Delphi SSL MITM Proxy based on INDY - problem with content loading - delphi

Question

I'm writing MITM ssl proxy using indy. i use IdHTTPserver component with self signed certificate for proxy server, and on event of CommandOther i do TcpCleint request to site and return data in HTTPServer. But problem is, some scripts, especially JS and some pictures from web pages not being loaded at all, or load after timeout, so i recieve html code in browser, but crippled by not working js (mostly). Here's my code for CommandOther:
procedure TForm3.IdHTTPServer1CommandOther(AContext: TIdContext;
ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
var
client: TIdTCPClient;
Headers, headers1: TIdHeaderList;
s, ResponseCode, ResponseText: string;
req,req2:string;
Size: Int64;
Strm,strm2: TIdTCPStream;
ssl: TIdSSLIOHandlerSocketOpenSSL;
clientcount:integer;
begin
Memo3.lines.Add('start');
client := TIdtCPClient.Create(nil);
ssl := TIdSSLIOHandlerSocketOpenSSL.Create(client);
client.IOHandler := ssl;
s := ARequestInfo.URI;
client.Host := Fetch(s, ':', True);
client.Port := StrToIntDef(s, 443);
client.ConnectTimeout := 2000;
s := '';
Memo3.lines.Add('connecting');
client.UseNagle:=true;
client.Connect;
//here i handle CONNECT command
AResponseInfo.ResponseNo := 200;
AResponseInfo.ResponseText := 'Connection established';
aresponseinfo.WriteHeader;
// activate SSL between this proxy and the client
TIdSSLIOHandlerSocketOpenSSL(AContext.Connection.Socket).PassThrough
:= false;
Memo3.lines.Add('connected');
while AContext.Connection.Connected and Client.Connected do
begin
try
memo4.Lines.Add('---start header-------');
headers1 := TIdHeaderList.Create(QuoteHTTP);
headers1.FoldLength := MaxInt;
repeat
s := AContext.Connection.IOHandler.ReadLn;
Memo4.lines.Add(s);
headers1.Add(s);
if s = '' then
Break;
until False;
client.WriteHeader(headers1);
memo4.Lines.Add('-----header written-----');
memo5.Lines.Add('----------');
if Headers1.IndexOfName('Content-Length') <> -1 then
begin
strm2:=TIdTCPStream.Create(client);
memo5.Lines.Add('post');
Size := StrToInt64(Headers1.Values['Content-Length']);
if Size > 0 then
AContext.Connection.IOHandler.ReadStream(Strm2, Size, False);
end;
memo4.Lines.Add('---response headers-------');
Headers := TIdHeaderList.Create(QuoteHTTP);
try
Headers.FoldLength := MaxInt;
repeat
s := client.IOHandler.ReadLn;
Memo4.lines.Add(s);
acontext.Connection.IOHandler.WriteLn(s);
Headers.Add(s);
if s = '' then
Break;
until False;
memo4.Lines.Add('---respone headers read-------');
Strm := TIdTCPStream.Create(AContext.Connection);
try
if Pos('chunked', Headers.Values['Transfer-Encoding']) <> 0 then
begin
memo4.Lines.Add('chunked');
repeat
s := client.IOHandler.ReadLn;
AContext.Connection.IOHandler.WriteLn(s);
Size := StrToInt64('$' + Fetch(s, ';'));
if Size = 0 then
Break;
client.IOHandler.ReadStream(Strm, Size, False);
s := client.IOHandler.ReadLn;
AContext.Connection.IOHandler.WriteLn(s);
until False;
repeat
s := client.IOHandler.ReadLn;
AContext.Connection.IOHandler.WriteLn(s);
until s = '';
end
else if Headers.IndexOfName('Content-Length') <> -1 then
begin
Size := StrToInt64(Headers.Values['Content-Length']);
end;
if Size > 0 then
client.IOHandler.ReadStream(Strm, Size, False);
end
else
begin
memo5.Lines.Add('big read(');
AResponseInfo.CloseConnection := true;
try
client.IOHandler.ReadStream(Strm, -1, True);
except
on E: EIdSocketError do
begin
raise;
end;
end;
end;
finally
Strm.Free;
end;
finally
Headers.Free;
strm2.Free;
headers1.Free;
end;
finally
client.Disconnect;
end;
client.Free;
end;
end;