Verify email in PHP

Validating emails in PHP is one of the common needs in website development. Effective email verification improves user input accuracy and prevents malicious registrations and information leakage. This article will introduce how to use PHP to write simple and effective email verification code to ensure that the email format entered by the user conforms to the specification. Through the guidance of this article, you can easily implement the email verification function and improve the user experience and security of your website. PHP editor Apple will explain the method of verifying emails in detail, allowing you to easily master the skills.

We will also demonstrate another way to validate emails in php using FILTER_SANITIZE_EMAIL and FILTER_VALIDATE_EMAIL filter name IDs and the fiter_var() function Address method. This method first cleans the email address and then verifies the email address.

We'll cover another way to validate emails in PHP using Regular Expressions. This method uses the preg_match() function to check whether the email is valid based on the provided regular expression.

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Validate email in PHP using filter_var() function and FILTER_VALIDATE_EMAIL

We can use the

filter_var() function to filter variables with a specific filter name. FILTER_VALIDATE_EMAIL Filter name specifies an email that requires validation. This function takes the email address as a string as the first argument and the filter ID specified above as the second argument. So we can check if the email provided is valid. If the function succeeds or returns false, the function returns the filtered data. Email is said to be valid, not that email exists. The filter id validates the email based on the syntax in RFC 822. We can test the verification of the email using valid and invalid emails.

For example, create a function

validateEmail() that accepts a parameter $email. Use the filter_var() function on the $email variable, specifying the filter ID FILTER_VALIDATE_EMAIL as the second parameter. Apply if-else conditions to the filter_var() function. In the if block, show the message saying the email is valid, and in the else condition, show the email is invalid. Outside the function, call the function twice. Provide arguments in the first function call, peter.piper@iana.org and first.last@example.123 on the second call.

We can assume that the email address provided in the example is accessed from the form using the

$_POST variable. The function in the example below is called twice. The first call passes a valid email address, the second an invalid email. The second email address is invalid because it contains a number from the top-level domain. The results are obvious.

Sample code:

<code>
<code class="php hljs" data-lang="php"><span style="display:flex;"><span><span style="color:#408080;font-style:italic">#php 7.x
</span></span></span><span style="display:flex;"><span><span style="color:#666"><?</span>php
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">funct<strong class="keylink">io</strong>n</span> <span style="color:#00f">validateEmail</span>(<span style="color:#19177c">$email</span>) {
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">if</span>(filter_var(<span style="color:#19177c">$email</span>, FILTER_VALIDATE_EMAIL)) {
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"</span><span style="color:#b68;font-weight:bold">{</span><span style="color:#19177c">$email</span><span style="color:#b68;font-weight:bold">}</span><span style="color:#ba2121">: A valid email"</span><span style="color:#666">.</span><span style="color:#ba2121">"<br>"</span>;
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">else</span> {
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"</span><span style="color:#b68;font-weight:bold">{</span><span style="color:#19177c">$email</span><span style="color:#b68;font-weight:bold">}</span><span style="color:#ba2121">: Not a valid email"</span><span style="color:#666">.</span><span style="color:#ba2121">"<br>"</span>;
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span>validateEmail(<span style="color:#ba2121">'peter.piper@iana.org'</span>);
</span></span><span style="display:flex;"><span>validateEmail(<span style="color:#ba2121">'first.last@example.123'</span>);
</span></span><span style="display:flex;"><span><span style="color:#bc7a00">?></span><span >
</span></span></span></code></code>

Output:

<code>
<code class="php hljs" data-lang="php"><span style="display:flex;"><span>phppeter<span style="color:#666">.</span>piper<span style="color:#666">@</span>iana<span style="color:#666">.</span>org<span style="color:#666">:</span> A valid email 
</span></span><span style="display:flex;"><span>first<span style="color:#666">.</span>last<span style="color:#666">@</span>example<span style="color:#666">.</span><span style="color:#666">123</span><span style="color:#666">:</span><span style="color:#008000;font-weight:bold">Not</span> a valid email
</span></span></code></code>

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Validating emails in PHP using the

FILTER_VALIDATE_EMAIL, FILTER_SANITIZE_EMAIL and filter_var() functions

We can remove all illegal characters from email address using appended

FILTER_SANITIZE_EMAIL filter name id in first method. The filter name id is the second parameter in the filter_var() function where the email address is the first parameter. This function returns the sanitized email. We can use this feature again to check the validity of the sanitized email address. For this we can follow the first approach using FILTER_VALIDATE_EMAIL filter name id.

For example, create a variable

$email and store an email address that contains illegal characters. Store the email ram(.mugu)@exa//mple.org as a string in a variable. Use the filter_var() function on a variable and use the FILTER_SANITIZE_EMAIL id as the second parameter. Store the function in the same $email variable. Then, apply the if-else statement like the first method. This time, use FILTER_VALIDATE_EMAIL email as the filter name in the function. Likewise, the message is displayed.

In the example below an email address with illegal characters is taken, the

filter_var() function filters these characters and sanitizes the provided email. The email address provided in the example contains illegal characters, such as () and //. The function first removes these characters from the email and then validates the email.

Sample code:

<code>
<code class="php hljs" data-lang="php"><span style="display:flex;"><span><span style="color:#408080;font-style:italic">#php 7.x
</span></span></span><span style="display:flex;"><span><span style="color:#666"><?</span>php
</span></span><span style="display:flex;"><span><span style="color:#19177c">$email</span> <span style="color:#666">=</span> <span style="color:#ba2121">"ram(.mugu)@exa//mple.org"</span>;
</span></span><span style="display:flex;"><span><span style="color:#19177c">$email</span> <span style="color:#666">=</span> filter_var(<span style="color:#19177c">$email</span>, FILTER_SANITIZE_EMAIL);
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">if</span>(filter_var(<span style="color:#19177c">$email</span>, FILTER_VALIDATE_EMAIL)) {
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"</span><span style="color:#b68;font-weight:bold">{</span><span style="color:#19177c">$email</span><span style="color:#b68;font-weight:bold">}</span><span style="color:#ba2121">: A valid email"</span><span style="color:#666">.</span><span style="color:#ba2121">"<br>"</span>;
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">else</span>{
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"</span><span style="color:#b68;font-weight:bold">{</span><span style="color:#19177c">$email</span><span style="color:#b68;font-weight:bold">}</span><span style="color:#ba2121">:Not a valid email"</span><span style="color:#666">.</span><span style="color:#ba2121">"<br>"</span>;
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span><span style="color:#bc7a00">?></span><span >
</span></span></span></code></code>

Output:

<code>
<code class="php hljs" data-lang="php"><span style="display:flex;"><span>ram<span style="color:#666">.</span>mugu<span style="color:#666">@</span>example<span style="color:#666">.</span>org<span style="color:#666">:</span> A valid email
</span></span></code></code>

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使用 preg_match() 函数根据正则表达式验证电子邮件

我们可以使用 preg_match() 函数来验证 PHP 中的电子邮件地址。此方法使用正则表达式作为电子邮件的验证规则。我们可以自己创建正则表达式并定义有效电子邮件的规则。preg_match() 函数接受两个参数，其中第一个是正则表达式，第二个是要检查的电子邮件。我们可以使用三元运算符和函数一起检查电子邮件的有效性。

例如，创建两个变量 $email_first 和 $email_secon，并在这些变量中存储两个电子邮件地址。首先存储有效的电子邮件 firstlast11@gmail.com，然后存储无效的电子邮件 firstlast@11gmail,com。编写一个带有一个参数的函数 validateEmail()。命名参数 $email。在函数内部，在 $regex 变量中编写一个正则表达式，如示例代码所示。然后编写一个三元运算符，其中要检查的条件是 preg_match() 函数。将 $regex 作为第一个参数，将 $email 作为第二个参数。当条件为真时打印电子邮件有效的消息，当条件为假时打印电子邮件无效的消息。回显整个三元表达式。在函数外，调用 validateEmail() 函数两次。在第一个函数调用中使用 $email_first 变量，在第二个函数调用中使用 $email_second 变量。

在下面的示例中，我们编写了一个正则表达式，用于创建验证电子邮件的规则。有效的电子邮件包含收件人姓名、@ 符号、域和顶级域。上面创建的正则表达式接受收件人姓名作为字母数字值。字母表由大写字母和小写字母组成。它也接受一个句点。电子邮件必须有 @ 符号。该域仅包含字母。然后电子邮件应该有一个句点。顶级域应该只由字母组成，并且长度应该是两个或三个。正则表达式是基于此规则创建的。第一封电子邮件是有效的，因为它满足所有规则，但第二封电子邮件无效。无效，因为域名中有数字，顶级域名前没有句号。

示例代码：

<code>
<code class="php hljs" data-lang="php"><span style="display:flex;"><span><span style="color:#408080;font-style:italic"># php 7.x
</span></span></span><span style="display:flex;"><span><span style="color:#666"><?</span>php
</span></span><span style="display:flex;"><span><span style="color:#19177c">$email_first</span> <span style="color:#666">=</span> <span style="color:#ba2121">'firstlast11@gmail.com'</span>;
</span></span><span style="display:flex;"><span><span style="color:#19177c">$email_second</span> <span style="color:#666">=</span><span style="color:#ba2121">'firstlast@11gmail,com'</span>;
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">function</span> <span style="color:#00f">validateEmail</span>(<span style="color:#19177c">$email</span>) {
</span></span><span style="display:flex;"><span><span style="color:#19177c">$regex</span> <span style="color:#666">=</span> <span style="color:#ba2121">"/^([a-zA-Z0-9\.]+@+[a-zA-Z]+(\.)+[a-zA-Z]{2,3})$/"</span>;
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> preg_match(<span style="color:#19177c">$regex</span>, <span style="color:#19177c">$email</span>) <span style="color:#666">?</span> <span style="color:#ba2121">"The email is valid"</span><span style="color:#666">.</span><span style="color:#ba2121">"<br>"</span> <span style="color:#666">:</span><span style="color:#ba2121">"The email is not valid"</span>;
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span>validateEmail(<span style="color:#19177c">$email_first</span>);
</span></span><span style="display:flex;"><span>validateEmail(<span style="color:#19177c">$email_second</span>);
</span></span><span style="display:flex;"><span><span style="color:#bc7a00">?></span><span >
</span></span></span></code></code>

输出：

<code>
<code class="text hljs" data-lang="text"><span style="display:flex;"><span>The email is valid 
</span></span><span style="display:flex;"><span>The email is not valid
</span></span></code></code>

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