


addslashes and other methods of clearing spaces are unsafe, addslashes spaces_PHP tutorial
addslashes and other methods of clearing spaces are unsafe, addslashes spaces
are unsafe, partly because there are so many spaces in the characters, for example "The problem with addslashes is that hackers can use 0xbf27 instead of single quotes, and addslashes just changes 0xbf27 to 0xbf5c27, which becomes a valid multi-byte character. 0xbf5c is still regarded as a single quote, so addslashes cannot successfully intercept. "
It is best to verify whether it is int or not according to the specific parameter requirements, plus the parameter operation method of the database. In fact, this is a SQL problem of the database, which should be solved from the source database itself, but some databases provide corresponding It’s just a method.
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Differences in several built-in functions of PHP to prevent SQL injection attacks
2010-12-24 13:09:22
SQL injection attack is the most common method used by hackers to attack websites. If your site does not use strict user input validation, it is often vulnerable to SQL injection attacks. SQL injection attacks are usually implemented by submitting bad data or query statements to the site database, which may cause records in the database to be exposed, changed or deleted.
In order to prevent SQL injection attacks, PHP comes with a function that can process the input string and perform preliminary security processing on the input at the lower level, that is, Magic Quotes. (php.ini magic_quotes_gpc). If the magic_quotes_gpc option is enabled, single quotes, double quotes, and other characters in the input string will be automatically preceded by backslashes.
But Magic Quotes is not a very universal solution, it does not block all potentially dangerous characters, and Magic Quotes is not enabled on many servers. Therefore, we also need to use various other methods to prevent SQL injection.
Many databases themselves provide this input data processing function. For example, PHP's MySQL operation functions include addslashes(), mysql_real_escape_string(), mysql_escape_string() and other functions, which can escape special characters and characters that may cause database operation errors. So what are the differences between these three functional functions? Let’s talk about it in detail below.
Although many domestic PHP programmers still rely on addslashes to prevent SQL injection, it is recommended that everyone strengthen checks to prevent SQL injection in Chinese. The problem with addslashes is that hackers can use 0xbf27 instead of single quotes, while addslashes only changes 0xbf27 to 0xbf5c27, which becomes a valid multi-byte character. 0xbf5c is still regarded as a single quote, so addslashes cannot successfully intercept.
Of course, addslashes is not useless. It is used for processing single-byte strings. For multi-byte characters, use mysql_real_escape_string.
In addition, for the example of get_magic_quotes_gpc in the php manual:
if (!get_magic_quotes_gpc()) {
$lastname = addslashes($_POST['lastname']);
} else {
$lastname = $_POST['lastname'];
}
It is best to check $_POST['lastname'] when magic_quotes_gpc is already open.
Let’s talk about the difference between the two functions mysql_real_escape_string and mysql_escape_string:
mysql_real_escape_string must be used in (PHP 4 >= 4.3.0, PHP 5). Otherwise, you can only use mysql_escape_string. The difference between the two is: mysql_real_escape_string takes into account the current character set of the connection, while mysql_escape_string does not.
To summarize:
* addslashes() is a forced addition;
* mysql_real_escape_string() will determine the character set, but there are requirements for the PHP version;
* mysql_escape_string does not consider the connection the current character set.
The way to prevent sql injection in dz is to use the addslashes function. At the same time, some replacements are made in the dthmlspecialchars function $string = preg_replace(/&(((#(d{3,5}|x[a- fA-F0-9]{4}));)/, &1, This replacement solves the injection problem and also solves some problems with Chinese garbled characters

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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