C++

Azure Storage: CORS Preflight Blob Request

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Azure Storage Blob Service REST API: Sample code to send a CORS pre-flight blob request. C++

#include <CkRest.h>
#include <CkAuthAzureStorage.h>

void ChilkatSample(void)
    {
    bool success = false;

    // Azure Blob Service Example: CORS Preflight Blob Request
    // See also: https://msdn.microsoft.com/en-us/library/azure/dn535599.aspx

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

    CkRest rest;

    // Connect to the Azure Storage Blob Service
    bool bTls = true;
    int port = 443;
    bool bAutoReconnect = true;
    // In this example, the storage account name is "chilkat".
    success = rest.Connect("chilkat.blob.core.windows.net",port,bTls,bAutoReconnect);
    if (success != true) {
        std::cout << rest.lastErrorText() << "\r\n";
        return;
    }

    // Provide Azure Cloud credentials for the REST call.
    CkAuthAzureStorage azAuth;
    azAuth.put_AccessKey("AZURE_ACCESS_KEY");
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    azAuth.put_Account("chilkat");
    azAuth.put_Scheme("SharedKey");
    azAuth.put_Service("Blob");
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    azAuth.put_XMsVersion("2021-08-06");
    success = rest.SetAuthAzureStorage(azAuth);

    // Note: The application does not need to explicitly set the following
    // headers: x-ms-date, Authorization.  These headers
    // are automatically set by Chilkat.

    // The preflight blob request requires the following two HTTP headers.
    // The Origin is the domain from which the actual request will be issued.
    success = rest.AddHeader("Origin","www.contoso.com");
    // The Access-Control-Request-Method is the HTTP method (such as GET, POST, PUT, etc.) of the actual request.
    success = rest.AddHeader("Access-Control-Request-Method","PUT");

    // The expected response is a 202 response status code with no response body.
    // The name of the container or blob resource in this example is "test". (Replace "test" with your container name.)
    const char *responseStr = rest.fullRequestNoBody("OPTIONS","/test");
    if (rest.get_LastMethodSuccess() != true) {
        std::cout << rest.lastErrorText() << "\r\n";
        return;
    }

    // When successful, the Azure Storage service will respond with a 200 response code,
    // with no response body.

    // If CORS is not enabled or no matching rule is found for the request, 
    // then a 403 status code is returned, with the following status text:
    // "CORS not enabled or no matching rule found for this request."
    if (rest.get_ResponseStatusCode() != 200) {
        // Examine the request/response to see what happened.
        std::cout << "response status code = " << rest.get_ResponseStatusCode() << "\r\n";
        std::cout << "response status text = " << rest.responseStatusText() << "\r\n";
        std::cout << "response header: " << rest.responseHeader() << "\r\n";
        std::cout << "response body (if any): " << responseStr << "\r\n";
        std::cout << "---" << "\r\n";
        std::cout << "LastRequestStartLine: " << rest.lastRequestStartLine() << "\r\n";
        std::cout << "LastRequestHeader: " << rest.lastRequestHeader() << "\r\n";
        return;
    }

    std::cout << "Success: Preflight Blob Request is accepted." << "\r\n";
    }