Pascal (Lazarus/Delphi)
Pascal (Lazarus/Delphi)
Azure File Service: Upload Large File
See more Azure Cloud Storage Examples
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 Pascal (Lazarus/Delphi) Downloads
program ChilkatDemo;
// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.
{$IFDEF FPC}
{$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}
uses
{$IFDEF UNIX}
cthreads,
{$ENDIF}
SysUtils,
CkDllLoader,
Chilkat.FileAccess,
Chilkat.Rest,
Chilkat.AuthAzureStorage,
Chilkat.BinData,
Chilkat.StringBuilder;
// ---------------------------------------------------------------------------
procedure RunDemo;
var
success: Boolean;
rest: TRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
localFilePath: string;
fac: TFileAccess;
szLocalFile: Integer;
azAuth: TAuthAzureStorage;
sbFileSize: TStringBuilder;
responseStr: string;
sbRange: TStringBuilder;
sbResponseBody: TStringBuilder;
bdFileData: TBinData;
numBytesLeft: Integer;
curIndex: Integer;
chunkSize: Integer;
begin
success := False;
// 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 := TRest.Create;
// Connect to the Azure Storage Blob Service
bTls := True;
port := 443;
bAutoReconnect := True;
// In this example, the storage account name is "chilkat".
success := rest.Connect('chilkat.file.core.windows.net',port,bTls,bAutoReconnect);
if (success <> True) then
begin
WriteLn(rest.LastErrorText);
Exit;
end;
// This example will upload a larger file.
localFilePath := 'qa_data/zips/somethingBig.zip';
fac := TFileAccess.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 := fac.FileSize(localFilePath);
if (szLocalFile < 0) then
begin
WriteLn(fac.LastErrorText);
Exit;
end;
// Provide Azure Cloud credentials for the REST calls.
azAuth := TAuthAzureStorage.Create;
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: 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.
// However, a few additional headers are required for the "Create File" operation:
rest.AddHeader('x-ms-type','file');
// This required header specifies the final size of the file (or the maximum size it can be).
sbFileSize := TStringBuilder.Create;
sbFileSize.AppendInt(szLocalFile);
rest.AddHeader('x-ms-content-length',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"
responseStr := rest.FullRequestNoBody('PUT','/pip/somethingBig.zip');
if (rest.LastMethodSuccess <> True) then
begin
WriteLn(rest.LastErrorText);
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 (rest.ResponseStatusCode <> 201) then
begin
// Examine the request/response to see what happened.
WriteLn('response status code = ' + rest.ResponseStatusCode);
WriteLn('response status text = ' + rest.ResponseStatusText);
WriteLn('response header: ' + rest.ResponseHeader);
WriteLn('response body (if any): ' + responseStr);
WriteLn('---');
WriteLn('LastRequestStartLine: ' + rest.LastRequestStartLine);
WriteLn('LastRequestHeader: ' + rest.LastRequestHeader);
Exit;
end;
WriteLn('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','update');
sbRange := TStringBuilder.Create;
sbResponseBody := TStringBuilder.Create;
bdFileData := TBinData.Create;
// Open the file. We'll be reading and uploading in chunks..
success := fac.OpenForRead(localFilePath);
if (success <> True) then
begin
WriteLn(fac.LastErrorText);
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
sbRange.Clear();
sbRange.Append('bytes=');
sbRange.AppendInt(curIndex);
sbRange.Append('-');
sbRange.AppendInt(curIndex + chunkSize - 1);
// This replaces the header if it already exists..
rest.AddHeader('x-ms-range',sbRange.GetAsString());
// Read the next chunk from the local file.
bdFileData.Clear();
success := fac.FileReadBd(chunkSize,bdFileData);
success := rest.FullRequestBd('PUT','/pip/somethingBig.zip?comp=range',bdFileData,sbResponseBody);
if (success <> True) then
begin
// This would indicate a failure where no response was received.
WriteLn(rest.LastErrorText);
Exit;
end;
// A 201 response indicates the chunk was uploaded.
if (rest.ResponseStatusCode <> 201) then
begin
// Examine the request/response to see what happened.
WriteLn('response status code = ' + rest.ResponseStatusCode);
WriteLn('response status text = ' + rest.ResponseStatusText);
WriteLn('response header: ' + rest.ResponseHeader);
WriteLn('response body (if any): ' + responseStr);
WriteLn('---');
WriteLn('LastRequestStartLine: ' + rest.LastRequestStartLine);
WriteLn('LastRequestHeader: ' + rest.LastRequestHeader);
Exit;
end;
WriteLn('Uploaded chunk from ' + curIndex + ' to ' + curIndex + chunkSize - 1);
curIndex := curIndex + chunkSize;
numBytesLeft := numBytesLeft - chunkSize;
end;
fac.FileClose();
WriteLn('success.');
rest.Free;
fac.Free;
azAuth.Free;
sbFileSize.Free;
sbRange.Free;
sbResponseBody.Free;
bdFileData.Free;
end;
// ---------------------------------------------------------------------------
begin
try
RunDemo;
except
on E: Exception do
WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
end;
WriteLn;
{$IFDEF MSWINDOWS}
WriteLn('Press Enter to exit...');
ReadLn;
{$ENDIF}
end.