C

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:

C

#include <C_CkFileAccess.h>
#include <C_CkRest.h>
#include <C_CkAuthGoogle.h>
#include <C_CkStringBuilder.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkFileAccess fac;
    const char *accessToken;
    HCkRest rest;
    HCkAuthGoogle authGoogle;
    const char *jsonResponse;
    HCkStringBuilder piggyPath;
    HCkJsonObject shallow;
    HCkJsonObject piggyData;
    int count;
    int i;
    const char *piggyJson;

    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.
    fac = CkFileAccess_Create();
    accessToken = CkFileAccess_readEntireTextFile(fac,"qa_data/tokens/firebaseToken.txt","utf-8");
    if (CkFileAccess_getLastMethodSuccess(fac) != TRUE) {
        printf("%s\n",CkFileAccess_lastErrorText(fac));
        CkFileAccess_Dispose(fac);
        return;
    }

    rest = CkRest_Create();

    // 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 = CkRest_Connect(rest,"chilkat.firebaseio.com",443,TRUE,TRUE);
    if (success != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkFileAccess_Dispose(fac);
        CkRest_Dispose(rest);
        return;
    }

    // If authentication is required...
    authGoogle = CkAuthGoogle_Create();
    CkAuthGoogle_putAccessToken(authGoogle,accessToken);
    CkRest_SetAuthGoogle(rest,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.
    jsonResponse = CkRest_fullRequestNoBody(rest,"GET","/pig-rescue/animal.json?shallow=true");
    if (CkRest_getLastMethodSuccess(rest) != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkFileAccess_Dispose(fac);
        CkRest_Dispose(rest);
        CkAuthGoogle_Dispose(authGoogle);
        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}
    printf("%s\n",jsonResponse);

    // Parse the response so we can iterate over each pig in the database..
    piggyPath = CkStringBuilder_Create();
    shallow = CkJsonObject_Create();
    piggyData = CkJsonObject_Create();
    CkJsonObject_Load(shallow,jsonResponse);
    count = CkJsonObject_getSize(shallow);
    i = 0;
    while (i < count) {

        // Get each individual pig's data.
        CkStringBuilder_Clear(piggyPath);
        CkStringBuilder_Append(piggyPath,"/pig-rescue/animal/");
        CkStringBuilder_Append(piggyPath,CkJsonObject_nameAt(shallow,i));
        CkStringBuilder_Append(piggyPath,"/.json");

        piggyJson = CkRest_fullRequestNoBody(rest,"GET",CkStringBuilder_getAsString(piggyPath));
        if (CkRest_getLastMethodSuccess(rest) != TRUE) {
            printf("%s\n",CkRest_lastErrorText(rest));
            CkFileAccess_Dispose(fac);
            CkRest_Dispose(rest);
            CkAuthGoogle_Dispose(authGoogle);
            CkStringBuilder_Dispose(piggyPath);
            CkJsonObject_Dispose(shallow);
            CkJsonObject_Dispose(piggyData);
            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"}
        printf("---- %d ----\n",i);
        printf("%s\n",piggyJson);

        // Let's get the pig's name, and the caption of the picture.
        CkJsonObject_Load(piggyData,piggyJson);
        printf("name: %s\n",CkJsonObject_stringOf(piggyData,"name"));
        printf("caption: %s\n",CkJsonObject_stringOf(piggyData,"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.  
    // 


    CkFileAccess_Dispose(fac);
    CkRest_Dispose(rest);
    CkAuthGoogle_Dispose(authGoogle);
    CkStringBuilder_Dispose(piggyPath);
    CkJsonObject_Dispose(shallow);
    CkJsonObject_Dispose(piggyData);

    }