Code archives/Networking/Web Page Exist?
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Function to see if a web page exists | |||||
; Web page/file exists code v2 by The Prof for Blitzers everywhere! ; ; This code will check to see if a web page exists. This is handy ; if you want to create your own error 404 pages dynamically in Blitz. ; Tested with 5 ISP web servers - seems OK - if problems let me know. ; Graphics 640,200,32,2 WebPage$="http://www.blitzbasic.com/index.html" ;case sensitive! If WebFileExists(WebPage$)=True Text 10,10,WebPage$+" exists!" Else Text 10,10,WebPage$+" Does not appear to exist :-(" EndIf WaitKey():End ; ***************************************************** Function WebFileExists(webFile$) ; Checks to see if the Web File (webfile$) exists on the net ; Modified from Blitz Get Deluxe - Thanks! ; Returns TRUE if the file exists, otherwise FALSE If Left (webFile$, 7) = "http://" Then webFile$ = Right (webFile$, Len (webFile$) - 7) slash = Instr (webFile$, "/") If slash webHost$ = Left (webFile$, slash - 1) webFile$ = Right (webFile$, Len (webFile$) - slash + 1) Else webHost$ = webFile$:webFile$ = "/" EndIf www = OpenTCPStream (webHost$, 80) If www WriteLine www, "GET " + webFile$ + " HTTP/1.1" WriteLine www, "Host: " + webHost$ WriteLine www, "User-Agent: BlitzWebFileExists" WriteLine www, "Accept: */*" WriteLine www, "" header$ = ReadLine (www) If TextInString("404",Header$)=False Return True EndIf CloseTCPStream www Else Return False EndIf End Function ; ************************************************* Function TextInString(t1$,t2$) ;Returns True IF t1$ is within the string t2$ ;i.e. I=IsTextInString("he","hello") will return TRUE ; because 'he' is within 'hello' L1=Len(t1$):L2=Len(t2$) For p=1 To (L2-L1+1) s$=Mid$(t2$,p,L1) If s$=t1$ Return True EndIf Next End Function |
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