RapidJson : How to get all Key_names from a JSON? (cocos2dx)

Question

From a Json string (or file), I want to collect key/value pairs without knowing the keys in advance. Let's say I have this Json:

{ "a":"1","b":"2","c":"3" }

I'd like to collect all key strings "a" , "b" , "c" , "d" and their respective values. BTW: I use rapidjson integration in Cocos2dX 3.3. Any idea?

What I'm on now is to use :

rapidjson::Document JSON; 

//..... collecting the JSON .... then

for (rapidjson::Value::MemberIterator M=JSON.MemberonBegin(); M!=JSON.MemberonEnd(); M++)
{
    //..... I have access to M->name and M->value here
    //..... but I don't know how to convert them to std::string or const char*
}

But I'm stuck with that.

Zenslainer · Answer 1 · 2015-01-09T15:28:59.657

5

I've just figured out that rapidjson::Value::MemberIterator has functions in it. So here is an example to enumerate key/pairs from a Json document. This example only log root keys. You will need extra work to retrieve sub-keys

const char *jsonbuf = "{\"a\":\"1\",\"b\":\"2\",\"c\":\"3\"}";

rapidjson::Document                 JSON;
rapidjson::Value::MemberIterator    M;
const char                          *key,*value;

JSON.Parse<0>(jsonbuf);

if (JSON.HasParseError())
{
    CCLOG("Json has errors!!!");
    return;
}

for (M=JSON.MemberonBegin(); M!=JSON.MemberonEnd(); M++)
{
    key   = M->name.GetString();
    value = M->value.GetString();

    if (key!=NULL && value!=NULL)
    {
        CCLOG("%s = %s", key,value);
    }
}

edited Jan 09 '15 at 15:28

answered Jan 09 '15 at 14:50

Zenslainer

159
1
9

1

What does the `<0>` mean in `JSON.Parse<0>(jsonbuf);` ? – Emadpres Jan 10 '15 at 16:45
The value is a parseFlag. 0 means kParseNoFlags. That's the default used value for common parsing . Please check parseFlags here: [link](http://bit.ly/1tVAf0z) – Zenslainer Jan 11 '15 at 05:25
1

@Emadpres Besides, the newer versions of RapidJSON has overloaded function of Parse() that doesn't need <0>. – Milo Yip Feb 11 '15 at 01:32
1

Thanks a lot, the tutorial on rapidJSON's web page suck – Dumisani Kunene Aug 30 '18 at 08:53

RapidJson : How to get all Key_names from a JSON? (cocos2dx)

1 Answers1