PHP Interview Best Practices in China Download - PHP Interview Best Practices in China Source code download

PHP Interview Best Practices in China

Other categories

1.0.0

Download

PHP interview best practices in China

English version (third party)

This warehouse mainly summarizes the knowledge points that are often asked in domestic PHP interviews. It only points out knowledge points in a targeted manner, and you need to find relevant information and study systematically by yourself. I hope you can understand not only what it is, but also why and the principles behind it.

If you have very systematic information on the corresponding knowledge points, you are welcome to PR to add links. It is not recommended that you use fork, the information will be updated at any time.

If you are currently in the following situations, this information is very suitable for you:

I’m planning to change my job, but I don’t know where to start.
The technology has encountered a bottleneck and I don’t know what to learn.
Ready to learn PHP, but don’t know how deep the field is?

Basics

Understand most of the array manipulation functions
The difference between string processing functions and mb_ series functions
& Quotes, combined with case analysis
Difference between == and ===
The difference between isset and empty
Understanding all magic functions
Differences between static, $this, and self
The difference between private, protected, public and final
OOP thinking
Respective usage scenarios of abstract classes and interfaces
What is Trait?
Differences between echo, print, and print_r (distinguish the difference between expressions and statements)
The difference between __construct and __destruct
static function (distinguishing between classes and functions) manual, SOF
__toString() function
The difference between single quotes ' and double quotes "
Common HTTP status codes, what do they mean?
What does 301 mean 404?

Advanced chapter

Autoload, Composer principle PSR-4, principle
Session sharing, survival time
Exception handling
How to iterate over foreach object
How to array the operation object $obj[key];
How to functionalize object $obj(123);
What is yield? Let’s talk about the usage scenario of yield.
What is PSR, PSR-1, 2, 4, 7
How to obtain client IP and server IP addresses
- Client IP
- Server IP
- Understand the concept of proxy transparent transmission of actual IP
How to enable PHP exception prompts
- php.ini turns on display_errors and sets error_reporting level
- At runtime, use ini_set(k, v); to dynamically set
How to return a 301 redirect
- [WARNING] Be careful that the script will continue to execute after setting 301. Don't think that the following will not execute. Use die or exit if necessary.
How to get the extension installation path
- phpinfo(); Page search extension_dir
- Command line php -i |grep extension_dir
- Runtime echo ini_get('extension_dir');
The principle of comparing strings and numbers. Pay attention to the octal system starting with 0 and the hexadecimal system starting with 0x.
- String comparison size, from left (high bit) to right, character by character ASCII comparison
What is the BOM header and how to remove it?
- 0xEF , 0xBB , 0xBF
- Detect, remove
What is MVC
Dependency injection implementation principle
How to execute a command asynchronously
What is a template engine, what problems it solves, and its implementation principles (Smarty, Twig, Blade)
How to implement chain operation $obj->w()->m()->d();
Use of Xhprof and Xdebug performance debugging tools
What is the difference between index array [1, 2] and associative array ['k1'=>1, 'k2'=>2]
How to use cache and scenarios

Practice

Given a two-dimensional array, sort according to a certain field
How to determine the uploaded file type, such as: only jpg upload is allowed
Exchange the values of two variables without using temporary variables $a=1; $b=2; => $a=2; $b=1;
There are garbled characters in strtoupper when converting Chinese. How do you solve it? php echo strtoupper('ab你好c');
Differences between Websocket, Long-Polling, Server-Sent Events(SSE)
What does the "Headers already sent" error mean and how to avoid it

Algorithm

Quick sort (handwritten)
Bubble sort (handwritten)
Binary search (understanding)
Find algorithm KMP (understand)
Depth and breadth first search (understand)
LRU cache elimination algorithm (understand that Memcached uses this algorithm)

Data structure (understanding)

Heap and stack characteristics
queue
Hash table
linked list

Comparison

The difference between Cookie and Session
The difference between GET and POST
The difference between include and require
The difference between include_once and require_once
The difference between Memcached and Redis
MySQL storage engines and their differences (you will definitely ask about the difference between MyISAM and Innodb)
The difference between HTTP and HTTPS
The difference between Apache and Nginx
The difference between define() and const
What are the differences between traits and interfaces and what pain points do traits solve?
The difference between Git and SVN

Database

MySQL
- CRUD
- JOIN, LEFT JOIN, RIGHT JOIN, INNER JOIN
- UNION
- GROUP BY + COUNT + WHERE combination case
- Commonly used MySQL functions, such as: now(), md5(), concat(), uuid(), etc.
- 1:1 , 1:n , n:n are applicable to each scenario
- Understand what a trigger is and describe a usage scenario
- Database optimization methods
  - Index, joint index (hit condition)
  - Sub-database and sub-table (水平分表and垂直分表)
  - Partition
  - Can use explain to analyze SQL performance issues and understand the meaning of each parameter
    - Focus on understanding type , rows , key
  - Slow Log (what is it used for, when is it needed)
MSSQL (understand)
- Query the latest 5 pieces of data
NOSQL
- Redis, Memcached, MongoDB
- Comparison and applicable scenarios (comparison can be made from the following dimensions)
  - persistence
  - Supports multiple data types
  - CPU multi-core available
  - Memory elimination mechanism
  - ClusterCluster
  - Support SQL
  - Performance comparison
  - support matters
  - Application scenarios
- What did you use to solve what problem before, and why did you choose it?

Server

View information such as CPU, memory, time, system version, etc.
find, grep to find files
awk processes text
View the directory where the command is located
Have you ever compiled PHP yourself? How to turn on the readline function
How to check the memory and CPU usage of the PHP process
How to add an extension to PHP
Modify PHP Session storage location and modify INI configuration parameters
What are the types of load balancing? Choose one you are familiar with and explain its principles.
How is the database master-slave replication MS synchronized? Push or pull? Will it be out of sync? what to do
How to ensure the availability of data so that even if it is deleted, it can be restored to the level of minutes. what will you do.
There are too many database connections, exceeding the maximum value. How to optimize the architecture. How can it be conveniently processed?
502 What is the possible reason? How to troubleshoot 504?

Architecture

Partial operation and maintenance (understanding):
- Load balancing (Nginx, HAProxy, DNS)
- Master-slave replication (MySQL, Redis)
- Data redundancy and backup (MySQL incremental and full principles)
- Monitoring and inspection (two dimensions of survival and service availability)
- MySQL, Redis, Memcached Proxy, Cluster purpose and principle
- Sharding
- High availability cluster
- RAID
- Source code compilation, memory tuning
cache
- Whenever you encounter situations where caching is needed at work, briefly describe why.
Search solutions
Performance tuning
Monitoring solutions in various dimensions
Log collection centralized processing solution
internationalization
Database design
static solution
Draw common PHP application architecture diagrams

Framework

ThinkPHP (TP), CodeIgniter (CI), Zend (non-OOP series)
Yaf, Phalcon (C extension)
Yii, Laravel, Symfony (pure OOP series)
Swoole, Workerman (network programming framework)
The comparison frame distinguishes several direction points
- Is it pure OOP?
- Class library loading method (write your own autoload vs. composer standard)
- Usability direction (CI basic framework, Laravel is a high development efficiency framework and how many basic components are there)
- Black box (compared to C extension system)
- Running speed (eg: Laravel loads a lot of things)
- Memory usage

design pattern

Singleton pattern (emphasis)
Factory pattern (key)
Observer pattern (emphasis)
Dependency injection (emphasis)
Decorator pattern
proxy mode
Combination mode

Safety

SQL injection
XSS and CSRF
Input filtering
Cookie security
Disable mysql_ functions
When storing user passwords in the database, what should be done to ensure security?
Verification code Session problem
Secure Session ID (so that even after interception, it cannot be simulated and used)
Directory permission security
Contains local and remote files
File upload PHP script
eval function executes script
disable_functions turns off high-risk functions
FPM independent users and groups, giving specific permissions to each directory
Understand the difference between Hash and Encrypt

Advanced level

PHP array underlying implementation (HashTable + Linked list)
Copy on write principle, when to GC
PHP process model, process communication method, process thread difference
What is the core principle of yield?
PDO prepare principle
What is the difference between PHP 7 and PHP 5
Swoole applicable scenarios and coroutine implementation methods

Front-end

Natively obtain DOM nodes and attributes
box model
CSS files, style tags, inline style attribute priority
HTML and JS running order (page JS from top to bottom)
JS array operations
Type judgment
this scope
.map() and this specific usage scenario analysis
Cookie reading and writing
JQuery operations
Ajax request (difference between synchronous and asynchronous) random number prohibits caching
What are the benefits of Bootstrap?
Cross-domain request N solutions
New technology (understand)
- ES6
- Modular
- Pack
- Build tools
- vue, react, webpack,
- frontendmvc
optimization
- Browser concurrent number limit for a single domain name
- Static resource cache 304 (If-Modified-Since and Etag principle)
- Combine multiple small icons and use position positioning technology to reduce requests
- Static resources are combined into a single request and compressed
- CDN
- Static resource delayed loading technology and preloading technology
- keep-alive
- Optimization of CSS at the head and JS at the tail (principle)

Network

IP address to INT
What does 192.168.0.1/16 mean?
What is the main function of DNS?
The difference between IPv4 and v6

Network Programming

TCP three-way handshake process
Differences between TCP and UDP, applicable scenarios respectively
Is there any way to ensure UDP high availability (understand)
How to solve TCP sticky packets?
Why is a heartbeat needed?
What is a long connection?
How is HTTPS secure?
The difference between streams and datagrams
There are several ways to communicate between processes, which one is the fastest?
What happens fork() ?

API chapter

What is RESTful
How to make DELETE requests compatible with browsers that do not support DELETE requests
What is the main function of APP_ID APP_SECRET of common APIs? Explain the process
How to ensure that the data in API requests is not tampered with?
The difference between JSON and JSONP
The difference between data encryption and signature verification
What is RSA
How to deal with API version compatibility
Current limiting (wooden bucket, token bucket)
In what scenarios is OAuth 2 mainly used?
JWT
What is the difference between json_encode(['key'=>123]); and return json_encode([]); in PHP? What problems will occur? How to solve

Bonus points

Understand common language features and applicability to different scenarios.
- PHP VS Golang
- PHP VS Python
- PHP VS JAVA
Learn about PHP extension development
Proficient in C