Found a total of 10000 related content
PHP's Superglobal Variables
Article Introduction：PHP has five most commonly used hyperglobal variables, namely $\_GET, $\_POST, $\_SERVER, $\_SESSION, and $\_COOKIE. ①$\_GET is used to obtain parameters in the URL, suitable for non-sensitive data transmission such as paging and filtering, but attention should be paid to input verification; ②$\_POST is used to receive sensitive data submitted by the form, such as login information, and it is necessary to prevent SQL injection and XSS attacks; ③$\_SERVER provides information about the server and script execution environment, such as the current script name, user IP and request method, and check whether the key exists before use; ④$\_SESSION is used to maintain user status across pages, and session\_st must be called first when using it.
2025-07-18
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224
Explain python class methods and static methods.
Article Introduction：Class methods automatically receive classes as the first parameter, suitable for creating or operating class-level data; static methods do not bind any parameters, suitable for functions related to classes but do not need to access classes or instances. 1. Class methods are often used as alternative constructors or processing class states, such as creating objects through string parsing; 2. Static methods are used to classify ordinary functions in classes, such as verifying whether age is legal; 3. If you need to access class states, use @classmethod, if you only need to classify tool functions, use @staticmethod, and use instance methods to access instance properties.
2025-07-08
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502
SQL Union-Based Injection Attacks
Article Introduction：Union-Based injection is an attack method in which an attacker takes advantage of the application not filtering user input correctly, inserting UNIONSELECT statements through injection points to merge query result sets to obtain sensitive data. 1. The principle is to use the UNION operator to combine multiple SELECT query results; 2. Attack examples, such as injecting UNIONSELECTusername and passwordFROMusers into URL parameters; 3. To determine whether the injection point needs to detect the number of columns, ORDERBY or NULL tests are commonly used; 4. Database names, user information, etc. can be extracted in actual combat; 5. Defense methods include using parameterized query, filtering input, minimum permission principle, hiding error information and deploying WAF.
2025-07-25
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641
What is type casting in C (static_cast, dynamic_cast)?
Article Introduction：In C, static_cast and dynamic_cast are two commonly used type conversion operators that are suitable for different scenarios and are significantly different. 1.static_cast performs type conversion at compile time, suitable for conversion between basic data type conversion, upward transformation, enumeration to integer transformation, and classes with conversion constructors or type conversion operators; it does not perform runtime checks, so it is not safe for downward transformation. 2. Dynamic_cast performs type checking at runtime, mainly used for downward transformation of polymorphic types, ensuring that the conversion is legal, and returning a null pointer or throwing an exception when it fails; it is suitable for scenarios where dynamic type checking is required, but the performance overhead is high. When selecting, it should be converted according to
2025-07-21
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314
Vue Custom Directives Creation Tutorial
Article Introduction：Custom instructions are suitable for use in scenarios where DOM is directly operated, such as automatic focus of input boxes, permission control, lazy loading of pictures, etc. Common scenarios include: 1. The input box automatically gets focus; 2. The permission control button is displayed or disabled; 3. The implementation of lazy loading or animation triggering; 4. The numerical formatting display. It can be registered globally or locally when creating, and the commonly used hooks are inserted and updated. For example, the permission directive v-permission can control whether the element is displayed according to the user role. When using it, you should pay attention to combining binding.value parameters and executing logic in appropriate hooks, while avoiding abuse to maintain data-driven principles.
2025-07-05
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497
How to parse strings in PHP?
Article Introduction：Parsing strings is a very common and important operation in PHP, and you will use it whether you are processing user input, reading file content, or interacting with a database. Today we will explore in-depth various methods and techniques for parsing strings in PHP. In PHP, there are many ways to parse strings, from simple string functions to regular expressions to more complex parsing libraries, each with its own unique application scenarios and advantages and disadvantages. Let’s start from the most basic and gradually deepen into more complex analytical techniques. First, let's take a look at the most commonly used string functions in PHP. These functions are simple and easy to use and are suitable for handling basic string operations. For example, the exploit() function can split the string into numbers according to the specified separator.
2025-05-20
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486
The Duality of PHP: Navigating Loose Typing vs. Strict Type Declarations
Article Introduction：PHP supports the coexistence of loose types and strict types, which is the core feature of its evolution from scripting languages to modern programming languages. 1. Loose types are suitable for rapid prototyping, handling dynamic user input, or docking with external APIs, but there are problems such as risk of implicit type conversion, difficulty in debugging and weak tool support. 2. Strict type is enabled by declare(strict_types=1), which can detect errors in advance, improve code readability and IDE support, and is suitable for scenarios with high requirements for core business logic, team collaboration and data integrity. 3. Mixed use should be used in actual development: Strict types are enabled by default, loose types are used only when necessary at the input boundaries, and verification and type conversion are performed as soon as possible. 4. Recommended practices include using PHPSta
2025-07-26
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995
PHP prepared statement SELECT
Article Introduction：Execution of SELECT queries using PHP's preprocessing statements can effectively prevent SQL injection and improve security. 1. Preprocessing statements separate SQL structure from data, send templates first and then pass parameters to avoid malicious input tampering with SQL logic; 2. PDO and MySQLi extensions commonly used in PHP realize preprocessing, among which PDO supports multiple databases and unified syntax, suitable for newbies or projects that require portability; 3. MySQLi is specially designed for MySQL, with better performance but less flexibility; 4. When using it, you should select appropriate placeholders (such as? or named placeholders) and bind parameters through execute() to avoid manually splicing SQL; 5. Pay attention to processing errors and empty results to ensure the robustness of the code; 6. Close it in time after the query is completed.
2025-07-12
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650
Dave The Diver: How To Catch Spider Crabs
Article Introduction：In Dave The Diver, there are some creatures that are not easy to catch. Or, catch alive that is. The spider crab is one of those very species, making it seem like the only way to bring these crustaceans back up to land is to viciously crack them up w
2025-01-10
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853
Prepare for Interview Like a Pro with Interview Questions CLI
Article Introduction：Prepare for Interview Like a Pro with Interview Questions CLI
What is the Interview Questions CLI?
The Interview Questions CLI is a command-line tool designed for JavaScript learners and developers who want to enhance their interview
2025-01-10
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1484
Soft Deletes in Databases: To Use or Not to Use?
Article Introduction：Soft Deletes: A Question of DesignThe topic of soft deletes, a mechanism that "flags" records as deleted instead of physically removing them, has...
2025-01-10
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1081
