I have URL below:
session.php?action=create_program
Then I have the following piece of code:
if( isset($_GET['action']) ){ $action= $_GET['action']; $action=''; }
It returns an empty string while it should return ''create_program'
I think you were trying to set it to empty if you didn't receive anything in your get request. So either do it like this
if( isset($_GET['action']) ){
$action= $_GET['action'];
} else {
$action='';
}
Or, even simpler, give a default value that remains set if the get parameter is absent.
$action = '';
if( isset($_GET['action']) ){
$action= $_GET['action'];
}
Finally, as suggested by Cashbee in the comment below, you can use the ternary operator to check whether $_GET['action'] was set and, in case it's not, give a default value to $action.
$action = isset($_GET['action']) ? $_GET['action'] : '';
Easy is the use of the ternary operator like this:
$action = isset($_GET['action']) ? $_GET['action'] : '';
You should always check if the variable is set or empty.
$action = empty($_GET['action']) ? '' : $_GET['action'];
Or even better, use the PHP filter functions.
$action = filter_input(INPUT_GET, 'action');
This has the advantage, you can even use rules, to give the appropriate result, like described in http://php.net/manual/de/function.filter-input.php
You are setting $action to empty at last that's why it is returning an empty string
if( isset($_GET['action']) )
{
$action= $_GET['action'];
// $action=''; //Just remove this code
}
//$action will be empty if not have $_GET['action'];, just for PHP7
$action = $_GET['action'] ?? '';
hope can help you!
Related
I'm trying to check whether a $_POST exists and if it does, print it inside another string, if not, don't print at all.
something like this:
$fromPerson = '+from%3A'.$_POST['fromPerson'];
function fromPerson() {
if !($_POST['fromPerson']) {
print ''
} else {
print $fromPerson
};
}
$newString = fromPerson();
Any help would be great!
if( isset($_POST['fromPerson']) )
{
$fromPerson = '+from%3A'.$_POST['fromPerson'];
echo $fromPerson;
}
Simple. You've two choices:
1. Check if there's ANY post data at all
//Note: This resolves as true even if all $_POST values are empty strings
if (!empty($_POST))
{
// handle post data
$fromPerson = '+from%3A'.$_POST['fromPerson'];
echo $fromPerson;
}
(OR)
2. Only check if a PARTICULAR Key is available in post data
if (isset($_POST['fromPerson']) )
{
$fromPerson = '+from%3A'.$_POST['fromPerson'];
echo $fromPerson;
}
Surprised it has not been mentioned
if($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_POST['fromPerson'])){
Everyone is saying to use isset() - which will probably work for you.
However, it's important that you understand the difference between
$_POST['x'] = NULL; and $_POST['x'] = '';
isset($_POST['x']) will return false on the first example, but will return true on the second one even though if you tried to print either one, both would return a blank value.
If your $_POST is coming from a user-inputted field/form and is left blank, I BELIEVE (I am not 100% certain on this though) that the value will be "" but NOT NULL.
Even if that assumption is incorrect (someone please correct me if I'm wrong!) the above is still good to know for future use.
isset($_POST['fromPerson'])
The proper way of checking if array key exists is function array_key_exists()
The difference is that when you have $_POST['variable'] = null it means that key exists and was send but value was null
The other option is isset() which which will check if array key exists and if it was set
The last option is to use empty() which will check if array key exists if is set and if value is not considered empty.
Examples:
$arr = [
'a' => null,
'b' => '',
'c' => 1
];
array_key_exists('a', $arr); // true
isset($arr['a']); // false
empty($arr['a']); // true
array_key_exists('b', $arr); // true
isset($arr['b']); // true
empty($arr['b']); // true
array_key_exists('c', $arr); // true
isset($arr['c']); // true
empty($arr['c']); // false
Regarding your question
The proper way to check if value was send is to use array_key_exists() with check of request method
if ($_SERVER['REQUEST_METHOD'] == 'POST' && array_key_exists('fromPerson', $_POST)
{
// logic
}
But there are some cases depends on your logic where isset() and empty() can be good as well.
In that case using method isset is not appropriate.
According to PHP documentation: http://php.net/manual/en/function.array-key-exists.php
(see Example #2 array_key_exists() vs isset())
The method array_key_exists is intended for checking key presence in array.
So code in the question could be changed as follow:
function fromPerson() {
if (array_key_exists('fromPerson', $_POST) == FALSE) {
return '';
} else {
return '+from%3A'.$_POST['fromPerson'];
};
}
$newString = fromPerson();
Checking presence of array $_POST is not necessary because it is PHP environment global variable since version 4.1.0 (nowadays we does not meet older versions of PHP).
All the methods are actually discouraged, it's a warning in Netbeans 7.4 and it surely is a good practice not to access superglobal variables directly, use a filter instead
$fromPerson = filter_input(INPUT_POST, 'fromPerson', FILTER_DEFAULT);
if($fromPerson === NULL) { /*$fromPerson is not present*/ }
else{ /*present*/ }
var_dump($fromPerson);exit(0);
Try
if (isset($_POST['fromPerson']) && $_POST['fromPerson'] != "") {
echo "Cool";
}
I would like to add my answer even though this thread is years old and it ranked high in Google for me.
My best method is to try:
if(sizeof($_POST) !== 0){
// Code...
}
As $_POST is an array, if the script loads and no data is present in the $_POST variable it will have an array length of 0. This can be used in an IF statement.
You may also be wondering if this throws an "undefined index" error seeing as though we're checking if $_POST is set... In fact $_POST always exists, the "undefined index" error will only appear if you try to search for a $_POST array value that doesn't exist.
$_POST always exists in itself being either empty or has array values.
$_POST['value'] may not exist, thus throwing an "undefined index" error.
Try isset($_POST['fromPerson'])?
if (is_array($_POST) && array_key_exists('fromPerson', $_POST)) {
echo 'blah' . $_POST['fromPerson'];
}
if( isset($_POST['fromPerson']) ) is right.
You can use a function and return, better then directing echo.
I like to check if it isset and if it's empty in a ternary operator.
// POST variable check
$userID = (isset( $_POST['userID'] ) && !empty( $_POST['userID'] )) ? $_POST['userID'] : null;
$line = (isset( $_POST['line'] ) && !empty( $_POST['line'] )) ? $_POST['line'] : null;
$message = (isset( $_POST['message'] ) && !empty( $_POST['message'] )) ? $_POST['message'] : null;
$source = (isset( $_POST['source'] ) && !empty( $_POST['source'] )) ? $_POST['source'] : null;
$version = (isset( $_POST['version'] ) && !empty( $_POST['version'] )) ? $_POST['version'] : null;
$release = (isset( $_POST['release'] ) && !empty( $_POST['release'] )) ? $_POST['release'] : null;
I recently came up with this:
class ParameterFetcher
{
public function fetchDate(string $pDate):string{
$myVar = "";
try{
if(strlen($_POST[$pDate]) > 0){
$myVar = $_POST[$pDate];
}
}catch (Exception $faild){
die("field NULL or not set for $pDate");
}
[ ... other stuff ]
to fetch a date obviously, but it can take ANY post param. You can also check for GET this way.
I am creating a PHP page, in one page I would like to show the main HTML based on which $_GET["action"]. However whatever which if ($action == "xxx") condition
// Action Judgement
$action = isset($_GET["action"]) ? $action : 'form';
$action = isset($action) && in_array($action, array('form', 'submit')) ? $action : 'form';
if($action == "form") { ?>
// only html <form>...</form> codes here
<?php } elseif($action == "submit") { ?>
// only php codes for processing here
<?php } ?>
If I put the URL like this abc.php?action=submit, the HTML codes are showing in the page. Is my coding wrong?
Your first line is wrong. Fix it by replacing it by
$action = isset($_GET["action"]) ? $_GET["action"] : 'form';
or you could even improve it by taking
$action = ( isset($_GET["action"]) && !empty($_GET["action"]) ) ? $_GET["action"] : 'form';
or even better (as Ben D suggested)
$action = !empty($_GET["action"]) ? $_GET["action"] : 'form';
You're confusing variables and forms.
if($action == "form") {
echo "only html <form>...</form> codes here";
} else if($action == "submit") {
only php codes for processing here
}
$action = isset($_GET["action"]) ? $_GET['action'] : 'form';
$action = isset($action) && in_array($action, array('form', 'submit')) ? $action : 'form';
What I'm doing is, if I haven't got an ID in either $_POST or $_SESSION then redirecting. Preference is given to $_POST. So I have this:
$bool = 0;
if (isset($_POST['id'])) {
$bool = 1;
} elseif (isset($_SESSION['id'])) {
$bool = 1;
}
if (!$bool) {
...//redirect
}
Is there a quicker way to write this, APART from just removing the braces?
if(!( isset($_POST['id']) || isset($_SESSION['id']) ))
redirect();
(not sure if I understand how what's given to $_POST is preference).
You could just do:
$has_id = isset($_POST['id']) || isset($_SESSION['id']);
if (!$has_id) {
// redirect
}
(I'd recommend you to give your variables more descriptive names than just $bool.)
Although if you aren't using the variable for anything else, you could just do:
if (!isset($_POST['id']) && !isset($_SESSION['id'])) {
// redirect
}
if (isset($_POST['id']) || isset($_SESSION['id'])) {
$bool = 1;
}
This will do it, simples
$bool = (isset($_POST['id']) || isset($_SESSION['id'])) ? 1 : 0; // if isset, 1
($bool == 1?header(Location: www.whatever.com):null;
Using Conditional Operator, you can achieve this in one line statement
Example:
c = (a == b) ? d : e;
I'm creating an edit page which should get called this way:
users.php?action=edit&id=5
This is my code for this:
} elseif (isset($_GET['action']) && $_GET['action'] == 'edit' && isset($_GET['id']) && is_numeric($_GET['id']) && $_GET['id'] > 0) {
As you see it's long. First a check with isset is needed. I know you can leave that out, but that way I'll get PHP notices when error reporting is set to 'E_ALL'.
I can create a function to make it shorter but that way I'll need to create too many functions as I have such code on different places in my scripts, each requiring different information.
Is there any way to make this code shorter?
Thanks!
Since action and id both are probably going to be used might as well set them at the top of the script:
$action = !empty($_GET['action'])?$_GET['action']:false;
$id = !empty($_GET['id'])?$_GET['id']:false;
switch ($action) {
case 'edit':
if ($id !== false) {
//processing here
}
break;
default:
echo 'No known action was passed through';
}
The initial variable declaration uses the ternary operator which is a shortened if/else as an fyi.
Extra Information
I prefer this method as appose to insane if/elseif/else statements, given that it is much easier to read and you do not have to think about your logic nearly as much, so it would make it less prone to errors.
You could write a function that takes an array of keys:
function check_get_params($keys) {
foreach ($keys as $key) {
if (! isset($_GET[$key]) ) {
return false;
}
}
return true;
}
Then your line above would be:
} elseif (check_get_params(array('action', 'id')) && $_GET['action'] == 'edit' && is_numeric($_GET['id'])) {
which would be cleaner as:
} elseif (check_get_params(array('action', 'id'))) {
if ($_GET['action'] == 'edit' && is_numeric($_GET['id'])) {
I would check parameters first:
$action = (isset($_GET['action']) && !empty($_GET['action'])) ? $_GET['action'] : false;
$id = (isset($_GET['id']) && !empty($_GET['id'])) ? $_GET['id'] : false;
settype($id, 'int'); // "123" became 123(int)
And then go with:
} elseif ($action && $id && $action == 'edit' && $id > 0) {
// here we are
}
I'm trying to check whether a $_POST exists and if it does, print it inside another string, if not, don't print at all.
something like this:
$fromPerson = '+from%3A'.$_POST['fromPerson'];
function fromPerson() {
if !($_POST['fromPerson']) {
print ''
} else {
print $fromPerson
};
}
$newString = fromPerson();
Any help would be great!
if( isset($_POST['fromPerson']) )
{
$fromPerson = '+from%3A'.$_POST['fromPerson'];
echo $fromPerson;
}
Simple. You've two choices:
1. Check if there's ANY post data at all
//Note: This resolves as true even if all $_POST values are empty strings
if (!empty($_POST))
{
// handle post data
$fromPerson = '+from%3A'.$_POST['fromPerson'];
echo $fromPerson;
}
(OR)
2. Only check if a PARTICULAR Key is available in post data
if (isset($_POST['fromPerson']) )
{
$fromPerson = '+from%3A'.$_POST['fromPerson'];
echo $fromPerson;
}
Surprised it has not been mentioned
if($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_POST['fromPerson'])){
Everyone is saying to use isset() - which will probably work for you.
However, it's important that you understand the difference between
$_POST['x'] = NULL; and $_POST['x'] = '';
isset($_POST['x']) will return false on the first example, but will return true on the second one even though if you tried to print either one, both would return a blank value.
If your $_POST is coming from a user-inputted field/form and is left blank, I BELIEVE (I am not 100% certain on this though) that the value will be "" but NOT NULL.
Even if that assumption is incorrect (someone please correct me if I'm wrong!) the above is still good to know for future use.
isset($_POST['fromPerson'])
The proper way of checking if array key exists is function array_key_exists()
The difference is that when you have $_POST['variable'] = null it means that key exists and was send but value was null
The other option is isset() which which will check if array key exists and if it was set
The last option is to use empty() which will check if array key exists if is set and if value is not considered empty.
Examples:
$arr = [
'a' => null,
'b' => '',
'c' => 1
];
array_key_exists('a', $arr); // true
isset($arr['a']); // false
empty($arr['a']); // true
array_key_exists('b', $arr); // true
isset($arr['b']); // true
empty($arr['b']); // true
array_key_exists('c', $arr); // true
isset($arr['c']); // true
empty($arr['c']); // false
Regarding your question
The proper way to check if value was send is to use array_key_exists() with check of request method
if ($_SERVER['REQUEST_METHOD'] == 'POST' && array_key_exists('fromPerson', $_POST)
{
// logic
}
But there are some cases depends on your logic where isset() and empty() can be good as well.
In that case using method isset is not appropriate.
According to PHP documentation: http://php.net/manual/en/function.array-key-exists.php
(see Example #2 array_key_exists() vs isset())
The method array_key_exists is intended for checking key presence in array.
So code in the question could be changed as follow:
function fromPerson() {
if (array_key_exists('fromPerson', $_POST) == FALSE) {
return '';
} else {
return '+from%3A'.$_POST['fromPerson'];
};
}
$newString = fromPerson();
Checking presence of array $_POST is not necessary because it is PHP environment global variable since version 4.1.0 (nowadays we does not meet older versions of PHP).
All the methods are actually discouraged, it's a warning in Netbeans 7.4 and it surely is a good practice not to access superglobal variables directly, use a filter instead
$fromPerson = filter_input(INPUT_POST, 'fromPerson', FILTER_DEFAULT);
if($fromPerson === NULL) { /*$fromPerson is not present*/ }
else{ /*present*/ }
var_dump($fromPerson);exit(0);
Try
if (isset($_POST['fromPerson']) && $_POST['fromPerson'] != "") {
echo "Cool";
}
I would like to add my answer even though this thread is years old and it ranked high in Google for me.
My best method is to try:
if(sizeof($_POST) !== 0){
// Code...
}
As $_POST is an array, if the script loads and no data is present in the $_POST variable it will have an array length of 0. This can be used in an IF statement.
You may also be wondering if this throws an "undefined index" error seeing as though we're checking if $_POST is set... In fact $_POST always exists, the "undefined index" error will only appear if you try to search for a $_POST array value that doesn't exist.
$_POST always exists in itself being either empty or has array values.
$_POST['value'] may not exist, thus throwing an "undefined index" error.
Try isset($_POST['fromPerson'])?
if (is_array($_POST) && array_key_exists('fromPerson', $_POST)) {
echo 'blah' . $_POST['fromPerson'];
}
if( isset($_POST['fromPerson']) ) is right.
You can use a function and return, better then directing echo.
I like to check if it isset and if it's empty in a ternary operator.
// POST variable check
$userID = (isset( $_POST['userID'] ) && !empty( $_POST['userID'] )) ? $_POST['userID'] : null;
$line = (isset( $_POST['line'] ) && !empty( $_POST['line'] )) ? $_POST['line'] : null;
$message = (isset( $_POST['message'] ) && !empty( $_POST['message'] )) ? $_POST['message'] : null;
$source = (isset( $_POST['source'] ) && !empty( $_POST['source'] )) ? $_POST['source'] : null;
$version = (isset( $_POST['version'] ) && !empty( $_POST['version'] )) ? $_POST['version'] : null;
$release = (isset( $_POST['release'] ) && !empty( $_POST['release'] )) ? $_POST['release'] : null;
I recently came up with this:
class ParameterFetcher
{
public function fetchDate(string $pDate):string{
$myVar = "";
try{
if(strlen($_POST[$pDate]) > 0){
$myVar = $_POST[$pDate];
}
}catch (Exception $faild){
die("field NULL or not set for $pDate");
}
[ ... other stuff ]
to fetch a date obviously, but it can take ANY post param. You can also check for GET this way.