(Visual FoxPro) 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

LOCAL lnSuccess
LOCAL loFac
LOCAL lcAccessToken
LOCAL loRest
LOCAL loAuthGoogle
LOCAL lcJsonResponse
LOCAL loPiggyPath
LOCAL loShallow
LOCAL loPiggyData
LOCAL lnCount
LOCAL i
LOCAL lcPiggyJson

* 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.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.FileAccess')
loFac = CreateObject('Chilkat.FileAccess')
lcAccessToken = loFac.ReadEntireTextFile("qa_data/tokens/firebaseToken.txt","utf-8")
IF (loFac.LastMethodSuccess <> 1) THEN
    ? loFac.LastErrorText
    RELEASE loFac
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rest')
loRest = 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.  
lnSuccess = loRest.Connect("chilkat.firebaseio.com",443,1,1)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loFac
    RELEASE loRest
    CANCEL
ENDIF

* If authentication is required...
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.AuthGoogle')
loAuthGoogle = CreateObject('Chilkat.AuthGoogle')
loAuthGoogle.AccessToken = lcAccessToken
loRest.SetAuthGoogle(loAuthGoogle)

* 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.
lcJsonResponse = loRest.FullRequestNoBody("GET","/pig-rescue/animal.json?shallow=true")
IF (loRest.LastMethodSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loFac
    RELEASE loRest
    RELEASE loAuthGoogle
    CANCEL
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}
? lcJsonResponse

* Parse the response so we can iterate over each pig in the database..
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loPiggyPath = CreateObject('Chilkat.StringBuilder')
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loShallow = CreateObject('Chilkat.JsonObject')
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loPiggyData = CreateObject('Chilkat.JsonObject')
loShallow.Load(lcJsonResponse)
lnCount = loShallow.Size
i = 0
DO WHILE i < lnCount

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

    lcPiggyJson = loRest.FullRequestNoBody("GET",loPiggyPath.GetAsString())
    IF (loRest.LastMethodSuccess <> 1) THEN
        ? loRest.LastErrorText
        RELEASE loFac
        RELEASE loRest
        RELEASE loAuthGoogle
        RELEASE loPiggyPath
        RELEASE loShallow
        RELEASE loPiggyData
        CANCEL
    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) + " ----"
    ? lcPiggyJson

    * Let's get the pig's name, and the caption of the picture.
    loPiggyData.Load(lcPiggyJson)
    ? "name: " + loPiggyData.StringOf("name")
    ? "caption: " + loPiggyData.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.  
* 

RELEASE loFac
RELEASE loRest
RELEASE loAuthGoogle
RELEASE loPiggyPath
RELEASE loShallow
RELEASE loPiggyData