Patterns and Anti-Patterns in the Software Lifecycle

In the stages of software development, there are many methods used to rectify errors in the programming. Patterns and Anti-Patterns quite do the exact job. In the cycle of software development, there are series of common occurring errors and problems. To make a software reliable, robust, reusable and extensible, one uses patterns in order to solve common occurring problems.

Pattern in Software Development:

While designing your software, you will at some stage feel the problem of continuously occurring errors of the same type again and again. If you go on solving them personally, not only you will waste time but you will lose your concentration. In order to solve this, we use Pattern to remove common occurring errors in software design. Pattern can be reusable for a given problem as the problem can occur many times.

Design Patterns provide general solutions that may not fit with specific problems. Design Patterns offer tested and proven development paradigms that speed up the process of development of software.

Types of Patterns:

• Algorithms Strategy Patterns: Solve high level algorithmic problems by exploiting characteristics on a computing platform.
• Structural Design Pattern: This solves problems related to global structures of applications being developed.
• Computational Design Patterns: Solve problems related to computation.
• Implementation Strategy Pattern: Solve problems related to implementation source code that supports program organization.

Design Pattern has three classification known as Structural Patterns, Behavioral Patterns and Creational Patterns.

Anti-Pattern in Software Development:

Anti-Pattern is a counter word used to describe Patterns. In this, pattern that is frequently used but is ineffective to a problem and has gone wrong is called anti-pattern. Anti-Pattern is used mostly as viable solution to a problem but due to some reasons in gets wrong. If you apply anti pattern, not only the answer to your problem will be ineffective but it will leave you into a more complex and worse situation than you were before.

It is better to first recognize the pattern before you implement it for a solution while developing your software as it may lead you to nowhere.

Applications of Anti-Pattern:

Anti-Pattern is used in many circumstances and fields depending upon the need. It is used in social and business operations on different levels like Organizational, Project Management. In Software Engineering, it is used in Software Design, Object Oriented Programming, Programming, Configuration Management, and Methodological.

Anti-Patterns look to be genuine in the starting but may soon be ineffective and can lead you into complex situations and it typically has more of consequences than advanatges.

http://www.anarsolutions.com/patterns-anti-patterns-software-lifecycle/utm_source=blogger

Making CI Effective in Any Size Organization

CI or Continuous Integration is a term used in DevOps that allows real time integration of data into the central system of the organization. Earlier to t

his, integration of data took place once in a while by manual means and that made the organization less effective and deprived of real time developments.

Continuous Integration and its Purpose:

The sole purpose of Continuous Integration is to create real time environment for the team members so that they can execute their work in a more efficient way than before. In continuous integration, the team members update their data into the central computer so that the rest folks can also have access to it. The difference between CI and other integration method is that it is real time and automated while the others are manual and are dependent on the team member for updating.

Making Continuous Integration Effective in Any Size Organization:

CI can be effective if it properly fits into the size organization. There must be proper analysis, feasibility check, and excellent management and only then CI will fit well with size organization. For making a good team organization, you need to have hardworking, punctual and innovative people in your team. The utmost important thing is that your team knows how to collaborate with their teammates. The proper collaboration of team members along with distinctive, proportional and well mined work distribution is the key trait of any best team organization. If you have such a team then CI will be effective automatically.

Some Advantages of Continuous Integration:

• Mitigating Risks: There’s a difference between your local working machine condition and the condition of that machine on which your product software will run. Sometimes it happens that the software which was working fine on your local machine works pathetically on your client’s computer. CI allows one to remove such problems by continuous testing and reexamining.
• Builds Confidence while Negotiating with Client: If you have an effective test suite tjhat sort outs all problems and error then the level of confidence inside you excels. Continuous testing removes errors, bugs and other small mistakes and makes your software more robust and secured and that will help you in taking a lead.
• Builds Better Communication making your work excellent: CI enhances communication level between your teammates and that helps in building the best software.

So if you want to build a software that has increased visibility, reduces overhead, mitigate risks, boosts confidence and makes your software effective and efficient then you should definitely try Continuous Integration.

Testing tools – JUnit and EasyMock

In order to enhance the productivity of developer and the software, we use JUnit and EasyMock which are basically best choices for testing tools. JUnit is done by isolating a single component from the rest. The method goes in four sections and thus a cycle is completed. In case of EasyMock, it is the method by which one isolates the component from the rest of the system as all of them are dependent on each other.

JUnit:

JUnit is performed in four phases and is done in isolated components in a repeatable way. The four phases are as follows:

1. Prepare: In this phases, the system sets up a baseline in order to test and it also defines the test result.
2. Execution: The Test starts now.
3. Validation: The system validates the result against the previous expectations or estimations.
4. Reset: The whole unit is set back to the original way like it was before prepare phase.

JUnit is a popular framework that is used for testing purpose of isolated components as it has effective API.

Important Characteristics of JUnit:

• JUnit is known to be an open source network for testing and writing codes.
• JUnit provides test runners for running tests.
• It gives you the facility of writing codes fast and helps you in running it.
• Two bars are there in order to display progress and report. If the bar is green then the test is running smoothly else if red then test failed.

Overview of EasyMock:

Before we understand EasyMock, we need to understand Mock Objects. Mark Object facilitates the running and testing of codes by JUnit. To test a component, one needs to isolate it from the rest as they are interconnected and are independent to each other. The Job of Mock Object is to isolate the component and this is done by EasyMock.

EasyMock is a framework that creates Mock Object which in return isolates the component in order to run. After the creation of Mock Object, a proxy object is created which takes the place of real object.

Life Cycle of EasyMock:

• Create Mock: In this phase, the mock object is created
• Expect: In this, the expected behavior of the mock object is recorded and in the later phase, it is verified.
• Replays: This phase replays the previously recorded behavior.
• Verification: This is the last phase where the recorded mock object is executed and if passed then the phase is complete.

JUnit and EasyMock work in collaboration as both are interdependent to easy other. One needs to test components and the other creates viable situation to run testing.

Developing enterprise applications using Microservices Architecture

Microservices Architecture is basically a distinctive method to d

evelop a software system. For many developers, this method has become a preferred tool for developing enterprise applications. Microservice architecture is given preference because it is scalable. It means that it supports variety of platforms and devices, especially internet, mobile, computer and wearable or if you are not sure what more you will require in such cloudy situation.

Characteristics of Microservice Architecture:

• Componentization of system is a special feature in Microservices. It has the ability to replace each piece being independent from other. It is also the ability to replace part of a system.
• Automation of infrastructure where continuous delivery being mandatory.
• It provides the feature of decentralizing data management which means that there will be different database for each service instead of one database for the whole system.
• It has smart end points and dumb pipes which eradicates the use of an Enterprise Service Bus.
• Organization is based around business capabilities rather than technology.
• The components here use simple methods of communication like Simple Restish protocol.
• The facility of decentralize components where every independent component can use their standard method of development.Advantage of Microservice Architecture:

Microservices allow the developer to deploy and redeploy a particular component by redefining it. It also means that the components can be broken down into multiple pieces and can be used as independent component for different use without compromising with the integrity of the application.

Other Advantages:

• In Microservices, codes for different services can be written in different language.
• In case if one of the Microservice fails then the other will work and will have no impact. The process is called Better fault Isolation.

Apart from these, Microservice Architecture allows reusability and lots of scalability. This makes this method much more preferable than any other method. It also increases the autonomy of the developing team.

Disadvantage of Microservice Architecture:

The drawback lies in developing an independent system which may be very painful as one can have to write unnecessary programing codes in order to make it function. Transaction management and multiple database can be a painful process for the user. Thought the system under Microservices will be independent but there must some coordination between them and sometimes having independent components can make it difficult for the developer.

In the last, despite of drawbacks or other complexity, Microservices has been implemented by many organizations like Amazon, Twitter, PayPal, EBay and Netflix and many more. In the last few year, Microservices has seen huge rise in use which shows the level of success and its importance in today’s architecture industry.

SAFe – Scaled Agile Framework

To carry out software development work, we use Scaled Agile Framework which is also known as SAFe. Most software development teams use scaled agile in order to boost the work quality, quantity, speed and productivity. Scaled agile and its whole framework is divided into three patterns; Team, Program and Portfolio.

Why one should use SAFe?

Scaled agile is an advanced method that is used in software development that overcomes many obstacles between the team. Here are few reasons why you must use scaled agile:

• Scaled agile is simple, lighter and easy to use yet it gives immense efficiency and can expand as per use.
• It enhances the level of productivity by 20-50% and that is why it is given prominence.
• Scaled Agile also enhances the level of quality by up to 50% and more. Such benefits are rarely available in other agile frameworks.
• It also enhances job productivity and job satisfaction. The major role of agile framework is to create a balance between the teams that are opting different fields but have the same goal.

When is the need to use SAFe?

We basically use scaled agile when the team is working independently. The other reason is quite similar like when the team is working on different aspects of agile implementation. However, they are facing constant and severe obstructions and obstacles then we use agile framework. While working on a large board we use scaled agile as it synchronizes the whole team into and brings them on one board. The other important reason is rise in productivity and quality of work.

Advantages of SAFe:

Scaled Agile offers many advantages for users and some of them are mentioned below.

• Scaled agile is available for free and is very approachable and easy to implement.
• The framework is in usable form and is easy to implement without much complexions.
• Scaled agile is more practical and specific rather than being complex. User knows where to implement it and how to implement it.
• It offers complete picture of software development which makes it easier for the developer.
• Scaled Agile promotes transparency at all levels making it more suitable for teams.
• Apart from this, scaled agile constantly evolves itself making it more robust day by day to ensure efficiency and quality.

Like every other software framework, scaled agile has various reasons to be criticized. The over simplified way of approach makes it mediocre for the developers. The one size fit all approach also portrays the feeling that everything is ok and nothing needs to be changed whereas change is the constant phenomenon. These reasons yet are nothing compared to its advantages. One can say that presently agile holds high ground and is suitable for use.

Exception Handling Best Practice

The process that responds to the occurrence of exceptions while computing is called Exception Handling Best Practice. This process often alters the working out or execution of any program and implements specific operating system, language of programming along with computer hardware. In other words, this process interrupts the continuity or lucidity of a normal and regular flow of operations and carries out instructions which had been registered previously. The handling of an exception for a certain program dependsentirely to its configuration of either a software exception or a hardware exception. Exception Handling Best Practice offers almost the same as error checking, however it does not allow the smooth and uninterrupted flow of a program. The very first exception handling was observed in a programming language, Lisp, as early as in the 1960s and 1970s. It has eventually emerged and evolved as a significant operation with new approach and demands.

Advantages of Exception Handling:

• Unlike the traditional custom of handling errors and glitches, exception handling provides with the advantage of simplifying complexities of a program. It offers one to read a program without much effort like the tradition system as language is very distinct.
• With the incorporation of a singular exception handler it is possible to handle several errors which are similar to each other. Considering one of the errors as a class parameter, other errors are dealt comparing with it.
• Exception handling has a very crucial advantage over the traditional error handling. This is because it can propagate or channelize all the errors to a certain situation where they can be easily handled.

 Disadvantages of Exception Handling:

• Since exception handling is too keen to deal with the ‘normal flow’ of a program, it mostly abhors the possibility of the generation of the code for error handling.
• There are no garbage collectors which are built-in and thus, exception handling may often result in the leakage of confidential resources. This might eventually block the working procedure of a running program.
• Exception handling has resulted in its exploitation as it offers to propagate errors in the desired direction to be handled. People tend not to follow the rigorous process of the traditional method and put exceptional handling in use as much as possible.

 Conclusion:

One has to be meticulous enough to implement exception handling; this is because there are certain cases where the traditional method may prove more fruitful. However, Exception Handling is one of the best error handling procedures to be used in codes. Its checks, navigates and resolves certain errors tactfully and helps a programmer to execute his work without being obstructed.

Duplication of code – importance of eliminating it!

Software development is a collaborative process and developers often struggle with the duplication of code.

Duplication occurs when multiple developers are working on a software project simultaneously but on different tasks or modules, and hence they are not aware if similar code is already written by other developer and then they end up writing the same code again. Another big reason is copy paste of the code by the developers resulting in either basic or parametric literal duplication. Developers often reuse the already available content under pressure of time and want to avoid intellectual strain on them. They often clone the code and then adopt the same either unintentionally or they are not aware of how to avert or get rid of it. At times, renaming of variables, changing values, inserting or deleting code fragments are followed with intention and then detailed design is not modified resulting in duplication of code.

Taking everything into account, there are three simple kinds of duplication that we can remove from our code that productively shape up on each other.

• Data Duplication

This one is the most basic type and is easily identifiable. This type of duplication can be eliminated by generating a way that parameterizes the alterations characterized by that data.

• Algorithm Duplication

To not repeat this type of duplication, it is mandatory to have a thorough knowledge of delegates and functional programming, as using delegates builds a much simpler method and casts the problem in the same light as refactoring any other kind of data.

• Type Duplication

A lot of times, the two methods that do pretty much the same thing, however, they just vary on the kind they operate on results in type duplication. Just like data, this duplication can be eliminated using generics to refactor out that type info.

For instance, imagine a functionality is tweaked a bit and that code is used 50 times in the project, now you will be required to go and make that small change 50 times to ensure the change is reflected at all places. Another classic example is bug fixing, developer may not be aware of duplicate code available in the project and might go and fix the bug at one instance as reported.

How to get rid of duplication?

Code duplication is important factor for high maintenance cost, and this problem is present in all medium to large software projects. Usage of Code duplication detection tools, Open source and Proprietary, can help to identify and fix the problem.

Conclusion:

Duplication has become a norm and you may get it in the code, and like we use various tools to test the performance of the project, it has become essential to get rid of duplication using the available tools. This will make your code shorter, easier to understand, and can be maintained without any hassle.

Angular JS2

Before knowing about Angular JS2 , you must have some basic ideas about Angular JS. Angular JS is nothing but a web application framework, this framework is based on mainly the open source front end. An individual community and Google mainly maintain it. The framework of Angular JS is on the first step read from the HTML page, This HTML page is embedded into a custom attribute of the tag which is additional.

The Basic Idea of Using Angular JS 2

The Angular JS is used on certain websites such as the NBC, ABC News, Walgreens, Sprint, Intel and Wolfram Alpha. This was mainly built with the idea of connecting components of software and creation of user interfaces when declarative program is on use. Now you will be knowing about the Angular JS2  whose main work is kick starting an application or MVP. Angular JS2  is also known as Angular 2. When more features came to existence the team of angular made a decision of rewriting the old frame work with a new one with more features which is termed as the Angular 2. Between Angular JS and Angular JS2  there is a presence of migration path which is known as the ng-upgrades. For the making of single page application advance features are provided by Angular 2 or Angular JS 2 .

Components of Angular JS2

The elements are offered by angular 2 instead of offering the controllers typical of the MVC architecture. Angular JS2  contains a very less number of directives when compared to Angular JS. It is a modular frame wok. A module encapsulates each piece of functionality and for other parts of application a service is exposed in Angular JS2 .

Different Modules of Angular JS2

There are two types of modules in an Angular JS 2 . With the user’s own application code the use of module is promoted by the Angular JS 2 . There were a lot of old cruft present in angular JS which was replaced and developed in Angular JS2 . It is not easy to upgrade the applications of Angular JS to Angular JS 2 , it is a different framework from that of Angular JS but Angular JS2  is based on the same path of ideas of the Angular JS. In case of the application of Angular JS 2  it consist of the component where each of the component consist of metadata, class and template. So this much introduction is enough to give you a basic idea about the Angular JS 2 .

Cryptography in .NET

The .NET Framework provides implementations of many standard cryptographic algorithms. These algorithms are easy to use and have the safest possible default properties. In addition, the .NET Framework cryptography model of object inheritance, stream design, and configuration is extremely extensible.

Object Inheritance

The .NET Framework security system implements an extensible pattern of derived class inheritance. The hierarchy is as follows:
•    Algorithm type class, such as SymmetricAlgorithm, AsymmetricAlgorithm or HashAlgorithm. This level is abstract.
•    Algorithm class that inherits from an algorithm type class; for example, Aes, RC2, or ECDiffieHellman. This level is abstract.
•    Implementation of an algorithm class that inherits from an algorithm class; for example, AesManaged, RC2CryptoServiceProvider, or ECDiffieHellmanCng. This level is fully implemented.

Using this pattern of derived classes, it is easy to add a new algorithm or a new implementation of an existing algorithm. For example, to create a new public-key algorithm, you would inherit from the AsymmetricAlgorithm class. To create a new implementation of a specific algorithm, you would create a non-abstract derived class of that algorithm.

How Algorithms Are Implemented in the .NET Framework

As an example of the different implementations available for an algorithm, consider symmetric algorithms. The base for all symmetric algorithms is SymmetricAlgorithm, which is inherited by the following algorithms:
1.    Aes
2.    DES
3.    RC2
4.    Rijndael
5.    TripleDES
You can choose which implementation is best for you. The managed implementations are available on all platforms that support the .NET Framework. The CAPI implementations are available on older operating systems, and are no longer being developed. CNG is the very latest implementation where new development will take place. However, the managed implementations are not certified by the Federal Information Processing Standards (FIPS), and may be slower than the wrapper classes.

Stream Design
The common language runtime uses a stream-oriented design for implementing symmetric algorithms and hash algorithms. The core of this design is the CryptoStream class, which derives from the Stream class. Stream-based cryptographic objects support a single standard interface (CryptoStream) for handling the data transfer portion of the object. Because all the objects are built on a standard interface, you can chain together multiple objects (such as a hash object followed by an encryption object), and you can perform multiple operations on the data without needing any intermediate storage for it. The streaming model also enables you to build objects from smaller objects. For example, a combined encryption and hash algorithm can be viewed as a single stream object, although this object might be built from a set of stream objects.

Cryptographic Configuration
Cryptographic configuration lets you resolve a specific implementation of an algorithm to an algorithm name, allowing extensibility of the .NET Framework cryptography classes. You can add your own hardware or software implementation of an algorithm and map the implementation to the algorithm name of your choice. If an algorithm is not specified in the configuration file, the default settings are used. For more information about cryptographic configuration, see Configuring Cryptography Classes.

Regular Expression : Useful Tools and Resources

A Regular Expression is a term used in Computer science and language. Regular Expression or Regex is a set or sequence of characters that define a search pattern. This method is mostly used in “find” or “search and replace” application. Regex is used in search operations where “find and replace” options are used, especially in word processor.

Features of Regex:

A Regular Expression is a very powerful method which is required at every step when you are using a programming language. It is of utmost importance when you are performing scan and replace option for future actions. If you want to improve your URL or if you want to modify your RSS feed then you must definitely use Regex. If you are a beginner in learning regular expression then you will find some difficulty in understanding its expressions but in a moment of time it will become very easy for you to work on it.

Applications of Regex:

Regular Expression or regex is used in wide variety of issues. The most common is word processing and string processing where regex is commonly and intensively used. In the above two, there is no need of factual expression. Apart from these, regex is also used in Data Wrangling, Data scraping, data validation, and simple parsing, the system of syntax highlighting system and many other tasks. This method is also used in Google search options.

Advantages of Regex:

Regular Expression is very flexible in nature and to run this application you don’t need to change much of your settings. The second advantage of regular expression is that it is fast in nature and does processing in a very fast speed. The regex is language independent. It means that there is no necessity to write a regular expression in a definite code or the code changes with different languages. The most basic advantage of regex is that it is efficient. You don’t need to write much for executing a task and it can be written in one single line of code. It is often more simpler than ‘substrings+ index’ approach.

Disadvantages of Regular Expression:

In the early phase of regex, it is hard to read and understand the code of regex. A simple code like ‘?’ has three meanings in different context. It is also hard to debug it as not much info is provided if the match is not found. The compilation part is only done at the runtime adding it to another disadvantage.

Some Resources and Tools:

• Expresso: Desktop Regex Tools
• The Regex Coach
• RegExr Desktop
• Regex Widget

Regular Expression as a tool provides various number of advantages for the user. It is often recommended to use Regex.

Nunit VS Inbuild TDD

Nunit VS Inbuild TDDUnit testing is a sort of testing done at the designer side. It is utilized to test techniques, properties, classes, and congregations. Unit testing is not testing done by the quality affirmation office. Unit testing is utilized to test a little bit of workable code (operational) called unit. This urges designers to adjust code without quick worries about how such changes may influence the working of different units or the program all in all. Unit testing can be tedious and dull, yet ought to be done completely with persistence.

What is NUnit?

NUnit is a developing, open source framework designed for writing and running tests in Microsoft .NET programming languages. NUnit, as JUnit, is a part of test-driven development (TDD), which is a piece of a bigger programming design paradigm known as the Extreme Programming (in XP).

NUnit options have a GUI like that utilized as a part of JUnit. The tests may be run persistently. Results are given quickly. Multiple tests may be run simultaneously. No subjective human judgments or translations of test outcomes are required. The effortlessness of the framework makes it conceivable to effectively adjust bugs as they are found. The present rendition of NUnit is composed in C#, a protest arranged programming (OOP) language that joins the energy of C++ with the effortlessness of Visual Basic. NUnit is one of a group of related testing frameworks known as xUnit.

• Unit Testing alludes to what you are testing, TDD to when you are testing.
• The two are orthogonal.

Unit Testing implies, well, testing singular units of conduct. An individual unit of conduct is the littlest conceivable unit of conduct that can be independently tried in isolation. (I realize that those two definitions are roundabout, however they appear to work out great practically speaking.)

You can compose unit tests before you compose your code, after you compose your code or while you compose your code.

The Difference Between NUnit Testing

TDD implies (once more, sort of self-evident) giving your tests a chance to drive your development (and your design). You can commit that with the unit tests, functional tests and acknowledgment tests. Generally, you utilize every one of the three.

The most essential piece of TDD happens to be the middle D. You let the tests drive you. The tests guide you, what to do next, when you are finished. They disclose to you what the API will be, what the design is. (This is critical: TDD is not tied in with writing tests first. There are a lot of ventures that compose tests first yet don’t rehearse TDD. Writing tests initially is essentially an essential for having the capacity to give the tests a chance to drive the development.)

Dependency Injection- Types and points of interests

The dependency injection designs the most well-known design paradigms today. It is procedure of evacuating dependency of object which makes the independent business objects. It is exceptionally valuable for Test Driven Development.

Background

This tip shows an overview of the dependency injection design, the distinctive sorts of dependency injection, and the points of interest and drawback of DI with c# source code cases.

   Situation of Object Dependency

Object dependency implies one object needs another object to execute   appropriately, in multi-tier application (Business Logic Tier,       Presentation Tier, and Service Tier), the exceptionally normal situation   is; Presentation Tier reliant on the Business Logic and the Business   Logic requires distinctive services in the premise of end user choice. For example for Insurance domain, distinctive services could resemble Adjudication Service, Claim Service, and Payment Service. If we require some property of the Payment service in that case the Client calls the Business object and the Business logic requires the thing of Service objects with the goal that Business object happens to be dependent on the Service object. The Business object is combined with the Service object.

In the above case class Business Logic Implementation dependent on various service objects. These firmly objects, coupled, are all most impossible for a reuse and actualize unit test as a result of the dependencies.

Meaning of DI

The way toward injecting (changing over) coupled objects to the decoupled objects is termed as the Dependency Injection.

Sorts of Dependency Injection

There are four sorts of DI:

• Setter Injection
• Constructor Injection
• Constructor Injection
• Interface-based injection
• Service Locator Injection

Constructor is utilized to interface parameter that uncovered through the parameterized temporary worker. It injects the dependencies through a temporary worker strategy as object creation different classes. The accompanying code test illustrates the idea, demonstrating the Business Logic Implementation and Service classes. Class Business Logic Implementation has a constructor with I Service interface as parameter of constructor.

Interface Injection

Interface Injection is like Getter and Setter DI, the Getter and Setter DI utilizes default getter and setter however Interface Injection utilizes support interface a sort of the explicit getter that sets the interface property. The accompanying code test illustrates the idea, I Set Service is a help interface which has strategy set Service Run Service which set the interface property.

Points of interest of DI

• Increases code reusability
• Reduces class coupling
• Improves application testing
• Improves code maintainability
• Centralized configuration

Drawback

The principle drawback of dependency injection is that utilizing many occasions together can turn into an extremely troublesome if there are an excessive number of occurrences and numerous dependencies that should be resolved.

Web Spidering – What Are Web Crawlers & How to Control Them

Web Crawler is an automated script or program that is designed in order to browse World Wide Web in a systematic and methodological way. The whole process executed through Web Crawler is known as web Spidering. Web Spidering, also known as Web indexing is a method to index context of websites by searching browsing World Wide Web. The purpose of web crawling is to provide up to date information in search results. Google and other search engines use web crawling in order to provide updated results.

Getting a Deep Insight of Web Spidering:

The basic job of web crawler is to visit different web pages and gather information. The information is later updated into the index entries of the respective search engines. The web crawlers create a copy of the page they have visited and when they return home, they update the pages into the index entries. This is done in order to give latest search results. Apart from search engines, many websites use it in order to be relevant in the search list. Many of the websites use crawlers in order to provide latest and relevant resources to the searcher.

What are Web Crawlers?

Web Crawlers are the ones who read all the pages of the websites they are destined to visit. Their job is to make a copy of the page visited, download the info and then later update it with the index. They are the sole reason for the survival of giant search engines but they have their side effect as well. Web Crawlers also misuse this method spidering by collecting information like email address, address, contact info and other private information and then they use it to spam and do other mischiefs with it.  They can consume lots of bandwidth pushing your website to slowing down and temporary shutdown.

How to Control Them?

Though the popular crawlers add to your advantage but there are many that are for ugly purpose and you should avoid them completely. They can cause inconvenience for visitors by slowing down the server speed, temporary slowdown, spamming your mail, stealing data and many more. Recaptcha from Google is used in order to avoid robotic crawlers and it helps a lot. You can use images while mentioning your contact details so that crawlers can’t access it. These two methods can ensure major control. Apart from these, there are many other methods used to control crawlers.

Web Spidering has both advantages and disadvantages. It is up to you how you deal with it to your advantage by avoiding maximum cons.