(Go) Azure Storage: CORS Preflight Blob Request

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

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    // 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.

    rest := chilkat.NewRest()

    // Connect to the Azure Storage Blob Service
    bTls := true
    port := 443
    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 {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        return
    }

    // Provide Azure Cloud credentials for the REST call.
    azAuth := chilkat.NewAuthAzureStorage()
    azAuth.SetAccessKey("AZURE_ACCESS_KEY")
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    azAuth.SetAccount("chilkat")
    azAuth.SetScheme("SharedKey")
    azAuth.SetService("Blob")
    // This causes the "x-ms-version: 2020-08-04" header to be automatically added.
    azAuth.SetXMsVersion("2020-08-04")
    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.)
    responseStr := rest.FullRequestNoBody("OPTIONS","/test")
    if rest.LastMethodSuccess() != true {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        azAuth.DisposeAuthAzureStorage()
        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.ResponseStatusCode() != 200 {
        // Examine the request/response to see what happened.
        fmt.Println("response status code = ", rest.ResponseStatusCode())
        fmt.Println("response status text = ", rest.ResponseStatusText())
        fmt.Println("response header: ", rest.ResponseHeader())
        fmt.Println("response body (if any): ", *responseStr)
        fmt.Println("---")
        fmt.Println("LastRequestStartLine: ", rest.LastRequestStartLine())
        fmt.Println("LastRequestHeader: ", rest.LastRequestHeader())
        rest.DisposeRest()
        azAuth.DisposeAuthAzureStorage()
        return
    }

    fmt.Println("Success: Preflight Blob Request is accepted.")

    rest.DisposeRest()
    azAuth.DisposeAuthAzureStorage()