Base64 strings to transfer files
lazarus / 38-Networking and Web Programming

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xinyiman · 2016-02-28 14:19

Speaking to a forum user recently told me that he used a Base64
strings to transfer files. Who tells me how I can put a file into a
string and then the string pull out the file?

Thamk you

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balazsszekely · 2016-02-28 16:08

Here you go:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
base64; function FileToBase64(const AFile: String; var Base64:
String): Boolean;var  MS: TMemoryStream;  Str: String;begin  Result :=
False;  if not FileExists(AFile) then    Exit;  MS :=
TMemoryStream.Create;  try    MS.LoadFromFile(AFile);    if MS.Size >
0 then    begin      SetLength(Str, MS.Size div SizeOf(Char));     
MS.ReadBuffer(Str[1], MS.Size div SizeOf(Char));      Base64 :=
EncodeStringBase64(Str);      Result := True;    end;  finally   
MS.Free;  end;end; function Base64Tofile(const AFile, Base64: String):
Boolean;var  MS: TMemoryStream;  Str: String;begin  Result := False; 
MS := TMemoryStream.Create;  try    Str :=
DecodeStringBase64(Base64);    MS.Write(Str[1], Length(Str) div
SizeOf(Char));    MS.Position := 0;    MS.SaveToFile(AFile);    Result
:= FileExists(AFile);  finally    MS.Free;  end;end; procedure
TForm1.Button1Click(Sender: TObject);var  Base64: String;begin  Base64
:= '';  if not FileToBase64('Test_In.txt', Base64) then  begin   
ShowMessage('Cannot convert file to base64!');    Exit;  end; 
Memo1.Text := Base64;  //convert back  if not
Base64Tofile('Test_Out.txt', Base64) then  begin   
ShowMessage('Cannot convert base64 to file!');    Exit;  end;end;

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engkin · 2016-02-29 01:34

A different way using streams based on the source of
EncodeStringBase64 & DecodeStringBase64:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses 
Classes, sysutils, base64; function StreamToBase64(AInputStream:
TStream): string;var  OutputStream: TStringStream;  Encoder:
TBase64EncodingStream;begin  Result := '';   OutputStream :=
TStringStream.Create('');  Encoder :=
TBase64EncodingStream.Create(OutputStream);   try   
Encoder.CopyFrom(AInputStream, AInputStream.Size);    Encoder.Flush;  
  Result := OutputStream.DataString;  finally    Encoder.Free;   
OutputStream.Free;  end;end; function Base64ToStream(const
ABase64:string; AOutStream: TStream; const AStrict:
Boolean=false):Boolean;var  InStream: TStringStream;  Decoder:
TBase64DecodingStream;begin  Result := False;  InStream :=
TStringStream.Create(ABase64);  try    if AStrict then      Decoder :=
TBase64DecodingStream.Create(InStream, bdmStrict)    else      Decoder
:= TBase64DecodingStream.Create(InStream, bdmMIME);    try     
 AOutStream.CopyFrom(Decoder, Decoder.Size);       Result := True;   
finally      Decoder.Free;    end;  finally    InStream.Free; 
end;end; function Base64ToFile(const Base64, AFile: String):
boolean;var  OutStream: TFileStream;begin  Result := False;  OutStream
:= TFileStream.Create(AFile, fmCreate or fmShareExclusive);  try   
 Base64ToStream(Base64, OutStream);     Result := True;  finally   
Outstream.Free;  end;end; function FileToBase64(const AFile: String):
string;var  InputStream: TFileStream;begin  if not FileExists(AFile)
then    Exit('');   InputStream := TFileStream.Create(AFile,
fmOpenRead or fmShareDenyWrite);  try    Result :=
StreamToBase64(InputStream);  finally    InputStream.Free;  end;end;