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Matt Schoen schoen@defectivestudios.com of Defective Studios

Intro

I came across the need to send structured data to and from a server on one of my projects, and figured it would be worth my while to use JSON. When I looked into the issue, I tried a few of the C# implementations listed on http://json.org, but found them to be too complicated to work with and expand upon. So, I've written a very simple JSONObject class, which can be generically used to encode/decode data into a simple container. This page assumes that you know what JSON is, and how it works. It's rather simple, just go to json.org for a visual description of the encoding format.

Usage

Users should not have to modify the JSONObject class themselves, and must follow the very simple procedures outlined below:

Sample data (in JSON format):

{
    "TestObject": {
        "SomeText": "Blah",
        "SomeObject": {
            "SomeNumber": 42,
            "SomeBool": true,
            "SomeNull": null
        },
        
        "SomeEmptyObject": { },
        "SomeEmptyArray": [ ],
        "EmbeddedObject": "{\"field\":\"Value with \\\"escaped quotes\\\"\"}"
    }
}

The test classes provide the best examples for how the API is intended to be used.

Features

It should be pretty obvious what this parser can and cannot do. If anyone reading this is a JSON buff (is there such a thing?) please feel free to expand and modify the parser to be more compliant. Currently I am using the .NET System.Convert namespace functions for parsing the data itself. It parses strings and numbers, which was all that I needed of it, but unless the formatting is supported by System.Convert, it may not incorporate all proper JSON strings. Also, having never written a JSON parser before, I don't doubt that I could improve the efficiency or correctness of the parser. It serves my purpose, and hopefully will help you with your project! Let me know if you make any improvements :)

Also, you JSON buffs (really, who would admit to being a JSON buff...) might also notice from my feature list that this thing isn't exactly to specifications. Here is where it differs:

Encoding

Encoding is something of a hard-coded process. This is because I have no idea what your data is! It would be great if this were some sort of interface for taking an entire class and encoding it's number/string fields, but it's not. I've come up with a few clever ways of using loops and/or recursive methods to cut down of the amount of code I have to write when I use this tool, but they're pretty project-specific.

The constructor, Add, and AddField functions now support a nested delegate structure. This is useful if you need to create a nested JSONObject in a single line. For example:

void DoRequest(string url, string jsonString) {
	// Web Request logic
}

void Test(string url) {
	DoRequest(url, new JSONObject(request => {
		request.AddField("sort", sort => sort.AddField("_timestamp", "desc"));
		request.AddField("query", new JSONObject(query => query.AddField("match_all", JSONObject.emptyObject)));
		request.AddField("fields", fields => fields.Add("_timestamp"));
	}).ToString());
}

Decoding

Decoding is much simpler on the input end, and again, what you do with the JSONObject will vary on a per-project basis. One of the more complicated way to extract the data is with a recursive function, as drafted below. Calling the constructor with a properly formatted JSON string will return the root object (or array) containing all of its children, in one neat reference! The data is in a public ArrayList called list, with a matching key list (called keys!) if the root is an Object. If that's confusing, take a glance over the following code and the print() method in the JSONObject class. If there is an error in the JSON formatting (or if there's an error with my code!) the debug console will read "improper JSON formatting".

void Test() {
	var encodedString = "{\"field1\": 0.5,\"field2\": \"sampletext\",\"field3\": [1,2,3]}";
	var jsonObject = new JSONObject(encodedString);
	AccessData(jsonObject);
}

void AccessData(JSONObject jsonObject) {
	switch (jsonObject.type) {
		case JSONObject.Type.Object:
			for (var i = 0; i < jsonObject.list.Count; i++) {
				var key = jsonObject.keys[i];
				var value = jsonObject.list[i];
				Debug.Log(key);
				AccessData(value);
			}
			break;
		case JSONObject.Type.Array:
			foreach (JSONObject element in jsonObject.list) {
				AccessData(element);
			}
			break;
		case JSONObject.Type.String:
			Debug.Log(jsonObject.stringValue);
			break;
		case JSONObject.Type.Number:
			Debug.Log(jsonObject.floatValue);
			break;
		case JSONObject.Type.Bool:
			Debug.Log(jsonObject.boolValue);
			break;
		case JSONObject.Type.Null:
			Debug.Log("Null");
			break;
		case JSONObject.Type.Baked:
			Debug.Log(jsonObject.stringValue);
			break;
	}
}

Decoding also supports a delegate format which will automatically check if a field exists before processing the data, providing an optional parameter for an OnFieldNotFound response. For example:

void Test(string jsonString) {
	var list = new JSONObject(jsonString);
	list.GetField("users", users => {
		foreach (var user in users.list) {
			var thisUser = user;
			users.GetField("sessions", sessions => {
				foreach (JSONObject gameSession in sessions.list) {
					Debug.Log(gameSession);
				}
			}, name => Debug.LogWarning(string.Format("No sessions for user {0}", thisUser["name"].stringValue)));
		}
		
	});
}

(O(n)) Random access

I've added a string and int [] index to the class, so you can now retrieve data as such (from above):

void Test() {
	var jsonObject = new JSONObject("{\"field\":[0,1,2]");
	var array = jsonObject["field"];
	Debug.Log(array[2].intValue); //Should output "2"
}

Change Log

v2.1.3

v2.1.2

v2.1.1

v2.1

v2.0

v1.4

Big update!

v1.3.2