(Lianja) 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 Lianja Extension Download Chilkat Lianja Extension

// 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.
loFac = createobject("CkFileAccess")
lcAccessToken = loFac.ReadEntireTextFile("qa_data/tokens/firebaseToken.txt","utf-8")
if (loFac.LastMethodSuccess <> .T.) then
    ? loFac.LastErrorText
    release loFac
    return
endif

loRest = createobject("CkRest")

// 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.  
llSuccess = loRest.Connect("chilkat.firebaseio.com",443,.T.,.T.)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loFac
    release loRest
    return
endif

// If authentication is required...
loAuthGoogle = createobject("CkAuthGoogle")
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 <> .T.) then
    ? loRest.LastErrorText
    release loFac
    release loRest
    release loAuthGoogle
    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}
? lcJsonResponse

// Parse the response so we can iterate over each pig in the database..
loPiggyPath = createobject("CkStringBuilder")
loShallow = createobject("CkJsonObject")
loPiggyData = createobject("CkJsonObject")
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 <> .T.) then
        ? loRest.LastErrorText
        release loFac
        release loRest
        release loAuthGoogle
        release loPiggyPath
        release loShallow
        release loPiggyData
        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) + " ----"
    ? 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