Php And Three Tier Architecture Computer Science Essay

To let clients to upload their ain metre readings online, WindPower launch a server-side page to file away this mark. The web page have to be able to bring forth and post dynamic content, every bit good as read information to database direction system ( DBMS ) for hallmark. Harmonizing to these demands, the usage of Common Gateway Interface ( CGI ) plan is necessary.

Why utilizing PHP

PHP is an unfastened beginning undertaking, particularly for Web database applications, as it has integrated tools for Web and database environments. In peculiar, the flexibleness of implanting books in HTML pages permits easy integrating of the HTML presentation and codification. Database bed integrating support is besides really good, more than 15 libraries available for about all popular interaction with the database waiter. Web Database Applications with PHP and MySQL, 2nd Edition, David Lane, Hugh E. Williams, O’Reilly.This is n’t to state that other scripting linguistic communications do non hold first-class characteristics. However, there are many grounds that make PHP go a better pick than others, particularly good back up to entree DBMS.

PHP has many first-class libraries that provide fast, customized entree to DBMSs and is an ideal tool for developing application logic in the in-between grade of a three-tier application.

Three-tier architecture:

Because PHP integrates so good with HTML, utilizing PHP to bring forth inactive sequence of characters is far less complicated, less interesting than other high-ranking linguistic communication.

A PHP book can be written utilizing field text, you can utilize any text editor to make, such as the Unix editors joe, vi, vim, or a Microsoft Windows editor such as Notepad or WordPad.

What is our system?

Our system is three-tier architecture. In this architecture, including a bunch of database at backend, a set of web waiters at the front terminal, every bit good as client from cyberspace.

In the first portion, there are some databases which is separate from the Web waiter. These databases hold a large-scale information, which means it requires more system resources to manage I / O and informations processing. As a consequence, its public presentation will be strengthened.

In the 2nd portion, there is a Web waiter. This architecture provides load equilibrating to manage a big figure of client demands from the Internet. In add-on, the database is a separate Web waiter. This architecture protection of databases, to forestall direct entree to the Internet. Conseguencely, safety will be improved.

In the concluding portion, clients can finish all the stairss and Web browser. Because the system is keeping the engine on the server side, the client does non necessitate to put in any plan in progress. In fact, clients can upload your ain metre reading at any Web browser can entree the Internet. Ultimately, the handiness will be strengthened.

Save informations into CSVr

In this design, the web waiter will make a Comma Separated Value ( CSV ) file to shop clients ‘ metre reading. While user imperativeness “ Submit ” button, their informations will be inserted into the CSV file incremantally.

The metre input page:

The inserted informations in CSV file:

How does it work?

In order to allow user hold a good utilizing experience, user interface is simple and convenient. There merely are 3 stairss to complete the uploading of the metre reading:

1. Log in, so unfastened metre reading upload page through the web browser.

2. Enter Account figure, Meter Serial figure, Meter reading and take the twenty-four hours.

3. Snap the submit button, the web page so, will expose “ Meter reading upload successful ” and client information for proof.

Measure 1:

Open a web browser, and enter “ hypertext transfer protocol: // ” . After user logged in, metre reading upload page will be displayed. Customer will happen their last metre reading.

Customer will happen their last metre reading:

Measure 2:

Enter “ Electricity Account no. “ , “ Meter Serial no. “ , “ Meter Reading ” , and take the information in calender or input the twenty-four hours manuelly in yyyy/mm/dd format. Then click the “ Submit ” button. If necessary, you can snap the “ reset ” button to re enter informations.

Customer informations sample:

Measure 3:

Click the “ Submit ” button, and so client, so you will see a notice: “ Meter reading upload successful ” and the information that they submitted. These means the information was successfully uploaded.

The presentment page:


In order to assist client input information right and avoid mistake go on in uploading metre reading, we should forestall them from uploading a metre reading that is less than the old reading and non leting meter readings for invalid day of the months. In add-on, the web page should be able to look message to advise user what misidentify being happen. Furthermore, user would non be able to subject their informations before the error were clean.

To allow the web site have ability to look into informations and do existent clip respond, it should utilize a engineering call AJAX ( Asynchronous JavaScript and XML ) . AJAX is a name of a group of engineering, include JavaScript, CSS, and XML. It could run on web browser and heighten the interactivity, serviceability and velocity.

JavaScript could be a client side scripting linguistic communication, developed by Netscape. JavaScript was released since 1996. At that clip, it supported Netscape Navigator 2.0 and Internet Explorer 3.0.

XML ( Extensile Markup Language ) was design to better informations description, storing, and interchanging. It released in 1998 by W3C. Its node construct design and the hierarchal construction provide good back up on informations hive awaying.

CSS ( Cascading Style Sheets ) is a Stylesheet linguistic communication. It is used to divide the informations bed and show bed in HTML. On other word, CSS could supply a fixable method to specify and arrange the looking of the web page.

The most of import use of AJAX is utilizing XHR ( XMLHttpRequest ) to play with web waiter. A XHR object will be created while user set up connexion to net waiter. The XHR object will go on between web browser and web waiter. The XHR object will listen to the web waiters ‘ update for web page make a partially update. Then XHR will go through the update to the web browser to regenerate the portion of web page. This mechanism successfully decreases the bandwidth utilizing and informations processing. AJAX was by and large utilizing on synergistic web page, such as Google Map, Google hunt suggestion, and stock monetary value quoting.

In our system, we are traveling to utilize JavaScript to make the proof, because JavaScript is a scripting linguistic communication. JavaScript is able to utilize map to formalize the informations that does client input with right informations we want. For illustration, is it input right twenty-four hours, month, and twelvemonth. In add-on, JavaScript could forestall user submit informations if informations was non run into the system enquired.

Make the variable:

First, the book in would make a batch of variables that we are traveling to utilize ( Pic 2.2 ) .

The proof map

Then, we will utilize the map to make the proof ( Pic 2.3 ) . On line 19, the codification is used to get down checking by if cringle with the conditions. The codification on line 22 qui vive user “ Please choice day of the month for metre reading! “ , if they have non input the twenty-four hours. From line 25 to 41, the map is setup to alarm user if they are non input the right twelvemonth, month, twenty-four hours, besides the metre reading.

The proof to the metre reading

From line 52, the JavaScript will look into the metre reading input. It will alarm if user input the metre reading is less so old or it is non a figure.

These codification will disenable the submit button

From line 120 to 136, the JavaScript will acquire the consequence from the book we talk above. If user input incorrect informations, the submit button will non let user to press it. If the information is right, the map will let go of the submit button. At this clip, user will see the text on the button is black, non gray.

The submit button

The book from line 147 to 160 is about the submit button. The submit button will play with JavaScript ( line 152 ) , to acquire validate information. Considering there are if the browser could non play with JavaScript, line 155 to 158 allow user see the submit button without JavaScript.

Using the JavaScript, there are some advantage and disadvantage.

On the negative side, there have security and dependability job. Because JavaScript is run on client computing machine, it is able be exploited for malicious intents, Such as: Dead-code interpolation, Code Transposition, Register Reassignment… Some user will halt JavaScript running, it will impact the system running.

Beside it, as the consequence of its portable, it running is to the full relied on client side web browser. That means if client browser does non back up JavaScript, or has non a new adequate version, some book will be failed in running.

Although JavaScript have some failing, there are many positive characteristic aid it become developers ‘ first pick.

First, JavaScript is non load on server side, that save the running resources and increase waiter capacity. In other word, client can run JavaScript maps instantly, alternatively of delay for waiter answer.

Second, JavaScript is comparatively simple to larn and implement. It is a unfastened beginnings high degree linguistic communication, it is easy to implement, compared with other programming linguistic communication like Python, Perl, C # aˆ¦

Last, JavaScript is a good compatible linguistic communication. It can infix into web page and other written in other linguistic communication, like PHP and Perl. It can play with other linguistic communication for assortment of applications nicely.

In Conclusion, AJAX ( particularly JavaScript and XML ) supply our system ability to make proof, which extremely decrease the happening rate of incorrect informations. And its compatibility with PHP extremely reduces development clip cost. Finally, because it run on client side, it straight save waiter computer science resources. It indirectly save disposal cost, hardware investing cost and salvage the development cost.


In order to increase traffic hypertext transfer protocol: // and hypertext transfer protocol: // we can utilize a website circuit board called “ add this. ” “ This ” is the easiest manner to portion we can Facebook, Twitter, and assorted web mail or other societal networking sites. “ Join the ” who can portion our web site are used by different sites it is merely one ball. If the site requires login, the user has logged in, “ add this ” automatically log on to the site. Furthermore, users need merely come in the information they want to portion or send and kick button, and so will be shared. This will retrieve to add users. It allows users to more easy portion can increase traffic to our web site.

“ Add this ” can besides assist us to roll up statistics, retrieve how many users to portion our web site or direct them to friends. “ Add this ” how much traffic can be collected back to your inactive pages, you can see what portion of the preliminaries on our web site. “ Add this ” shared informations to an bing Google Analytics study is easy, lets you view the “ Add This ” portion custom events, on your splashboard. “ Add this ” will demo all informations in the past 30 yearss on any available sphere. It can assist us to update our web site, so that more people can see and utilize our site.

“ YouTube ” is one of the largest picture sharing site, one of the grounds it can be so successful because “ YouTube ” are utilizing the “ add this ” , it allows “ YouTube ” of a turning figure of tourers. No merely “ YouTube ” have a great selling accomplishments, but besides “ YouTube ” have utilizing other web site to allow more people know. It is a good illustration to cognize about the power of “ portion ” .

“ Add this ” is making by a web page signifier. The signifier has asked where to set the button. And need to choose the button manner like does it needs to hold the portion count and how the button looks. And the web site will automatically make the codification by your choice and web maestro merely necessitate to copy the hypertext markup language codification in to our web page ‘s hypertext markup language file so we can holding “ Add this ” map. “ Add this ” has the largest unfastened aggregation of services, and it will allow “ Add this ” go better. “ Add this ” besides support 50 linguistic communications, and it will automatically interpret to the linguistic communications that suitable for us. “ Add this ” besides trusted by sites like Whitehouse and a batch of authorities there is no uncertainty that the secure is really save. “ Add this ” besides can suitable for differ web browser, such as “ Internet Explorer ” , ” Firefox ” and “ Chrome ” .

For utilizing the “ add this ” can straight increase our web log traffic and FAQ site, because it can supply a really simple manner to let users to portion our web site and web log. Through the usage of electronic mail and the largest societal networking site “ Facebook. ” When the web log and web site to increase traffic, we can accept inquiries in the signifier of more and more users, we can work out this job, the signifier and reply inquiries every bit shortly as possible to our users. This is besides a figure of advantages, use the “ add this. ” Frist we can more easy to garner statics, because we can cognize more about how the people know our web site is them know it on hunt engine or they know our web site by their friends. Not merely, but besides “ Add this ” can back up flash and SSL/ HTTPS security it will suitable for our web site, it can carry through the demands set out in our FAQ web site and our web log. On the other manus, nomadic web browse is besides need to believe about ; because a batch of people are shoping by their nomadic phone, “ Add this ” is support by humanoid Mobile OS that will be increase traffic. Another advantage for utilizing “ Add this ” is, it will be more easy to reply the inquiry organize our users, because if users ever portion our reply, more people can see our it, more people can cognize about the inquiry without inquiring us.

Although “ Add this ” got a batch of advantage, but we need to utilize more human resources to command this stopper in on our web site. In add-on, possibly we need to utilize a better waiter to host our FAQ web site and web log.

Use the “ Add this ” We need to set more human resources and clip to command and roll up statistics. We will “ add this ” underside of the inquiries and replies for each, which allows users to easy portion our site to other states. Our “ Add this ” button will hold “ Facebook ” , “ Twitter “ “ G-mail ” and “ Hotmail ” it is the general sharing ways. To commanding “ Add this ” , we will look into the statistics every twenty-four hours and grade it down in a file, and “ Add this ” can expose the informations form the last 30 yearss across the spheres that have across us. And “ Add this ” can end product differ study theoretical account like different flow chart for our chink sum-up ; content ; services and geographics, it is easy to allow our making study to the web maestro. This study can assist webmasters understand how people know and what we ever do our web site, their friends, so the site decision maker can utilize this statistical information to better our site.


Virtual host is much cheaper than a dedicated waiter. Rather than a machine to host a Web site, ISP can put up a machine ‘s host 100s of web sites. To the user is shoping your site, it looks like you have a dedicated waiter. Drawback to the practical host, your site is to portion resources, machinery and all other sites hosted on this machine. You may besides be limited to what sort of plan can run on the waiter. If you can run the CGI plan, you may be limited to really simple books or take from the list the book has prechosen by the ISP. You may besides bind to any e-commerce solutions for Internet service suppliers have chosen.

Virtual hosting is a manner to host multiple spheres on a computing machine utilizing a IP reference. This allows a machine to portion resources such as memory and processor rhythms to more effectual usage of its resources.

A widely used Web application is shared hosting. Shared Web Hosting Dedicated Web waiter is lower than the monetary value, because many clients can shack on a waiter.

Virtual web is normally used in big companies, whose concern theoretical account is to supply low cost web hosting clients. Most such sites web hosting service clients on a planetary graduated table shared server hosting, web hosting engineerings.

Many companies use practical waiters for internal usage, there is a proficient or administrative ground to maintain several separate sites, such as client extranet site, the staff extranet, intranet, assorted sections within the endeavor web. If there are no security concerns, the site construction, they can be combined into a individual practical host waiter engineering to cut down direction and administrative operating expense, the figure of separate waiters required to back up the concern.

Our system is the three-tier architecture. In this model, including a group of back-end database, a Web waiter front terminal, and the client in the signifier of the Internet. In the first portion, there is database. The database is separate from the Web waiter. It has a big information, which means it requires more system resources to manage I / O and informations processing. As a consequence, its public presentation will be strengthened. In the 2nd portion, there is a Web waiter. This architecture can supply burden equilibrating to manage a big figure of client petitions in the signifier of the Internet. In add-on, the database is isolated to organize a web waiter, which consists of the database in the signifier of protection to forestall direct entree to the Internet. As a consequence, safety will be improved. In the concluding portion, clients can finish all the stairss and Web browser. Because the system is keeping the engine on the server side, the client does non necessitate to put in any plan. In fact, clients can upload metre reading at any clip, if the Web browser can entree the Internet. As a consequence, handiness will be strengthened.

A specific definition of “ the cloud ” because of the controversial web log, in popular scientific diaries, and even in my ain office. In the popular definition is based on the fact that the clouds are invariably altering, like the Internet itself. Whether your definition may be, “ cloud ” of class includes many different engineerings. Including the figure of cloud computer science and cloud hosting.

Cloud hosting was developed old ages ago and in certain ways mimics cloud calculating. It is a type of web hosting, there is a load balancer to find how much CPU and other resources to the demands of each client. Then, the distribution of these resources as required, from the hosting supplier ‘s waiter farm. Users will merely pay for what they use. Cloud hosting can host the site, but truly desire to construct a scalable practical environment, resource-intensive application development.

Cloud hosting is really utile if you are developing an API ( application programming interface ) or anyone who needs a batch of CPU or other resources. The illustrations include:

aˆ? If you need to upload 1000s of images, resize them, and deploy it on the site like iStock Photo.

aˆ? If you have a undertaking necessitating 1000s of computations no clip bound.

Cloud computer science is Internet-based computer science, that is, shared resources, package and information to computing machines and other equipment demands, such as the power grid.

Cloud computer science is aA paradigm shiftA following the displacement fromA mainframeA toA client-serverA in the early 1980s. Detailss of the selected users, who no longer necessitate specialised cognition, or control, engineering substructure “ cloud ” , to back up them. Overcast calculating depict a new addendum, ingestion, and IT service bringing theoretical account based on the Internet, it normally involves excessively, the Internet provides a practical dynamic scalability and regular resources. This is a byproduct and the effects of the easy entree to the distant computing machine ‘s Internet web site. This normally takes the signifier of Web-based tool or application, users can entree and utilize the Web browser as if it is a plan installed on your local computing machine. NIST, provides a more nonsubjective and specific definition here. The alleged “ cloud ” is used as a metaphor for the Internet, based on the usage of clouds pulling in the yesteryear on behalf of the telephone web, and subsequently to the Internet computing machine web diagram depicts an abstract as the great implicit in substructure. A typical cloud calculating suppliers to supply a common concern on-line application is accessed from another Web service or package, such as a web site, and package and informations are stored on the waiter. A cardinal factor is the cloud to custom-make and make a user-defined experience.

Most cloud calculating substructure services, including through the constitution of joint centres and waiters. Clouds frequently individual point of entree for all calculating demands of consumers. Commercial merchandises is by and large expected to run into quality of service ( QoS ) demands of clients, including service degree understandings are normally ( SLA ) . The chief cloud service suppliers including Microsoft, HP, IBM, Salesforce, and Amazon, and Google.


Secure Sockets Layer ( SSL ) and Transport Layer Security ( TLS ) provide unafraid encoding protocol for communications webs, such as the Internet.A SSL and TSL encrypted web connexions subdivision of the application bed, terminal to stop to guarantee the safety of theodolite at the conveyance bed. Several versions of the protocol widely used in applications such as Web browse, e-mail, Internet facsimile, messaging and voice-over-IP ( VoIP ) .

The Secure Sockets Layer ( SSL ) is a common security direction protocol for the Internet transmittal. SSL developed by Netscape for conveying private paperss via the Internet. It besides received support from Microsoft and other Internet client / waiter development and the criterion until germinating into Transport Layer Security. SSL is now a portion of, including a modern Web browser such as IE, Firefox and Chrome, the Web waiter merchandises.

Both Web waiters and Web browsers rely on SSL encoding protocol to make a alone private communicating channels through the public Internet. Each SSL Certificate contains two key: one populace and one private key. Public key used to code information and decrypt information encrypted utilizing the private key. When the Web browser ‘s security sphere, A-level encoding built on the footing of the client SSL certifications and Web browser, and ability Caozuoxitong host waiter. As more and more widespread usage of SSL, and some types of SSL certifications has emerged: Extended Validation ( EV ) SSL Certificates and Domain Validation ( DV ) of the SSL certification.

Extended Validation ( EV ) SSL certification is a new type of SSL certification, which aims to supply users with more assurance, who you are, you control or have their ain web sites. EV SSL Certificates provide high security Web browsers information to clearly place the site of tissue individuality. The development of the web to find the EV SSL certification ‘s browser is considered to be high-security browser. Their purpose is to trip alone ocular cues indicate the presence of EV SSL certifications.

As people use e-commerce, concern and societal activities of the web, they would portion their personal and confidential information.A High-profile fraud and phishing cozenages can do the users concerned about the incidents of individuality their issues.A Before they enter sensitive informations, they want to turn out that the site is to believe that their information will be encrypted.A Without it, they may abandon their shopping cart or other dealing, and other topographic points to make business.A High security web browsers and EV SSL Certificates provide third-party and the ocular show, so that consumer assurance and construct trust in online concern proof.

Domain Validation ( DV ) of the SSL certification waiter security certifications, supplying a minimal degree of hallmark, from the commercial certification authorization.

How does it work? When the user through the SSL registration procedure, you will have an e-mail reference of your pick and SSL to verify sphere ownership confirmation e-mail links. You merely need to open the nexus and verify that “ I agree ” , your order will be successfully validated and SSL will shortly be issued. This makes the job sphere proof SSL fastest, because it requires several proceedingss to finish the full procedure. Domain Validation SSL is the most suited who need SSL, and want the immediate and safe and normal signifiers of site shopping cart.

DV besides offers SSL certifications to code and high dependability, because they have a criterion CA RapidSSL, Geotrust ‘s, Thawte issued. For more information about sphere proof SSL in the SSL sphere name merely. SSL equipment, you want to expose your company name and location of the proposed installing of concern proof SSL certifications.

Before a DV SSL certification can be issued, the publishing enfranchisement authorization to verify the contacts in the field of the certification of blessing request.A This blessing is normally caused by e-mail, but can besides be by telephone or by other methods. This is because the issue of DV SSL certification normally can be automated, SSL certifications DV monetary value is normally higher than the warrant or EV SSL certification, you need the human factor in the procedure of publishing certifications, and other organisations to supply low-level confirmation procedure.

Although DV SSL certification proprietor ‘s consent, they do non seek to verify who the proprietor of this sphere is really of import. Verify that the sphere to do this an ideal pick for a certification, a adult male fishing and jobber onslaughts.

Transport Layer Security ( TLS ) is a protocol to guarantee privateness and informations unity between client / waiter applications communicate through the Internet. TLS provides endpoint hallmark and communications privateness over the Internet utilizing encoding. When the communicating between waiter and client, TLS to guarantee that no 3rd party may listen in or fiddle with any message. TLS is the Secure Sockets Layer ( SSL ) replacement.

TLS is composed of two beds: Thallium Record Protocol and the TLS Handshake Protocol. TLS Record Protocol provides some, such as the Data Encryption Standard ( DES ) encrypted unafraid connexion. Thallium Record Protocol can besides be used without encoding. TLS Handshake Protocol allows the waiter and clients authenticate each other, negociate an encoding algorithm and cryptanalytic keys before informations exchange.

TLS protocol is based on Netscape ‘s SSL 3.0 protocol, nevertheless, TLS and SSL are non interoperable. TLS protocol does incorporate a mechanism that allows TLS to accomplish the return to the SSL 3.0. The latest browser versions support TLS. TLS Working Group, established in 1996 to go on work on the TLS protocol and related applications.