Checking if a URL is valid (Views: 714)
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Problem/Question/Abstract: You are given a list of URLs, which may or may not include the file name- eg www.msn.com instead of www.msn.com/default.asp. You want to check them automatically. The function provided does this. Answer: This function will check the url with or without a file. The only precondition is that you must be online. URLs can be given with or without the http:/ prefix - its adds the http:// prefix if absent- this is vital for the internetOpenUrl function which also supports FTP:// and gopher:// I am checking the return code for '200' or '302' - redirects but you may wish to check for other codes. Just modify the result := line to accomodate these codes. uses wininet; function CheckUrl(url: string): boolean; var hSession, hfile, hRequest: hInternet; dwindex, dwcodelen: dword; dwcode: array[1..20] of char; res: pchar; begin if pos('http://', lowercase(url)) = 0 then url := 'http://' + url; Result := false; hSession := InternetOpen('InetURL:/1.0', INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0); if assigned(hsession) then begin hfile := InternetOpenUrl( hsession, pchar(url), nil, 0, INTERNET_FLAG_RELOAD, 0); dwIndex := 0; dwCodeLen := 10; HttpQueryInfo(hfile, HTTP_QUERY_STATUS_CODE, @dwcode, dwcodeLen, dwIndex); res := pchar(@dwcode); result := (res = '200') or (res = '302'); if assigned(hfile) then InternetCloseHandle(hfile); InternetCloseHandle(hsession); end; end; |