(Delphi DLL) 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.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
success: Boolean;
localFilePath: PWideChar;
fac: HCkFileAccess;
szLocalFile: Integer;
azAuth: HCkAuthAzureStorage;
sbFileSize: HCkStringBuilder;
responseStr: PWideChar;
sbRange: HCkStringBuilder;
sbResponseBody: HCkStringBuilder;
bdFileData: HCkBinData;
numBytesLeft: Integer;
curIndex: Integer;
chunkSize: Integer;

begin
// 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.

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.file.core.windows.net',port,bTls,bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// This example will upload a larger file.
localFilePath := 'qa_data/zips/somethingBig.zip';
fac := CkFileAccess_Create();
// 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.
szLocalFile := CkFileAccess_FileSize(fac,localFilePath);
if (szLocalFile < 0) then
  begin
    Memo1.Lines.Add(CkFileAccess__lastErrorText(fac));
    Exit;
  end;

// Provide Azure Cloud credentials for the REST calls.
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,'File');
// This causes the "x-ms-version: 2020-08-04" header to be automatically added.
CkAuthAzureStorage_putXMsVersion(azAuth,'2020-08-04');
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.

// However, a few additional headers are required for the "Create File" operation:
CkRest_AddHeader(rest,'x-ms-type','file');

// This required header specifies the final size of the file (or the maximum size it can be).
sbFileSize := CkStringBuilder_Create();
CkStringBuilder_AppendInt(sbFileSize,szLocalFile);
CkRest_AddHeader(rest,'x-ms-content-length',CkStringBuilder__getAsString(sbFileSize));

// 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"
responseStr := CkRest__fullRequestNoBody(rest,'PUT','/pip/somethingBig.zip');
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// 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 (CkRest_getResponseStatusCode(rest) <> 201) 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('Successfully created somethingBig.zip');

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

// Make sure the headers from the "Create File" operation are removed.
CkRest_ClearAllHeaders(rest);

// The x-ms-write header is required for each "Put Range" request.
CkRest_AddHeader(rest,'x-ms-write','update');

sbRange := CkStringBuilder_Create();
sbResponseBody := CkStringBuilder_Create();
bdFileData := CkBinData_Create();

// Open the file.  We'll be reading and uploading in chunks..
success := CkFileAccess_OpenForRead(fac,localFilePath);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkFileAccess__lastErrorText(fac));
    Exit;
  end;

numBytesLeft := szLocalFile;
curIndex := 0;
while numBytesLeft > 0 do
  begin

    chunkSize := numBytesLeft;
    // Azure allows for 4MB max chunks  (4 x 1024 x 1024 = 4194304)
    if (chunkSize > 4194304) then
      begin
        chunkSize := 4194304;
      end;

    // 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
    CkStringBuilder_Clear(sbRange);
    CkStringBuilder_Append(sbRange,'bytes=');
    CkStringBuilder_AppendInt(sbRange,curIndex);
    CkStringBuilder_Append(sbRange,'-');
    CkStringBuilder_AppendInt(sbRange,curIndex + chunkSize - 1);

    // This replaces the header if it already exists..
    CkRest_AddHeader(rest,'x-ms-range',CkStringBuilder__getAsString(sbRange));

    // Read the next chunk from the local file.
    CkBinData_Clear(bdFileData);
    success := CkFileAccess_FileReadBd(fac,chunkSize,bdFileData);

    success := CkRest_FullRequestBd(rest,'PUT','/pip/somethingBig.zip?comp=range',bdFileData,sbResponseBody);
    if (success <> True) then
      begin
        // This would indicate a failure where no response was received.
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
        Exit;
      end;

    // A 201 response indicates the chunk was uploaded.
    if (CkRest_getResponseStatusCode(rest) <> 201) 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('Uploaded chunk from ' + IntToStr(curIndex) + ' to ' + IntToStr(curIndex + chunkSize - 1));

    curIndex := curIndex + chunkSize;
    numBytesLeft := numBytesLeft - chunkSize;
  end;

CkFileAccess_FileClose(fac);

Memo1.Lines.Add('success.');

CkRest_Dispose(rest);
CkFileAccess_Dispose(fac);
CkAuthAzureStorage_Dispose(azAuth);
CkStringBuilder_Dispose(sbFileSize);
CkStringBuilder_Dispose(sbRange);
CkStringBuilder_Dispose(sbResponseBody);
CkBinData_Dispose(bdFileData);

end;