学生信息系统的设计与开发.doc

1、毕 业 设 计（论 文）英 文 翻 译课题名称湖北汽车工业学院学生信息系统的设计与开发系 部信息管理系专 业信息管理与信息系统班 级T373-2学 号01姓 名王 金 海指导教师薛 昌 春2 0 0 7年3月18日Extreme ASP.NET1.1Web Deployment ProjectsWhen ASP was first released, Web programming was more difficult because you needed IIS to serve your ASP pages. Later, ASP.NET 2.0 and Visual Studio 200

2、5 made everything easier by introducing the Web site model of development. Instead of creating a new project inside Visual Studio, the Web site model lets you point to a directory and start writing pages and code. Furthermore, you can quickly test your site with the built-in ASP.NET Development Serv

3、er, which hosts ASP.NET in a local process and obviates the need to install IIS to begin developing. The beauty of the Web site model is that you can develop your Web application without thinking about packaging and deployment. Need another class? Add a .cs file to the App_Code directory and start w

4、riting. Want to store localizable strings in a resource file? Add a .resx file to the App_GlobalResources directory and type in the strings. Everything just works; you dont have to think about the compilation and deployment aspect at all. When you are ready to deploy, you have several options. The s

5、implest choice is to copy your files to a live server and let everything be compiled on-demand (as it was in your test environment). The second option is to use the aspnet_compiler.exe utility and precompile the application into a binary release, which leaves you nothing but a collection of assembli

6、es, static content, and configuration files to push to the server. The third option is to again use aspnet_compiler.exe, but to create an updateable binary deployment where your .as*x files remain intact (and modifiable) and all of your code files are compiled into binary assemblies.This seems to co

7、ver every possible scenario, leaving the developer to focus simply on writing the Web application, with packaging and deployment decisions to be made later when the application is actually deployed. There was a fair amount of backlash against this model, however, especially from developers who were

8、used to their Web projects being real projects, specified in real project files, that let you inject pre-and post-build functions, exclude files from the build process, move between debug and release builds with a command-line switch, and so on. In response, Microsoft quickly introduced the Web Appl

9、ication Project or WAP, initially released as an add-in to Visual Studio 2005, and now included in Visual Studio 2005 Service available for download from WAP provides an alternative to the Web site model that is much closer to the Visual Studio .NET 2005 Web Project model. The new WAP model compiles

10、 all of the source code files during the build process and generates a single assembly in the local /bin directory for deployment. WAP also makes it much easier to incrementally adopt the new partial class codebehind model introduced in ASP.NET 2.0 because you can now open a Visual Studio .NET 2003

11、project and only your .sln and .csproj (or .vbproj) files will be modified during the conversion. You can then convert each file and its codebehind class to the new partial class model independently of any other file in the project (by right-clicking on the file in the Solution Explorer and selectin

12、g Convert to Web Application), or just leave them using the old model. This is in contrast to converting a Visual Studio .NET 2003 Web project to the Web site model, which converts all files at once and does not support incremental adoption.Finally, there is a new project type called Web Deployment

13、Projects (the main topic of this column), which introduces myriad additional deployment options for both Web site projects and Web Application Projects. Web Deployment Projects fill the remaining holes in the deployment options for both Web site apps and Web Application Projects and make it possible

14、 to implement practically any deployment scenario in a simple and extensible way. To understand exactly what this new project type adds, lets first review what we had before Web Deployment Projects were available.When you build an application using the Web site model, you have the option of precompi

15、ling the site for deployment. You can access the precompilation utility through the Build | Publish menu in Visual Studio 2005 or directly through the command-line utility aspnet_compiler.exe. Figure1 shows the interface to this tool exposed by Visual Studio.The first decision you have to make when

16、using the publish utility is whether you want your .as*x files to be updatable once deployed (use the Allow this precompiled site to be updatable option of -u switch in the aspnet_compiler.exe command-line utility). This decision hinges on whether you want to be able to make minor changes to your pa

17、ges once deployed without having to go through the entire deployment process again. You may, in fact, want to explicitly disallow any modifications to the deployed pages and require that all modifications go through the standard deployment (and hopefully testing) process, in which case publishing th

18、e site as not updatable is the proper choice.When a site is published as not updatable, it is possible to completely remove all .as*x files and publish only binary assemblies (plus configuration files and static content). However, without the physical files in place, it is impossible for ASP.NET to

19、tell which classes to use for which endpoint requests. For example, if a request comes into your application for Page1.aspx and you have used non-updatable binary deployment, there very well may not be any Page1.aspx file on disk, and there is nothing in the existing configuration files to indicate

20、which class in the collection of assemblies deployed to the /bin directory should actually be the handler for this request. To remedy this, the compilation process will also generate a collection of .compiled files that contain endpoint-to-type mapping and file dependency information in a simple XML

21、 format, and these files must be published along with the binary assemblies in the /bin directory of the deployed site. As an example, if you did have a page named Page1.aspx in your application, the aspnet_compiler.exe utility would generate a file named piled (with the hash code varying) that cont

22、ained the following XML: The other major decision you have to make when publishing a Web site with this utility is the granularity of the packaging of the generated assemblies. You can either create a separate assembly for each directory in your site or create a separate assembly for each compilable

23、 file in your site (.aspx, .ascx, .asax, and so on.) by checking the Use fixed naming and single page assemblies (or -fixednames in the aspnet_compiler.exe command-line utility). This decision is not as obvious as you might think, as each option has its own potential issues. If you elect to not use

24、the -fixednames option, then every time you publish your application a completely new set of assemblies will be generated, with completely different names from the ones published earlier. This means that deployment is trickier because you must take care to delete all of the previously published asse

25、mblies on the live server before deploying the new assemblies or youll generate redundant class definition errors on the next request. Using the -fixednames option will resolve this problem as each file will correspond to a distinctly named assembly that will not change from one compilation to the n

26、ext. If you have a large site, however, generating a separate assembly for each page, control, and Master Page can easily mean managing the publication of hundreds of assemblies. It is this problem of assembly granularity in deployment that Web Deployment Projects solve in a much more satisfying way

27、, as you will see.You can also introduce assembly signing into the compilation process to create strong-named, versioned assemblies, suitable for deployment in the Global Assembly Cache (GAC) if needed. You can mark the generated assemblies with the assembly-level attribute AllowPartiallyTrustedCall

28、ers using the -aptca option, which would be necessary if you did deploy any assemblies to the GAC and were running ASP.NET at a low or medium level of trust. (Keep in mind that this attribute should only be applied to assemblies that have been shown not to expose any security vulnerabilities, as usi

29、ng it with a vulnerability could expose a luring attack.)One other detail about publishing your site is that if you do elect to use Web Application Projects instead of the Web site model, the Build | Publish dialog box will look quite different, as shown in Figure2. Web Application Projects assume t

30、hat you want to publish the application as updatable .as*x files and precompiled source files (the same model it uses in development), so the binary-only deployment options are not available. This utility is really closer in nature to the Copy Web site utility available with Web sites than it is to

31、the Publish Web Site utility since it involves copying files produced by the standard build process.Technically you are not restricted from using binary-only (non-updatable) deployment, even if you are using Web Application Projects. If you think about it, the output of the build of a WAP is a valid

32、 Web site, which you can then pass through the aspnet_compiler.exe utility to generate create a binary deployment. You just cant invoke it from the Visual Studio 2005 interface which, fortunately, Web Deployment Projects rectify.So whats missing from the existing compilation and deployment options p

33、resented so far? Primarily two things: the ability to control the naming of assemblies, especially for deployment purposes, and the ability to consolidate all of the output assemblies into a single assembly for simplified deployment. Web Deployment Projects solve both of these problems. Perhaps even

34、 more significantly, however, they also tie up a lot of loose ends in the deployment story that existed with Web site applications and Web Application Projects.At their core, Web Deployment Projects (available for download at represent just another type of project you add to your solution. Like all

35、Visual Studio project files, Web deployment projects are MSBuild scripts that can be compiled directly in the IDE or run from the command line. Instead of specifying a collection of source code files to compile, however, Web Deployment Projects contain build commands to compile and package Web sites

36、 (or Web Application Projects). This means that they will invoke the aspnet_compiler.exe utility (among others) to create a deployment of a particular Web application. Web Deployment Projects are shipped as a Visual Studio add-in package that includes an easy-to-use menu item for injecting new proje

37、cts and a complete set of property pages to control all of the available settings. To add one to an existing application, right-click on an existing Web site (or Web Application Project) and select the Add Web Deployment Project item as shown in Figure3. This will add a new .wdproj file containing a

38、n MSBuild script to your solution, which will generate a deployment of the application you created it from.Once the Web Deployment Project is part of your solution, you can access the property pages of the project file to control exactly what the project does for you, as shown in Figure4. The defaul

39、t setting for a new deployment project is to deploy the application in updatable mode, with all the .as*x files intact, and the source files compiled into a single assembly deployed in the top-level /bin directory. These deployment projects work the same regardless of whether the source application

40、is using the Web site model or the Web Application Project model, which means that you can now select either development model without impacting your deployment options. One of the most significant features of Web Deployment Projects is the ability to configure the deployment to be all binary (not u

41、pdatable) in the form of a single assembly, the name of which you can choose. Using this model of deployment means that you can update your entire site merely by pushing a single assembly to the /bin directory of your live site, and not concern yourself with deleting existing assemblies prior to dep

42、loying or dealing with a partially deployed site causing errors. It is still necessary to deploy the .compiled files for the endpoint mappings, but these files only change when you add, delete, or move pages in your site.Web Deployment Projects provide flexibility in deployment and let you make pack

43、aging and deployment decisions independently of how you actually built your Web applications. This independence between development and deployment was partially achieved in the original release of ASP.NET 2.0 with the aspnet_compiler.exe utility, but never fully realized because of the constraints i

44、mposed when performing the deployment. With Web Deployment Projects, the separation between development and deployment is now complete, and your decision about how to build your applications will no longer impact your deployment choices.Merging AssembliesMuch of what Web Deployment Projects provide

45、is just a repackaging of existing utilities exposed via MSBuild tasks and a new interface, but there are also a couple of completely new features included. The most intriguing is the ability to merge assemblies.When you install Web Deployment Projects, you will find an executable called aspnet_merge

46、.exe in the installation directory. This executable is capable of taking the multi-assembly output of a precompiled site and merging the assemblies into one. This is the utility that is incorporated into your build script if you select the merge option in a Web Deployment Project. As an example of w

47、hat is possible with this utility, consider the output of a precompiled Web site, run without the updatable switch, shown in Figure5. The source application for this output contained two subdirectories, a top-level global.asax file, a class defined in App_Code, and a user control. The end result of the compilation is five different assemblies and a collection of .compiled files. If you run the aspnet_merge.exe utility on this directory with the -o switch to request a single assembly output, shown at the bottom of Figure5, the result is a m