Java

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:

Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = 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.
    CkFileAccess fac = new CkFileAccess();
    String accessToken = fac.readEntireTextFile("qa_data/tokens/firebaseToken.txt","utf-8");
    if (fac.get_LastMethodSuccess() != true) {
        System.out.println(fac.lastErrorText());
        return;
        }

    CkRest rest = new 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.  
    success = rest.Connect("chilkat.firebaseio.com",443,true,true);
    if (success != true) {
        System.out.println(rest.lastErrorText());
        return;
        }

    // If authentication is required...
    CkAuthGoogle authGoogle = new CkAuthGoogle();
    authGoogle.put_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.
    String jsonResponse = rest.fullRequestNoBody("GET","/pig-rescue/animal.json?shallow=true");
    if (rest.get_LastMethodSuccess() != true) {
        System.out.println(rest.lastErrorText());
        return;
        }

    // 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}
    System.out.println(jsonResponse);

    // Parse the response so we can iterate over each pig in the database..
    CkStringBuilder piggyPath = new CkStringBuilder();
    CkJsonObject shallow = new CkJsonObject();
    CkJsonObject piggyData = new CkJsonObject();
    shallow.Load(jsonResponse);
    int count = shallow.get_Size();
    int i = 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");

        String piggyJson = rest.fullRequestNoBody("GET",piggyPath.getAsString());
        if (rest.get_LastMethodSuccess() != true) {
            System.out.println(rest.lastErrorText());
            return;
            }

        // 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"}
        System.out.println("---- " + i + " ----");
        System.out.println(piggyJson);

        // Let's get the pig's name, and the caption of the picture.
        piggyData.Load(piggyJson);
        System.out.println("name: " + piggyData.stringOf("name"));
        System.out.println("caption: " + piggyData.stringOf("picture.caption"));

        i = i+1;
        }

    // 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.  
    // 
  }
}