What is &#x27;Contenteditable True Laravel 8&#x27;?In HTML5, we can set the contenteditable=&quot;true&quot; attribute to HTML tags to enable the user to edit the content in the tag on the browser side. Example. The Contenteditable attribute is compatible with all browsers (compatibility with versions before IE6 has not been tested), and in some cases, we can completely replace input or Textarea with a div to enable data collection. For example, when using ajax, we can get the content of a div when submitting a form. The DEMO code is as follows: {     &lt;style type=&quot;text/css&quot;&gt;       .demoEdit{     border:1px solid #dddddd;width:450px;min- height:20px;_height:20px;outline:0px;padding:2px;     } // outline:0px; The style solves the effect of the container getting the focus and displaying a dashed box in FF browsers.       .demoEdit p{     margin:0px;padding:0px;     }     &lt;/style&gt;       &lt;div contenteditable=&quot;true&quot; style=&quot;border:1px solid #dddddd;width:360px;min-height:20px;_height:20px;outline:0px;&quot;&gt;&lt;/div&gt;       &lt;div contenteditable=&quot;true&quot; class=&quot;demoEdit&quot;&gt;&lt;/div&gt;   } The cursor height will be as high as the container height or not show the cursor when the container gets the focus under FF browser, at this time if the container default adds a placeholder, such as &lt;br/&gt; or can solve this problem. The contentEditable property in Html can be used to turn on the editable state of certain elements. Perhaps you have never used the contentEditable property, or even heard of it, the role of contentEditable is quite amazing. You can make divs or entire web pages, as well as spans and other elements set to writable. The most common types of text we use are input and textarea. With the contentEditable property, you can enter content into divs, tables, p, spans, bodies, and many other elements. In particular, contentEditable is now supported in the html5 standard.If you need a VPS to run Laravel 8, you can choose LightNode. We provide stable and high-performance VPS hosting servers. Our VPS nodes locate in more than 20 locations in the world.Go to buy: <a href="https://www.lightnode.com" target="_blank">lightnode.com</a>

Library

Contenteditable True Laravel 8

Procedural programming and object-oriented programming embody two different ways of thinking for programmers, and this article focuses on the differences and connections between procedural programming and object-oriented programming. procedural programming is a process-centred way of thinking. It starts by analysing the steps needed to solve a problem, and then uses functions to implement these steps step by step, calling them in turn when they are used, a basic sequential way of thinking. The procedural development approach is a layer of abstraction from the underlying structure of the computer, which divides the program into two parts: the data and the operations that manipulate the data, with the core problem being the development and optimisation of data structures and algorithms. Common programming languages that support procedural development include C, COBOL and others. Object-oriented is a systematic way of thinking according to people&#x27;s understanding of the objective world, using the concept of building models based on objects (entities), simulating the objective world to analyse, design and implement software programming ideas, through the object-oriented concept to make computer software systems can correspond with the real world systems one by one. The object-oriented approach treats everything directly as an independent object, and what is considered in the process of dealing with a problem is no longer primarily how to describe it in terms of data structures, but directly how to reproduce the relationship between the various objects in the problem. The underlying implementation of the object-oriented approach also includes procedural thinking. Common programming languages that support object-orientation include C++, C#, Java and others. Specifically, object-oriented and procedural approaches differ in the following four ways. 1) Different starting points Object-oriented uses a conventional way of thinking to deal with problems in the objective world, emphasising the mapping of &quot;actions&quot; in the problem-solving domain directly onto the interfaces between objects. In contrast, process orientation emphasizes the abstraction and modularity of the process, and is process-centred construction or processing of objective world problems. 2) Different levels of logic Object-oriented use of computer logic to simulate the physical existence of the objective world, a collection of classes of objects as a unit to deal with the problem, as far as possible to bring the computer world to the objective world, in order to make the way to deal with the problem more clear and direct, object-oriented use of class hierarchy to reflect the inheritance and development between classes. The basic unit of procedural processing is the module that can clearly and accurately express the process, using the module hierarchy to outline the relationship and function between modules or modules, abstracting the objective world&#x27;s problems into processes that the computer can handle. 3) Different ways of data processing and control procedures Object-oriented data and the corresponding code encapsulated into a whole, in principle, other objects can not directly modify its data, that is, the object can only be modified by its own member functions to complete, control the program is through the &quot;event-driven&quot; to activate and run the program. The procedural approach is to process the data directly through the program, and to display the results of the process once it has been completed, in the control mode is to call or return to the program according to the design, and not to navigate freely. 4) Different ways of analysis and design and coding conversion Object-oriented throughout the software life cycle of analysis, design and coding, is a smooth process, from analysis to design to coding is the use of a consistent model representation, to achieve a seamless connection. In contrast, process orientation emphasises the transformation between analysis, design and coding according to rules throughout the software lifecycle, achieving a seamless connection. A comparison of the characteristics, advantages and disadvantages of object-oriented and procedural approaches is shown below. Object-oriented Features: abstraction, inheritance, encapsulation, polymorphism Advantages: easy to maintain, easy to reuse, easy to extend, low coupling Disadvantages: lower performance than procedural     Procedural Features: modularity of functionality, flow of code Pros: high performance, suitable for resource-constrained, real-time situations Disadvantages: not object-oriented easy to maintain, easy to reuse, easy to extend The object-oriented approach to programming has four basic characteristics. 1) Abstraction: This is the process of ignoring aspects of a subject that are not relevant to the current goal in order to pay fuller attention to aspects that are relevant to the current goal. Abstraction does not intend to understand the whole problem, but only to select a part of it, without using some of the details for the time being. Abstraction consists of two aspects, one being process abstraction and the other being data abstraction. Process abstraction means that any operation that explicitly defines a function can be viewed by the user as a single entity, although this operation may actually be performed by a series of lower-level operations. Data abstraction defines the data type and the operations imposed on an object of that type, and qualifies the value of the object to be modified and observed only through the use of those operations. 2) Inheritance: This is a hierarchical model for linking classes and allows and encourages the reuse of classes, it provides a way to explicitly express commonality. A new class of objects can be derived from an existing class, a process known as class inheritance. The new class inherits the characteristics of the original class, which is called the derived class (child class) of the original class, and the original class is called the base class (parent class) of the new class. A derived class can inherit methods and instance variables from its base class, and the class can modify or add new methods to make it more suitable for particular needs. This also reflects the relationship between the general and the particular in nature. Inheritance is a good solution to the problem of software reusability. 3) Encapsulation: This means that processes and data are enclosed and access to data is only possible through defined interfaces. Object-oriented computing begins with this basic concept that the real world can be portrayed as a series of fully autonomous, encapsulated objects that access other objects through a protected interface. Once the properties of an object have been defined, it is necessary to determine the visibility of these properties, i.e. which properties are visible to the external world and which properties are used to represent internal state. The interface to the object is defined at this stage. As a rule, direct access to the actual representation of an object should be prohibited and the object should be accessed through the operational interface, which is called information hiding. Encapsulation ensures that modules have a good degree of independence and makes it easier to maintain and modify the application. Modifications to the application are limited to the internals of the class, thus minimising the impact of changes to the application. 4) Polymorphism: This means that objects of different classes are allowed to respond to the same message. For example, the same copy-and-paste operation has different effects in a word processor and a drawing program. Polymorphism includes parametric polymorphism and inclusion polymorphism. Polymorphic languages have the advantage of flexibility, abstraction, shared behaviour and shared code, and are a good solution to the problem of homonymy of application functions.

Differences Between Procedural programming and object-oriented programming

1. BackgroundMutually exclusive access to shared resources has traditionally been a problem that many business systems need to solve. In distributed systems, distributed locks are often used as a general-purpose solution.2. From single-computer locking to distributed lockingIn a stand-alone environment, when a shared resource cannot provide mutually exclusive access itself, to prevent data corruption caused by simultaneous read/write access to the shared resource by multiple threads/multi-processes, a third party provides the capability of mutual exclusion, which is often the kernel or a library that provides the capability of mutual exclusion. . If we evolve to a distributed environment, we need a distributed service that provides the same function, different machines get a lock through the service, and the machine that gets the lock can access the shared resources in an exclusive way, so the service is collectively called distributed lock service, and the lock is also called distributed lock.To abstract the concept of distributed locks, first of all, a distributed lock needs to be a resource that provides concurrency control and outputs an exclusive state, that is.Lock = Resource + Concurrency Control + Ownership DisplayAs an example, take a common single lock.Spinlock = BOOL + CAS (optimistic lock)Mutex = BOOL + CAS + notification (pessimistic lock)Spinlock and Mutex are both a Bool resource, via the atomic CAS instruction: when it is now 0 set to 1, it holds the lock if it succeeds and not if it fails if it does not provide a display of ownership, e.g. AtomicInteger, it is also via the resource (Integer) + CAS, but it does not explicitly hint at ownership and therefore will not be, Of course, the &quot;ownership display&quot; can be seen more like a wrapper for some form of service provision.In a stand-alone environment, the kernel has a &quot;God&#x27;s perspective&quot; and can know the survival of the process and release the lock resources held by the process when it hangs, but in a distributed environment, this becomes a challenge, and to cope with various machine failures, downtime, etc., it is necessary to provide a new feature to the lock: availability.Any service that provides three characteristics can provide the ability of distributed locks. The resources can be files, KVs, etc. The availability of locks is ensured by creating atomic operations such as files and KVs, indicating ownership by the result of successful creation, and also by TTL or sessions.3. System Classification of Distributed LocksBased on the security of the lock resource itself, we classify distributed locks into two camps.- distributed systems based on asynchronous replication, such as MySQL, tair, Redis, etc.- distributed consistent systems based on the Paxos protocol, such as a zookeeper, etc., etc.In distributed systems based on asynchronous replication, there is a risk of data loss (lock loss), not safe enough, often through the mechanism of TTL to assume a fine-grained lock service, the system is simple to access, suitable for very time-sensitive services, expect to set a short validity period, perform short-term tasks, and the impact of lock loss on the business is relatively controllable.The distributed system based on the Paxos protocol, which guarantees multiple copies of data through consistency protocols and high data security, often undertakes coarse-grained lock services through the mechanism of leases (sessions), this system requires a certain threshold and is suitable for services that are sensitive to security, wish to hold locks for a long time and do not expect lock loss to occur.

Technical Practice of Distributed Locking in Storage Systems

Process: is a basic unit of concurrently executing programs that allocates and manages resources during execution, and is a dynamic concept that competes for the resources of a computer system.Thread: An execution unit of a process, a scheduling entity within the process section. A basic unit of independent operation that is smaller than a process. Threads are also known as lightweight processes.A program has at least one processor and a process has at least one thread.Differences between processes and threadsAddress space: Threads of the same process share the address space of this process, while processes are independent of each other.Resource ownership: Threads within the same process share the resources of this process such as memory, I/O, CPU, etc., but the resources between processes are independent.When a process crashes, it does not affect other processes in protected mode, but a thread crashes and the whole process dies. So multi-process is more robust than multi-thread.Process switching consumes more resources and is more efficient. So when it comes to frequent switching, it is better to use threads than processes. Similarly, if concurrent operations are required and some variables are shared, only threads can be used and not processes.Execution process: Each independent process has a program entry, a sequential execution sequence, and a program entry. However, threads cannot be executed independently and must be dependent on the application, which provides control over the execution of multiple threads.Threads are the basic unit of processor scheduling, but processes are not.Both can execute concurrently.Thread safety is a concept in computer program code when programming with multiple threads.In programs where multiple threads with shared data are executing in parallel, thread-safe code ensures that each thread can execute properly and correctly without surprises such as data contamination through synchronization mechanisms.Thread safety problems are mostly caused by global and static variables, and local variable escapes may also cause thread safety problems. If each thread has only read operations on global variables and static variables, but no write operations, the global variables are generally thread-safe; if multiple threads perform write operations at the same time, thread synchronization should be considered, otherwise, thread safety may be affected.

Difference Between Threads and Processes? What Is Thread Safety

BGP (Border Gateway Protocol) is a routing protocol used to connect independent systems on the Internet. It is an enhanced, refined, and scalable protocol developed by the Internet Engineering Task Force.BGP4 supports the CIDR addressing scheme, which increases the number of available IP addresses on the Internet.BGP was designed to replace the original Exterior Gateway Protocol, EGP. It is also considered to be a path vectoring protocol.BGP is mainly used for interconnection between Internet AS (Autonomous Systems). The most important function of BGP is to control the propagation of routes and to select the best route. After interconnection using the BGP protocol, all backbone routing devices of network operators will judge the best route to the IP segment of IDC rooms to ensure high-speed access for users of different network operators.The server room that uses the BGP solution to achieve dual-line interconnection or multi-line interconnection is called the BGP server room.Advantages of BGP server room1. The server only needs to set an IP address, and the best access route is determined by the backbone router on the network according to the number of route hops and other technical indicators, which will not take up any system resources of the server. The server&#x27;s uplink and downlink routing can choose the optimal path, so it can truly achieve high-speed single-IP high-speed access.2. because the BGP protocol itself has the characteristics of redundant backup and loop elimination, so when the IDC service provider has more than one BGP interconnection line that can achieve mutual backup of the route, the route will automatically switch to other lines when a line fails.3. the use of BGP protocol can also make the network has strong scalability can be interconnected with other operators IDC network, easy to achieve a single IP multi-line, to do all interconnected operators of the user access are very fast. This is a dual-IP dual-line that can not be compared.BGP server room line technologyBGP is a routing protocol between autonomous systems, and its main function is to exchange network reachability information with other BGP speakers. A BGP speaker is any device configured for BGP. BGP uses TCP as its transport protocol (port 179), which provides reliable data transfer.Two BGP routers form a transport protocol connection. These two routers are called neighbors or peers. Once the transport connection is formed, the two pairs of routers exchange messages to open and confirm the connection parameters. In this step, the routers exchange information such as BGP version number, AS number, duration, BGP identity, and other optional parameters. If any of the parameters do not agree between the peers, an error notification is sent and this peer connection is not established.If the peer routers all agree on these parameters, the entire BGP routing table is exchanged via the UPDATE message, which contains a list of reachable destinations through each system (i.e., Network Layer Reachability Information NLRI) and the path attributes for each route. The path attributes contain information such as the source of the route (ORIGIN) and the level of priority.The BGP table is valid for each peer during the BGP connection. If a routing message changes, neighboring routers use incremental updates (messages) to pass this information. BGP does not require that routing information be refreshed. If no route changes are generated, BGP peers only exchange keepalive messages, which are sent periodically to ensure that the connection is kept alive.BGP server room advantage analysisBGP room is the server renters through the technical means, the actual different operators can access a common IP, and different operators can achieve the fastest access speed between the relevant network technology.BGP server room to a certain extent to solve the problem of north-south interoperability of various users, improve the access speed of users, and the effect of single IP dual lines realized with the BGP protocol. The program is through the BGP protocol, directly one of the lines of IP mapping another line IP, when visitors browse your website, will automatically select the fastest line of access according to the actual situation so that users of various operators can achieve the best access speed.1. The rented server has only one IP, and the user&#x27;s access route is chosen by the router to access according to the visitor&#x27;s actual access speed by selecting the optimal access path. And does not take up any server resources. The server&#x27;s uplink and downlink are routers to choose the best route, so this can achieve the best access speed between operators to achieve the real BGP effect.2. Because the BGP protocol itself has the characteristics of redundant backup, eliminating loops, when you host or rent a server failure, you can achieve mutual backup. The company&#x27;s main business is to provide a wide range of products and services to its customers.3. The BGP server rental is also a good expansion and integration and can be realized and other operators interconnection, easy to achieve a single IP multi-line, so that all interconnected operators of the user access is very fast. This is a dual-IP dual-line server rental that can not be achieved.

What's LightNode's BGP Server Room?

DDoS Attack IntroductionDistributed Denial of Service (DDoS) combines multiple computers as an attack platform to launch DDoS attacks on one or more targets through remote connections using malicious programs to consume the performance of the target server or network bandwidth, thus causing the server to fail to provide services normally.Attack PrincipleUsually, the attacker uses an illegal account to install the DDoS master program on one computer and install the proxy program on multiple computers on the network. Within a set period, the master program communicates with a large number of proxy programs, and when the proxy programs receive instructions to launch an attack on the target, the master program can even activate hundreds or thousands of proxy program runs in a few seconds.The harm of DDoS attackDDoS attacks can cause the following hazards to your business.1. Significant financial lossAfter a DDoS attack, your source server may not be able to provide services, resulting in users not being able to access your business, thus causing huge economic losses and brand losses.For example, when an e-commerce platform is under DDoS attack, the website cannot be accessed normally or even shut down for a short period, resulting in legitimate users not being able to place orders for goods, etc.2. Data leakageHackers may take the opportunity to steal the core data of your business during DDoS attacks on your server.3. Malicious competitionSome industries have vicious competition, competitors may maliciously attack your service through a DDoS attack, to gain an advantage in the industry competition.For example, a game business suffered a DDoS attack and the number of game players dropped drastically, causing the game business to go offline completely and quickly within a few days.Common types of DDoS attacks1. Malformed message	Malformed messages mainly include Frag Flood, Smurf, Stream Flood, Land Flood, IP malformed messages, TCP malformed messages, UDP malformed messages, etc.	The malformed message attack refers to the attack purpose of the denial of service by sending a defective IP message to the target system, which makes the target system crash when processing such a message.2. Transport layer DDoS attack The transport layer DDoS attack mainly includes Syn Flood, Ack Flood, UDP Flood, ICMP Flood, RstFlood, and so on.Take the Syn Flood attack as an example, it uses the three handshake mechanism of TCP protocol, when the server-side receives a Syn request, the server-side must use a listening queue to keep the connection for a certain time. Thus, the server&#x27;s resources are consumed by constantly sending Syn requests to the server, but not responding to Syn+Ack messages. When the listening queue is full, the server will not be able to respond to normal user requests, achieving the purpose of denial-of-service attacks.3. DNS DDoS Attack	DNS DDoS attacks mainly include DNS Request Flood, DNS Response Flood, False Source + Real Source DNS Query Flood, Authoritative Server Attack, and Local Server Attack.	Take the DNS Query Flood attack as an example, it essentially performs a real Query request, which is a normal business behavior. However, if multiple puppet machines launch a huge number of domain name query requests at the same time, the server cannot respond to normal Query requests, which leads to denial of service.4. Connection-based DDoS attack	Connection-based DDoS attack mainly refers to TCP slow connection attack, connection exhaustion attack, Loic, Heroic, Slowloris, Pyloris, Xoic, and other slow attacks.	Take the Slowloris attack as an example, the target of the attack is the concurrency limit of the Web server. When the number of concurrent connections to the Web server reaches the upper limit, the Web service cannot accept new requests. when the Web service receives a new HTTP request, it establishes a new connection to process the request and closes the connection after processing is complete. If the connection is always connected, a new connection needs to be established when a new HTTP request is received for processing. And when all connections are connected, the Web will not be able to process any new requests.Slowloris attack uses the characteristics of the HTTP protocol to achieve the purpose of the attack. HTTP requests with \r\n\r\n mark the end of Headers, if the Web server only received \r\n, it is considered that the HTTP Headers part is not finished, will keep the connection and wait for the subsequent request content.5. Web application layer DDoS attack	Web application layer attacks mainly refer to HTTP Get Flood, HTTP Post Flood, CC, and other attacks.	Usually, application-layer attacks completely simulate user requests, similar to various search engines and crawlers, these attacks and normal business do not have a strict boundary, it is difficult to distinguish.Some resource-consuming transactions and pages in Web services. For example, the paging and table splitting in Web applications, if the parameters of the control page are too large, frequent page turns will take up more Web service resources. Especially in the case of high concurrency and frequent calls, transactions like this become the target of early CC attacks.Since most of the attacks nowadays are hybrid, frequent operations that simulate user behavior can be considered CC attacks. For example, the access to websites by various vote swiping software is, in a way, a CC attack.CC attacks target the back-end business of Web applications, which will directly affect the functionality and performance of Web applications, including Web response time, database services, disk read/write, etc., in addition to causing a denial of service.How to determine whether the business has been subject to a DDoS attack?Your business may have been subject to a DDoS attack when the following conditions occur.1. When the network and equipment are normal, the server suddenly has disconnection, access lag, user dropout, etc.2. There is a significant increase in server CPU or memory usage.There is a significant increase in traffic in the outbound or inbound direction of the network.3. Your business website or application suddenly experiences a large number of unknown accesses.4. Login to the server fails or is too slow.

What's DDoS Attack? How to protect

다른 게시글