[DUG] Help - Mime64 insanity !
Robert Martin
rob at chreos.co.nz
Wed Aug 10 09:07:38 NZST 2016
Hi guys
Thanks for your suggestions.
Todd, Joylon is %100 right. The StringList was added as a debug mechanism.
The issue is that I create an XML (Utf-8 so I can deal with foreign
languages). When I load back in the XML I am getting errors in my
code (which has worked fine prior to rebuilding in Xe2). I opened the
xml in the Edge browser (because I like the way XML is displayed) and
noted what looked like corruption in the Mime text of the images.
Opening the XML in Notepad++ showed corruption (overwritten characters
and I couldn't arrow through them). So I assumed the issue was with the
Mime text.
After Joylon and Peter's suggestions about the BOM preamble I had
another look and they are right. The only difference is the preamble.
I knew about this but had assumed it not to be an issue as my XML has
the preamble too and only the Mime appears corrupt. However I have just
re tested importing the XML file and if I ignore the error message
(changed my code to keep going) the images are loading and displaying
correctly.
I now thing that
a) The mime is correct
b) Edge browser has trouble displaying long string text on a single line
c) There is some sort of bug in Notepad++ that causes problems on Utf-8
BOM encoded text files with long single line files
d) the problem is with another (none Mime field in my file)
Thanks for all your help, I spent ages on this but was getting tripped
up by false assumptions.
Cheers
Rob
On 10/08/2016 8:37 AM, Jolyon Direnko-Smith wrote:
> @Todd - looking at the code I suspect that the stringlist is in there
> as a temporary facility to dump the encoded data to a file for
> inspection/diagnostics (the function returns the encoded string as
> it's result as well as writing it out to a file using a string list
> for convenience).
>
> I think in this case, the BOM behaviour of a string list has caused a
> bit of Heisenbergnostics - the thing observing the thing has changed
> the thing. :)
>
> Using a file/string stream to output the resulting string might have
> avoided introducing the BOM complication, but if this is a temporary
> diagnostic facility, and if it is the BOM which is the problem, then
> just turning off the BOM facility on the string list does the job just
> as nicely.
>
> :)
>
> On 9 August 2016 at 18:35, Todd Martin <todd.martin.nz at gmail.com
> <mailto:todd.martin.nz at gmail.com>> wrote:
>
> Why are you using a TStringlist at all?
>
> If you're encoding to Base64, encoding to UTF8 is meaningless.
>
> Todd
>
>
> On 9 Aug 2016 5:54 p.m., "Peter Ingham"
> <ping_delphilist at 3days.co.nz <mailto:ping_delphilist at 3days.co.nz>>
> wrote:
>
> If you look at the output file in a hex editor, what do you see?
>
> If the first 3 bytes are |0xEF,0xBB,0xBF, then that is a "Byte
> Order Mark".|
>
> |UTF-8 is a method for encoding UNICODE characters using 8-Bit
> Bytes.|
>
> |A file containing 7-Bit ASCII (high-order bit of every
> character zero), when converted to UTF-8 is likely to look|||
> very similar. For anything else, all bets are off. Treating
> them as universally equivalent is asking for trouble.
>
> Many text editors will look for Byte Order marks (of varying
> types) and use them without displaying them (e.g: see
> https://en.wikipedia.org/wiki/Byte_order_mark#UTF-8
> <https://en.wikipedia.org/wiki/Byte_order_mark#UTF-8>).
>
>
> Regards
>
> On 9/08/2016 5:01 p.m., Robert Martin wrote:
>> Hi guys
>>
>>
>> I have been struggling to get some basic Mime encoding working, I have
>> the following code which I use to Mime64 Encode a picture contained in a
>> TImage component....
>>
>> Base64 := TMime64.create;
>> try
>> MemoryStream := TMemoryStream.Create;
>> MemoryStream.Position := 0;
>> Image.Picture.Graphic.SaveToStream(MemoryStream);
>>
>> ReportImage.ImageMime :=
>> Base64.Encode_New(MemoryStream);
>> .....
>>
>> Function shown below...
>>
>>
>>
>> function TMime64.Encode_New(aSourceStream: TMemoryStream): String;
>> var
>> IdEncoderMIME : TIdEncoderMIME;
>> Sl : TStringList;
>> begin
>> Result := '';
>> try
>>
>> IdEncoderMIME := TIdEncoderMIME.Create(nil);
>> sl := TStringList.Create;
>> try
>> aSourceStream.Position := 0;
>> Result := IdEncoderMIME.EncodeStream(aSourceStream);
>>
>> sl.Text := Result;
>> sl.SaveToFile('d:\d\a.txt', TEncoding.UTF8);
>> finally
>> IdEncoderMIME.Free;
>> sl.Free;
>> end;
>> except
>> on E : Exception do begin
>> raise EMimeError.Create(E.Message);
>> end;
>> end;
>> end;
>>
>> The issue is that when I try to save the results in a UTF8 formatted
>> file (the destination is to be a UTF-8 formatted XML file), there are
>> 'bad' characters in the file which are invisible in Notepad++ but are
>> present.
>>
>> If I save without specifying the file encoding (
>> sl.SaveToFile('d:\d\a.txt') instead of sl.SaveToFile('d:\d\a.txt',
>> TEncoding.UTF8) ) I have what appears to be a clean ASCII file. My
>> understanding is that ASCII characters have the same byte value (0-127)
>> in an ASCII formatted file or a UTF-8 formatted file so I don't
>> understand why the values would change.
>>
>> Any suggestions.
>>
>>
>> p.s. I have to be able to save the file as UTF-8 because that is what
>> the destination XML is encoded in. Currently it is 'corrupt' because of
>> the 'bad' characters.
>>
>> p.p.s TIdEncoderMIME.EncodeStream returns a String. I am using Delphi Xe2.
>>
>> p.p.p.s I know it is something stupid I am doing !
>>
>>
>>
>>
>> Thanks
>> Rob
>>
>>
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