Xbase++

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:

Xbase++

LOCAL nSuccess
LOCAL oFac
LOCAL cAccessToken
LOCAL oRest
LOCAL oAuthGoogle
LOCAL cJsonResponse
LOCAL oPiggyPath
LOCAL oShallow
LOCAL oPiggyData
LOCAL nCount
LOCAL i
LOCAL cPiggyJson

nSuccess := 0

//  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.
oFac := CreateObject("Chilkat.FileAccess")
cAccessToken := oFac:ReadEntireTextFile("qa_data/tokens/firebaseToken.txt", "utf-8")
IF (oFac:LastMethodSuccess != 1)
    ? oFac:LastErrorText
    oFac:destroy()
    RETURN
ENDIF

oRest := CreateObject("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.  
nSuccess := oRest:Connect("chilkat.firebaseio.com", 443, 1, 1)
IF (nSuccess != 1)
    ? oRest:LastErrorText
    oFac:destroy()
    oRest:destroy()
    RETURN
ENDIF

//  If authentication is required...
oAuthGoogle := CreateObject("Chilkat.AuthGoogle")
oAuthGoogle:AccessToken := cAccessToken
oRest:SetAuthGoogle(oAuthGoogle)

//  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.
cJsonResponse := oRest:FullRequestNoBody("GET", "/pig-rescue/animal.json?shallow=true")
IF (oRest:LastMethodSuccess != 1)
    ? oRest:LastErrorText
    oFac:destroy()
    oRest:destroy()
    oAuthGoogle:destroy()
    RETURN
ENDIF

//  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}
? cJsonResponse

//  Parse the response so we can iterate over each pig in the database..
oPiggyPath := CreateObject("Chilkat.StringBuilder")
oShallow := CreateObject("Chilkat.JsonObject")
oPiggyData := CreateObject("Chilkat.JsonObject")
oShallow:Load(cJsonResponse)
nCount := oShallow:Size
i := 0
DO WHILE i < nCount

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

    cPiggyJson := oRest:FullRequestNoBody("GET", oPiggyPath:GetAsString())
    IF (oRest:LastMethodSuccess != 1)
        ? oRest:LastErrorText
        oFac:destroy()
        oRest:destroy()
        oAuthGoogle:destroy()
        oPiggyPath:destroy()
        oShallow:destroy()
        oPiggyData:destroy()
        RETURN
    ENDIF

    //  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"}
    ? "---- " + Str(i) + " ----"
    ? cPiggyJson

    //  Let's get the pig's name, and the caption of the picture.
    oPiggyData:Load(cPiggyJson)
    ? "name: " + oPiggyData:StringOf("name")
    ? "caption: " + oPiggyData:StringOf("picture.caption")

    i := i + 1
ENDDO

//  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.  
//

oFac:destroy()
oRest:destroy()
oAuthGoogle:destroy()
oPiggyPath:destroy()
oShallow:destroy()
oPiggyData:destroy()