【C++】rapidjson: 读取复杂的json串

Rapidjson简介：C++11模板库方式实现的json解析库

Rapidjson文档：
http://rapidjson.org/zh-cn/index.html
 

以如下json为例，使用rapidjson解析

{
  "data": {
    "security_token": "CAIS+QJ1q6Ft5B2yfSj...Hvo2LHm",
    "access_key_id": "STS.NTAgDURZo3op8zMRrfYvPG6yF",
    "access_key_secret": "HgeVRTDRH2TpKSDibH87wE2JyfXcJiDP1n3DagMTkBJB",
    "expiration": 1599035693,
    "resources": [
      {
        "path": "dog-test/9062e25d-86c0-46d2-a2e5-7c003e461118/pictures/",
        "endpoint": "https://oss-cn-shenzhen.aliyuncs.com"
      }
    ]
  }
}

以上json串包含：Object，Array，Key-Value，嵌套Object，嵌套Array等基本结构。

解析代码如下：

#include "rapidjson/document.h"

// 解析OSS STS response中的json串
// pStrRespData为待解析json串
bool parse_osssts_json_data(myyk::SOSSInfo &struSTSResponse, string *pStrRespData)
{
    struSTSResponse.result = false;

    rapidjson::Document doc;
    doc.Parse((*pStrRespData).c_str());

    if(!doc.IsObject())
    {
        LogError(string("Authorization response format isn't json format: ") + *pStrRespData);
        return false;
    }

    // 鉴权成功
    if(doc.HasMember("data"))
    {
        rapidjson::Document::Object dataObj = doc["data"].GetObject();

        struSTSResponse.mStrSecurityToken = dataObj["security_token"].GetString();
        struSTSResponse.mStrAccessKeyId = dataObj["access_key_id"].GetString();
        struSTSResponse.mStrAccessKeySecret = dataObj["access_key_secret"].GetString();
        struSTSResponse.expiresTime = dataObj["expiration"].GetInt64();       // 授权到期时间点

        rapidjson::Document::Array array = dataObj["resources"].GetArray();  // json array type
        if(array.Size() < 1)
        {
            LogInfo("OSS STS response json parse failed, 'resources' array size < 1");
            return false;
        }

        rapidjson::Document::Object resObj = array[0].GetObject();
        string path = resObj["path"].GetString();    // <bucketName>/<savePath>, aiot-rcb/9062e25d-86c0-46d2-a2e5-7c003e461118/pictures/
        struSTSResponse.mStrEndpoint = resObj["endpoint"].GetString();    // endPoint, https://oss-cn-shenzhen.aliyuncs.com
        bool bRet =  [&]()->bool {
                auto index = path.find_first_of('/');
                if( string::npos == index ){
                    return false;
                }

                struSTSResponse.mStrBucketName = path.substr(0, index);
                struSTSResponse.mOSSSavePath = path.substr(index+1);
                return true;
            }();

        if(!bRet)
        {
            LogError("OSS STS response json parse failed, 'bucket name' not found");
            return false;
        }

        LogInfo("OSS STS response json parse success.");
        struSTSResponse.result = true;
        return true;
    }

    return false;
}