i have the following if-clause:
if(empty($var)){
$errors[]="Failure";
}
this is for a form that will be display an errormessage when a user has made no entries. i would like to hide this field when a user has made something specific so that he cant see this input field. this div will only being displayed when another variable is set. because of the "empty" problem i got the errormessage even when there is no inputfield. so my question is:
how can i add further terms to that clause that it will be like:
if(empty($var) only when $var2===true ){
$errors[]="Failure";
}
i already tried to use && but this doesn't work the correct way. thats why i'm asking and thought maybe there is another way. thanks to all.
Try:
if(empty($var) AND $var2) {
$errors[]="Failure";
}
If $var is empty and $var2 is TRUE it will be inside the if condition. did you mean something like that
Probably $var2 is 1 and not true, because in other case this need to work
if(empty($var) && $var2===true){
$errors[]="Failure";
}
Try
if(empty($var) && $var2==true){
$errors[]="Failure";
}
== instead of === or check for logical bugs.
Related
I can't understand that if sentence. Why can't I just check if $view is set? 2 more questions -What does "$_GET("$view")!" "!" sign mean there? What does ! change? Moreover, why does it equal = " "?
<?php
$myurl=htmlspecialchars($_SERVER["PHP_SELF"]);
$view="";
if(isset($_GET["$view"]) && $_GET("$view")! = "") { $view =$_GET["$view"];};
include(head.html);
switch($view] {
case "" :
include(main.html);
break;
case "people" :
include(people.html);
break;
case:"contact":
include(contact.html);
break;
default :
include(404.html);
break;
};
include_once(foot.html;
?>
Thanks for all the help
I think you messed up your code. This will not execute, due to numerous errors. The if statement is probably
if(isset($_GET[$view]) && $_GET[$view] != "")
Ie, first check that the $view key exists, then check that key it is not empty. Note the difference between a key that does not exist, and a key that exist but is empty, and why you check for both in this case.
Why can't I just check if $view is set?
Because apparently the author of that code didn't want the empty string to be valid. This will be the case if, say, there is a field called $view and the user does not put anything in it.
Actually, you could do that, since $view is initialized to the empty string anyway! This code was probably copy/pasted or written by a novice.
What does ! change?
It's actually !=, written in a confusing way. These two are the same:
&& $_GET("$view")! = "")
&& $_GET("$view") != "")
Also, your code has a bug. $_GET("$view") is not valid, the () should be []. So, here is the corrected and readable code:
if (isset($_GET["$view"]) && $_GET["$view"] != "") {
$view = $_GET["$view"];
}
Also:
switch($view] // ...what is this?
include_once(foot.html; // and this?
case:"contact": // ummmm
$view="";
if(isset($_GET["$view"]) && $_GET("$view")! = "") { $view =$_GET["$view"];};
You actually set $view=""; as an empty parameter
There for isset($_GET["$view"] looks like this isset($_GET[""]
You whole if statement with the above code is ignored
Likewise your switch($view); also looks like switch("")
This means only your first case will be executed no matter what you have in your $_GET
Check this portion of your code too for errors. the colon after case needs to be removed
case:"contact":
include(contact.html);
break;
For first, use correctly [] and (). Then you have to learn about operators: http://www.w3schools.com/php/php_operators.asp
For now your code is non-sense.
I am in a very puzzling situation. Intially when an user visits a particular page, a popup is shown. User can accept it or decline it. When a user declines it, after 5 page visits, the pop up is again shown to user. This part is working perfectly. When user clicks ok, an ajax call is made and the SESSION variable is set to ok. Lets say initially $_SESSION['count'] = 0. I have two condition statements.
if($_SESSION['count']%5 === 0)
{ // do something
}
elseif($_SESSION['count'] === "ok")
{ // do something
}
Now when an user press ok, an ajax call is made updating $_SESSION['count'] = "ok".
When the user again reloads the page, condition if($_SESSION['count']%5 === 0) gets true even though $_SESSION['count'] is now ok. Later after much experimenting, i came to know that in php i am able to divide or find modulus string by number which will result in zero. How can i handle this?
You can use is_numeric to check if it is a count or 'ok'
http://php.net/manual/en/function.is-numeric.php
if(is_numeric($_SESSION['count']) && $_SESSION['count']%5 === 0)
{ // do something
}
elseif($_SESSION['count'] === "ok")
{ // do something
}
Though generally, I would set ok to be the value of a different variable in $_SESSION as a best practice. If I was looking at the code I would find it very odd to see something called count having a string value.
PHP is very good at implicit casting.
A solution to your issue is simply re-arrange your if else tree.
if($_SESSION['count'] === "ok")
{
// do something
}
elseif($_SESSION['count'] % 5 === 0)
{
// do something
}
Readability
Something to bare in mind, is that a variable count should really contain a value. Perhaps using a different variable might make your code a little less confusing to a reader.
In php, (int) "some string" == 0, so check if $_SESSION['count'] is an integer (e.g. using is_numeric()) before doing the modulus.
Check this working example. It may help:
if(!isset($_SESSION['foo'])) {
$_SESSION['foo'] = 0;
} else {
$_SESSION['foo']++;
}
var_dump($_SESSION['foo']%3);
if(is_numeric($_SESSION['count']) AND $_SESSION['count']%5 === 0)
{ // do something
}
elseif($_SESSION['count'] === "ok")
{ // do something
}
if((isset($_GET[example]))&&($_GET['example']=='somevalue')){ ... }
OR
if((!empty($_GET[example]))&&($_GET['example']=='somevalue')){ ... }
OR just
if($_GET['example']=='somevalue'){ ... }
I am asking that why I have seen many example where people check first if $_GET['example'] is set and then if $_GET['example']=='somevalue' ( first and second example above ).
I don't understand why not just use the last solution ( if $_GET['example']=='somevalue' then $_GET['example'] is obviously set ).
This question refers to any other variable ( $_POST, $_SERVER, ecc ).
if((isset($_GET[example]))&&($_GET['example']=='somevalue')){ ... }
Is the right one, you want to know that the "variable" exists (or is set) in order to use it. Empty just checks wether it has data of any kind or not.
For example:
<?php
$foo= 0;
if (empty($foo)) { // True because $foo is empty
echo '$foo is either 0, empty, or not set at all';
}
if (isset($foo)) { // True because $foo is set
echo '$foo is set even though it is empty';
}
if (isset($var)) { // FALSE because $var was not declared before
...
}
?>
The differences between isset and empty are subtle but important. They are most relevant when used alone. If you are checking that a variable exists and is a truethy value (e.g. any string that is not all spaces or 0s) you can use either interchangeably.
When to use isset
Use isset when it's important to know if the variable has been defined and is not null:
if (isset($maybeExistsMaybeNull)) {
// variable defined and is not NULL
}
When to use !empty
Use !empty when it's important to know if the variable has be defined and is truthy
if (!empty($mightBeEmpty)) {
// variable defined, and isn't "", " ", 0, "0" etc.
}
!empty is a great shorthand for exists and is something.
When to use array_key_exists
Use array_key_exists when it's important to know if the key exists and the value is of no importance:
if (array_key_exists('something', $array)) {
// $array['something'] exists, could be literally anything including null
}
When not to use isset
If your code looks like this:
if (isset($something) && $something) {
// code is shorter with !empty
}
When not to use !empty
If your code looks like this:
if (!empty($something) && $something === "") {
// you meant isset. this is unreachable.
}
Then you're writing code that can't be executed
Code that throws errors is error prone
Avoid writing code that issues notices/warnings that you are ignoring. For example in the question:
if((isset($_GET[example]))&&($_GET['example']=='somevalue')){ ... }
The first use of example is an undeclared constant. Or is it undeclared - what if you've got define('example', "foo"); somewhere else in the code.
if($_GET['example']=='somevalue'){ ... }
If the url doesn't contain ?example=.. that's going to issue a notice too.
Writing code without displaying errors means you can very easily miss mistakes like the first.
In context: isset and !empty are equivalent
For the example given, these two language constructs act exactly the same.
There is no case where one will act differently than the other, neither will issue a notice if the variable is undefined, and no measurable difference in performance between the two.
As others have said for checking things like $_GET and $_POST you would ideally want to use:
if ( isset($_GET['example']) && $_GET['example'] =='somevalue' ) {
// process data
}
So you always want to firstly make sure that the variable has been set (and not set to null) or in other words exists. Then proceed to check if the variable contains the data that you were expecting. If you try to make reference to a variable which doesn't exist (by not checking isset()) php will give you a notice saying 'undefined variable...etc etc'.
If you wanted to find out if a variable is set but are not concerned too much by what then you could use:
if ( !empty($_GET['example']) ) {
// process data
}
But I would be careful about using empty() on strings in this regard as empty can behave strangely with string data like '0' or ' '.
So I would always do the first one, to a) make sure the variable exists and b) is what you were expecting it to be.
This is something that you'll probably do a lot of and it helps to put together a class/functions which handles this checking for you so you dont have to do it everytime.
function checkValue($key, $value) {
if(array_key_exists($key, $_REQUEST)){
if ($_REQUEST[$key] == $value) {
return true;
} else {
return false;
}
} else {
return false;
}
}
I just use Request as a default instead of switching out (though it is preferable to switch in some cases between POST and GET for security (imo)).
Now you can just call this function anywhere
if (checkValue('Item', 'Tom') === true){} etc
the best is
if((isset($_GET[example]))&&('somevalue'==$_GET['example'])){ ... }
The difference between
'somevalue'==$_GET['example']
AND
$_GET['example']=='somevalue'
If you mistype the == and type = instead, the first notaion will raise an error to notify you.
if((isset($_GET[example]))&&($_GET['example']=='somevalue')){ ... }
dispatch_address_postcode
isn't mandatory and it will still run even if it's blank:
if (!is_null($_POST['personal_info_first_name']) &&
!is_null($_POST['personal_info_surname']) &&
!is_null($_POST['personal_info_email']) &&
!is_null($_POST['personal_info_telephone']) &&
!is_null($_POST['dispatch_address_country']) &&
!is_null($_POST['dispatch_address_first_name']) &&
!is_null($_POST['dispatch_address_surname']) &&
!is_null($_POST['dispatch_address_address']) &&
!is_null($_POST['dispatch_address_town']) &&
!is_null($_POST['dispatch_address_postcode']) &&
!is_null($_POST['dispatch_address_county']) &&
( ($_POST['payment_method'] == "Pay by credit card.") ||
(
($_POST['payment_method'] == "Pay by new credit card.") &&
!is_null($_POST['card_number']) &&
!is_null($_POST['expiration_date']) &&
!is_null($_POST['security_code'])
)
)
)
What gives?
"dispatch_address_postcode isn't mandatory and it will still run even if it's blank…"
Just look at that sentence again. If the field is not mandatory, it is perfectly okay if the code runs if the field is blank. If a field isn't mandatory, don't test it as mandatory.
The real problem is though, is_null only tests if the variable is null. POSTed values will never be null, if they're empty they will be '' (an empty string). All your !is_null tests will always be true, and you will get a warning if the variable isn't set (something you don't want to happen). The more appropriate test would be !empty.
Even more appropriate tests would include a test if the value appears to be valid (does email look like an email address, does telephone have at least x digits in it?). You should also loop through the fields to make your code more readable, endless nested and chained if conditions are no joy to look at.
$mandatoryFields = array('foo' => 'email', 'bar' => 'telephone');
foreach ($mandatoryFields as $field => $rule) {
if (empty($_POST[$field]) || !validateByRule($_POST[$field], $rule)) {
raiseHell();
}
}
It looks like you're trying to make sure all post variables are submitted. Would you like help with that?
Using !empty() may not be the answer to your specific question, but it would definitely help with what it looks like you're trying to do.
empty() returns TRUE if the $_POST key isn't set, if its an empty array, or even if its an empty string, so using !empty() is a good way to make sure that the user has filled in the information.
Try writing your own is_valid function and use that rather than is_null.
For example (and this is by no means comprehensive):
function is_valid(&$array, $key, $required=false) {
if(!array_key_exists($array))
return false;
$value = trim($array[$key]);
if(empty($value) && $required)
return false;
return true;
}
Use like so:
if(is_valid($_POST, 'personal_info_first_name', true) && ...)
!is_null($_POST['personal_info_first_name']) && !isset($_POST['personal_info_first_name'])
use array_key_exists('card_number', $_POST) && !empty($_POST['card_number'])
Edit: Please consider this before a downvote. I'm leaving this here to serve as a "what not to do". I would delete it because it's bad, but then nobody would learn from my mistakes.
DO NOT DO THIS - read the comments for great info on why this is bad
My answer is going to be wildly different, but I am a wildly different guy...
I JUST found that this will work. Instead of all that isset and things, just assign the variables programmatically! I think I have some refactoring to do... y'know on all my code...
if (!is_array($_POST)){exit "$_POST isn't an array";}
foreach ($_POST as $param => $value){
${$param} = secure($value);
}
//now you have a set of variables that are named exactly as the posted param
//for example, $_POST['personal_info_first_name'] == $personal_info_first_name
if ($payment_method == "Pay by credit card."){
//do stuff that you were gonna do anyways
} else if ($payment_method == "Pay by new credit card.") {
if ($card_number && $expiration_date && $security_code){
//do stuff that you were gonna do anyways
} else {
exit("info missing for credit card transaction");
}
} else {
exit("unknown payment method")
}
function secure($input){
//sanitize user input
}
If you use this code, then it doesn't matter what is null and what isn't within the foreach because anything that's null just won't be made. Then you can use nicer looking code (and probably faster code) to check for anything that is required.
Below is a snippet of PHP that I need to get working, I need to make sure that 3 items are not set already and not === ''
I have the part to make it check if not set but when I try to see if the values are empty as well (I might not even be thinking clearly right now, I might not need to do all this) But I need to make sure that redirect, login_name, and password are all not already set to a value, if they are set to a value I need to make sure that the value is not empty.
Can someone help, when I add in check to see if values are empty, I get errors with my syntax, also not sure if I should have 5-6 checks like this in 1 if/else block like that, please help
I need to check the following:
- $_GET['redirect'] is not set
- $_REQUEST['login_name'] is not set
- $_REQUEST['login_name'] is not != to ''
- $_REQUEST['password'] is not set
- $_REQUEST['password'] is not != to ''
if (!isset($_GET['redirect']) && (!isset($_REQUEST['login_name'])) && (!isset($_REQUEST['password']))){
//do stuff
}
UPDATE
Sorry It is not very clear, I was a bit confused about this. Based on Hobodaves answer, I was able to modify it and get it working how I need it. Below is the code how I need it, it works great like this... So if that can be improved then that is the functionality that I need, I just tested this.
if (!isset($_GET['redirect'])
&& empty($_GET['redirect'])
&& isset($_REQUEST['login_name'])
&& !empty($_REQUEST['login_name'])
&& isset($_REQUEST['password'])
&& !empty($_REQUEST['password'])
) {
echo 'load user';
}
if this was loaded then it will run the login process
login.php?login_name=test&password=testing
If this is loaded then it will NOT run the login process
login.php?login_name=test&password=
if (!isset($_GET['redirect'])
&& !isset($_REQUEST['login_name'])
&& empty($_REQUEST['login_name'])
&& !isset($_REQUEST['password'])
&& empty($_REQUEST['password'])
) {
// do stuff
}
This is exactly what you describe, (not != empty === empty). I think you should edit your question though to explain what you're triyng to do, so we can suggest better alternatives.
Edit:
Your updated question can be simplified as:
if (empty($_GET['redirect'])
&& !empty($_REQUEST['login_name'])
&& !empty($_REQUEST['password'])
} {
// load user
}
A more maintainable solution would be storing each key in an array, and then foreach over it and check if isset or empty. You're not very DRY with your current solution.
The implementation would look someting like:
<?php
$keys = array('login_name', 'password');
foreach($keys as $key)
{
if(!isset($_REQUEST[$key]) || empty($_REQUEST['key'])
// Show error message, kill script etc.
}
// Dot stuff
?>
If a global variable is not set, that is the same as being empty. Thus:
!is_set(($_REQUEST['username'])) is the same as empty($_REQUEST['username'])
So based on your update, you can simplify to:
if (empty($_GET['redirect'])
&& !empty($_REQUEST['login_name'])
&& !empty($_REQUEST['password'])
) {
echo 'load user';
}
please read!
Sorry, the previous answer I gave will not give you what you want. Here is why:
If you use !_REQUEST['password'], it will return true if the password is empty or if it is not set. However if you use if($_REQUEST['password']) it will pass the conditional anytime that global variable is set, even if it is empty.
Therefore I recommend:
$no_redirect = (!$_GET['redirect']);
$login_name = (!$_REQUEST['login_name']) ? false : true;
$password = (!$_REQUEST['login_name']) ? false : true;
if($no_redirect && $login_name && $password) {
echo 'load user';
}
Sorry for the previously bad info.
You could create an array
$array = array(
$_GET['redirect'],
$_GET['redirect'],
$_REQUEST['login_name'],
$_REQUEST['login_name'],
$_REQUEST['password'],
$_REQUEST['password']
);
foreach($array as $stuf)
{
if(!empty($stuff) && $tuff !=0)
//do something
}