C

Lower-Level REST API Methods (Google Cloud Storage)

See more REST Examples

The FullRequest* methods, such as FullRequestBinary, FullRequestMultipart, FullRequestNoBody, FullRequestStream, FullRequestString, etc. are high-level REST API methods that both send the request and receive the response. It is often the case that an application needs make a REST call, but with a finer level of control. The Chilkat REST API provides this feature. An application can break a REST call into the following parts:

1. Send the HTTP request. (via the SendReq* methods)
2. Receive the HTTP response header. (ReadResponseHeader)
3. Receive the HTTP response body. (via the ReadRespBody* methods)

This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.

C

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkAuthGoogle gAuth;
    HCkRest rest;
    BOOL bAutoReconnect;
    HCkJsonObject jsonReqBody;
    HCkJsonObject objVersioning;
    int responseStatusCode;
    const char *responseBodyStr;

    success = FALSE;

    // This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.
    // It will create a bucket in Google Cloud Storage.

    // It requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    gAuth = CkAuthGoogle_Create();
    // Obtain an access token as shown in one of the following examples:
    // See Get Access Token using a Service Account JSON Key
    // See Get Access Token using a P12 File

    rest = CkRest_Create();

    // Connect using TLS.
    bAutoReconnect = TRUE;
    success = CkRest_Connect(rest,"www.googleapis.com",443,TRUE,bAutoReconnect);

    // Provide the authentication credentials (i.e. the access key)
    success = CkRest_SetAuthGoogle(rest,gAuth);

    // Build the JSON request body for creating a bucket.
    // The only required property is the "name", but we'll add more
    // to make a better example..
    jsonReqBody = CkJsonObject_Create();
    success = CkJsonObject_AddStringAt(jsonReqBody,-1,"name","chilkat-bucket-c");
    success = CkJsonObject_AddStringAt(jsonReqBody,-1,"kind","storage#bucket");
    success = CkJsonObject_AddStringAt(jsonReqBody,-1,"location","US");

    objVersioning = CkJsonObject_Create();
    CkJsonObject_AppendObject2(jsonReqBody,"versioning",objVersioning);
    success = CkJsonObject_AddBoolAt(objVersioning,-1,"enabled",TRUE);

    // Show the HTTP request body we'll be sending.
    printf("%s\n",CkJsonObject_emit(jsonReqBody));

    // Add the required query parameter.
    // See https://cloud.google.com/storage/docs/json_api/v1/buckets/insert
    success = CkRest_AddQueryParam(rest,"project","chilkattest-1050");

    // Add the Content-Type HTTP request header.
    success = CkRest_AddHeader(rest,"Content-Type","application/json; charset=UTF-8");

    // Send the REST HTTP request.
    success = CkRest_SendReqStringBody(rest,"POST","/storage/v1/b",CkJsonObject_emit(jsonReqBody));
    if (success == FALSE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkAuthGoogle_Dispose(gAuth);
        CkRest_Dispose(rest);
        CkJsonObject_Dispose(jsonReqBody);
        CkJsonObject_Dispose(objVersioning);
        return;
    }

    // Read the response header.
    responseStatusCode = CkRest_ReadResponseHeader(rest);
    if (responseStatusCode < 0) {
        // We were unable to receive the response header.
        printf("%s\n",CkRest_lastErrorText(rest));
        CkAuthGoogle_Dispose(gAuth);
        CkRest_Dispose(rest);
        CkJsonObject_Dispose(jsonReqBody);
        CkJsonObject_Dispose(objVersioning);
        return;
    }

    if (responseStatusCode != 200) {
        // The response was not successful.  We'll still need to receive 
        // the response body, which may contain an error message from the server.
        // If the response has no body, then the method for reading the
        // response body can still be called.  It will simply return with an empty
        // response body.

        // We can examine the response header and status text:
        printf("Response status text: %s\n",CkRest_responseStatusText(rest));
        printf("Response header: %s\n",CkRest_responseHeader(rest));
    }

    // Read the response body.  In this case we're expecting it to be JSON..
    responseBodyStr = CkRest_readRespBodyString(rest);
    if (CkRest_getLastMethodSuccess(rest) != TRUE) {
        // We were unable to receive the response body.
        // Note: If the response did not include a body (such as for cases where
        // the Content-Length header is 0, or if the response status code implicitly
        // indicates no body, then ReadRespBodyString returns cktrue, and the
        // responseBodyString will be an empty string.
        printf("%s\n",CkRest_lastErrorText(rest));
        CkAuthGoogle_Dispose(gAuth);
        CkRest_Dispose(rest);
        CkJsonObject_Dispose(jsonReqBody);
        CkJsonObject_Dispose(objVersioning);
        return;
    }

    // Show the JSON response.
    printf("Json Response: %s\n",responseBodyStr);


    CkAuthGoogle_Dispose(gAuth);
    CkRest_Dispose(rest);
    CkJsonObject_Dispose(jsonReqBody);
    CkJsonObject_Dispose(objVersioning);

    }