使用INDY TCP組件實現基於協議採用XML方式的檔案傳輸

 我實現了個，傳輸的檔案大小都沒問題，但是除了文本類型的檔案開啟後查看正常外，其它的檔案比如PDF，rar檔案等都無法開啟。

問題我已經找到並解決了，問題的原因是：因為考慮到XML的編碼問題，所以我對傳輸的檔案資料部分的內容進行了加密，在用戶端解密，但是可能是加密解密過程中丟失了某些資訊，所以才會無法開啟。現在我已經把加密解密過程換成採用Mime編碼和解碼。

編碼：

ItemChildNode.NodeValue := MimeEncodeString(ATask_File_Tran_Response.DataString);

解碼：

Result.DataString := MimeDecodeString(ItemChildNode.NodeValue);

具體採用的編碼解碼單元為：

unit EDCode;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;

function MimeEncodeString (const s: AnsiString): AnsiString;
function MimeEncodeStringNoCRLF (const s: AnsiString): AnsiString;
function MimeDecodeString (const s: AnsiString): AnsiString;
procedure MimeEncodeStream (const InputStream: TStream; const OutputStream: TStream);
procedure MimeEncodeStreamNoCRLF (const InputStream: TStream; const OutputStream: TStream);
procedure MimeDecodeStream (const InputStream: TStream; const OutputStream: TStream);
function MimeEncodedSize (const i: Cardinal): Cardinal;
function MimeEncodedSizeNoCRLF (const i: Cardinal): Cardinal;
function MimeDecodedSize (const i: Cardinal): Cardinal;
procedure DecodeHttpBasicAuthentication (const BasicCredentials: AnsiString;
out UserId, PassWord: AnsiString);
procedure MimeEncode (const InputBuffer; const InputByteCount: Cardinal; out OutputBuffer);
procedure MimeEncodeNoCRLF (const InputBuffer; const InputByteCount: Cardinal; out OutputBuffer);
procedure MimeEncodeFullLines (const InputBuffer; const InputByteCount: Cardinal; out OutputBuffer);
function MimeDecode (const InputBuffer; const InputBytesCount: Cardinal; out OutputBuffer): Cardinal;
function MimeDecodePartial (const InputBuffer; const InputBytesCount: Cardinal;
out OutputBuffer; var ByteBuffer: Cardinal; var ByteBufferSpace: Cardinal): Cardinal;
function MimeDecodePartialEnd (out OutputBuffer; const ByteBuffer: Cardinal;
const ByteBufferSpace: Cardinal): Cardinal;
procedure Base64Encode(InputFile, OutputFile: string);
procedure Base64Decode(InputFile, OutputFile: string);

const
MIME_ENCODED_LINE_BREAK = 76;
MIME_DECODED_LINE_BREAK = MIME_ENCODED_LINE_BREAK div 4 * 3;
BUFFER_SIZE = MIME_DECODED_LINE_BREAK * 3 * 4 * 16;
MIME_ENCODE_TABLE : array[0..63] of Byte = (
065, 066, 067, 068, 069, 070, 071, 072, // 00 - 07
073, 074, 075, 076, 077, 078, 079, 080, // 08 - 15
081, 082, 083, 084, 085, 086, 087, 088, // 16 - 23
089, 090, 097, 098, 099, 100, 101, 102, // 24 - 31
103, 104, 105, 106, 107, 108, 109, 110, // 32 - 39
111, 112, 113, 114, 115, 116, 117, 118, // 40 - 47
119, 120, 121, 122, 048, 049, 050, 051, // 48 - 55
052, 053, 054, 055, 056, 057, 043, 047); // 56 - 63

MIME_PAD_CHAR = Byte ('=');

MIME_DECODE_TABLE : array[Byte] of Cardinal = (
255, 255, 255, 255, 255, 255, 255, 255, // 00 - 07
255, 255, 255, 255, 255, 255, 255, 255, // 08 - 15
255, 255, 255, 255, 255, 255, 255, 255, // 16 - 23
255, 255, 255, 255, 255, 255, 255, 255, // 24 - 31
255, 255, 255, 255, 255, 255, 255, 255, // 32 - 39
255, 255, 255, 062, 255, 255, 255, 063, // 40 - 47
052, 053, 054, 055, 056, 057, 058, 059, // 48 - 55
060, 061, 255, 255, 255, 255, 255, 255, // 56 - 63
255, 000, 001, 002, 003, 004, 005, 006, // 64 - 71
007, 008, 009, 010, 011, 012, 013, 014, // 72 - 79
015, 016, 017, 018, 019, 020, 021, 022, // 80 - 87
023, 024, 025, 255, 255, 255, 255, 255, // 88 - 95
255, 026, 027, 028, 029, 030, 031, 032, // 96 - 103
033, 034, 035, 036, 037, 038, 039, 040, // 104 - 111
041, 042, 043, 044, 045, 046, 047, 048, // 112 - 119
049, 050, 051, 255, 255, 255, 255, 255, // 120 - 127
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255);

type
PByte4 = ^TByte4;
TByte4 = packed record
b1: Byte;
b2: Byte;
b3: Byte;
b4: Byte;
end;

PByte3 = ^TByte3;
TByte3 = packed record
b1: Byte;
b2: Byte;
b3: Byte;
end;

implementation

function MimeEncodeString (const s: AnsiString): AnsiString;
var
l : Cardinal;
begin
if Pointer (s) <> nil then
begin
l := Cardinal (Pointer (Cardinal (s) - 4)^);
SetLength (Result, MimeEncodedSize (l));
MimeEncode (Pointer (s)^, l, Pointer (Result)^);
end
else
Result := '';
end;

function MimeEncodeStringNoCRLF (const s: AnsiString): AnsiString;
var
l : Cardinal;
begin
if Pointer (s) <> nil then
begin
l := Cardinal (Pointer (Cardinal (s) - 4)^);
SetLength (Result, MimeEncodedSizeNoCRLF (l));
MimeEncodeNoCRLF (Pointer (s)^, l, Pointer (Result)^);
end
else
Result := '';
end;

function MimeDecodeString (const s: AnsiString): AnsiString;
var
ByteBuffer, ByteBufferSpace: Cardinal;
l : Cardinal;
begin
if Pointer (s) <> nil then
begin
l := Cardinal (Pointer (Cardinal (s) - 4)^);
SetLength (Result, (l + 3) div 4 * 3);
ByteBuffer := 0;
ByteBufferSpace := 4;
l := MimeDecodePartial (Pointer (s)^, l, Pointer (Result)^, ByteBuffer, ByteBufferSpace);
Inc (l, MimeDecodePartialEnd (Pointer (Cardinal (Result) + l)^,
ByteBuffer, ByteBufferSpace));
SetLength (Result, l);
end
else
Result := '';
end;

procedure MimeEncodeStream (const InputStream: TStream; const OutputStream: TStream);
var
InputBuffer : array[0..BUFFER_SIZE - 1] of Byte;
OutputBuffer : array[0.. (BUFFER_SIZE + 2) div 3 * 4 + BUFFER_SIZE div
MIME_DECODED_LINE_BREAK * 2 - 1] of Byte;
BytesRead : Cardinal;
IDelta, ODelta : Cardinal;
begin
BytesRead := InputStream.Read (InputBuffer, SizeOf (InputBuffer));

while BytesRead = SizeOf (InputBuffer) do
begin
MimeEncodeFullLines (InputBuffer, SizeOf (InputBuffer), OutputBuffer);
OutputStream.Write (OutputBuffer, SizeOf (OutputBuffer));
BytesRead := InputStream.Read (InputBuffer, SizeOf (InputBuffer));
end;

MimeEncodeFullLines (InputBuffer, BytesRead, OutputBuffer);

IDelta := BytesRead div MIME_DECODED_LINE_BREAK; // Number of lines processed.
ODelta := IDelta * (MIME_ENCODED_LINE_BREAK + 2);
IDelta := IDelta * MIME_DECODED_LINE_BREAK;
MimeEncodeNoCRLF(Pointer(Cardinal (@InputBuffer) + IDelta)^, BytesRead - IDelta,
Pointer (Cardinal (@OutputBuffer) + ODelta)^);

OutputStream.Write (OutputBuffer, MimeEncodedSize (BytesRead));
end;

procedure MimeEncodeStreamNoCRLF (const InputStream: TStream; const OutputStream: TStream);
var
InputBuffer : array[0..BUFFER_SIZE - 1] of Byte;
OutputBuffer : array[0.. ((BUFFER_SIZE + 2) div 3) * 4 - 1] of Byte;
BytesRead : Cardinal;
begin
BytesRead := InputStream.Read (InputBuffer, SizeOf (InputBuffer));
while BytesRead = SizeOf (InputBuffer) do
begin
MimeEncodeNoCRLF (InputBuffer, SizeOf (InputBuffer), OutputBuffer);
OutputStream.Write (OutputBuffer, SizeOf (OutputBuffer));
BytesRead := InputStream.Read (InputBuffer, SizeOf (InputBuffer));
end;

MimeEncodeNoCRLF (InputBuffer, BytesRead, OutputBuffer);
OutputStream.Write (OutputBuffer, (BytesRead + 2) div 3 * 4);
end;

procedure MimeDecodeStream (const InputStream: TStream; const OutputStream: TStream);
var
ByteBuffer, ByteBufferSpace: Cardinal;
InputBuffer : array[0..BUFFER_SIZE - 1] of Byte;
OutputBuffer : array[0.. (BUFFER_SIZE + 3) div 4 * 3 - 1] of Byte;
BytesRead : Cardinal;
begin
ByteBuffer := 0;
ByteBufferSpace := 4;
BytesRead := InputStream.Read (InputBuffer, SizeOf (InputBuffer));
while BytesRead > 0 do
begin
OutputStream.Write(OutputBuffer, MimeDecodePartial(InputBuffer, BytesRead,
OutputBuffer, ByteBuffer, ByteBufferSpace));
BytesRead := InputStream.Read (InputBuffer, SizeOf (InputBuffer));
end;
OutputStream.Write (OutputBuffer, MimeDecodePartialEnd (OutputBuffer, ByteBuffer,
ByteBufferSpace));
end;

procedure DecodeHttpBasicAuthentication (const BasicCredentials: AnsiString; out UserId, PassWord: AnsiString);
label
Fail;
const
LBasic = 6; { Length ('Basic ') }
var
DecodedPtr, p : PAnsiChar;
i, l : Cardinal;
begin
p := Pointer (BasicCredentials);
if p = nil then goto Fail;

l := Cardinal (Pointer (p - 4)^);
if l <= LBasic then goto Fail;

Dec (l, LBasic);
Inc (p, LBasic);

GetMem (DecodedPtr, (l + 3) div 4 * 3 { MimeDecodedSize (l) });
l := MimeDecode (p^, l, DecodedPtr^);
i := 0;
p := DecodedPtr;
while (l > 0) and (p[i] <> ':') do
begin
Inc (i);
Dec (l);
end;
SetString (UserId, DecodedPtr, i);
if l > 1 then
SetString (PassWord, DecodedPtr + i + 1, l - 1)
else
PassWord := '';

FreeMem (DecodedPtr);
Exit;

Fail:
UserId := '';
PassWord := '';
end;

function MimeEncodedSize (const i: Cardinal): Cardinal;
begin
Result := (i + 2) div 3 * 4 + (i - 1) div MIME_DECODED_LINE_BREAK * 2;
end;

function MimeEncodedSizeNoCRLF (const i: Cardinal): Cardinal;
begin
Result := (i + 2) div 3 * 4;
end;

function MimeDecodedSize (const i: Cardinal): Cardinal;
begin
Result := (i + 3) div 4 * 3;
end;

procedure MimeEncode (const InputBuffer; const InputByteCount: Cardinal; out OutputBuffer);
var
IDelta, ODelta : Cardinal;
begin
MimeEncodeFullLines (InputBuffer, InputByteCount, OutputBuffer);
IDelta := InputByteCount div MIME_DECODED_LINE_BREAK;
ODelta := IDelta * (MIME_ENCODED_LINE_BREAK + 2);
IDelta := IDelta * MIME_DECODED_LINE_BREAK;
MimeEncodeNoCRLF (Pointer (Cardinal (@InputBuffer) + IDelta)^,
InputByteCount - IDelta, Pointer (Cardinal (@OutputBuffer) + ODelta)^);
end;

procedure MimeEncodeFullLines (const InputBuffer; const InputByteCount: Cardinal; out OutputBuffer);
var
b, OuterLimit : Cardinal;
InPtr, InnerLimit : ^Byte;
OutPtr : PByte4;
begin
if InputByteCount = 0 then Exit;
InPtr := @InputBuffer;
OutPtr := @OutputBuffer;

InnerLimit := InPtr;
Inc (Cardinal (InnerLimit), MIME_DECODED_LINE_BREAK);

OuterLimit := Cardinal (InPtr);
Inc (OuterLimit, InputByteCount);

while Cardinal (InnerLimit) <= OuterLimit do
begin

while InPtr <> InnerLimit do
begin
b := InPtr^;
b := b shl 8;
Inc (InPtr);
b := b or InPtr^;
b := b shl 8;
Inc (InPtr);
b := b or InPtr^;
Inc (InPtr);
OutPtr^.b4 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr^.b3 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr^.b2 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr^.b1 := MIME_ENCODE_TABLE[b];
Inc (OutPtr);
end;
OutPtr^.b1 := 13;
OutPtr^.b2 := 10;
Inc (Cardinal (OutPtr), 2);

Inc (InnerLimit, MIME_DECODED_LINE_BREAK);
end;

end;

procedure MimeEncodeNoCRLF (const InputBuffer; const InputByteCount: Cardinal; out OutputBuffer);
var
b, OuterLimit : Cardinal;
InPtr, InnerLimit : ^Byte;
OutPtr : PByte4;
begin
if InputByteCount = 0 then Exit;
InPtr := @InputBuffer;
OutPtr := @OutputBuffer;

OuterLimit := InputByteCount div 3 * 3;

InnerLimit := @InputBuffer;
Inc (Cardinal (InnerLimit), OuterLimit);
while InPtr <> InnerLimit do
begin
b := InPtr^;
b := b shl 8;
Inc (InPtr);
b := b or InPtr^;
b := b shl 8;
Inc (InPtr);
b := b or InPtr^;
Inc (InPtr);
OutPtr^.b4 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr^.b3 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr^.b2 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr^.b1 := MIME_ENCODE_TABLE[b];
Inc (OutPtr);
end;
case InputByteCount - OuterLimit of
1:
begin
b := InPtr^;
b := b shl 4;
OutPtr.b2 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr.b1 := MIME_ENCODE_TABLE[b];
OutPtr.b3 := MIME_PAD_CHAR;
OutPtr.b4 := MIME_PAD_CHAR;
end;
2:
begin
b := InPtr^;
Inc (InPtr);
b := b shl 8;
b := b or InPtr^;
b := b shl 2;
OutPtr.b3 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr.b2 := MIME_ENCODE_TABLE[b and $3F];
b := b shr 6;
OutPtr.b1 := MIME_ENCODE_TABLE[b];
OutPtr.b4 := MIME_PAD_CHAR; { Pad remaining byte. }
end;
end;
end;

function MimeDecode (const InputBuffer; const InputBytesCount: Cardinal;
out OutputBuffer): Cardinal;
var
ByteBuffer, ByteBufferSpace: Cardinal;
begin
ByteBuffer := 0;
ByteBufferSpace := 4;
Result := MimeDecodePartial(InputBuffer, InputBytesCount,
OutputBuffer, ByteBuffer, ByteBufferSpace);
Inc (Result, MimeDecodePartialEnd(Pointer (Cardinal(@OutputBuffer) + Result)^,
ByteBuffer, ByteBufferSpace));
end;

function MimeDecodePartial (const InputBuffer; const InputBytesCount: Cardinal;
out OutputBuffer; var ByteBuffer: Cardinal; var ByteBufferSpace: Cardinal): Cardinal;
var
lByteBuffer, lByteBufferSpace, c: Cardinal;
InPtr, OuterLimit : ^Byte;
OutPtr : PByte3;
begin
if InputBytesCount > 0 then
begin
InPtr := @InputBuffer;
Cardinal (OuterLimit) := Cardinal (InPtr) + InputBytesCount;
OutPtr := @OutputBuffer;
lByteBuffer := ByteBuffer;
lByteBufferSpace := ByteBufferSpace;
while InPtr <> OuterLimit do
begin
c := MIME_DECODE_TABLE[InPtr^];
Inc (InPtr);
if c = $FF then Continue;
lByteBuffer := lByteBuffer shl 6;
lByteBuffer := lByteBuffer or c;
Dec (lByteBufferSpace);
if lByteBufferSpace <> 0 then Continue;
OutPtr^.b3 := Byte (lByteBuffer);
lByteBuffer := lByteBuffer shr 8;
OutPtr^.b2 := Byte (lByteBuffer);
lByteBuffer := lByteBuffer shr 8;
OutPtr^.b1 := Byte (lByteBuffer);
lByteBuffer := 0;
Inc (OutPtr);
lByteBufferSpace := 4;
end;
ByteBuffer := lByteBuffer;
ByteBufferSpace := lByteBufferSpace;
Result := Cardinal (OutPtr) - Cardinal (@OutputBuffer);
end
else
Result := 0;
end;

function MimeDecodePartialEnd (out OutputBuffer; const ByteBuffer: Cardinal;
const ByteBufferSpace: Cardinal): Cardinal;
var
lByteBuffer : Cardinal;
begin
case ByteBufferSpace of
1:
begin
lByteBuffer := ByteBuffer shr 2;
PByte3 (@OutputBuffer)^.b2 := Byte (lByteBuffer);
lByteBuffer := lByteBuffer shr 8;
PByte3 (@OutputBuffer)^.b1 := Byte (lByteBuffer);
Result := 2;
end;
2:
begin
lByteBuffer := ByteBuffer shr 4;
PByte3 (@OutputBuffer)^.b1 := Byte (lByteBuffer);
Result := 1;
end;
else
Result := 0;
end;
end;

procedure Base64Encode(InputFile, OutputFile: string);
var
Ms: TMemoryStream;
Ss: TStringStream;
Str: string;
List: TStringList;
begin {Base64 encode}
Ms := TMemoryStream.Create;
try
Ms.LoadFromFile(InputFile);
Ss := TStringStream.Create(Str);
try
MimeEncodeStream(Ms, Ss);
List := TStringList.Create;
try
List.Text := Ss.DataString;
List.SaveToFile(OutputFile);
finally
List.Free;
end;
finally
Ss.Free;
end;
finally
Ms.Free;
end;
end;

procedure Base64Decode(InputFile, OutputFile: string);
var
Ms: TMemoryStream;
Ss: TStringStream;
List: TStringList;
begin {Base64 decode}
List := TStringList.Create;
try
List.LoadFromFile(InputFile);
Ss := TStringStream.Create(List.Text);
try
Ms := TMemoryStream.Create;
try
MimeDecodeStream(Ss, Ms);
Ms.SaveToFile(OutputFile);
finally
Ms.Free;
end;
finally
Ss.Free;
end;
finally
List.Free;
end;
end;

end.