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Getting image dimensions and size over HTTP with TNMHTTP component

Hi There,

I am attempting to get image information by requesting the image header via HTTP using the TNMHTTP component. I don't want to download the whole image to find out this information to save bandwidth.

There is a command:
http1.head('http://path.to/image.jpg');

But I cant seem to find where to get the image dimension and file size information out of this.

I notice that many browsers can tell you the size and dimensions of an image before it downloads it (without the image size being set in the HTML even).

Thanks in advance
Pea

ASKER CERTIFIED SOLUTION

Eddie Shipman

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Eddie Shipman

There was no need to post a second question. I would have the one deleted where you
do not accept an answer..

Anyway, Here is how to do it with Indy components:

function GetFileSize(AURL: String): Integer;
var
idHTTP1: TidHTTP;
begin
Result := 0;
idHTTP1 := TidHTTP.Create(nil);
try
idHTTP1.Head(AURL);
Result := idHTTP1.Response.ContentLength;
finally
idHTTP1.Free;
end;
end;

Now with NMHTTP:

function GetFileSize(AURL: String): Integer;
var
NMHTTP1: TNMHTTP;
i: Integer;
s: String;
slHeader: TStringList;
begin
slHeader := TStringList.Create;
Result := 0;
NMHTTP1: TNMHTTP.Create(nil);
try
NMHTTP1.InputFileMode := False;
NMHTTP1.Head(AURL);
slHeader.Text := NMHTTP1.Header;
for i := 0 to slHeader.Count-1 do
if Pos('Length', slHeader[i]) > 0 then
s := slHeader[i];
Result := StrToInt(Trim(Copy(s, 16, Length(S))));
finally
NMHTTP1.Free;
slHeader.Fre;
end;
end;

Eddie Shipman

Please accept the answer if it helped you solve your problem. That is the spirit of this forum.

petervullings

ASKER

Thanks Eddie. I'm well aware of the spirit of it, being a contributer myself (though a little infrequent). Thanks for the reminder :)

Eddie Shipman

I still have found no way to get the dimensions without looking at the IMG tag. But if the IMG tag doesn't
have the dimensions in it, you'd be out of luck.