99 lines
2.8 KiB
Markdown
99 lines
2.8 KiB
Markdown
---
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title: PHP 5 Forms - Validate E-mail and URL
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---
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This chapter shows how to validate names, e-mails, and URLs.
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### PHP - Validate Name
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The code below shows a simple way to check if the name field only contains letters and whitespace. If the value of the name field is not valid, then store an error message:
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```php
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$name = test_input($_POST["name"]);
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if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
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$nameErr = "Only letters and white space allowed";
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}
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```
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> **The preg_match() function searches a string for pattern, returning true if the pattern exists, and false otherwise.**
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### PHP - Validate E-mail
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The easiest and safest way to check whether an email address is well-formed is to use PHP's filter_var() function.
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In the code below, if the e-mail address is not well-formed, then store an error message:
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```php
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$email = test_input($_POST["email"]);
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if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
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$emailErr = "Invalid email format";
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}
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```
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### PHP - Validate URL
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The code below shows a way to check if a URL address syntax is valid (this regular expression also allows dashes in the URL). If the URL address syntax is not valid, then store an error message:
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```php
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$website = test_input($_POST["website"]);
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if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
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$websiteErr = "Invalid URL";
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}
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```
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### PHP - Validate Name, E-mail, and URL
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Now, the script looks like this:
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#### Example
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```php
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<?php
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// define variables and set to empty values
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$nameErr = $emailErr = $genderErr = $websiteErr = "";
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$name = $email = $gender = $comment = $website = "";
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if ($_SERVER["REQUEST_METHOD"] == "POST") {
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if (empty($_POST["name"])) {
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$nameErr = "Name is required";
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} else {
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$name = test_input($_POST["name"]);
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// check if name only contains letters and whitespace
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if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
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$nameErr = "Only letters and white space allowed";
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}
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}
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if (empty($_POST["email"])) {
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$emailErr = "Email is required";
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} else {
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$email = test_input($_POST["email"]);
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// check if e-mail address is well-formed
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if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
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$emailErr = "Invalid email format";
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}
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}
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if (empty($_POST["website"])) {
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$website = "";
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} else {
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$website = test_input($_POST["website"]);
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// check if URL address syntax is valid (this regular expression also allows dashes in the URL)
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if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
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$websiteErr = "Invalid URL";
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}
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}
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if (empty($_POST["comment"])) {
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$comment = "";
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} else {
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$comment = test_input($_POST["comment"]);
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}
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if (empty($_POST["gender"])) {
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$genderErr = "Gender is required";
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} else {
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$gender = test_input($_POST["gender"]);
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}
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}
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?>
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```
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