[RESOLVED] JSON to ....

[max_carpenter]

Afternoon Everyone,

I have been working on this app for awhile now and most of the inputs I have had to read are XML which are all working very nicely however there is something I have never come acrss before apart from hearing of it I have never had any interaction with it and that is JSON!

I have been looking on the net for over an hour and I am completly lost at how to translate from JSON so I can use values contained within it. More specifically I am trying to query the Apply itune stores database for track information. Here is an example of one of the returned JSON strings:

{
 "resultCount":1,
 "results": [
{"wrapperType":"track", "kind":"song", "artistId":255772678, "collectionId":270137469, "trackId":270137520, "artistName":"Hadouken!", "collectionName":"Love, Sweat and Beer - EP", "trackName":"Girls", "collectionCensoredName":"Love, Sweat and Beer - EP", "trackCensoredName":"Girls", "artistViewUrl":"https://itunes.apple.com/gb/artist/hadouken!/id255772678?uo=4", "collectionViewUrl":"https://itunes.apple.com/gb/album/girls/id270137469?i=270137520&uo=4", "trackViewUrl":"https://itunes.apple.com/gb/album/girls/id270137469?i=270137520&uo=4", "previewUrl":"http://a717.phobos.apple.com/us/r1000/113/Music/b2/e8/f8/mzm.xrpvmzgz.aac.p.m4a", "artworkUrl30":"http://a176.phobos.apple.com/us/r1000/040/Music/20/98/3c/mzi.azgszqgw.30x30-50.jpg", "artworkUrl60":"http://a240.phobos.apple.com/us/r1000/040/Music/20/98/3c/mzi.azgszqgw.60x60-50.jpg", "artworkUrl100":"http://a1585.phobos.apple.com/us/r1000/040/Music/20/98/3c/mzi.azgszqgw.100x100-75.jpg", "collectionPrice":1.99, "trackPrice":0.79, "releaseDate":"2007-12-24T08:00:00Z", "collectionExplicitness":"notExplicit", "trackExplicitness":"notExplicit", "discCount":1, "discNumber":1, "trackCount":4, "trackNumber":3, "trackTimeMillis":205973, "country":"GBR", "currency":"GBP", "primaryGenreName":"Alternative"}]
}

This can be seen for yourself by entering https://itunes.apple.com/search?term...=music&limit=1 into your browser (works on firefox but I am told IE tries to download it as a file)

Now I need to get quite a few bits of information out of this JSON return but I have no idea how to go about it. I have seen a few things online that can convert it to a custom object also heard an Array. The other option I have heard is converting it to XML and I would be more than happy to have it in XML as I know exactly how to query that but to be honest I don't care how its stored within the application as long as I can read each attribute as and when I need it.

So for instance it would be nice to do something like

Dim Artist as string = jsonobj(jsoninput, "artistName")

which from the above JSON example my string would contain "Hadouken!"

Has anyone had any dealing with JSON and please be able to provide me some advice because I have tried a couple of libraries but im stabbing in the dark nothing I have read has made any sense.

Thanks,
Max

[dbasnett]

Take a look at http://msdn.microsoft.com/en-us/libr...=vs.90%29.aspx and http://social.msdn.microsoft.com/Sea...l%20basic&ac=8

[jmcilhinney]

Look at the JavaScriptSerializer class.

[Evil_Giraffe]

You need to use a JSON serialiser to deserialise it. I think the default choice in .NET is JSON.Net

[.paul.]

you can read it with a JavaScriptSerializer:

Public Class JSON_resultArray
    Public results() As JSON_result
End Class

Public Class JSON_result
    Public wrapperType As String
    Public kind As String
    Public artistName As String
    Public collectionName As String
    Public trackName As String
    Public collectionCensoredName As String
    Public trackCensoredName As String
    Public artistViewUrl As String
    Public collectionViewUrl As String
    Public trackViewUrl As String
    Public previewUrl As String
    Public artworkUrl30 As String
    Public artworkUrl60 As String
    Public artworkUrl100 As String
    Public releaseDate As String
    Public collectionExplicitness As String
    Public trackExplicitness As String
    Public country As String
    Public currency As String
    Public primaryGenreName As String
End Class

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim json = TextBox1.Text

        Dim ser As New System.Web.Script.Serialization.JavaScriptSerializer
        Dim results As JSON_resultArray = DirectCast(ser.Deserialize(Of JSON_resultArray)(json), JSON_resultArray)
        Stop
    End Sub

End Class

edit: too slow

[max_carpenter]

I have been looking at documents like this but that's whats getting me confused I have never done serialization etc. I have this code:

        Dim json As String
        Dim reader As StreamReader = New StreamReader("C:\json.txt")
        json = reader.ReadToEnd
        reader.Close()


        Dim obj As New List(Of ApplicationItem)()
        Dim ms As New MemoryStream(Encoding.Unicode.GetBytes(json))
        Dim serializer As New System.Runtime.Serialization.Json.DataContractJsonSerializer(obj.[GetType]())
        obj = DirectCast(serializer.ReadObject(ms), List(Of ApplicationItem))
        ms.Close()
        ms.Dispose()

which runs with no errors but how to I read the individual attributes still? By the was json.txt contains the json I posted in the first post.

As for the JavaScriptSerializer jmcil I have no idea to even where begin with this its not reconised and I have no clue what needs to be referenced...

Regards,
Max

[max_carpenter]

Thanks for the code paul but I am still getting the below error with nothing obvious to import or reference:

[.paul.]

add a reference to:

System.Web.Extensions

[max_carpenter]

Am I being a complete idiot today or is something missing (don't be afraid to be honest)

[.paul.]

which version of vb are you using?

[jmcilhinney]

Advanced web functionality is not included in the Client Profile. You'll need to target the full Framework.

[.paul.]

actually scrub that. it's obviously vb2010 or greater.
i found it in vb2012 + i can't find it in vb2010 either...

sorry. someone else might have a solution.

[max_carpenter]

Well done jmcil as per normal :-) Didn't even realise that. Ok Im targetting the full framework now and have imported system.web.extensions and no errors with the code now. Now just need to know how to actualy grab the results...

[kareninstructor]

After I did a lot of research I found JSON.NET to be more inline with our web team who is non-Microsoft.

[max_carpenter]

I did take a brief look at JSON.Net before I posted but it seemed overly complex for what I needed I just want a really simple way of converting a relatively basic JSON to something I can read and the code that paul has paste seems like it will do the trick nicely but I am just trying to figure out how to read each of the values now. Doesn't help I am trying to do it inbetween support calls but I just can't see what im doing.

[kareninstructor]

Here is JSON.NET example using a string to read into a class and one example reading from disk. Follow my lead to complete.
Must of course download the library

Imports Newtonsoft.Json
Imports Newtonsoft.Json.Schema
Imports Newtonsoft.Json.Linq
Module Module1
    Public Sub ParseFromString()
        Dim Contents As String = IO.File.ReadAllText(IO.Path.Combine(Application.StartupPath, "TextFile1.txt"))

        Dim DocObject = JObject.Parse(Contents)
        Try

            Dim ResultCount As Integer = CInt(DocObject("resultCount"))
            If ResultCount > 0 Then
                '
                ' Yeah I realize there is only one but we are demoing count with hopes
                ' the count indicates how many rows/records are being pushed in.
                '
                For x As Integer = 0 To ResultCount - 1
                    Console.WriteLine("[{0}] [{1}]", x + 1, CStr(DocObject("results")(x)("artistName")))
                Next

                Console.WriteLine("-----------------------------")

                Dim Test1 =
                    (
                        From T In DocObject("results").Children
                        Select New AppleRecord With
                               {
                                   .WrapperType = T("wrapperType").ToString,
                                   .Kind = T("kind").ToString,
                                   .ArtistId = CInt(T("artistId")),
                                   .CollectionName = T("collectionName").ToString,
                                   .PreviewUrl = T("previewUrl").ToString
                               }
                           ).ToList

                For Each item As AppleRecord In Test1
                    Console.WriteLine("[{0}] [{1}] [{2}] [{3}] [{4}]",
                                      item.WrapperType,
                                      item.Kind,
                                      item.ArtistId,
                                      item.CollectionName,
                                      item.PreviewUrl
                                      )
                Next
            Else
                Console.WriteLine("No records")
            End If

        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try



    End Sub
    Public Sub ReadFromFile()

        Using reader As IO.StreamReader = IO.File.OpenText(IO.Path.Combine(Application.StartupPath, "TextFile1.txt"))

            Dim DocObject As JObject = CType(JToken.ReadFrom(New JsonTextReader(reader)), JObject)

            Try
                Dim ResultCount As Integer = CInt(DocObject("resultCount"))
                If ResultCount > 0 Then
                    '
                    ' Yeah I realize there is only one but we are demoing count with hopes
                    ' the count indicates how many rows/records are being pushed in.
                    '
                    For x As Integer = 0 To ResultCount - 1
                        Console.WriteLine("[{0}] [{1}]", x + 1, CStr(DocObject("results")(x)("artistName")))
                    Next

                    Console.WriteLine("-----------------------------")

                    Dim Test1 =
                        (
                            From T In DocObject("results").Children
                            Select New AppleRecord With
                                   {
                                       .WrapperType = T("wrapperType").ToString,
                                       .Kind = T("kind").ToString,
                                       .ArtistId = CInt(T("artistId")),
                                       .CollectionName = T("collectionName").ToString,
                                       .PreviewUrl = T("previewUrl").ToString
                                   }
                               ).ToList

                    For Each item As AppleRecord In Test1
                        Console.WriteLine("[{0}] [{1}] [{2}] [{3}] [{4}]",
                                          item.WrapperType,
                                          item.Kind,
                                          item.ArtistId,
                                          item.CollectionName,
                                          item.PreviewUrl
                                          )
                    Next
                Else
                    Console.WriteLine("No records")
                End If

            Catch ex As Exception
                Console.WriteLine(ex.Message)
            End Try


        End Using

    End Sub
    Public Class AppleRecord
        Public Property WrapperType() As String
        Public Property Kind() As String
        Public Property ArtistId() As Integer
        Public Property CollectionId() As Integer
        Public Property TrackId() As Integer
        Public Property ArtistName() As String
        Public Property CollectionName() As String
        Public Property TrackName() As String
        Public Property CollectionCensoredName() As String
        Public Property TrackCensoredName() As String
        Public Property ArtistViewUrl() As String
        Public Property CollectionViewUrl() As String
        Public Property TrackViewUrl() As String
        Public Property PreviewUrl() As String
        Public Property ArtworkUrl30() As String
        Public Property ArtworkUrl60() As String
        Public Property ArtworkUrl100() As String
        Public Property CollectionPrice() As Double
        Public Property TrackPrice() As Double
        Public Property ReleaseDate() As String
        Public Property CollectionExplicitness() As String
        Public Property TrackExplicitness() As String
        Public Property DiscCount() As Integer
        Public Property DiscNumber() As Integer
        Public Property TrackCount() As Integer
        Public Property TrackNumber() As Integer
        Public Property TrackTimeMillis() As Integer
        Public Property Country() As String
        Public Property Currency() As String
        Public Property PrimaryGenreName() As String
        Public Sub New()
        End Sub
    End Class
End Module

[kareninstructor]

As per my last reply, here is the JSON which I formatted via JSON.NET methods

{
  "resultCount": 1,
  "results": [
    {
      "wrapperType": "track",
      "kind": "song",
      "artistId": 255772678,
      "collectionId": 270137469,
      "trackId": 270137520,
      "artistName": "Hadouken!",
      "collectionName": "Love, Sweat and Beer - EP",
      "trackName": "Girls",
      "collectionCensoredName": "Love, Sweat and Beer - EP",
      "trackCensoredName": "Girls",
      "artistViewUrl": "https://itunes.apple.com/gb/artist/hadouken!/id255772678?uo=4",
      "collectionViewUrl": "https://itunes.apple.com/gb/album/girls/id270137469?i=270137520&uo=4",
      "trackViewUrl": "https://itunes.apple.com/gb/album/girls/id270137469?i=270137520&uo=4",
      "previewUrl": "http://a717.phobos.apple.com/us/r1000/113/Music/b2/e8/f8/mzm.xrpvmzgz.aac.p.m4a",
      "artworkUrl30": "http://a176.phobos.apple.com/us/r1000/040/Music/20/98/3c/mzi.azgszqgw.30x30-50.jpg",
      "artworkUrl60": "http://a240.phobos.apple.com/us/r1000/040/Music/20/98/3c/mzi.azgszqgw.60x60-50.jpg",
      "artworkUrl100": "http://a1585.phobos.apple.com/us/r1000/040/Music/20/98/3c/mzi.azgszqgw.100x100-75.jpg",
      "collectionPrice": 1.99,
      "trackPrice": 0.79,
      "releaseDate": "2007-12-24T08:00:00Z",
      "collectionExplicitness": "notExplicit",
      "trackExplicitness": "notExplicit",
      "discCount": 1,
      "discNumber": 1,
      "trackCount": 4,
      "trackNumber": 3,
      "trackTimeMillis": 205973,
      "country": "GBR",
      "currency": "GBP",
      "primaryGenreName": "Alternative"
    }
  ]
}

[max_carpenter]

Apologies for being half asleep yesterday its all resolved now much easier than using that json.net library. Thanks to everyone that has helped here is the end Result:

Public Class JSON_result
    Public wrapperType As String
    Public kind As String
    Public artistName As String
    Public collectionName As String
    Public trackName As String
    Public collectionCensoredName As String
    Public trackCensoredName As String
    Public artistViewUrl As String
    Public collectionViewUrl As String
    Public trackViewUrl As String
    Public previewUrl As String
    Public artworkUrl30 As String
    Public artworkUrl60 As String
    Public artworkUrl100 As String
    Public releaseDate As String
    Public collectionExplicitness As String
    Public trackExplicitness As String
    Public country As String
    Public currency As String
    Public primaryGenreName As String
End Class

Public Class JSON_resultArray
    Public Vars() As JSON_result
End Class

Sub Main()

        Dim ser As New System.Web.Script.Serialization.JavaScriptSerializer
        Dim results As JSON_resultArray = DirectCast(ser.Deserialize(Of JSON_resultArray)(json), JSON_resultArray)


        Console.WriteLine(results.Vars(0).artistName)
        Console.WriteLine(results.Vars(0).collectionName)

End Sub

[kareninstructor]

Hello, you really should check resultCount as a general rule of thumb, no different than checking the Count property of a DataTable. For example, if there are no items the index would be out of range. At best check how many items are in Vars()

Console.WriteLine(results.Vars(0).artistName)

What we do is (although not done here) besides a count is a success field/element which indicates a record or records are valid for a given operation which I have seen often when working with partner's data.