(Objective-C) Azure File Service: Upload Large File

Sample code to upload a large file to a directory in a share in the Azure File Service. A file is uploaded by first creating the file in the Azure share and then writing ranges of bytes to the file. Azure imposes a 4MB limit for each PUT to write a range. Files larger than 4MB need to be uploaded by making multiple "Put Range" calls. This example uploads a large file requiring multiple "Put Range" calls.

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

// Azure File Service Example: Upload a large file.  
// See:  https://docs.microsoft.com/en-us/rest/api/storageservices/create-share
// also see: https://docs.microsoft.com/en-us/rest/api/storageservices/put-range

// 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.file.core.windows.net" port: [NSNumber numberWithInt: port] tls: bTls autoReconnect: bAutoReconnect];
if (success != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

// This example will upload a larger file.
NSString *localFilePath = @"qa_data/zips/somethingBig.zip";
CkoFileAccess *fac = [[CkoFileAccess alloc] init];
// Note: The FileSize method returns a signed 32-bit integer.  If the file is potentially larger than 2GB, call FileSizeStr instead to return
// the size of the file as a string, then convert to an integer value.
int szLocalFile = [[fac FileSize: localFilePath] intValue];
if (szLocalFile < 0) {
    NSLog(@"%@",fac.LastErrorText);
    return;
}

// Provide Azure Cloud credentials for the REST calls.
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 = @"File";
// This causes the "x-ms-version: 2020-08-04" header to be automatically added.
azAuth.XMsVersion = @"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.

// However, a few additional headers are required for the "Create File" operation:
[rest AddHeader: @"x-ms-type" value: @"file"];

// This required header specifies the final size of the file (or the maximum size it can be).
CkoStringBuilder *sbFileSize = [[CkoStringBuilder alloc] init];
[sbFileSize AppendInt: [NSNumber numberWithInt: szLocalFile]];
[rest AddHeader: @"x-ms-content-length" value: [sbFileSize GetAsString]];

// Send a PUT request to create the file (or replace the file if it already exists).
// This will initialize the file in the Azure file storage.  To upload content, we'll need
// to do the "Put Range" operation one or more times.

// The following will create the file "somethingBig.zip" in the share "pip"
NSString *responseStr = [rest FullRequestNoBody: @"PUT" uriPath: @"/pip/somethingBig.zip"];
if (rest.LastMethodSuccess != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

// When successful, the Azure File Service will respond with a 201 (Created) response status code,
// with no XML response body.  If an error response is returned, there will be an XML 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(@"%@",@"Successfully created somethingBig.zip");

// --------------------------------------------------------------------------------
// Upload the file data...

// Make sure the headers from the "Create File" operation are removed.
[rest ClearAllHeaders];

// The x-ms-write header is required for each "Put Range" request.
[rest AddHeader: @"x-ms-write" value: @"update"];

CkoStringBuilder *sbRange = [[CkoStringBuilder alloc] init];
CkoStringBuilder *sbResponseBody = [[CkoStringBuilder alloc] init];
CkoBinData *bdFileData = [[CkoBinData alloc] init];

// Open the file.  We'll be reading and uploading in chunks..
success = [fac OpenForRead: localFilePath];
if (success != YES) {
    NSLog(@"%@",fac.LastErrorText);
    return;
}

int numBytesLeft = szLocalFile;
int curIndex = 0;
while (numBytesLeft > 0) {

    int chunkSize = numBytesLeft;
    // Azure allows for 4MB max chunks  (4 x 1024 x 1024 = 4194304)
    if (chunkSize > 4194304) {
        chunkSize = 4194304;
    }

    // The only tricky part here is to correctly add the x-ms-range header.
    // It will be formatted like this:
    // x-ms-range: bytes=0-759623
    [sbRange Clear];
    [sbRange Append: @"bytes="];
    [sbRange AppendInt: [NSNumber numberWithInt: curIndex]];
    [sbRange Append: @"-"];
    [sbRange AppendInt: [NSNumber numberWithInt: (curIndex + chunkSize - 1)]];

    // This replaces the header if it already exists..
    [rest AddHeader: @"x-ms-range" value: [sbRange GetAsString]];

    // Read the next chunk from the local file.
    [bdFileData Clear];
    success = [fac FileReadBd: [NSNumber numberWithInt: chunkSize] binData: bdFileData];

    success = [rest FullRequestBd: @"PUT" uriPath: @"/pip/somethingBig.zip?comp=range" binData: bdFileData responseBody: sbResponseBody];
    if (success != YES) {
        // This would indicate a failure where no response was received.
        NSLog(@"%@",rest.LastErrorText);
        return;
    }

    // A 201 response indicates the chunk was uploaded.
    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(@"%@%d%@%d",@"Uploaded chunk from ",curIndex,@" to ",curIndex + chunkSize - 1);

    curIndex = curIndex + chunkSize;
    numBytesLeft = numBytesLeft - chunkSize;
}

[fac FileClose];

NSLog(@"%@",@"success.");