Delphi DLL

Azure Storage: CORS Preflight Blob Request

See more Azure Cloud Storage Examples

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Rest, AuthAzureStorage;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
azAuth: HCkAuthAzureStorage;
responseStr: PWideChar;

begin
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.

rest := CkRest_Create();

// Connect to the Azure Storage Blob Service
bTls := True;
port := 443;
bAutoReconnect := True;
// In this example, the storage account name is "chilkat".
success := CkRest_Connect(rest,'chilkat.blob.core.windows.net',port,bTls,bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Provide Azure Cloud credentials for the REST call.
azAuth := CkAuthAzureStorage_Create();
CkAuthAzureStorage_putAccessKey(azAuth,'AZURE_ACCESS_KEY');
// The account name used here should match the 1st part of the domain passed in the call to Connect (above).
CkAuthAzureStorage_putAccount(azAuth,'chilkat');
CkAuthAzureStorage_putScheme(azAuth,'SharedKey');
CkAuthAzureStorage_putService(azAuth,'Blob');
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
CkAuthAzureStorage_putXMsVersion(azAuth,'2021-08-06');
success := CkRest_SetAuthAzureStorage(rest,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 := CkRest_AddHeader(rest,'Origin','www.contoso.com');
// The Access-Control-Request-Method is the HTTP method (such as GET, POST, PUT, etc.) of the actual request.
success := CkRest_AddHeader(rest,'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 := CkRest__fullRequestNoBody(rest,'OPTIONS','/test');
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// 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 (CkRest_getResponseStatusCode(rest) <> 200) then
  begin
    // Examine the request/response to see what happened.
    Memo1.Lines.Add('response status code = ' + IntToStr(CkRest_getResponseStatusCode(rest)));
    Memo1.Lines.Add('response status text = ' + CkRest__responseStatusText(rest));
    Memo1.Lines.Add('response header: ' + CkRest__responseHeader(rest));
    Memo1.Lines.Add('response body (if any): ' + responseStr);
    Memo1.Lines.Add('---');
    Memo1.Lines.Add('LastRequestStartLine: ' + CkRest__lastRequestStartLine(rest));
    Memo1.Lines.Add('LastRequestHeader: ' + CkRest__lastRequestHeader(rest));
    Exit;
  end;

Memo1.Lines.Add('Success: Preflight Blob Request is accepted.');

CkRest_Dispose(rest);
CkAuthAzureStorage_Dispose(azAuth);

end;