Lazarus Pascal Requires Chilkat v11.7.0+
Lazarus Pascal
Box: Upload a Large File in Parts and Commit the Session
See more Box Examples
Run the reusable setup once per HttpCurl object, then select names and execute the operation. The setup is repeated here only to make this published example independently runnable. Resolve documents by name, then perform the explicit chunked-upload session, part, and commit loop. Supports 20 MB through 2 GB using int. Saves recovery information and honors bounded commit Retry-After.
See the Box API guide for setup and the complete workflow.
Chilkat Lazarus Pascal 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.HttpCurl,
Chilkat.FileAccess,
Chilkat.HttpResponse,
Chilkat.StringBuilder,
Chilkat.JsonObject,
Chilkat.Crypt2,
Chilkat.Http,
Chilkat.BinData;
// ---------------------------------------------------------------------------
procedure RunDemo;
var
success: Boolean;
curl: THttpCurl;
setupCommand: TStringBuilder;
setupReplacements: Integer;
parentName: string;
folderName: string;
authorizedCommand1: TStringBuilder;
headerReplacement1: Integer;
localPath: string;
file: TFileAccess;
sizeString: string;
sizeText: TStringBuilder;
sizeMatch: TJsonObject;
fileSize: Integer;
http: THttp;
response: THttpResponse;
request: TJsonObject;
session: TJsonObject;
partSize: Integer;
uploadUrl: string;
commitUrl: string;
hash: TCrypt2;
fileDigest: string;
commit: TJsonObject;
partResponse: TJsonObject;
chunk: TBinData;
range: TStringBuilder;
digestHeader: TStringBuilder;
offset: Integer;
partIndex: Integer;
partLength: Integer;
lastByte: Integer;
partDigest: string;
attempts: Integer;
waitSeconds: Integer;
retryHeader: TStringBuilder;
retryMatch: TJsonObject;
completed: Boolean;
begin
success := False;
// Requires Chilkat 11.7.0 or later and a previously unlocked Chilkat bundle.
// See Global Unlock Sample.
// Guide: Box API Guide.
success := False;
// BEGIN ONE-TIME SETUP
// This block is repeated so each published example can run on its own.
// In an application, run the setup example once and pass the SAME curl object
// to operation code below. Do not recreate it for every operation.
// See Reusable Box HttpCurl Setup.
curl := THttpCurl.Create;
curl.SetVar('access_token','BOX_ACCESS_TOKEN');
curl.SetVar('parent_name','/');
// Box's fixed root ID is an implementation detail; callers supply names.
curl.SetVar('parent_id','0');
setupCommand := TStringBuilder.Create;
// Register findParent; registration sends no request.
setupCommand.SetString('curl -X GET "https://api.box.com/2.0/folders/0/items?limit=1000&fields=id,type,name" -H "Authorization: Bearer ACCESS_TOKEN"');
setupReplacements := setupCommand.Replace('ACCESS_TOKEN',curl.GetVar('access_token'));
success := curl.AddFunction('findParent',setupCommand.GetAsString());
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// Register findFolder; registration sends no request.
setupCommand.SetString('curl -X GET "https://api.box.com/2.0/folders/{{parent_id}}/items?limit=1000&fields=id,type,name" -H "Authorization: Bearer ACCESS_TOKEN"');
setupReplacements := setupCommand.Replace('ACCESS_TOKEN',curl.GetVar('access_token'));
success := curl.AddFunction('findFolder',setupCommand.GetAsString());
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// Register findFile; registration sends no request.
setupCommand.SetString('curl -X GET "https://api.box.com/2.0/folders/{{folder_id}}/items?limit=1000&fields=id,type,name" -H "Authorization: Bearer ACCESS_TOKEN"');
setupReplacements := setupCommand.Replace('ACCESS_TOKEN',curl.GetVar('access_token'));
success := curl.AddFunction('findFile',setupCommand.GetAsString());
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// Register findDestination; registration sends no request.
setupCommand.SetString('curl -X GET "https://api.box.com/2.0/folders/0/items?limit=1000&fields=id,type,name" -H "Authorization: Bearer ACCESS_TOKEN"');
setupReplacements := setupCommand.Replace('ACCESS_TOKEN',curl.GetVar('access_token'));
success := curl.AddFunction('findDestination',setupCommand.GetAsString());
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// Register getFileDetails; registration sends no request.
setupCommand.SetString('curl -X GET "https://api.box.com/2.0/files/{{file_id}}?fields=id,sha1,file_version" -H "Authorization: Bearer ACCESS_TOKEN"');
setupReplacements := setupCommand.Replace('ACCESS_TOKEN',curl.GetVar('access_token'));
success := curl.AddFunction('getFileDetails',setupCommand.GetAsString());
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// Register getEnterprise; registration sends no request.
setupCommand.SetString('curl -X GET "https://api.box.com/2.0/users/me?fields=enterprise" -H "Authorization: Bearer ACCESS_TOKEN"');
setupReplacements := setupCommand.Replace('ACCESS_TOKEN',curl.GetVar('access_token'));
success := curl.AddFunction('getEnterprise',setupCommand.GetAsString());
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// Register output rules once. Chilkat 11.7.0 evaluates {{name}} variables
// when extracting each output, using the current value at that time.
success := curl.AddOutput2('findParent','entries','name','{{parent_name}}',True,'id','parent_id');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
success := curl.AddOutput2('findFolder','entries','name','{{folder_name}}',True,'id','folder_id');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
success := curl.AddOutput2('findFile','entries','name','{{file_name}}',True,'id','file_id');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
success := curl.AddOutput2('findDestination','entries','name','{{destination_name}}',True,'id','destination_id');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
success := curl.AddOutput('getFileDetails','file_version.id','file_version_id');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
success := curl.AddOutput('getFileDetails','sha1','file_sha1');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
success := curl.AddOutput('getEnterprise','enterprise.id','enterprise_id');
if (success <> True) then
begin
WriteLn(curl.LastErrorText);
Exit;
end;
// END ONE-TIME SETUP
// The name lookups below assume each listing fits in one page (1000 items).
// Parent and destination names select root children; folder_name selects a child
// of parent_name. "/" selects the root parent. These are not arbitrary paths.
// BEGIN OPERATION -- keep the configured object when reusing it.
// Inputs are names. Retain cached IDs when the selected names have not changed.
parentName := '/';
folderName := 'documents';
if ((curl.GetVar('parent_name') <> parentName) or ((parentName = '/') and (curl.VarDefined('parent_id') = False))) then
begin
curl.SetVar('parent_name',parentName);
curl.ClearVar('parent_id');
curl.ClearVar('folder_id');
curl.ClearVar('file_id');
curl.ClearVar('file_version_id');
curl.ClearVar('file_sha1');
if (parentName = '/') then
begin
curl.SetVar('parent_id','0');
end;
end;
if (curl.GetVar('folder_name') <> folderName) then
begin
curl.SetVar('folder_name',folderName);
curl.ClearVar('folder_id');
curl.ClearVar('file_id');
curl.ClearVar('file_version_id');
curl.ClearVar('file_sha1');
end;
// Resolve the named destination first. HttpCurl does not expand variables
// inside multipart -F attributes in the tested build, so this upload is two phases.
curl.ClearTargetOutput('*');
authorizedCommand1 := TStringBuilder.Create;
authorizedCommand1.SetString('curl -X GET "https://api.box.com/2.0/folders/{{folder_id}}?fields=id" -H "Authorization: Bearer {{access_token}}"');
headerReplacement1 := authorizedCommand1.Replace('{{access_token}}',curl.GetVar('access_token'));
success := curl.DoYourThing(authorizedCommand1.GetAsString());
if ((success <> True) or (curl.StatusCode <> 200)) then
begin
WriteLn('Box request failed. HTTP status: ' + curl.StatusCode);
WriteLn('Failure reason: ' + curl.FailReason);
WriteLn(curl.ResponseBodyStr);
Exit;
end;
// This example limits size to 2 GB so offsets fit all generated languages' integers.
// The source must not change during hashing or upload. Create qa_output first.
localPath := 'qa_data/large-document.zip';
file := TFileAccess.Create;
// Check the decimal size before converting so an oversized file cannot overflow int.
sizeString := file.FileSizeStr(localPath);
if (file.LastMethodSuccess <> True) then
begin
WriteLn(file.LastErrorText);
Exit;
end;
sizeText := TStringBuilder.Create;
sizeText.SetString(sizeString);
sizeMatch := TJsonObject.Create;
if (sizeText.RegexMatch('^([0-9]{1,9}|1[0-9]{9}|2000000000)$',sizeMatch,100) <> 1) then
begin
WriteLn('Choose an input between 20 MB and 2 GB for this example.');
Exit;
end;
fileSize := StrToInt(sizeString);
if (fileSize < 20971520) then
begin
WriteLn('Choose an input between 20 MB and 2 GB for this example.');
Exit;
end;
http := THttp.Create;
http.AuthToken := curl.GetVar('access_token');
response := THttpResponse.Create;
request := TJsonObject.Create;
request.UpdateString('folder_id',curl.GetVar('folder_id'));
request.UpdateString('file_name','large-document.zip');
request.UpdateInt('file_size',fileSize);
success := http.HttpJson('POST','https://upload.box.com/api/2.0/files/upload_sessions',request,'application/json',response);
if (success <> True) then
begin
WriteLn(http.LastErrorText);
Exit;
end;
if (response.StatusCode <> 201) then
begin
WriteLn(response.BodyStr);
Exit;
end;
session := TJsonObject.Create;
success := session.Load(response.BodyStr);
if (success <> True) then
begin
WriteLn(session.LastErrorText);
Exit;
end;
success := session.WriteFile('qa_output/box_upload_session.json');
if (success <> True) then
begin
WriteLn(session.LastErrorText);
Exit;
end;
partSize := session.IntOf('part_size');
uploadUrl := session.StringOf('session_endpoints.upload_part');
commitUrl := session.StringOf('session_endpoints.commit');
if ((partSize <= 0) or (uploadUrl = '') or (commitUrl = '')) then
begin
WriteLn('Invalid session response.');
Exit;
end;
hash := TCrypt2.Create;
hash.HashAlgorithm := 'sha1';
hash.EncodingMode := 'base64';
fileDigest := hash.HashFileENC(localPath);
if (hash.LastMethodSuccess <> True) then
begin
WriteLn(hash.LastErrorText);
Exit;
end;
success := file.FileOpen(localPath,2147483648,1,3,0);
if (success <> True) then
begin
WriteLn(file.LastErrorText);
Exit;
end;
commit := TJsonObject.Create;
partResponse := TJsonObject.Create;
chunk := TBinData.Create;
range := TStringBuilder.Create;
digestHeader := TStringBuilder.Create;
offset := 0;
partIndex := 0;
while offset < fileSize do
begin
chunk.Clear();
success := file.FileReadBd(partSize,chunk);
if (success <> True) then
begin
WriteLn(file.LastErrorText);
file.FileClose();
Exit;
end;
partLength := chunk.NumBytes;
if (partLength <= 0) then
begin
WriteLn('Unexpected end of file.');
file.FileClose();
Exit;
end;
lastByte := offset + (partLength - 1);
range.Clear();
range.Append('bytes ');
range.AppendInt(offset);
range.Append('-');
range.AppendInt(lastByte);
range.Append('/');
range.AppendInt(fileSize);
partDigest := hash.HashBdENC(chunk);
if (hash.LastMethodSuccess <> True) then
begin
WriteLn(hash.LastErrorText);
file.FileClose();
Exit;
end;
digestHeader.SetString('sha=');
digestHeader.Append(partDigest);
http.SetRequestHeader('Digest',digestHeader.GetAsString());
http.SetRequestHeader('Content-Range',range.GetAsString());
success := http.HttpBd('PUT',uploadUrl,chunk,'application/octet-stream',response);
if ((success <> True) or (response.StatusCode <> 200)) then
begin
WriteLn('Part failed. HTTP status: ' + response.StatusCode);
WriteLn(response.BodyStr);
WriteLn('Inspect the saved session and server list_parts before retrying this part.');
file.FileClose();
Exit;
end;
success := partResponse.Load(response.BodyStr);
if (success <> True) then
begin
file.FileClose();
Exit;
end;
commit.I := partIndex;
// Copy the server's acknowledged part fields into the commit manifest.
commit.UpdateString('parts[i].part_id',partResponse.StringOf('part.part_id'));
commit.UpdateInt('parts[i].offset',partResponse.IntOf('part.offset'));
commit.UpdateInt('parts[i].size',partResponse.IntOf('part.size'));
commit.UpdateString('parts[i].sha1',partResponse.StringOf('part.sha1'));
success := commit.WriteFile('qa_output/box_upload_parts.json');
if (success <> True) then
begin
WriteLn(commit.LastErrorText);
file.FileClose();
Exit;
end;
offset := offset + partLength;
partIndex := partIndex + 1;
end;
file.FileClose();
http.RemoveRequestHeader('Content-Range');
digestHeader.SetString('sha=');
digestHeader.Append(fileDigest);
http.SetRequestHeader('Digest',digestHeader.GetAsString());
attempts := 0;
retryHeader := TStringBuilder.Create;
retryMatch := TJsonObject.Create;
completed := False;
while (attempts < 10) and (completed = False) do
begin
success := http.HttpJson('POST',commitUrl,commit,'application/json',response);
if (success <> True) then
begin
WriteLn('Commit failed: ' + response.StatusCode);
WriteLn(response.BodyStr);
Exit;
end;
if (response.StatusCode = 201) then
begin
completed := True;
end
else
begin
if (response.StatusCode <> 202) then
begin
WriteLn('Unexpected commit status: ' + response.StatusCode);
Exit;
end;
// Box's asynchronous commit response supplies Retry-After in seconds.
retryHeader.SetString(response.GetHeaderField('Retry-After'));
if (retryHeader.RegexMatch('^[0-9]{1,2}$',retryMatch,100) <> 1) then
begin
WriteLn('Commit pending. Preserve the session and inspect Retry-After before resuming: ' + retryHeader.GetAsString());
Exit;
end;
waitSeconds := StrToInt(retryHeader.GetAsString());
if ((waitSeconds < 1) or (waitSeconds > 60)) then
begin
WriteLn('Commit pending. Resume commit after Retry-After: ' + response.GetHeaderField('Retry-After'));
Exit;
end;
http.SleepMs(waitSeconds * 1000);
end;
attempts := attempts + 1;
end;
if (completed = False) then
begin
WriteLn('Commit still pending; retain session and part manifests to resume commit later.');
Exit;
end;
WriteLn('Upload committed: ' + response.BodyStr);
curl.Free;
setupCommand.Free;
authorizedCommand1.Free;
file.Free;
sizeText.Free;
sizeMatch.Free;
http.Free;
response.Free;
request.Free;
session.Free;
hash.Free;
commit.Free;
partResponse.Free;
chunk.Free;
range.Free;
digestHeader.Free;
retryHeader.Free;
retryMatch.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.