Mega Code Archive
Checking if a URL is valid
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Title: Checking if a URL is valid
Question: 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;
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