how to validate a url

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  • Yang Li Ke
    #1

    how to validate a url

    Hi,

    Anyone can tell me how to validate
    if a web page is online or 404 ?

    Thanx

    Yang

    --


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    • Julien CROUZET aka c2c
      #2
      Re: how to validate a url

      Erwin Moller <since_humans_r ead_this_I_am_s pammed_too_much @spamyourself.c om> writes:
      [color=blue]
      > Yang Li Ke wrote:
      >[color=green]
      > > Hi,
      > >
      > > Anyone can tell me how to validate
      > > if a web page is online or 404 ?
      > >[/color][/color]

      A portable an reliable method :

      404 :
      02/09 16:22 root@fusion ~# telnet localhost 80 Err 1 #16
      #I send :
      HEAD /does_not_exists .php HTTP/1.0

      #I receive
      HTTP/1.1 404 Not Found
      Date: Tue, 02 Sep 2003 14:24:04 GMT
      Server: Apache/1.3.26 (Unix) PHP/4.3.3 mod_ssl/2.8.10 OpenSSL/0.9.6g
      Connection: close
      Content-Type: text/html; charset=iso-8859-1

      online :
      #I send :
      HEAD / HTTP/1.0

      #Ireceive :
      HTTP/1.1 200 OK
      Date: Tue, 02 Sep 2003 14:25:03 GMT
      Server: Apache/1.3.26 (Unix) PHP/4.3.3 mod_ssl/2.8.10 OpenSSL/0.9.6g
      Content-Location: index.html.en
      Vary: negotiate,accep t-language,accept-charset
      TCN: choice
      Last-Modified: Wed, 29 Jan 2003 10:58:19 GMT
      ETag: "381a2-a71-3e37b3cb;3f546a d9"
      Accept-Ranges: bytes
      Content-Length: 2673
      Connection: close
      Content-Type: text/html
      Content-Language: en
      Expires: Tue, 02 Sep 2003 14:25:03 GMT

      So, You can easily use it with the help of fopen(), fputs(), etc....

      Good luck.

      --
      Julien CROUZET



        Comment

        • Erwin Moller
          #3
          Re: how to validate a url

          Yang Li Ke, still there??

          What Julien suggested is maybe not working.
          Here is a little script of my, and it does not output the headers.

          Julien, do you know why I do not receive any headers this way??

          ---------------------------------


          <?
          $theurl = @$_POST["theurl"];
          ?>

          <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
          <html>
          <head>
          <title>urltes t</title>
          </head>
          <body>

          Check any URL:
          <form action="" method="POST" name="urlform">
          <input type="hidden" name="getdata" value="Y">
          <br>
          <input type=text size=40 name="theurl" value="<? echo $theurl; ?>">
          <br>
          <input type="submit" value="haal data">
          </form>

          <?
          if (isset($_POST["getdata"])) {
          // okay get the url
          // only works if track_errors = On is set in php.ini
          $php_errormsg = "";
          $handle = @fopen ($theurl, "r");
          if ($php_errormsg != "") {
          ?>
          Cannot open URL....
          <?
          } else
          {

          ?>
          <hr>
          <b>The content of <i>$theurl</i>:</b>
          <br>
          $php_errormsg= <? echo $php_errormsg; ?>
          <hr>
          <pre>
          <?
          while (!feof ($handle)) {
          $buffer = fgets($handle, 4096);
          echo htmlentities($b uffer);
          }
          fclose ($handle);
          ECHO "</pre>";
          }
          }
          ?>

          </body>
          </html>

            Comment

            • Julien CROUZET aka c2c
              #4
              Re: how to validate a url

              Erwin Moller <since_humans_r ead_this_I_am_s pammed_too_much @spamyourself.c om> writes:
              [color=blue]
              > Yang Li Ke, still there??
              >
              > What Julien suggested is maybe not working.
              > Here is a little script of my, and it does not output the headers.
              >
              > Julien, do you know why I do not receive any headers this way??
              >
              > ---------------------------------
              >
              >
              > <?
              > $theurl = @$_POST["theurl"];
              > ?>
              >
              > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
              > <html>
              > <head>
              > <title>urltes t</title>
              > </head>
              > <body>
              >
              > Check any URL:
              > <form action="" method="POST" name="urlform">
              > <input type="hidden" name="getdata" value="Y">
              > <br>
              > <input type=text size=40 name="theurl" value="<? echo $theurl; ?>">
              > <br>
              > <input type="submit" value="haal data">
              > </form>
              >
              > <?
              > if (isset($_POST["getdata"])) {
              > // okay get the url
              > // only works if track_errors = On is set in php.ini
              > $php_errormsg = "";
              > $handle = @fopen ($theurl, "r");[/color]

              Here, you open the socket
              [color=blue]
              > if ($php_errormsg != "") {
              > ?>
              > Cannot open URL....
              > <?
              > } else
              > {
              >
              > ?>
              > <hr>
              > <b>The content of <i>$theurl</i>:</b>
              > <br>
              > $php_errormsg= <? echo $php_errormsg; ?>
              > <hr>
              > <pre>
              > <?
              > while (!feof ($handle)) {
              > $buffer = fgets($handle, 4096);[/color]

              here you read the socket till the server close the connection
              [color=blue]
              > echo htmlentities($b uffer);
              > }
              > fclose ($handle);
              > ECHO "</pre>";
              > }
              > }
              > ?>
              >
              > </body>
              > </html>[/color]

              You must send "HEAD /page.php HTTP/1.0\n\n" to have an answer.

              And be careful of "while (!feof(" cause sometimes apache
              doesn't close the connection after the answer, and wait for
              another query during {x} seconds.

              Close you socket once you received the status.

              Good luck again =)

              --
              Julien CROUZET

                Comment

                • Julien CROUZET aka c2c
                  #5
                  Re: how to validate a url

                  "Yang Li Ke" <yanglike@sympa tico.ca> writes:
                  [color=blue][color=green]
                  > >$php_errorms g = "";
                  > >$handle = @fopen ($theurl, "r");
                  > >if ($php_errormsg != "") {[/color]
                  >
                  > I dont really understand how will the $php_errormsg get a value if u dont
                  > put any $php_errormsg = something;
                  >[/color]

                  "The previous error message: $php_errormsg
                  $php_errormsg is a variable containing the text of the last error
                  message generated by PHP. This variable will only be available within
                  the scope in which the error occurred, and only if the track_errors
                  configuration option is turned on (it defaults to off)."

                  It is a reserved variable.

                  --
                  Julien CROUZET

                    Comment

                    • Erwin Moller
                      #6
                      Re: how to validate a url

                      Thanks for explaining Julien.
                      :-)


                        Comment

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