Objective-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. Objective-C

#import <CkoRest.h>
#import <CkoAuthAzureStorage.h>
#import <NSString.h>

BOOL success = NO;

//  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.

CkoRest *rest = [[CkoRest alloc] init];

//  Connect to the Azure Storage Blob Service
BOOL bTls = YES;
int port = 443;
BOOL bAutoReconnect = YES;
//  In this example, the storage account name is "chilkat".
success = [rest Connect: @"chilkat.blob.core.windows.net" port: [NSNumber numberWithInt: port] tls: bTls autoReconnect: bAutoReconnect];
if (success != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

//  Provide Azure Cloud credentials for the REST call.
CkoAuthAzureStorage *azAuth = [[CkoAuthAzureStorage alloc] init];
azAuth.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.Account = @"chilkat";
azAuth.Scheme = @"SharedKey";
azAuth.Service = @"Blob";
//  This causes the "x-ms-version: 2021-08-06" header to be automatically added.
azAuth.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" value: @"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" value: @"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.)
NSString *responseStr = [rest FullRequestNoBody: @"OPTIONS" uriPath: @"/test"];
if (rest.LastMethodSuccess != YES) {
    NSLog(@"%@",rest.LastErrorText);
    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 intValue] != 200) {
    //  Examine the request/response to see what happened.
    NSLog(@"%@%d",@"response status code = ",[rest.ResponseStatusCode intValue]);
    NSLog(@"%@%@",@"response status text = ",rest.ResponseStatusText);
    NSLog(@"%@%@",@"response header: ",rest.ResponseHeader);
    NSLog(@"%@%@",@"response body (if any): ",responseStr);
    NSLog(@"%@",@"---");
    NSLog(@"%@%@",@"LastRequestStartLine: ",rest.LastRequestStartLine);
    NSLog(@"%@%@",@"LastRequestHeader: ",rest.LastRequestHeader);
    return;
}

NSLog(@"%@",@"Success: Preflight Blob Request is accepted.");