Title: Decorate url`s (plain text to HTML conversion)
Question: How to decorate url's while plain text to HTML conversion (replace http://delphi3000.com with delphi3000.com)
Answer:
There are two ways.
The tradional one - You must make full featured text parser. This is an awful peace of work ! For example, try to implement rules for URL search ;)
The second - look at the text from bird's eye view with help of regular expressions engine. Your application will be implemented very fast and will be robust and easy to support !
Unfortunately, Delphi component palette contains no TRegularExpression component. But there are some third-party implementations.
I'll use in my examples the TRegExpr (You can download it from http://anso.virtualave.net/delphi_stuff.htm).
uses
RegExpr;
type
TDecorateURLsFlags = (durlProto, durlAddr, durlPort, durlPath, durlBMark, durlParam);
TDecorateURLsFlagSet = set of TDecorateURLsFlags;
function DecorateURLs (const AText : string;
AFlags : TDecorateURLsFlagSet = [durlAddr, durlPath]
) : string;
const
URLTemplate =
'(?i)'
+ '('
+ '(FTP|HTTP)://' // Protocol
+ '|www\.)'
+ '([\w\d\-]+(\.[\w\d\-]+)+)' // TCP addr / domain name
+ '(:\d\d?\d?\d?\d?)?' // port number
+ '(((/[%+\w\d\-\\\.]*)+)*)' // unix path
+ '(\?[^\s=&]+=[^\s=&]+(&[^\s=&]+=[^\s=&]+)*)?' // request params
+ '(#[\w\d\-%+]+)?'; // bookmark
var
PrevPos : integer;
s, Proto, Addr, HRef : string;
begin
Result := '';
PrevPos := 1;
with TRegExpr.Create do try
Expression := URLTemplate;
if Exec (AText) then
REPEAT
s := '';
if CompareText (Match [1], 'www.') = 0 then begin
Proto := 'http://';
Addr := Match [1] + Match [3];
HRef := Proto + Match [0];
end
else begin
Proto := Match [1];
Addr := Match [3];
HRef := Match [0];
end;
if durlProto in AFlags
then s := s + Proto; // Match [1] + '://';
if durlAddr in AFlags
then s := s + Addr; // Match [2];
if durlPort in AFlags
then s := s + Match [5];
if durlPath in AFlags
then s := s + Match [6];
if durlParam in AFlags
then s := s + Match [9];
if durlBMark in AFlags
then s := s + Match [11];
Result := Result + System.Copy (AText, PrevPos,
MatchPos [0] - PrevPos) + '' + s + '';
PrevPos := MatchPos [0] + MatchLen [0];
UNTIL not ExecNext;
Result := Result + System.Copy (AText, PrevPos, MaxInt); // Tail
finally Free;
end;
end;
Note, that You can easely extract any part of URL (see AFlags parameter).
Conclusion
"Free Your mind" ((c) The Matrix ;)) and You'll find many other tasks there regular expressions can save You incredible part of stupid coding work !
P.S. Sorry for terrible english. My native language is Pascal ;)