![WCF Instance
Focus on the server side
Applications differ in their needs for scalability, performance,
throughput, transactions, and queued calls
(1) per-call
services allocate (and destroy) a new service instance per client request
This is the default behavior
(2) session
allocate a service instance per client connection.
[ServiceContract(SessionMode = SessionMode.Required)]
(3) Singleton
all clients share the same service instance across all connections and
activations
[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)](https://image.slidesharecdn.com/day6-120903043138-phpapp02/85/Day6-15-320.jpg)
Day6
- 1. CSE 136 - Lecture 6 Service Layer WCF Business Layer Security Regular Expression
- 2. Overview
- 3. What is Service Layer
- 5. Service Layer as services wrapper
- 6. Design Patterns in Service Layer Remote Façade Pattern A set of methods that modify the granularity existing operations already implemented elsewhere. A service is already a remote façade over the business layer Data Transfer Object Pattern Object that carries data across an application’s boundaries ex: XML file as input format for ChangeGrade() Adapter Pattern Converts the interface of one class into another interface that a client expects ex: UCSD GPA system takes in % points also Proxy Pattern Client will create a proxy, and proxy will communicate with the service
- 7. WCF - windows communication foundation A set of .NET libraries An SDK for developing and deploying services on Windows A WCF Service is a unit of functionality exposed to the world can be local or remote, developed by multiple parties using any technology A WCF Client is merely the party consuming a service's functionality can be literally anything: ASP.NET (MVC) JAVA app Mobile apps
- 8. WCF - Same vs cross machines
- 9. ABC of WCF This was an interview question A - Address Every service is associated with a unique address. Where are you? B - Binding SSL, call-backs, encryption-key A binding is a consistent set of choices regarding the transport protocol, message encoding, communication pattern, reliability, security, transaction propagation, and interoperability How should I talk with you? C - Contract The contract is a platform-neutral and standard way of describing what the service does. What am I giving/getting from you.
- 10. WCF ABC - Address Every service is associated with a unique address. The address provides two important elements (1) the location of the service IP address URL (2) transport protocol or transport schema used to communicate with the service http net.tcp Examples net.tcp://localhost:8002/MyService http://www.wcf.org:8001 net.pipe://localhost/MyPipe net.msmq://localhost/MyService
- 11. WCF ABC - Binding Basic Binding - expose a WCF service as a legacy ASMX web service TCP Binding - Offered by the NetTcpBinding class, this uses TCP for cross-machine communication on the intranet. It supports a variety of features, including reliability, transactions, and security, and is optimized for WCF-to-WCF communication Web Service binding - Offered by the WSHttpBinding class, this uses HTTP or HTTPS for transport, and is designed to offer a variety of features such as reliability, transactions, and security over the Internet IPC Binding - Same-machine communication Others (skip) : MSMQ, Duplex WS, etc
- 12. WCF ABC - Contract The contract is a platform-neutral and standard way of describing what the service does Service contracts (method definition) Describe which operations the client can perform on the service Data contracts (parameter types) Define which data types are passed to and from the service. WCF defines implicit contracts for built-in types such as int and string, but you can easily define explicit opt- in data contracts for custom types.
- 13. WCF ABC quick example
- 14. WCF Operation Focus on the client side (1) Request & Reply (for CSE 136) Most common calls - If no response, client gives up always put try/catch in the client code (2) One-way Send and forget (3) Call-back (not for CSE 136) The service is the client and the client becomes the service HTTP cannot be used for callbacks TCP and the IPC protocols support duplex communication Observer Design Pattern
- 15. WCF Instance Focus on the server side Applications differ in their needs for scalability, performance, throughput, transactions, and queued calls (1) per-call services allocate (and destroy) a new service instance per client request This is the default behavior (2) session allocate a service instance per client connection. [ServiceContract(SessionMode = SessionMode.Required)] (3) Singleton all clients share the same service instance across all connections and activations [ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)
- 16. RESTful Services CRUD : Create, Read, Update, and Delete RESTFul : using http methods Get - Read Post - Create Put - Update Delete - Delete REST stands for “Representational State Transfer” Skip for 136
- 17. WCF Security (authentication) Verifying that the caller of a service is indeed who the caller claims to be Windows authentication Username and password X509 certificate Custom mechanism & other 3rd parties No authentication (CSE 136)
- 18. Business Logic Layer Security User-based Security Authorization deals with what the caller (user) is allowed to do. Callers are mapped to logical roles. (Role ex: Faculty, Staff, or Student) Code-based Security Authenticate the code source Authorize code for access Enforce the code access
- 19. BLL Security : user-identity 1
- 20. BLL Security : user-identity 2
- 21. BBL Security : Code-identity-based 1 Authenticate code identity Information about the origin of a piece of code (such as the URL where it is run from) are collected and presented to the authorization layer Ex: Tourist visa from China Authorize code, not users, to access resources All trust decisions to access protected resources are made for particular pieces of code, based on security settings evolving around information about the origin of code Ex: Tourism visa from China can visit, not work and study Enforce the authorization The granularity of enforcement functions on the level of individual pieces of code (such as individual assemblies) .NET CLR enforces the security Ex: Employer checking for U.S. Visa
- 22. BBL Security : Code-identity-based 2 Authenticate code identity Authenticates assemblies exe & dll By collecting evidence about the assembly Ex: assembly's URL or strong name Signed by Microsoft Authorize code, not users, to access resources Authorizes assemblies By granting assemblies a set of permissions to access protected resources (such as the file system or registry) Enforce the authorization By checking that all assemblies calling to a protected resource have the appropriate permission to access that resource (.NET CLR)
- 23. .NET code-based Security : Evidence • Publisher • Site (url) • Zone (where on the computer) • Strong name (signed key)
- 24. .NET code-based Security : Policy Similar to homeland security policy Visitors with “Iraq visa” (membership) has limited access to certain “government buildings" (permission set)
- 25. .NET code-based Security : Code Group and membership
- 26. .NET code-based Security : Permission set
- 27. .NET code-based Security : Example Ex: immigration document type Visa, Diplomatic ID, birth-certificate Ex: Chinese Visa
- 28. Regular Expressions 1 What is regular expression pattern describing a certain amount of text a series of letters, digits, dots, underscores, signs and hyphens What are its common usages Formatting Validating Parsing
- 31. Review question Difference between macro and micro services? What design patterns exist in the services layer? What .NET libraries does 136 use to implement the service layer? What is the ABC of WCF? Difference between authenticate and authorize? What is security policy? (rules defined) What are the four levels of .NET policies? What is code group? (groups of code in a policy) What is membership? (identify a group of code) What is permission set? (set of permissions assigned to a group of code)
- 32. Your assignment Due Next Thursday Create a Service Layer project Just a wrapper project Continue development of your BLL Continue development of unit tests for your BLL
- 33. Lab Due: Grade your DAL with test cases
- 34. References .NET : Architecting Applications for the Enterprise Learning WCF