How to receive external array in php

PHP is a widely used server-side scripting language that helps us build web applications and dynamic websites. In PHP, we often need to receive data from outside and use them to perform different tasks. Among them, receiving an external array is a very common task as it allows us to handle multiple values ​​without having to hardcode them in the code. In this article, we'll cover how to receive external arrays and provide some best practices to ensure your code is efficient and safe.

1. Receive array from URL parameters

URL parameters are query strings specified in the URL. They are used to send additional data to the web server and pass them to the PHP script. These parameters can contain any type of data, including arrays. We can use the $_GET array to receive these parameters and convert them into an array. Here is an example:

<code>// URL: http://example.com?names[]=Alice&names[]=Bob&names[]=Charlie

$names = $_GET['names'];
print_r($names); // 输出 Array([0] => Alice [1] => Bob [2] => Charlie)</code>

In this example, we use URL parameters to pass an array named "names". We first use the $_GET array to obtain this parameter, and then use the print_r function to print the contents of the array. Since we used the "[]" symbol to define the array, PHP will automatically convert the parameter into an array.

2. Receiving arrays from POST requests

In addition to using URL parameters to pass arrays, we can also use the POST method to send data to a PHP script. In PHP, we can use the $_POST array to receive this data. To receive an array from a POST request, we just need to send the array as a form element in the form. Here is an example:

<code><!-- HTML 表单 -->
<form action="process.php" method="post">
  <input type="text" name="names[]" value="Alice">
  <input type="text" name="names[]" value="Bob">
  <input type="text" name="names[]" value="Charlie">
  <input type="submit" value="提交">
</form>

<!-- PHP 脚本 -->
$names = $_POST['names'];
print_r($names); // 输出 Array([0] => Alice [1] => Bob [2] => Charlie)</code>

In this example, we create an array named "names" in the HTML form and set the name of the form element to "names[]". When the user submits the form, we can use the $_POST array to receive this array called "names" and print its contents using the print_r function.

3. Receive array from JSON string

In addition to HTTP requests, we can also use JSON format to pass data to PHP scripts. JSON is a lightweight data exchange format that can serialize any type of data into a string and pass it between different applications. In PHP, we can convert JSON string to array using json_decode function. Here is an example:

<code>// JSON 字符串
$json = '{"names": ["Alice", "Bob", "Charlie"]}';

// 将 JSON 字符串转化为数组
$data = json_decode($json, true);

// 输出数组
print_r($data['names']); // 输出 Array([0] => Alice [1] => Bob [2] => Charlie)</code>

In this example, we first create an array called "names" and serialize it into a JSON string. We then convert the JSON string to an array using the json_decode function and print the contents of the array using the print_r function.

It should be noted that if we do not set the second parameter to true, the json_decode function will return an object instead of an array.

4. Best practices for handling external arrays

When we receive arrays from the outside, we need to consider some best practices to ensure the validity and security of the code. Here are some best practices:

1. Validate Arrays

Before processing an external array, we should validate the array to make sure it contains the correct data. For example, we can check if all the values ​​in the array are integers or strings. This prevents some common security vulnerabilities such as SQL injection attacks.

2. Using filters

PHP provides some built-in filters that can help us filter and validate input data. For example, we can use the filter_input_array function to filter arrays in POST and GET requests. This can help us reduce code duplication and improve code readability.

3. Avoid hardcoding arrays

When we deal with arrays, we should avoid hardcoding arrays as much as possible. Instead, we should store the array in a constant or configuration file and read data from it. This improves code maintainability and testability.

4. Use the correct data type

When using external arrays, we should always use the correct data type. For example, if we need to store an array in a database, we should use the correct SQL data type such as "TEXT" or "INTEGER".

5. Prevent duplicate submission

When we receive an array from the outside, we should prevent multiple submissions of the same data. For example, we can use unique identifiers in each form element and use sessions or cookies in PHP scripts to track submitted data.

Conclusion

Receiving external arrays is a very common task in PHP programming, but it is also a task that needs to be handled with care. In this article, we introduced methods for receiving arrays from URL parameters, POST requests, and JSON strings, and provided some best practices to ensure the validity and security of your code. We hope this article has been helpful to you so that you can develop PHP applications and websites more efficiently.

The above is the detailed content of How to receive external array in php. For more information, please follow other related articles on the PHP Chinese website!