Basic PHP development tutorial: form verification email and URL

1. Verify names, emails, and URLs

In this section we will introduce how to verify names, e-mails, and URLs .

2. Verify the name

#The following code will use a simple way to detect whether the name field contains letters and spaces. If the name field value does not Legal, the error message will be output:

$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
  $nameErr = "只允许字母和空格";
}

Note:

preg_match — perform regular expression matching.

Syntax: int preg_match ( string $pattern , string $subject [, array $matches [, int $flags ]] )

at Search the subject string for content that matches the regular expression given by pattern. If matches is provided, it will be populated with the results of the search. $matches[0] will contain text that matches the entire pattern, $matches[1] will contain text that matches the first captured subpattern in parentheses, and so on.

We have introduced detailed regular expressions in the PHP regular expression course.

3. Verification email

The following code will use a simple method to detect whether the e-mail address is legitimate. If the e-mail address is illegal, an error message will be output:

$email = test_input($_POST["email"]);
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {
  $emailErr = "非法邮箱格式";
}

4. Verify URL

The following code will check whether the URL address is legal. (The following regular expression operation URL contains dashes: "-"). If the URL address is illegal, an error message will be output:

$website = test_input($_POST["website"]);
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
  $websiteErr = "非法的 URL 的地址";
}

5. Verify Name, E-mail, and URL

The code is as follows:

<?php
// 定义变量并默认设置为空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
 
if ($_SERVER["REQUEST_METHOD"] == "POST") {
   if (empty($_POST["name"])) {
      $nameErr = "Name is required";
      } else {
         $name = test_input($_POST["name"]);
         // 检测名字是否只包含字母跟空格
         if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
         $nameErr = "只允许字母和空格";
         }
     }
   
   if (empty($_POST["email"])) {
      $emailErr = "Email is required";
   } else {
      $email = test_input($_POST["email"]);
      // 检测邮箱是否合法
      if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {
         $emailErr = "非法邮箱格式";
      }
   }
     
   if (empty($_POST["website"])) {
      $website = "";
   } else {
      $website = test_input($_POST["website"]);
      // 检测 URL 地址是否合法
     if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
         $websiteErr = "非法的 URL 的地址";
      }
   }
 
   if (empty($_POST["comment"])) {
      $comment = "";
   } else {
      $comment = test_input($_POST["comment"]);
   }
 
   if (empty($_POST["gender"])) {
      $genderErr = "性别是必需的";
   } else {
      $gender = test_input($_POST["gender"]);
   }
}
?>