(Objective-C) Upload File in Blocks and Commit the Block List

See more Azure Cloud Storage Examples

Demonstrates how to upload a file in blocks and then commit the block list. For files larger than 64MB, this is the way to upload to Azure Storage. Azure limits the size of each block to a maximum of 4MB.

For more information, see https://learn.microsoft.com/en-us/rest/api/storageservices/put-block-list?tabs=microsoft-entra-id

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#import <CkoRest.h>
#import <CkoAuthAzureStorage.h>
#import <CkoXml.h>
#import <CkoFileAccess.h>
#import <CkoStringBuilder.h>
#import <NSString.h>
#import <CkoBinData.h>

// Azure Blob Service Example: Upload a file in blocks, and then commit the block list.
// See also: https://msdn.microsoft.com/en-us/library/azure/dd135726.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".
BOOL 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.

// As the blocks are uploaded, we'll keep an XML block list for the subsequent commit..
CkoXml *xml = [[CkoXml alloc] init];
xml.Tag = @"BlockList";

// Any type of file can be uploaded in this way.  It can a text file, binary file, anything...
// This example will upload an XML file that is approximately 275K in size.  It can be downloaded
// at http://www.chilkatsoft.com/hamlet.xml
CkoFileAccess *fac = [[CkoFileAccess alloc] init];
success = [fac OpenForRead: @"qa_data/xml/hamlet.xml"];
// Assuming success for the example..

// We'll upload in 16K blocks (normally a program would upload in larger block sizes than this,
// but this is just an example...)
int blockSize = 16384;

// How many 16K blocks?  (Including 1 for the last partial block)
int numBlocks = [[fac GetNumBlocks: [NSNumber numberWithInt: blockSize]] intValue];

CkoStringBuilder *sbResponseBody = [[CkoStringBuilder alloc] init];
CkoStringBuilder *uriPath = [[CkoStringBuilder alloc] init];
NSString *blockId = 0;
CkoBinData *dataBlock = [[CkoBinData alloc] init];
int i = 0;
while (i < numBlocks) {

    [dataBlock Clear];
    success = [fac ReadBlockBd: [NSNumber numberWithInt: i] blockSize: [NSNumber numberWithInt: blockSize] bd: dataBlock];
    if (success == NO) {
        NSLog(@"%@",fac.LastErrorText);
        return;
    }

    // Generate a base64 block ID.  
    // (Chilkat provides a helper method named GenBlockId to make this easy)
    // A pre-base64 encoded block ID length of 4 is sufficient in this case because
    // this file certainly won't have more than 99,999 blocks..
    blockId = [fac GenBlockId: [NSNumber numberWithInt: i] length: [NSNumber numberWithInt: 4] encoding: @"base64"];

    // Add this blockId to the list of blocks to be committed.
    [xml NewChild2: @"Latest" content: blockId];

    // Build the URI path
    [uriPath Clear];
    success = [uriPath Append: @"/mycontainer/hamlet.xml?comp=block&blockId="];
    success = [uriPath Append: blockId];

    // Upload this block..
    [sbResponseBody Clear];
    success = [rest FullRequestBd: @"PUT" uriPath: [uriPath GetAsString] binData: dataBlock responseBody: sbResponseBody];
    if (success == NO) {
        NSLog(@"%@",rest.LastErrorText);
        return;
    }

    // Verify that we received a 201 status code.
    if ([rest.ResponseStatusCode intValue] != 201) {
        // 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): ",[sbResponseBody GetAsString]);
        NSLog(@"%@",@"---");
        NSLog(@"%@%@",@"LastRequestStartLine: ",rest.LastRequestStartLine);
        NSLog(@"%@%@",@"LastRequestHeader: ",rest.LastRequestHeader);
        return;
    }

    i = i + 1;
}

[fac FileClose];

// Now commit the blocks.
// Let's have a look at the XML that will commit the blocks:
NSString *xmlStr = [xml GetXml];
NSLog(@"%@",xmlStr);

// The XML will look like this:

// <?xml version="1.0" encoding="utf-8" ?>
// <BlockList>
//     <Latest>MDAwMA==</Latest>
//     <Latest>MDAwMQ==</Latest>
//     <Latest>MDAwMg==</Latest>
//     <Latest>MDAwMw==</Latest>
//     <Latest>MDAwNA==</Latest>
//     <Latest>MDAwNQ==</Latest>
//     <Latest>MDAwNg==</Latest>
//     <Latest>MDAwNw==</Latest>
//     <Latest>MDAwOA==</Latest>
//     <Latest>MDAwOQ==</Latest>
//     <Latest>MDAxMA==</Latest>
//     <Latest>MDAxMQ==</Latest>
//     <Latest>MDAxMg==</Latest>
//     <Latest>MDAxMw==</Latest>
//     <Latest>MDAxNA==</Latest>
//     <Latest>MDAxNQ==</Latest>
//     <Latest>MDAxNg==</Latest>
//     <Latest>MDAxNw==</Latest>
// </BlockList>

// Send the PUT Block List...
NSString *responseStr = [rest FullRequestString: @"PUT" uriPath: @"/mycontainer/hamlet.xml?comp=blocklist" bodyText: xmlStr];
if (rest.LastMethodSuccess != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

// When successful, the Azure Storage service will respond with a 201 response status code,
// with no response body.

if ([rest.ResponseStatusCode intValue] != 201) {
    // 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.");