Codemotion Rome 2014


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Web API 2.x at Codemotion

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  • One advantage of convention-based routing is that templates are defined in a single place, and the routing rules are applied consistently across all controllers. Unfortunately, convention-based routing makes it hard to support certain URI patterns that are common in RESTful APIs. 
  • Codemotion Rome 2014

    1. 1. WEB API 2.X What’s new and ….. Ugo Lattanzi Head of Technologies @ Gaia Microsoft MVP, MCP Twitter: @imperugo Blog (en): Blog (it): E-mail:
    2. 2. Agenda • Who am I? • What’s ASP.NET Web API? • What’s a RESTful service?; • Routing old and new; • Global Error Handling; • Help Page; • CORS; • BSON serialization; • Ignore route; • …. caching;
    3. 3. WHO AM I?
    4. 4. Who am I? • Head of Technologies at Gaia (; • Microsoft MVP (ASP.NET / IIS); • Speaker / Trainer; • Book / Article author; • “Opensourcer”; • Github lover; • Everything about Web Dev;
    5. 5. What’s ASP.NET Web API?
    6. 6. Web API and REST • When you speak about Web API, probably you should know REST, but was does it mean? • RESTfull= REpresentational State Transfer
    7. 7. RESTful what????
    8. 8. Web API and REST It is not a WebService (SOAP), a pattern or a protocol, but is a style of software architecture for distributed systems such as the World Wide Web
    9. 9. Web API and REST ASP.NET Web API is a framework (FW 4.x) for processing data and returning data, typically in json or xml (RESTful services); It seems like MVC but it isn't, if you need both, use both.
    10. 10. What is similar to MVC? • Released with NuGet; • Routing; • Controllers and Actions; • Filters; • ModelBindings; • Dependency Injection;
    11. 11. What is different from MVC? • Dispatching (based on http verbs); • Formatters; • Async everywhere; • Self hosted (no need for IIS); • Content negotiation; • Everything is under System.Web.Http;
    12. 12. RESTful • Stateless architecture based on HTTP; • Each url is a resources (no transaction between two requests); • Base on HTTP Verbs (GET, POST, PUT, DELETE); • The status of the response is based on HTTP Status code (401, 200, 404 and so on);
    13. 13. DEMO
    14. 14. ROUTING
    15. 15. Attribute Routing Allows you to override the default routing for a single action/controller; /customers/1/orders /api/v1/products /api/v2/products Good Article:
    17. 17. Global error handling (the problem) There’s no easy way in Web API to log or handle errors globally (prev v2.x); I.E.: • Exceptions thrown from controller constructors • Exceptions thrown from message handlers • Exceptions thrown during routing • Exceptions thrown during response content serialization Good Article:
    18. 18. Global error handling (the solution) WEB API (2.x) provides two new user-replaceable services, IExceptionLogger and IExceptionHandler, to log and handle unhandled exceptions. The services are very similar, with two main differences:
    19. 19. Global error handling (the solution)
    20. 20. Global error handling (CatchBlock)
    22. 22. There is a specific endpoint to call
    23. 23. Help Page • “Automatic” API Documentation; • Based on MVC (all via nuget); • Template on top of Bootstrap • Support validation attributes; • Code comments; • Support complex types also for GET Methods (new); • Support for Enums;
    24. 24. Help Page (Document your code)
    25. 25. Help Page (Enable the XML output)
    26. 26. Help Page (Specify the documentation file)
    27. 27. Do you know postman?
    28. 28. CORS
    29. 29. CORS - Cross-Origin Resource Sharing - (the problem) By default it's not possible to make HTTP requests using Javascript from a source domain that is different from the called endpoint. For example, this means that it's not possible to call the URL from a domain This limitation was introduced for security reasons: in fact, without this protection, malicious javascript code could get info from another site with the user noticing.
    30. 30. CORS (the problem)
    31. 31. CORS (the problem) Ok, but sometimes we need to do this. How can we do that? • JSONP is easy to use and it's supported by all browsers; the only problem is that the only HTTP VERB supported is GET, which has a limitation on the length of the string that can be passed as query parameter. • Otherwise, if you need to send lot of information we can't use this way, so the soulution could be to "proxy" the request locally and forward the data server side or to use CORS.
    32. 32. CORS (the solution) Basically CORS communication allow you to bypass the problem by defining some rules that makes the request more "secure". Of course the first thing we need is a browser that supports CORS: fortunately all the latest browsers support it. Anyway, we have to consider that, looking at the real world, there are several clients that are still using Internet Explorer 8 which, among other things, doesn't fully support CORS (IE8 has limited support for CORS).
    33. 33. CORS (the solution) •Internet Explorer 10/11 •Chrome (all versions) •Firefox 3.5+ •Safari 4.x
    34. 34. CORS
    35. 35. CORS
    36. 36. CORS
    37. 37. CACHING
    38. 38. CACHING • Did you know that HTTP supports caching? • Do we really need to use server side caching? • What do I need to do in my code?
    39. 39. Caching How does it work? The client will ask the server if it has an updated copy of the resource by sending some information about the cached resources it holds using a request header called ETag If there are no updates, the server return 304 with an empty body, otherwise a 200 with the new data
    40. 40. Caching Source:
    41. 41. Cache Cow It’s an open source library available on nuget (the source code is on github) that allows you to enable caching in you APIs; Supports different providers to store the cache (memcache, ravendb, azure caching, Redis and so on);
    42. 42. Cache cow
    43. 43. THANKS Ugo Lattanzi Head of Technologies @ Gaia Microsoft MVP, MCP Twitter: @imperugo Blog (en): Blog (it): E-mail: