Software Engineering for Internet Applications - Student Community

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A final problem with cookies is that a small percentage of users havedisabled them due to the privacy problems raised in the "UserTracking" chapter of Philip and Alex's Guide to Web Publishing(http://philip.greenspun.com/panda/user-tracking).A reasonable engineering approach to using cookies is to send aunique identifier for the data rather than the data. Information aboutthe contents of the shopping cart will be kept in some sort of log onthe server. This means that it can be picked up from another location.To see how this works in practice, go to an operating system shelland request the home page of photo.net:bash-2.03$ telnet www.eveandersson.com 80Trying 64.94.245.206...Connected to www.eveandersson.com.Escape character is '^]'.GET / HTTP/1.0HTTP/1.0 200 OKSet-Cookie: ad_browser_id=3291092; Path=/;Expires=Fri, 01-Jan-2010 01:00:00 GMTSet-Cookie:ad_session_id=3291093%2c0%2c6634C478EF46FC%2c10622158; Path=/; Max-Age=86400Set-Cookie: last_visit=1071622158; path=/;expires=Fri, 01-Jan-2010 01:00:00 GMTContent-Type: text/html; charset=iso-8859-1MIME-Version: 1.0Date: Wed, 17 Dec 2003 00:49:18 GMTServer: AOLserver/3.3.1+ad13Content-Length: 8289Connection: close...Note that two cookies are set. The first one, ad_browser_id isgiven an explicit expiration date in January 2010. This instructs thebrowser to record the cookie value, in this case "87717925", on thehard drive. The cookie's value will continue to be sent back up to theserver for the next decade, even if the user quits and restarts thebrowser. What's the point of having a browser cookie? If the usersays "I prefer text-only" or "I prefer French language" that's probablydescription, MIT has one or more full-semester courses exclusivelydevoted to that topic.Experiences like these led us to develop Software Engineering forInternet Applications and the corresponding survey course in buildingcomputer systems for collaboration.Using this book for a thesis projectMost computer science programs require bachelor's candidates toengage in an open-ended development project, either as a"capstone" project or a thesis. Oftentimes this freedom inherent inthis requirement serves as the quantity of rope sufficient for a studentto hang him or herself. The student might choose to build anythingfrom a graphics system to a compiler. A faculty member supervisingthe project might have to do a fair amount of work merely todetermine what standards are appropriate in the student's chosenarea. For example, if it is a compiler project, is it reasonable to expectthe student to develop a complete Ada compiler in Lisp in one year?The core of an ML type-inferencer? A simple optimizing modificationto gcc?If you agree with the student to work within the framework of InternetApplication Workbook the project has enough structure that risk isminimized yet enough flexibility that the student's creativity canflower. For example, using this book means that the student will beusing a relational database management system. All of the code thatyou have to review will be in SQL. Yet the student is free toexperiment with the operating system and HTML glue environment ofhis or her choice. The student will be building an Internet applicationthat has user registration, content management, a discussion forum,and full-text search, and a combination of the book and the publicInternet provide a good context for evaluating the student'sachievement in these areas. Yet almost any client will put before thestudent idiosyncratic challenges that should give the student anopportunity to build something unusual.We consider Mozart to have been creative although he did notdevelop new musical forms, relying instead on the structure laiddown by Haydn. A student will accomplish more if he or she canspend the first months of a project working rather than figuring outwhat field in which to work, roughly what the scope of the projectshould be, what tools to choose from an unlimited palette, etc.16333
332• spend a term learning how to implement lists, stacks, hashtables• spend a term learning that sorting is O(n log n)• spend a term learning how to interpret a high-level language• spend a term learning how to build a time-sharing operatingsystem• spend a term learning about the underpinnings of severaldifferent kinds of database management systems• spend a term learning about AI algorithmsStudents in MIT course 6.001 (Structure and Interpretation ofComputer Programs, based on the Abelson/Sussman textbook of thesame name) learn all of the above in one semester, albeit not verythoroughly. By the end of the semester, they're either really excitedabout the challenges in computer science or... they've wised up andswitched to biology.Survey courses have been similarly successful on the electricalengineering side of our department. In the good old days, MIT offered6.01, a linear networks course. Students learned RLC networks indetail. But they forgot why they'd wanted to major in electricalengineering. Today the first hardware course is 6.002, wherestudents play with op-amps before learning about the transistor!One of the most celebrated courses at MIT is the Aeronautics andAstronautics department's Unified Engineering. Here is the firstsemester's description from the course catalog:Presents the principles and methods of engineering, as well as theirinterrelationships and applications, through lectures, recitations,design problems, and labs. Disciplines introduced include: statics,materials and structures, dynamics, fluid dynamics, thermodynamics,materials, propulsion, signal and system analysis, and circuits.Topics: mechanics of solids and fluids; statics and dynamics forbodies systems and networks; conservation of mass and momentum;properties of solids and fluids; temperature, conservation of energy;stability and response of static and dynamic systems. Applicationsinclude particle and rigid body dynamics; stress and deformations intruss members; airfoils and nozzles in high-speed flow; passive andactive circuits. Laboratory exposure to empirical methods inengineering; illustration of principles and practice. Design of typicalaircraft or spacecraft elements.Note that this is all presented in one semester, albeit with double thestandard credit hours. For almost every topic in the courseworthwhile information to keep with the browser. The text-onlypreference may be related to a slow Internet connection to thatcomputer. If the computer is in a home full of Francophones, chancesare that all the people who share the browser will prefer French.The second cookie set, ad_session_id is set to expire after onehour ("Max-Age=3600"). If not explicitly set to expire it would expirewhen the user quit his or her browser. Things worth associating witha session ID include the contents of a shopping cart on anecommerce site, though note that if photo.net were a shopping site, itwould not be a good idea to expire the session cookie after one hour!It is annoying to build up a cart, be called away from your computerfor a few hours, and then have to start over when you return to whatyou thought was a working Web page.If we were logged into photo.net, there would be a third cookie, onethat identifies the user. Languages and presentation preferencesstored on the server on behalf of the user would then overridepreferences kept with the browser ID.2.4 Server-side StorageYou've got ID information going out to and coming back frombrowsers, either via using the cookie extension to HTTP or via URLrewriting. Now you have to figure out a way to keep associatedinformation on the Web server.For flexibility in how you present and analyze user-contributed data,you'll probably want to keep the information in a structured form. Forexample, it would be nice to have a table of all the items put intoshopping carts by various users. And another table of orders. Andanother table of reader-contributed product reviews. And anothertable of questions and answers.What's a good tool for storing tables of information? Consider first aspreadsheet program. These are inexpensive and easy to use. Oneshould never apply more complex technology than necessary forsolving a problem. Something like Visicalc, Lotus 1-2-3, MicrosoftExcel, or StarOffice Calc would seem to serve nicely.The problem with a spreadsheet program is that it is designed for oneuser. The program listens for user input from two sources: mouseand keyboard. The program reports its results to one place: thescreen. Any source of persistence for a Web server has to contend17
Page 1 and 2: SoftwareEngineering forInternetAppl
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Page 5 and 6: end-users. We use every opportunity
Page 7 and 8: • availability of magnet content
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Page 11 and 12: you supply English-language queries
Page 13 and 14: What to do during lecturesWe try to
Page 15: The one-term cram courseWhen teachi
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Page 21 and 22: has permission to perform each task
Page 23 and 24: UDDIUnixcustomer's credit card. If
Page 25 and 26: thousands of concurrent users. This
Page 27 and 28: OraclePerlnamed XYZ" without the pr
Page 29 and 30: LDAPLinuxbits per color, a vastly s
Page 31 and 32: FilterFirewallFlat-fileGIF318functi
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Page 35 and 36: system. The authors of the core pro
Page 37 and 38: Sign-OffsTry to schedule comprehens
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Page 41 and 42: Client Tenure In Job (new, mid-term
Page 43 and 44: ReferencesEngagement ManagementSQL*
Page 45 and 46: Decision-makers often bring senior
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Page 49 and 50: 300always been written by programme
Page 51 and 52: 17.3 Professionalism in the Softwar
Page 53 and 54: Try to make sure that your audience
Page 55 and 56: Chapter 17WriteupIf I am not for my
Page 57 and 58: Suppose that an RDBMS failure were
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select 227, 891, 'algorithm', curre
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create table km_object_views (objec
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• object-create• object-display
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The trees chapter of SQL for Web Ne
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);274-- ordering within a form, low
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and start the high-level document f
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Example Ontology 2: FlyingWe want a
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systems. What would a knowledge man
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spreadsheet". Other users can comme
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Chapter 15Metadata (and Automatic C
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{site url}{site description}en-usCo
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drawing on the intermodule API that
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At this point you have something of
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• description• URL for a photo
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Here's a raw SOAP request/response
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Chapter 14Distributed Computing wit
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conduct programmer job interviews h
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Most admin pages can be excluded fr
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content that should distinguish one
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Chapter 13Planning ReduxA lot has c
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the Internet-specific problem of no
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wouldn't see these dirty tricks unl
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12.8 Exercise 4: Big BrotherGeneral
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than one call to contains in the sa
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A third argument against the split
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way 1 1/16One might argue that this
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absquatulate 612bedizen 36, 9211cry
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What if the user typed multiple wor
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Chapter 12S E A R C HRecall from th
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long as it is much easier to remove
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features that are helpful? What fea
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made it in 1938)? Upon reflection,
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environment, we identify users by t
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those updates by no more than 1 min
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Balancer and mod_backhand, a load b
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translation had elapsed--the site w
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It seems reasonable to expect that
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11.1.5 Transport-Layer EncryptionWh
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such as ticket bookings would colla
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give their site a unique look and f
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It isn't challenging to throw hardw
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Chapter 11Scaling GracefullyLet's l
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10.15 Beyond VoiceXML: Conversation
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Consider that if you're authenticat
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In this example, we:194• ask the
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As in any XML document, every openi
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(http://www.voicegenie.com). These
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Chapter 10Voice (VoiceXML)questions
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9.15 MoreStandards information:•
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9.14 The FutureIn most countries th
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9.10 Exercise 7: Build a Pulse Page
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9.6 Keypad HyperlinksLet's look at
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text/xml,application/xml,applicatio
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Protocol (IP) routing, a standard H
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Software Engineering for Internet Applications - Student Community

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