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Small LINQ to JSON Library

, 6 Dec 2011 CPOL
A small LinqToJSON library in C#, and how it works
LinqToJSON-all.zip
DemoApp
Properties
JSON.Linq
ClassDiagram1.cd
internal
JSON.Linq.sln.docstates
JSON.Linq.suo
Properties
public
Ranslant.JSON.Linq.dll
LINQToJSON-dll.zip
Ranslant.JSON.Linq.dll
LinqToJSON-doc.zip
doc
Linq.Json_fichiers
LinqToJSON-src.zip
ClassDiagram1.cd
JSON.Linq.sln.docstates
JSON.Linq.suo
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Ranslant.JSON.Linq;

namespace DemoApp
{
    class Program
    {
        static void Main(string[] args)
        {
            EncodingTests();

            // uncomment the line below to get the exception
            //Writetest2_MustTriggerException("testfail.json");   // won't trigger an exception: code is commented out. Remove the comment marker to get the exception
            
            WriteTest1_MustSucceed("test1.json");

            ReadTest_MustSucceed("test1.json", true);

            // uncomment the line below to get the exception
            //ReadTest_mustFail("testfail.json");   // failed as expected, until the json content was fixed in the file

            WriteReadTest_MustSucceed("WRtest.json");

        }

        private static void EncodingTests()
        {
            // write the data
            WriteJsonDataWithByteOrderMark("simpson_ascii.json", new ASCIIEncoding());
            WriteJsonDataWithByteOrderMark("simpson_utf8.json", new UTF8Encoding(true)); // use new UTF8Encoding(true) to get the UTF-8 3bytes ByteOrderMark 
            WriteJsonDataWithByteOrderMark("simpson_utf16LE.json", new UnicodeEncoding(false, true));
            WriteJsonDataWithByteOrderMark("simpson_utf16BE.json", new UnicodeEncoding(true, true));


            // read the data
            JDocument doc01 = JDocument.Load("simpson_ascii.json", null);
            JDocument doc02 = JDocument.Load("simpson_utf8.json", null);
            JDocument doc03 = JDocument.Load("simpson_utf16LE.json", null);
            JDocument doc04 = JDocument.Load("simpson_utf16BE.json", null);

            JDocument doc1 = JDocument.Load("simpson_ascii.json", new ASCIIEncoding());

            JDocument doc2 = JDocument.Load("simpson_utf8.json", new UTF8Encoding());
            JDocument doc3 = JDocument.Load("simpson_utf16LE.json", new UnicodeEncoding());
            //JDocument doc31 = JDocument.Load("simpson_utf16BE.json", new UnicodeEncoding()); // fails as expected
            //JDocument doc32 = JDocument.Load("simpson_utf16BE.json", new UnicodeEncoding(false, true, true)); // fails as expected
            JDocument doc33 = JDocument.Load("simpson_utf16BE.json", new UnicodeEncoding(true, true, true));

            JDocument doc4 = JDocument.Load("simpson_ascii.json", new UTF8Encoding());  // works, this is expected though, since all ascii characters are also encoded over 8 bits. They are therefore properly recognized.
            //JDocument doc41 = JDocument.Load("simpson_ascii.json", new UnicodeEncoding());  // fails as expected
            //JDocument doc5 = JDocument.Load("simpson_utf8.json", new ASCIIEncoding()); // fails as expected
            //JDocument doc36 = JDocument.Load("simpson_utf16LE.json", new ASCIIEncoding()); // fails as expected
            //JDocument doc37 = JDocument.Load("simpson_utf16LE.json", new UTF8Encoding());  // fails as expected
        }

        private static void WriteJsonDataWithByteOrderMark(string filename, Encoding encoding)
        {
            // example of JDocument written only through the constructor:
            new JDocument(
                        new JObjectMember("D'oh",
                                 new JObject(
                                            new JObjectMember("First Name", new JString("Homer")),
                                            new JObjectMember("Family Name", new JString("Simpson")),
                                            new JObjectMember("Is Fat?", new JTrue()),
                                            new JObjectMember("Children",
                                                new JArray
                                                        (
                                                            new JString("Bart"),
                                                            new JString("Lisa"),
                                                            new JString("Maggie")
                                                          )
                                            )
                                        )
                         ),
                         new JObjectMember("never gets older",
                                    new JObject(
                                                new JObjectMember("First Name", new JString("Bart")),
                                                new JObjectMember("Family Name", new JString("Simpson"))
                                                )
                                            )
                                ).Save(filename, encoding, true);
        }

        private static void WriteReadTest_MustSucceed(string filename)
        {
            if (filename.Length == 0)
                return;

            JDocument docW = WriteTest1_MustSucceed(filename);
            JDocument docR = ReadTest_MustSucceed(filename, false);

            //todo: compare docW and DocR
        }

        private static void ReadTest_mustFail(string filename)
        {
            if (filename.Length == 0)
                return;
            // the JSON data provided has to be voluntarily faulty and therefore allowed to check that an exception is properly thrown
            // I took test1.json, renamed it to testfail.json and modified it to make it faulty by removing tokens or adding wrong content for instance
            JDocument doc = JDocument.Load(filename);

        }

        private static JDocument ReadTest_MustSucceed(string filename, bool consoleOutput)
        {
            if (filename.Length == 0)
                return null;


            // first, load the document
            JDocument jDoc = JDocument.Load(filename);

            if (consoleOutput)
            {
                // then, you can use LINQ to parse the document
                var q = from o in jDoc.GetMembers()
                        select o;
                foreach (var o in q)
                {
                    // you can filter the values using their type
                    if (o.Value is JString || o.Value is JNumber)
                        Console.WriteLine("string or number: {0} : {1}", o.Name, o.Value.ToString(0));
                    else
                        if (o.Value is JFalse || o.Value is JTrue || o.Value is JNull)
                            Console.WriteLine("true, false or null: {0} : {1}", o.Name, o.Value.ToString(0));

                    // you can filter the values using their type 
                    if (o.Value is JObject)
                    {
                        JObject obj = o.Value as JObject;
                        Console.WriteLine("---(OBJECT)---\r\n\tobject name:{0} ({1} members)", o.Name, obj.Count);

                        Console.WriteLine("\t---All members (per member name, with type):");

                        var names = from name in obj.GetNames()
                                    select name;
                        foreach (var name in names)
                        {
                            // you can get an object with its name
                            IJValue value = obj[name];

                            if (value is JString || value is JNumber || value is JFalse || value is JTrue || value is JNull)
                                Console.WriteLine("\t{0} ({1}) : {2}", name, value.GetType().ToString(), value.ToString(0));
                            else
                                Console.WriteLine("\t{0} ({1})", name, value.GetType().ToString());
                        }

                        Console.WriteLine("\t---All values (without the member name):");
                        var values = from value in obj.GetValues()
                                     select value;
                        foreach (var value in values)
                        {
                            Console.WriteLine("\t{0}", value.ToString(1));
                        }

                        Console.WriteLine("\t---All members (with GetMembers()):");
                        var members = from member in obj.GetMembers()
                                      select member;
                        foreach (var member in members)
                        {
                            Console.WriteLine("\t{0} : {1}", member.Name, member.Value.ToString(0));
                        }
                    }

                    if (o.Value is JArray)
                    {
                        JArray jarray = o.Value as JArray;

                        Console.WriteLine("---(ARRAY)---\r\n\tarray name:{0} ({1} members)", o.Name, jarray.Count);

                        // you can use GetValues()
                        foreach (IJValue val in jarray.GetValues())
                        {
                            Console.WriteLine("\t-----element type {0}", val.GetType().ToString());
                        }

                        // ... or an index: jarray[i]
                        for (int i = 0; i < jarray.Count; i++)
                        {
                            Console.WriteLine("\t-----element type {0}", jarray[i].GetType().ToString());
                        }
                    }
                }
                Console.WriteLine();
                Console.WriteLine("Press ENTER to continue...");
                Console.ReadLine();
            }

            return jDoc;
        }

        private static void Writetest2_MustTriggerException(string filename)
        {
            if (filename.Length == 0)
                return;

            // all below should fail
            /**/
            // remove or put back the space between /** and the following / to switch the comments on / off

            JArray arrTest = new JArray(
                        new JNumber("+"), //fails as expected: we need a number
                        new JNumber("abcd"), //fails as expected: we need a number
                        new JNumber(""), //fails as expected: we need a number
                        new JNumber("123,654"), // fails as expected: the decimal separator is '.'
                        new JNumber("0xAB"), // fails as expected: no hexadecimal
                        new JNumber("0145"), // fails as expected: no octal
                        new JNumber("0123.123e456"), // fails as expected: if the number begins with 0, the next char must be '.'
                        new JNumber("+12"), // fails as expected: number begins with digit or -
                        new JNumber(".5"), // fails as expected: number begins with digit or -
                        new JNumber("6."), // fails as expected: decimal separator without fractional part
                        new JNumber("6,"), // fails as expected: decimal separator not '.' and fractional part missing
                        new JNumber("6 "), // fails as expected: no spaces after the number
                        new JNumber(" 6"), // fails as expected: number begins with digit or -
                        new JNumber("0x45") // fails as expected: no hexadecimal
                    );

            JDocument doc1 = new JDocument();
            doc1.Add("1", new JString(@"\a")); // fails as expected: \a is not allowed

            doc1.Add("0", new JString(@"\n\test\\""me:{}")); // fails as expected: \\"" will be read as 
            doc1.Add("1", new JNull());
            doc1.Add("1", new JString(@""));    //fails as expected: name "1" is used twice

            doc1.Add("2", new JString(@"\u1"));  //fails as expected: \u should be followed by four hexadecimal digits
            doc1.Add("3", new JString(@"\u123G"));  //fails as expected: \u should be followed by four hexadecimal digits
            //*/
        }

        private static JDocument WriteTest1_MustSucceed(string filename)
        {
            if (filename.Length == 0)
                return null;

            // you can create an empty object and add values
            JObject obj = new JObject();

            obj.Add("_number", new JNumber(-3.14));
            obj.Add("_true", new JTrue());   // notice the use of JTrue 
            obj.Add("_null", new JNull());   // notice the use of JNull

            // you can also add the values directly, thanks to JObjectMember
            JObject homer = new JObject(
                                new JObjectMember("First Name", new JString("Homer")),
                                new JObjectMember("Family Name", new JString("Simpson")),
                                new JObjectMember("Is Yellow?", new JTrue()), // notice the use of JTrue 
                                new JObjectMember("Is Blue?", new JFalse()) // notice the use of JFalse
                                );

            // you can create an empty array and add values
            JArray arr = new JArray();
            // ... either only one value
            arr.Add(new JNumber("-15.64"));

            // ... or more than one at once
            // Notice that prefixing your strings with @ will help keeping them be valid JSON strings
            arr.Add(new JString(@"Unicode: \u12A0"),
                    new JString(@"\n\test\""me:{}"),   // this string is valid because
                // 1. \test is seen as \t + est
                // 2. \"" will be checked as \"
                    new JString("\\n\\test\\\"me:{}"),  // same string, without the prefix @
                    new JString(@"\\test"),             // how to get the Json string \\test
                    new JString("\\\""),
                    new JString(@"\\"),
                    homer);                 // we added an object in the array :)

            // or you can add the value directly
            JArray otherArray = new JArray(
                        new JString("test2"),
                        new JString(string.Empty),
                        new JNull());           // notice the use of JNull
            // ... you can still add values 
            otherArray.Add(obj);

            // here some valid numbers
            JArray arrTest = new JArray(
                new JNumber("-0.3"),
                new JNumber("12"),
                new JNumber("0"),
                new JNumber("5"),
                new JNumber("12345"),
                new JNumber("3.45"),
                new JNumber("12.35"),
                new JNumber("54e-5"),
                new JNumber("12.54E+45"),
                new JNumber("1.5e-8"),
                new JNumber("12345.6789"),
                new JNumber("0.987"),
                new JNumber(4.16e-8)
                );

            // JDocument is a JObject itself, therefore we have the same two possibilities:
            // 1. add object members in the JDocument constructor

            JDocument doc = new JDocument(
                new JObjectMember("_false", new JFalse()),
                new JObjectMember("_false2", new JFalse())
                );   // the same name cannot be used twice!

            // 2. add object members with Add()

            // Add() has two forms:
            // 1. with JObjectMember
            // you can give one
            doc.Add(new JObjectMember("_Father Of the Year", homer));
            // or more
            doc.Add(
                new JObjectMember("_array", arr),
                new JObjectMember("_string1", new JString("string1")),
                new JObjectMember("_number2", new JNumber("-3.14"))
                );

            // 2. directly give the name and the value
            doc.Add("_otherArray", otherArray);
            doc.Add("_obj", obj);

            doc.Save(filename);

            return doc;
        }
    }
}

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Guillaume Ranslant
Software Developer IPG
Germany Germany
since 2010: C# with WPF
since 2002: C++ (MFC / QT)
since 1995: C, Java, Pascal
 

"if a drummer can do it, anobody can" - Bruce Dickinson

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