/0/40887/cca07901-1771-24f8-5d25-d2f3dd04804a.png)


注意点は、引数に指定する内容を`nullpter`にすることです。
*（いっそデフォルト引数にしてほしい・・・）*

## 自分で保存先を指定する例
もし自分でCookieファイルの保存先を指定したい場合は、以下のようにする必要があります。

```cpp
HttpClient::getInstance()->enableCookies(FileUtils::getInstance()->getWritablePath() + "hogeCookieFile.txt");
```

`FileUtils::getInstance()->getWritablePath()`で書き込み可能なパスを指定するのが重要です。

## ダメな例

```cpp
HttpClient::getInstance()->enableCookies("hogeCookieFile.txt");
```

これだと読み込みで失敗してしまいます。

![スクリーンショット 2014-10-26 15.12.35.png](https://qiita-image-store.s3.amazonaws.com/0/40887/6a896b63-10b4-c022-df93-7698da9ee1ad.png)


# 有効にしたら後は普通にsendするだけ

```cpp
auto request = createRequest(HttpRequest::Type::GET, "http://localhost:8000/login/hoge");
HttpClient::getInstance()->enableCookies(nullptr);
HttpClient::getInstance()->send(request);
request->release();
```

---
# おまけ
一応、以下にソースコードをすべて、載せておきます。

## ソースコード

```cpp:HelloWorldScene.cpp
#include "HelloWorldScene.h"
#include "network/HttpClient.h"

USING_NS_CC;
using namespace cocos2d::network;

HttpRequest* createRequest(HttpRequest::Type method, const std::string &requestURL);

Scene* HelloWorld::createScene()
{
    // 'scene' is an autorelease object
    auto scene = Scene::create();
    
    // 'layer' is an autorelease object
    auto layer = HelloWorld::create();

    // add layer as a child to scene
    scene->addChild(layer);

    // return the scene
    return scene;
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !Layer::init() )
    {
        return false;
    }
    
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();

    /////////////////////////////
    // 2. add a menu item with "X" image, which is clicked to quit the program
    //    you may modify it.

    // add a "close" icon to exit the progress. it's an autorelease object
    auto closeItem = MenuItemImage::create(
                                           "CloseNormal.png",
                                           "CloseSelected.png",
                                           CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));
    
	closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
                                origin.y + closeItem->getContentSize().height/2));

    ///////////////////////////
    // ここからHttp通信
    
    // login通信
    auto request = createRequest(HttpRequest::Type::GET, "http://localhost:8000/login/hoge");
    // Cookieを有効にする
    HttpClient::getInstance()->enableCookies(nullptr);
    HttpClient::getInstance()->send(request);
    request->release();
    
    // MenuItemLabelをタッチするとクエスト一覧を取得
    auto l2 = Label::createWithSystemFont("GET quest", "Arial", 20);
    auto menuItem = MenuItemLabel::create(l2, [this](Ref *ref){
        // クエスト一覧取得（要ログイン）
        auto request = createRequest(HttpRequest::Type::GET, "http://localhost:8000/quest");
        HttpClient::getInstance()->send(request);
        request->release();
    });
    menuItem->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));
    
    // create menu, it's an autorelease object
    auto menu = Menu::create(closeItem, menuItem, NULL);
    menu->setPosition(Vec2::ZERO);
    this->addChild(menu, 1);
    
    return true;
}

HttpRequest* createRequest(HttpRequest::Type method, const std::string &requestURL)
{
    HttpRequest* request = new HttpRequest();
    request->setUrl(requestURL.c_str());
    request->setRequestType(method);
    request->setResponseCallback([](HttpClient* client, HttpResponse* response) {
        if (!response) {
            CCLOG("%s response not found", response->getHttpRequest()->getTag());
            return;
        }
        
        if (0 != std::strlen(response->getHttpRequest()->getTag())) {
            CCLOG("%s completed", response->getHttpRequest()->getTag());
        }
        
        long statusCode = response->getResponseCode();
        auto statusString = StringUtils::format("HTTP Status Code: %ld, tag = %s", statusCode, response->getHttpRequest()->getTag());
        CCLOG("response code: %ld", statusCode);
        
        if (!response->isSucceed()) {
            CCLOG("response failed");
            CCLOG("error buffer: %s", response->getErrorBuffer());
            return;
        }
        
        std::string responseString(response->getResponseData()->begin(), response->getResponseData()->end());
        CCLOG("response = %s", responseString.c_str());
    });
    request->setTag(requestURL.c_str());
    
    return request;
}


void HelloWorld::menuCloseCallback(Ref* pSender)
{
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WP8) || (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
	MessageBox("You pressed the close button. Windows Store Apps do not implement a close button.","Alert");
    return;
#endif

    Director::getInstance()->end();

#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    exit(0);
#endif
}
```

```cpp:HelloWorldScene.h
#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"

class HelloWorld : public cocos2d::Layer
{
public:
    // there's no 'id' in cpp, so we recommend returning the class instance pointer
    static cocos2d::Scene* createScene();

    // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
    virtual bool init();
    
    // a selector callback
    void menuCloseCallback(cocos2d::Ref* pSender);
    
    // implement the "static create()" method manually
    CREATE_FUNC(HelloWorld);
};

#endif // __HELLOWORLD_SCENE_H__
```