🚀 go-pugleaf

"melk" <NOSPAMi_melk@libero.it> wrote in message
news:4242c7fd@newsgroups.borland.com...

> I have to write out to the ASP page directly a JPEG byte array,

There are several steps you have to do in order for that to work.

1) prepare a VARIANT that contains a SAFEARRAY that contains the raw bytes

2) set the IResponse::ContentType property to "image/jpeg".

3) call IResponse::AddHeader() to add an additional "Content-Length" header
value.

4) pass the VARIANT to IResponse::BinaryWrite().

> first I tried to looking for a Method of IRepsonse Interface
"ContentStream"
> that I saw use in Delphi code but i can't find it in BC++ 6...

There is no such property/method in IResponse.  The Delphi code must have
been using something else.

> this method accept a Stream type like one that exit from
TJPEGImage::SaveToStream..

You are probably looking at code realted to the Indy library
(http://www.indyproject.org).  That has nothing to do with ASP programming.

> finaly I tried to use IResponse::binaryWrite without effect, it
> doesn't write on the page..

BinaryWrite() is what you need to use.  You probably just did not set it up
properly.  Try the following code:

    #include <memory>

    {
        Response->Clear();
        Response->put_Buffer(VARIANT_TRUE);

        try
        {
            std::auto_ptr<TMemoryStream> MemStream(new TMemoryStream);
            JPEGImage->SaveToStream(MemStream.get());

            SAFEARRRAYBOUND bounds = {0, MemStream->Size-1};

            TVariant v;
            v.parray = ::SafeArrayCreate(VT_UI1, 1, &bounds);
            v.vt = VT_ARRAY|VT_UI1;

            if( v.parray == NULL )
                throw Exception("Cannot create the array of bytes");

            void *data = NULL;
            if( FAILED(::SafeArrayAccessData(v.parray, &data)) )
                throw Exception("Cannot access the array of bytes");

            memcpy(data, MemStream->Memory, MemStream->Size);
            ::SafeArrayUnaccessData(v.parray);

            Response->put_Status(WideString("200 OK"));
            Response->put_ContentType(WideString("image/jpeg"));
            Response->AddHeader(WideString("Content-Length"),
WideString(IntToStr(MemStream->Size)));
            Response->BinaryWrite(v);
        }
        catch(const Exception &e)
        {
            Response->Clear();
            Response->put_Status(WideString("500 " + e.Message));
        }

        Response->Flush();
    }


Gambit

Hi Thanks for your replay, I tried to use but it seems doesn't work!!! I
know that it coused by me, but I realy net Help...

this is the code you sent me with my integration...; the first time I tried
to use it, it gave me a memory write error so I only add a line to malloc
"data" before memcpy...
Now it doesn't give me any error, but no picture was write to the page...
I tried olso to get the header text from the IIS response, and it doesn't
contain the bitmap byte...

I olso tried to write to file the "data" buffer whitout pass from the
"SafeArrayAccessData(v.parray, &data)" function and it write the picture
file well!!!

        Graphics::TBitmap *bmp = new Graphics::TBitmap();
        TJPEGImage *jpg = new TJPEGImage();

        TRect re(0,0,50,50);
        bmp->Width = 100;
        bmp->Height = 100;
        bmp->Canvas->Brush->Color = clBlue;
        bmp->Canvas->FillRect(re);

        jpg->Assign(bmp);
        jpg->CompressionQuality = 30;

        Response->put_Buffer(true);
        Response->put_Expires(0);
        Response->Clear();

        try
        {
            std::auto_ptr<TMemoryStream> MemStream(new TMemoryStream);
            jpg->SaveToStream(MemStream.get());

            SAFEARRAYBOUND bounds = {0, MemStream->Size-1};

            TVariant v;
            v.parray = ::SafeArrayCreate(VT_UI1, 1, &bounds);
            v.vt = VT_ARRAY|VT_UI1;

            if( v.parray == NULL )
                throw Exception("Cannot create the array of bytes");

            void *data = NULL;

            //Get a pointer to beginning of data area in Jpeginmemory
            if( FAILED(::SafeArrayAccessData(v.parray, &data)) )
                throw Exception("Cannot access the array of bytes");

            //Copy jpeg data to it
            data = malloc(sizeof(byte)*MemStream->Size);
            memcpy(data, MemStream->Memory, MemStream->Size);

            //Unlock the data
            ::SafeArrayUnaccessData(v.parray);

            Response->put_Status(WideString("200 OK"));
            Response->put_ContentType(WideString("image/jpeg"));
            Response->AddHeader(WideString("Content-Length"),
                                   WideString(IntToStr(MemStream->Size)));

            Response->BinaryWrite(v);
            Response->End();

            free(data);
        }
        catch(const Exception &e)
        {
            Response->Clear();
            Response->put_Status(WideString("500 " + e.Message));
        }

        Response->Flush();

        delete jpg;
        delete bmp;

"melk" <NOSPAMi_melk@libero.it> wrote in message
news:42443927@newsgroups.borland.com...

> Hi Thanks for your replay, I tried to use but it seems doesn't work!!!

Just saying it doesn't work says nothing about the actual problem you are
having.

> the first time I tried to use it, it gave me a memory write
> error so I only add a line to malloc "data" before memcpy...

That was not the correct thing to do.

> I olso tried to write to file the "data" buffer whitout pass from the
> "SafeArrayAccessData(v.parray, &data)" function and it write
> the picture file well!!!

You allocated memory for the buffer yourself instead of letting
SafeArrayAccessData() do it for you.

>         Graphics::TBitmap *bmp = new Graphics::TBitmap();
>         TJPEGImage *jpg = new TJPEGImage();

Wrap those in try...catch or try..finally blocks, or use an std::auto_ptr,
to ensure the memory is freed correctly in case an exception occurs.

>             SAFEARRAYBOUND bounds = {0, MemStream->Size-1};

Change that to this instead:

    SAFEARRAYBOUND bounds;
    bounds.lLbound = 0;
    bounds.cElements = MemStream->Size;

>             data = malloc(sizeof(byte)*MemStream->Size);

Get rid of that.

>             Response->End();

You don't need to call that since Flush() is called later.

>             free(data);

Get rid of that.


Gambit

Thank you it works right!!

I'm finding a lots of difficulty to try without debuging... do you now if
there is some method to debug this kind of object?

Thanks again!!


"Remy Lebeau (TeamB)" <no.spam@no.spam.com> ha scritto nel messaggio
news:424458ef$1@newsgroups.borland.com...
>
> "melk" <NOSPAMi_melk@libero.it> wrote in message
> news:42443927@newsgroups.borland.com...
>
> > Hi Thanks for your replay, I tried to use but it seems doesn't work!!!
>
> Just saying it doesn't work says nothing about the actual problem you are
> having.
>
> > the first time I tried to use it, it gave me a memory write
> > error so I only add a line to malloc "data" before memcpy...
>
> That was not the correct thing to do.
>
> > I olso tried to write to file the "data" buffer whitout pass from the
> > "SafeArrayAccessData(v.parray, &data)" function and it write
> > the picture file well!!!
>
> You allocated memory for the buffer yourself instead of letting
> SafeArrayAccessData() do it for you.
>
> >         Graphics::TBitmap *bmp = new Graphics::TBitmap();
> >         TJPEGImage *jpg = new TJPEGImage();
>
> Wrap those in try...catch or try..finally blocks, or use an std::auto_ptr,
> to ensure the memory is freed correctly in case an exception occurs.
>
> >             SAFEARRAYBOUND bounds = {0, MemStream->Size-1};
>
> Change that to this instead:
>
>     SAFEARRAYBOUND bounds;
>     bounds.lLbound = 0;
>     bounds.cElements = MemStream->Size;
>
> >             data = malloc(sizeof(byte)*MemStream->Size);
>
> Get rid of that.
>
> >             Response->End();
>
> You don't need to call that since Flush() is called later.
>
> >             free(data);
>
> Get rid of that.
>
>
> Gambit
>
>

"melk" <NOSPAMi_melk@libero.it> wrote in message
news:424a9805@newsgroups.borland.com...

> I'm finding a lots of difficulty to try without debuging... do you now if
> there is some method to debug this kind of object?

Yes, there is a way, but not with Borland's tools, at least not entirely.
Have a look at the following article:

    http://support.microsoft.com/default.aspx?scid=kb;en-us;196378

You can probably attach the BCB debugger to the appropriate process, but
getting it to debug just the specific ASP object after that may be tricky.
To be honest, I have never tried to debug the internals of an ASP object
before, so I cannot provide you with any futher help in that area.


Gambit