.NetDeploymentNOEA / PQC 2005 Application Deployment and Versioning Source: Joe Hummel, kursus i.Net, jan. 2003

2.NetDeploymentNOEA / PQC 2007 Objectives “Before.NET, the Component Object Model (COM) was the prevalent application design model..NET replaces COM with an entirely new model that is programming-language independent, registry-free, tamper-resistant, and version-aware …” Assembly navngivning Versionsstyring Deployment

3.NetDeploymentNOEA / PQC 2007 Del 1 Assembly naming…

4.NetDeploymentNOEA / PQC 2007 Remember component based developement Application layers gives many components / classes Example: –A typical stand-alone GUI app has 3 components –Packed as 1 EXE and 2 DLLs Front-end object app.exe business.dll data.dll

5.NetDeploymentNOEA / PQC 2007 Remember assemblies 1 assembly = 1 or more compiled classes –.EXE represents one assembly with classes + Main program –.DLL represents one assembly with classes Development Tools.EXE /.DLL code.vb code.cs assembly

6.NetDeploymentNOEA / PQC 2007 Assembly names An assembly may have a 4-part "name": –Friendly, for humans readable name –culture –version number –public key token DataComponent, Culture=neutral, Version= , PublicKeyToken= abcdef

7.NetDeploymentNOEA / PQC 2007 Assigning name 1.Friendly, for humans readable name: –Required –set by Project properties >> Assembly Name 2.Culture 3.Version number 4.Public key token optional, set by.NET attributes

8.NetDeploymentNOEA / PQC 2007 Assembly-level attributes Visual Studio projects uses a special file for these See "AssemblyInfo.cs" using System.Reflection;. [assembly: AssemblyDelaySign(false)] [assembly: [assembly: AssemblyVersion(" ")] [assembly: AssemblyCulture("")] // neutral

9.NetDeploymentNOEA / PQC 2007 Recall reference to assembly When assembly A referes to assembly B… –…metadata are stored in both assembly manifests PE/COFF HeaderCLR MetadataCode App.exe Public Key Token (8 bytes) extern Component PE/COFF HeaderCLR MetadataCode Public Key (128 bytes + 32 byte header) Signature Component.dll /r:Component.dll Version

10.NetDeploymentNOEA / PQC 2007.NET is version-avare By default CLR loads only the exact version –The program stops if the exact version can not be found –Example: –App.exe is compiled to v of Component.dll –then App.exe only runs if v can be loaded NOTE: version-avare loading requires that the assembly has a "strong name" …

11.NetDeploymentNOEA / PQC 2007.NET is tamper-proof CLR uses cryptography to avoid tampering –assemblies can be digitally-signed –based on public / private key encrypting –CLR cannot load the assembly, if it suspects tampering is the client's public key not correct (the DLL replaced by a hacker?) digitial signature doesn't match (the DLL replaced by a hacker?) Assemblies with a digital signature has a "strong name"

12.NetDeploymentNOEA / PQC 2007 Generate a public-private key pair use "SN" command-line utility –-k option generates key pair –place the file in the root of the Visual Studio project folder

13.NetDeploymentNOEA / PQC 2007 Protect the key file! The key file is the key to ensure the security You don't want all your developers has access to it… This is why Visual Studio don't supports key generation –have to use a command-line tool and why.NET supports "delayed" signing –Developers works with unsigned assemblies in-house –Before deployment the deploy team signs the assemblies with the key using System.Reflection;. [assembly: AssemblyDelaySign(true)]

14.NetDeploymentNOEA / PQC 2007 Part 2 Version control…

15.NetDeploymentNOEA / PQC 2007 version control problem Problem: –application A uses component B –you want to make a new version of B –is it hereafter safe for A to use the new version of B?

16.NetDeploymentNOEA / PQC 2007 Version control in.NET Version control in.NET is very simple: –CLR loads only the assembly if the version number matches precisely –if you want the app shall use a new version then don't change the version number –if you don't want the app to use the new version then change the version number –There is a third posibilty, see later.....

17.NetDeploymentNOEA / PQC 2007 Del 3 Deployment…

18.NetDeploymentNOEA / PQC 2007 Deployment the registry database is gone in.NET How are apps / assemblies deployed? In a way we return to the (good?) old days with DOS –CLR uses a wellknown search algoritm –Customize searching by.config (".ini") files

19.NetDeploymentNOEA / PQC 2007 What are the options? 1. Private assembly (APPBASE) –install EXE / DLLs in the same directory –easiest form of deployment ("xcopy") 2. Global assembly cache (GAC) –install DLLs into GAC –allows you to share DLLs, install different versions –allows you to pre-JIT 3. Download cache (CODEBASE) –you can tell CLR where to download from –allows you to install / upgrade from server –users can also download via Internet Explorer (URL to.exe)

20.NetDeploymentNOEA / PQC 2007 Further options... 4.Use web services (like option 3) 5.In.Net 3.0+ / WPF run in the browser(msie, firefox....) or as a windows app. 6.Use Silverlight (as in Flash)

21.NetDeploymentNOEA / PQC 2007 Recall the GAC… Global Assembly Cache How to put something in the GAC? –administrator rights are need'ed –assembly must have a “strong name” –use "gacutil" command-line tool:

22.NetDeploymentNOEA / PQC 2007 Assembly search algorithm (approx) Use file found at CODEBASE Match in Global Cache? Apply Version Policy CODEBASE hint provided? Does file match reference? Assembly.Load Fails Is file found via probing dir? Use file found from probing dir Use file found in Global Cache Y N N N N Y Y Y Does file match reference? N Y Assumes CLR is looking for an assembly based on 4-part name

23.NetDeploymentNOEA / PQC 2007 Config files XML-based config files can be used for controlling CLR loading Examples: –load another version of an assembly –download assembly from a given server

24.NetDeploymentNOEA / PQC 2007 Example #1 Version redirect –App.exe is compiled against v of Component.dll –we want that App.exe uses version <assemblyIdentity name="Component" publicKeyToken=" abcdef" /> <bindingRedirect oldVersion=" " newVersion=" " /> App.exe.config

25.NetDeploymentNOEA / PQC 2007 Example #2 Download assembly to download cache Specify assembly location by CODEBASE hint <assemblyIdentity name="Component" publicKeyToken=" abcdef" /> <codeBase version=" " href=" App.exe.config

26.NetDeploymentNOEA / PQC 2007 Summary.NET supports full component based developement.NET development deployment seems to be better: –programming language undependent –no registry –version-aware –tamper-resistant My fear? –"DLL hell" to be replaced by ".config file hell"…

27.NetDeploymentNOEA / PQC 2007 References Books: –J. Richter, "Applied Microsoft.NET Framework Programming" Web sites: – –Download-based deployment: nts/default.aspxhttp://msdn.microsoft.com/msdnmag/issues/02/07/NetSmartClie nts/default.aspx sp?url=/msdn-files/026/002/880/msdncompositedoc.xmlhttp://msdn.microsoft.com/code/default.asp?url=/code/sample.a sp?url=/msdn-files/026/002/880/msdncompositedoc.xml