How to output error information and prompt the user in php

When developing PHP programs, errors often occur for various reasons. In order to develop high-quality PHP programs, we need to catch and handle errors in a timely manner. This article will describe how to output error messages and prompt the user.

Error types

Before understanding the output error message, you first need to understand the error types in PHP. Generally speaking, there are three types of errors in PHP:

1. Grammar errors: Grammatical errors in program writing, such as missing semicolons, mismatched brackets, etc. This will cause the program to fail to run properly.

2. Runtime errors: errors that occur during the running of the program, such as division by zero, undefined variables, etc. These errors are usually caused by data.

3. Logic errors: Program logic errors, such as inaccurate judgment conditions, algorithm errors, etc. These errors are usually caused by developer errors.

php error output

In PHP, you can decide whether error information will be output by setting the error reporting level. Usually, in the development environment, we will need to set the error reporting level to the highest level to facilitate timely discovery of errors in the program. In a production environment, we need to reduce the output of error information and prevent the leakage of sensitive information.

In PHP, we can set the error reporting level through the error_reporting() function. Common error reporting levels include:

1.E_ALL: Output all errors.

2.E_ERROR | E_WARNING | E_PARSE: Only output fatal errors, warning messages and syntax errors.

3.E_ERROR: Only fatal errors are output.

In a development environment, we usually set the error reporting level to E_ALL so that problems can be discovered and resolved as early as possible.

The following is an example of setting the error reporting level:

<?php
error_reporting(E_ALL);
?>

In addition to setting the error reporting level, we can also control error output by setting the ini configuration file. A commonly used configuration is display_errors. In the development environment, we set it to On to facilitate debugging. In a production environment, we need to set it to Off to prevent information leakage.

The following is an example of setting the ini configuration file:

<?php
ini_set(&#39;display_errors&#39;, 1);
?>

Error prompt

When we turn on the error output, sometimes we need to display the error message to the user. So that users can quickly know that there is a problem with the program. Common error prompting methods include:

1. By directly outputting the error message: This method is the simplest, directly outputting the error message so that the user can view the error message through the browser page. For example:

<?php
$errorMsg = "您的账户余额不足，请重新充值！";
echo $errorMsg;
?>

2. Jump through the page: When an error occurs in the program, we can jump the user to an error page and display the error message. For example:

<?php
header("Location: error.php?msg=您的账户余额不足，请重新充值！");
?>

3. Through pop-up windows: When the user submits the form, we can prompt the user through a pop-up window when the submission fails. For example:

<?php
$errorMsg = "您的账户余额不足，请重新充值！";
echo "<script>alert('$errorMsg');</script>";
?>

Summary

php error output and prompts are crucial to the stability and security of the program. We need to catch errors and output them in a timely manner during development, and try our best in the production environment Reduce the output of error messages to ensure system security and stability.

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