Can't use function return value in write context

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Can't use function return value in write context

lightnb

I have a function that's supposed to query mysql with a zip code, and generate an html <select> box with possible cities. Instead, it crashes the site and gives this error:

Fatal error: Can't use function return value in write context in /home/rahl/public_html/RVM/include/functions.php on line 298

The content of the function is:

function zip_code_city_handler($zip)
	{

global $zip;

$query = "SELECT * FROM zip WHERE zip = '$zip'";

$result = safe_query($query);

if (mysql_num_rows($result) = 1)
	{
	$city_select = "<select>";
	while($row = mysql_fetch_array($result))
		{
		$city_select .= "<option>".$row['city']."</option>";
		}
	$city_select .= "</select>";
	}
	else
	{
	$row = mysql_fetch_array( $result );
	$city_select = $row['city'];
	}

	return $city_select;
}

I've never gotten this error before and I'm not really sure what it means...

Any help is appreciated, as always.

Thanks,

Nick

NightShift58

It means that your function is returning an unspeakable value - make that unwritable value. True and false are examples of that.

You have a coding error in the function:

if (mysql_num_rows($result) = 1)

This resolves to a value assignment and not a condition test. Use "==" instead of "=".

lightnb

oops... That fixed the error. Thank you

Now I'm getting:

# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query=query

I think this is causing the problem:

	if(empty($error))
		{
		$query = mysql_query("UPDATE Users SET title='$title',last_name='$l_name',first_name='$f_name',zip='$zip' WHERE handle='$user_name'") 
		or die(mysql_error());  

	safe_query($query);

NightShift58

Change the function safe_query as follows:

function safe_query ($query = "")
    {
    if(empty($query))
        {
        return FALSE;
        }
    $result = mysql_query($query)
        or die("I've Failed You: <li>errorno=".mysql_errno()."<li>error=".mysql_error()."<li>query=".$query);
    return $result;
    }

(Missing "$" in final "query".)

lightnb

wow. how do you always find the needle in the haystack? (or the missing $ in 3000 lines of code)

I now get:

query=1

So I'm guessing the query got screwed up somewhere...

NightShift58

On second thought, I would change it to this:

function safe_query ($query = "") {
  $result = FALSE;
  if (!empty($query)) {
    $result = @mysql_query($query);
    if (!$result) {
      echo "I've Failed You:<br>";
      echo "<li>Script Name: " . $_SERVER['PHP_SELF'];
      echo "<li>Include File: " . __FILE__;
      echo "<li>errorno=" . mysql_errno();
      echo "<li>error="   . mysql_error();
      echo "<li>query= "  . $query;
      exit;
    }
  }
  return $result;
}

lightnb

Error now reads:

I've Failed You:
# Script Name: /RVM/registration/register2.php
# Include File: /home/rahl/public_html/RVM/include/functions.php
# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query= 1

lightnb

register2.php reads:

<?PHP

$location_ID ="RVM Registration"; // Set the location variable 

// Include Database connection information 

Require('../include/SQL_connect.php');

// Include the shared registration functions

Require('../include/functions.php');

// Include the registration forms functions page

Require('../registration/registration_forms.php');


// Check to see if the form has been submited


if (isset($HTTP_POST_VARS["submit"])) //if the form has been submited, do the following
	{

$title = $HTTP_POST_VARS["title"];
$f_name = $HTTP_POST_VARS["f_name"];
$l_name = $HTTP_POST_VARS["l_name"];
$zip = $HTTP_POST_VARS["zip"];	

$ret_error = form_validator_names($title, $l_name, $f_name, $zip);

registration_form_2();

}else //(if the form has not be submited)
{
$user_name = $HTTP_GET_VARS["user_name"];
registration_form_2(); //display the form
}

?>

NightShift58

Try this:

function safe_query ($query = "") {
  $result = FALSE;
  if (!empty($query)) {
    $result = @mysql_query($query);
    if (!$result) {
      echo "I've Failed You:<br>";
      echo "<li>Script Name: " . $_SERVER['PHP_SELF'];
      echo "<li>Include File: " . __FILE__;
      echo "<li>errorno=" . mysql_errno();
      echo "<li>error="   . mysql_error();
      echo "<li>query= "  . $query;
      var_dump(debug_backtrace());
      exit;
    }
  }
  return $result;
}

lightnb

I've Failed You:
# Script Name: /RVM/registration/register2.php
# Include File: /home/rahl/public_html/RVM/include/functions.php
# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query= 1array(2) { [0]=> array(4) { ["file"]=> string(48) "/home/rahl/public_html/RVM/include/functions.php" ["line"]=> int(217) ["function"]=> string(10) "safe_query" ["args"]=> array(1) { [0]=> &bool(true) } } [1]=> array(4) { ["file"]=> string(53) "/home/rahl/public_html/RVM/registration/register2.php" ["line"]=> int(29) ["function"]=> string(20) "form_validator_names" ["args"]=> array(4) { [0]=> &string(3) "Dr." [1]=> &string(4) "last" [2]=> &string(4) "nick" [3]=> &string(5) "23456" } } }

NightShift58

# array(2) {
#   [0]=> array(4) {
#     ["file"]=> string(48) "/home/rahl/public_html/RVM/include/functions.php"
#     ["line"]=> int(217)
#     ["function"]=> string(10) "safe_query"
#     ["args"]=> array(1) {
#       [0]=> &bool(true)
#     }
#   }
#   [1]=> array(4) {
#     ["file"]=> string(53) "/home/rahl/public_html/RVM/registration/register2.php"
#     ["line"]=> int(29)
#     ["function"]=> string(20) "form_validator_names"
#     ["args"]=> array(4) {
#       [0]=> &string(3) "Dr."
#       [1]=> &string(4) "last"
#       [2]=> &string(4) "nick"
#       [3]=> &string(5) "23456"
#     }
#   }
# }

The calling line is Line 29 in register2.php with the values listed.

NightShift58

lightnb wrote:
wow. how do you always find the needle in the haystack? (or the missing $ in 3000 lines of code)

Probably because I make more mistakes than you do...

NightShift58

function safe_query ($query = "") {
  $result = FALSE;
  if (!empty($query)) {
    $result = @mysql_query($query);
    if (!$result) {
      echo "I've Failed You:<br>";
      echo "<li>Script Name: " . $_SERVER['PHP_SELF'];
      echo "<li>Include File: " . __FILE__;
      echo "<li>errorno=" . mysql_errno();
      echo "<li>error="   . mysql_error();
      echo "<li>query= "  . $query;
      echo "<pre>";
      print_r(debug_backtrace());
      echo "</pre>";
      exit;
    }
  }
  return $result;
}

It should make the display a bit more readable. Make sure that you only use this when testing...

lightnb

Line 29 reads:

$ret_error = form_validator_names($title, $l_name, $f_name, $zip);

and the variables:

[0]=> &string(3) "Dr."
#       [1]=> &string(4) "last"
#       [2]=> &string(4) "nick"
#       [3]=> &string(5) "23456"

are correct as well.

I don't see where it's getting "Query=1" though...

lightnb

I've Failed You:
# Script Name: /RVM/registration/register2.php
# Include File: /home/rahl/public_html/RVM/include/functions.php
# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query= 1

Array
(
    [0] => Array
        (
            [file] => /home/rahl/public_html/RVM/include/functions.php
            [line] => 220
            [function] => safe_query
            [args] => Array
                (
                    [0] => 1
                )

    )

[1] => Array
    (
        [file] => /home/rahl/public_html/RVM/registration/register2.php
        [line] => 29
        [function] => form_validator_names
        [args] => Array
            (
                [0] => Dr.
                [1] => last
                [2] => nick
                [3] => 23456
            )

    )

)

So does:

[args] => Array
                (
                    [0] => 1
                )

mean that the safe_query function itself is setting the value to one?

NightShift58

This could be part of the problem:

function cleanup_input ($value = "", $presrve = "", $allowed_tags = "")

{

Global $continue;

if(empty($preserve))
    {
    $value = strip_tags($value, $allowed_tags);
    }
$value = htmlspecialchars($value);
return $value;
}

You've got 2 spellings for "$preserve".

EDIT: Why are you using "global $continue". It's not being bused for anything in this function.

NightShift58

Change to:

function cleanup_input ($value="", $preserve="", $allowed_tags="") {
  if($preserve == "") {
    $value = strip_tags($value, $allowed_tags);
  }
  return htmlspecialchars($value);
}

lightnb

NightShift58 wrote:
Why are you using "global $continue". It's not being bused for anything in this function.

You know, just in case.... Honestly, I don't know why that's there, considering a $continue variable isn't used in the entire site....

I've modified the cleanup_input function as sugguested but still get an error:

I've Failed You For The Last Time:
# Script Name: /RVM/registration/register2.php
# Include File: /home/rahl/public_html/RVM/include/functions.php
# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query= 1

Array
(
    [0] => Array
        (
            [file] => /home/rahl/public_html/RVM/include/functions.php
            [line] => 217
            [function] => safe_query
            [args] => Array
                (
                    [0] => 1
                )

    )

[1] => Array
    (
        [file] => /home/rahl/public_html/RVM/registration/register2.php
        [line] => 29
        [function] => form_validator_names
        [args] => Array
            (
                [0] => Dr.
                [1] => Lastname
                [2] => Nick
                [3] => 23456
            )

    )

)

NightShift58

Try this:

function safe_query ($query="") {
  echo "<hr>$query<hr>";
  $result = FALSE;
  if (!empty($query)) {
    $result = @mysql_query($query);
    if (!$result) {
      echo "I've Failed You:<br>";
      echo "<li>Script Name: " . $_SERVER['PHP_SELF'];
      echo "<li>Include File: " . __FILE__;
      echo "<li>errorno=" . mysql_errno();
      echo "<li>error="   . mysql_error();
      echo "<li>query= "  . $query;
      echo "<pre>";
      print_r(debug_backtrace());
      echo "</pre>";
      exit;
    }
  }
  return $result;
}

lightnb

is the contents of the query it lists at the top of the screen.

Somehow it's getting a value of 1 from somewhere.