(DataFlex) Firebase GET - Reading Data

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:

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-9.5.0-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoFac
    String sAccessToken
    Handle hoRest
    Variant vAuthGoogle
    Handle hoAuthGoogle
    String sJsonResponse
    Handle hoPiggyPath
    Handle hoShallow
    Handle hoPiggyData
    Integer iCount
    Integer i
    String sPiggyJson
    String sTemp1
    Boolean bTemp1

    // 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.
    Get Create (RefClass(cComCkFileAccess)) To hoFac
    If (Not(IsComObjectCreated(hoFac))) Begin
        Send CreateComObject of hoFac
    End
    Get ComReadEntireTextFile Of hoFac "qa_data/tokens/firebaseToken.txt" "utf-8" To sAccessToken
    Get ComLastMethodSuccess Of hoFac To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoFac To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End

    // 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.  
    Get ComConnect Of hoRest "chilkat.firebaseio.com" 443 True True To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // If authentication is required...
    Get Create (RefClass(cComChilkatAuthGoogle)) To hoAuthGoogle
    If (Not(IsComObjectCreated(hoAuthGoogle))) Begin
        Send CreateComObject of hoAuthGoogle
    End
    Set ComAccessToken Of hoAuthGoogle To sAccessToken
    Get pvComObject of hoAuthGoogle to vAuthGoogle
    Get ComSetAuthGoogle Of hoRest vAuthGoogle To iSuccess

    // 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.
    Get ComFullRequestNoBody Of hoRest "GET" "/pig-rescue/animal.json?shallow=true" To sJsonResponse
    Get ComLastMethodSuccess Of hoRest To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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}
    Showln sJsonResponse

    // Parse the response so we can iterate over each pig in the database..
    Get Create (RefClass(cComChilkatStringBuilder)) To hoPiggyPath
    If (Not(IsComObjectCreated(hoPiggyPath))) Begin
        Send CreateComObject of hoPiggyPath
    End
    Get Create (RefClass(cComChilkatJsonObject)) To hoShallow
    If (Not(IsComObjectCreated(hoShallow))) Begin
        Send CreateComObject of hoShallow
    End
    Get Create (RefClass(cComChilkatJsonObject)) To hoPiggyData
    If (Not(IsComObjectCreated(hoPiggyData))) Begin
        Send CreateComObject of hoPiggyData
    End
    Get ComLoad Of hoShallow sJsonResponse To iSuccess
    Get ComSize Of hoShallow To iCount
    Move 0 To i
    While (i < iCount)

        // Get each individual pig's data.
        Send ComClear To hoPiggyPath
        Get ComAppend Of hoPiggyPath "/pig-rescue/animal/" To iSuccess
        Get ComNameAt Of hoShallow i To sTemp1
        Get ComAppend Of hoPiggyPath sTemp1 To iSuccess
        Get ComAppend Of hoPiggyPath "/.json" To iSuccess

        Get ComGetAsString Of hoPiggyPath To sTemp1
        Get ComFullRequestNoBody Of hoRest "GET" sTemp1 To sPiggyJson
        Get ComLastMethodSuccess Of hoRest To bTemp1
        If (bTemp1 <> True) Begin
            Get ComLastErrorText Of hoRest To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        // 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"}
        Showln "---- " i " ----"
        Showln sPiggyJson

        // Let's get the pig's name, and the caption of the picture.
        Get ComLoad Of hoPiggyData sPiggyJson To iSuccess
        Get ComStringOf Of hoPiggyData "name" To sTemp1
        Showln "name: " sTemp1
        Get ComStringOf Of hoPiggyData "picture.caption" To sTemp1
        Showln "caption: " sTemp1

        Move (i + 1) To i
    Loop

    // 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.  
    // 


End_Procedure