VB.NET

Firebase GET - Reading Data

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Demonstrates how to read parts of a Firebase JSON database. The data used in this example is at Chilkat Firebase Pigs Database, and is shown here:

VB.NET

Dim success As Boolean = False

' Demonstrates how to read parts of a Firebase JSON database.

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' This example assumes a JWT authentication token, if required, has been previously obtained.
' See Get Firebase Access Token from JSON Service Account Private Key for sample code.

' Load the previously obtained Firebase access token into a string.
Dim fac As New Chilkat.FileAccess
Dim accessToken As String = fac.ReadEntireTextFile("qa_data/tokens/firebaseToken.txt","utf-8")
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


Dim rest As New Chilkat.Rest

' Make the initial connection (without sending a request yet).
' Once connected, any number of requests may be sent.  It is not necessary to explicitly
' call Connect before each request.  
success = rest.Connect("chilkat.firebaseio.com",443,True,True)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If

' If authentication is required...
Dim authGoogle As New Chilkat.AuthGoogle
authGoogle.AccessToken = accessToken
rest.SetAuthGoogle(authGoogle)

' Chilkat's sample data (pig-rescue data) is publicly readable at: https://chilkat.firebaseio.com/.json

' Let's get the animals with the shallow parameter so we can see how many pigs exist.
Dim jsonResponse As String = rest.FullRequestNoBody("GET","/pig-rescue/animal.json?shallow=true")
If (rest.LastMethodSuccess <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' The JSON returned should look like this:  
' {"-KI3bD-FU_Dake7sYOiP":true,"-KI3bD-FU_Dake7sYOiT":true,"-KI3bD-FU_Dake7sYOiS":true,"-KI3bD-FU_Dake7sYOiU":true,"-KI3bD-FU_Dake7sYOiV":true,"-KI3bD-FU_Dake7sYOiR":true,"-KI3bD-FU_Dake7sYOiQ":true}
Debug.WriteLine(jsonResponse)

' Parse the response so we can iterate over each pig in the database..
Dim piggyPath As New Chilkat.StringBuilder
Dim shallow As New Chilkat.JsonObject
Dim piggyData As New Chilkat.JsonObject
shallow.Load(jsonResponse)
Dim count As Integer = shallow.Size
Dim i As Integer = 0
While i < count

    ' Get each individual pig's data.
    piggyPath.Clear()
    piggyPath.Append("/pig-rescue/animal/")
    piggyPath.Append(shallow.NameAt(i))
    piggyPath.Append("/.json")

    Dim piggyJson As String = rest.FullRequestNoBody("GET",piggyPath.GetAsString())
    If (rest.LastMethodSuccess <> True) Then
        Debug.WriteLine(rest.LastErrorText)
        Exit Sub
    End If


    ' Show this piggy's data...
    ' An example of one pig's data is shown here:
    ' {"birth":"February, 1998","from":"Middle Ave.","gender":"F","in-date":"January, 2000",
    '   "name":"Molly II","picture":{"caption":"Molly in the Pasture","description":"Black pig","file":"molly_th.jpg"},
    '   "species":"pot belly pig","type":"Cathy's Herd"}
    Debug.WriteLine("---- " & i & " ----")
    Debug.WriteLine(piggyJson)

    ' Let's get the pig's name, and the caption of the picture.
    piggyData.Load(piggyJson)
    Debug.WriteLine("name: " & piggyData.StringOf("name"))
    Debug.WriteLine("caption: " & piggyData.StringOf("picture.caption"))

    i = i + 1
End While

' Note: In many of the Chilkat examples, you may notice strange ways
' of doing something that should be simpler and shorter.  For example,
' building the piggyPath (above) could've been written differently,
' with some simple string concatenation.
' 
' The reason is that the Chilkat examples are written in a 
' proprietary "example code" scripting language,
' and then automatically generated to each of the different programming
' languages you see on example-code.com.  The code generation is
' limited in what it can do.  For example, string concatentation
' is not yet a feature of the "example code" scripting language (as of May 2016), 
' and therefore you won't see the use of a programming language's string
' concatentation operators in any example.  
'