[Resolved] help with calculating incremental user id, please

[kubik]

hi everybody!

i'm sweating over my very first php script ... and so far g things are going reasonably well ... here's the quick scenario ...

• the entire thing is going to be some sort of survey
• user comes to index.php and chooses one of two options (radio buttons)
• submitting the form calls my "setup.php" script (see script below)
• the script reads the "user_id.txt" file (contains only a number - for the first user, this would be "0")
• the script increments this number by "1" and replaces the old id in "user_id.txt"
• the script then creates a new text file with the composite file name "user_"."$newid".".txt" and writes a bunch of info

the script itself works perfectly fine (i'm very surprised) but for the reading of "$previd" (line 6) and the calculation of "$newid" (line 7) ... for some reason, i'm quite stuck since the result is always "1", no matter how often i run the script ... (argh.)

any helping hand you guys could lend to help me fix this would be very, very much appreciated!! 😃

cheers,

kubik

PHP:

• [FONT=courier new]
  1 : <?php
  2 : //part 1 - open "user_id.txt" file, read old id, calculate new id, replace old id with new one, close
  3 : //
  4 : $filename = "user_id.txt";
  5 : $handle = fopen ($filename, "w+");
  6 : $previd = fread ($handle, filesize($filename));
  7 : $newid = $previd + 1;
  8 : fwrite ($handle, $newid);
  9 : fclose ($handle);
  10: //
  11: //part 2 - create unique user id file, write info
  12: //
  13: $filename1 = "user$newid.txt";
  14: $handle1 = fopen ("user$newid.txt", "a+");
  15: $fcontentd = date ("d.m.Y, H:i:s");
  16: $fcontentip = $REMOTE_ADDR;
  17: $fcontentb = $HTTP_USER_AGENT;
  18: fwrite ($handle1, "$fcontentd"."\n"."\n"."$fcontentip"."\n"."\n"."$fcontentb"."\n"."\n");
  19: //
  20: //part 3 - if (on previous page) the user chose "opt2" goto "setup_b.php", else (opt1) goto "survey01.php"
  21: // document option and close file
  22: //
  23: if ($option == 2) {
  24: fwrite ($handle1, "survey option 2 - personalized"."\n"."\n");
  25: header ("Location: setup_b.php");
  26: } else {
  27: fwrite ($handle1, "survey option 1 - automated"."\n"."\n");
  28: header ("Location: survey01.php");
  29: }
  30: fclose ($handle1);
  31: ?>[/FONT]

[ahundiak]

fopen($filename,'w+')
will actually delete the file then open it.
http://www.php.net/manual/en/function.fopen.php

I think you need to open for file for reading, grab the idea, close the file and reopen for writing and write the new id.

You could also use file($filename) to just read the file in without opening it. Just be aware you get an array back. Manual has details.

[kubik]

hi ahundiak,

thank you very much for your help!! that was the hint i couldn't have figured out on my own if my life had depended on it (open for reading -> grabbing id -> closing -> open for writing), i slightly modified your tip by simply reopening the file using [FONT=courier new]fopen ($filename, "w")[/FONT] which truncates its length to zero.

script works like a charm now! 😃

thanks again + cheers,

kubik

(just in case it might be useful for someone else ... this works just fine 🙂 )

PHP:

• [FONT=courier new]
  <?php
  //part 1 - open "user_id.txt" file, read old id, calculate new id, close "user_id.txt"
  //reopen "user_id.txt" and truncate file length to "0", write new id, close file
  //
  $filename = "user_id.txt";
  $handle = fopen ($filename, "r");
  $previd = fread ($handle, filesize($filename));
  $newid = $previd + 1;
  fclose ($handle);
  $handle = fopen ($filename, "w");
  fwrite ($handle, $newid);
  fclose ($handle);
  //
  //part 2 - create unique user id file, write info
  //
  $filename1 = "user_$newid.txt";
  $handle1 = fopen ($filename1, "a+");
  $fcontentd = date ("d.m.Y, H:i:s");
  $fcontentip = $REMOTE_ADDR;
  $fcontentb = $HTTP_USER_AGENT;
  fwrite ($handle1, "$fcontentd"."\n"."\n"."$fcontentip"."\n"."\n"."$fcontentb"."\n"."\n");
  //
  //part 3 - if (on previous page) the user chose "opt2" goto "setup_b.php", else (opt1) goto "survey01.php"
  // document option and close file
  //
  if ($option == 2) {
  fwrite ($handle1, "survey option 2 - personalized"."\n"."\n");
  header ("Location: setup_b.php");
  } else {
  fwrite ($handle1, "survey option 1 - automated"."\n"."\n");
  header ("Location: survey01.php");
  }
  fclose ($handle1);
  ?>[/FONT]