Objective-C

Azure Storage: Download Blob to File

See more Azure Cloud Storage Examples

Sample code to download an Azure blob to a file. Objective-C

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

BOOL success = NO;

// 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: Content-Length, x-ms-date, Authorization.  These headers
// are automatically set by Chilkat.

// Setup a file stream for the download
CkoStream *fileStream = [[CkoStream alloc] init];
fileStream.SinkFile = @"C:/temp/qa_output/starfish.jpg";

// Indicate that the call to FullRequestNoBody should send the response body
// to fileStream if the response status code is 200.
// If a non-success response status code is received, then nothing
// is streamed to the output file and the error response is returned by FullRequestNoBody.
int expectedStatus = 200;
[rest SetResponseBodyStream: [NSNumber numberWithInt: expectedStatus] autoSetStreamCharset: YES responseStream: fileStream];

// The Azure blob container is "test", the file is "starfish.jpg"
NSString *responseStr = [rest FullRequestNoBody: @"GET" uriPath: @"/test/starfish.jpg"];
if (rest.LastMethodSuccess != YES) {

    // 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.");