PSR-3 is a PHP-FIG (PHP Framework Interoperability Group) recommendation that establishes a standardized interface for logging libraries in PHP applications. This interface defines methods and rules that allow developers to work with logs consistently across different frameworks and libraries, making it easier to replace or change logging libraries within a project without changing the codebase that calls the logger.
Standardized Logger Interface: PSR-3 defines a Psr\Log\LoggerInterface
with a set of methods corresponding to different log levels, such as emergency()
, alert()
, critical()
, error()
, warning()
, notice()
, info()
, and debug()
.
Log Levels: The standard specifies eight log levels (emergency, alert, critical, error, warning, notice, info, and debug), which follow an escalating level of severity. These are based on the widely used RFC 5424 Syslog protocol, ensuring compatibility with many logging systems.
Message Interpolation: PSR-3 includes a basic formatting mechanism known as message interpolation, where placeholders (like {placeholder}
) within log messages are replaced with actual values. For instance:$logger->error("User {username} not found", ['username' => 'johndoe']);
This allows for consistent, readable logs without requiring complex string manipulation.
Flexible Implementation: Any logging library that implements LoggerInterface
can be used in PSR-3 compatible code, such as Monolog, which is widely used in the PHP ecosystem.
Error Handling: PSR-3 also allows the log()
method to be used to log at any severity level dynamically, by passing the severity level as a parameter.
Here’s a basic example of how a PSR-3 compliant logger might be used:
use Psr\Log\LoggerInterface;
class UserService
{
private $logger;
public function __construct(LoggerInterface $logger)
{
$this->logger = $logger;
}
public function findUser($username)
{
$this->logger->info("Searching for user {username}", ['username' => $username]);
// ...
}
}
For more details, you can check the official PHP-FIG documentation for PSR-3.
PSR-2 is a coding style guideline for PHP developed by the PHP-FIG (Framework Interop Group) to make code more readable and consistent, allowing development teams to collaborate more easily. The abbreviation “PSR” stands for “PHP Standards Recommendation”.
{
for classes and methods should be on the next line, whereas braces for control structures (like if
, for
) should be on the same line.=
, +
).Here’s a simple example following these guidelines:
<?php
namespace Vendor\Package;
class ExampleClass
{
public function exampleMethod($arg1, $arg2 = null)
{
if ($arg1 === $arg2) {
throw new \Exception('Arguments cannot be equal');
}
return $arg1;
}
}
PSR-2 has since been expanded and replaced by PSR-12, which includes additional rules to further improve code consistency.
PSR-1 is a PHP Standards Recommendation created by the PHP-FIG (Framework Interop Group) that defines basic coding standards for PHP code style and structure to ensure interoperability between different PHP projects and frameworks. Its main purpose is to establish a consistent baseline for PHP code, making it easier to understand and collaborate on projects across the PHP ecosystem. PSR-1, also known as the Basic Coding Standard, includes several key guidelines:
File Formatting:
<?php
or <?=
tags.Namespace and Class Names:
StudlyCaps
(PascalCase).Constants, Properties, and Method Naming:
CONST_VALUE
).camelCase
.Autoloading:
include
or require
statements.PSR-1 is considered a foundational standard, and it works in tandem with PSR-2 and PSR-12, which define more detailed code formatting guidelines. Together, these standards help improve code readability and consistency across PHP projects.
Churn PHP is a tool that helps identify potentially risky or high-maintenance pieces of code in a PHP codebase. It does this by analyzing how often classes or functions are modified (churn rate) and how complex they are (cyclomatic complexity). The main goal is to find parts of the code that change frequently and are difficult to maintain, indicating that they might benefit from refactoring or closer attention.
In essence, Churn PHP helps developers manage technical debt by flagging problematic areas that could potentially cause issues in the future. It integrates well with Git repositories and can be run as part of a CI/CD pipeline.
PHPmetrics is a static analysis tool designed for PHP code, providing insights into the code’s complexity, maintainability, and overall quality. It helps developers by analyzing various aspects of their PHP projects and generating reports that visualize metrics. This is especially useful for evaluating large codebases and identifying technical debt.
It’s commonly integrated into continuous integration workflows to maintain high code quality throughout the development lifecycle.
By using PHPmetrics, teams can better understand and manage their code's long-term maintainability and overall health.
Dephpend is a static analysis tool for PHP that focuses on analyzing and visualizing dependencies within a codebase. It provides insights into the architecture and structure of PHP projects by identifying the relationships between different components, such as classes and namespaces. Dephpend helps developers understand the coupling and dependencies in their code, which is crucial for maintaining a modular and scalable architecture.
This tool is particularly useful in large codebases where maintaining a clear architecture is essential for scaling and reducing technical debt. By visualizing dependencies, developers can refactor code more confidently and ensure that new additions don't introduce unwanted complexity.
PHP Mess Detector (PHPMD) is a static analysis tool for PHP that helps detect potential problems in your code. It identifies a wide range of code issues, including:
PHPMD is configurable, allowing you to define custom rules or use predefined rule sets like "unused code" or "naming conventions." It works similarly to PHP_CodeSniffer, but while CodeSniffer focuses more on style and formatting issues, PHPMD is more focused on the logic and structure of the code.
In summary, PHPMD helps ensure code quality and maintainability by pointing out potential "messes" that might otherwise go unnoticed.
PHP_CodeSniffer, often referred to as "Codesniffer," is a tool used to detect violations of coding standards in PHP code. It ensures that code adheres to specified standards, which improves readability, consistency, and maintainability across projects.
In summary, PHP_CodeSniffer helps improve the overall quality and consistency of PHP projects, making them easier to maintain in the long term.
Deptrac is a static code analysis tool for PHP applications that helps manage and enforce architectural rules in a codebase. It works by analyzing your project’s dependencies and verifying that these dependencies adhere to predefined architectural boundaries. The main goal of Deptrac is to prevent tightly coupled components and ensure a clear, maintainable structure, especially in larger or growing projects.
Deptrac is especially useful in maintaining decoupling and modularity, which is crucial in scaling and refactoring projects. By catching architectural violations early, it helps avoid technical debt accumulation.
Composer Unused is a tool for PHP projects that helps identify unused dependencies in the composer.json
file. It allows developers to clean up their list of dependencies and ensure that no unnecessary libraries are lingering in the project, which could bloat the codebase.
composer.json
.composer.json
but are not used in the project code.composer.json
: The tool helps identify and remove unused dependencies, making the project leaner and more efficient.Composer Unused is typically used in PHP projects to ensure that only the necessary dependencies are included. This can lead to better performance and reduced maintenance effort by eliminating unnecessary libraries.