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REST Api with Asp Core
- 1. REST API inASP Core Irina Scurtu .NET Technical Lead Trainer @ Scoala Informala @Fortech
- 3. AGENDA What is REST|1 REST Constraints| 2 HTTP Status Codes| 3 HTTP Headers | 4 Richardson Maturity Model | 5 Copyright 2017 © Fortech. All rights reserved.
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- 5. REST ▪ Architectural style ▪The architectural style of web ▪ Everything is a resource
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- 9. CLIENT-SERVER ▪ We needto have a server ▪ We need to have a client ▪ The server is not aware of the client ▪ The server does data transformation under the hood ▪ The client simply uses the resources Client Server Request/Response
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- 11. STATELESS ▪The server keepsno state ▪ No identifier, no trace at all ▪If there is a trace, it’s contained in the request ▪ Eg: authentication details ▪The server treats each request as a new one
- 12. CACHE ▪The most importantspec of the HTTP ▪The server must mark the response as cacheable or not cacheable ▪It may increase the perceived performance ▪It may save database roundrips especially if the data doesn’t change often ▪Done through headers
- 13. LAYERED SYSTEM ▪ Theclient can talk with an intermediate ▪ It only receives the resource ▪ It doesn’t matter if there is a load balancer involved or a proxy, or a gateway
- 14. UNIFORM RESOURCE ▪Everything isa resource ▪A resource is anything that can be named ▪Every resource must have an URL ▪ Any document that can be read on the client, is a representation of a resource ▪ Has 4 subconstraints
- 15. 1.IDENTIFICATION OF RESOURCES ▪Aresource needs to be addressable ▪A resource doesn’t correspond to a database table ▪It can be a subset, or a transformed entity
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- 17. 1.IDENTIFICATION OF RESOURCES ▪/getLocation ▪ /newCat ▪ /feedCat ▪ /getAllCats ▪ /getBlackCats ▪ /getHungerLevel ▪ /getCatOwners BAD!!!! Hard to remember!
- 18. 2.MANIPULATION OF RESOURCESTHROUGH REPRESENTATIONS ▪A client doesn’t interact with the domain objects ▪It doesn’t query the database directly ▪It sends a representation of a resource to be updated
- 19. 3.SELF-DESCRIPTIVE MESSAGES ▪Each request/responseincludes details and meaning ▪Each request/response must be able to be understood in isolation ▪Add meaning through:
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- 22. 4.HATEOAS ▪Hypermedia as engineof application state ▪ We should use the links( hypermedia with text) to navigate the app ▪ A response should include a links section that allows the hierarchical navigation { "links": { {“rel": “self” , "href": "/superheroes" }, {“rel”: "next“, "href": "/superheroes?page=2" } } }
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- 26. 2 URLs foreach resource A collection /superheroes/getAll vs /superheroes An element /superheroes/getSuperhero?id=1 vs /superheroes/1
- 27. Guidelines ▪ Cool URIsdon't change ▪ Use nouns not verbs ▪ Plural not singular ▪ Concrete /things vs /dogs ▪ Variations - > query strings - not different endpoints
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- 29. OK ?! 200 OrWhen OK really means OK
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- 31. 202 - Accepted -For further processing - For enqueuing something
- 32. 204 – Nocontent - After deleting a resource
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- 34. 403 - Identified butnot allowed to perform an operation Inapropriate picture
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- 36. 405 – NotAllowed
- 37. 406 – NotAcceptable - Accept header – xml - Server does only json Server Client Sends only xml Knows to read only json
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- 39. 415 Accept header hasa media type you don’t support
- 40. Header fields A suuuuupersmall list
- 41. Accept ▪ The mimetype the client prefers and understands Accept : text/xml Accept : application/json
- 42. Content-Type ▪ The mimetype of the request body ▪ Describes the content of the request Content-Type : text/xml
- 43. Location ▪ After anon-idempotent operation
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- 46. Level 0 ▪ YOUKNOW how to use it ▪ Single endpoint • Go to a restaurant and order pizza, curry and Chinese The food is good?
- 47. Level 1 ▪ Oneverb - different locations • Go to the italian restaurant to order pizza • Go to the Chinese restaurant to order Chinese food • Go to the Indian restaurant to order curry
- 48. Level 2 ▪Uses HttpVerbs and multiple resource endpoints • Order a pizza from Italian restaurant • After 5 minutes change the order to add extra mozzarella
- 49. Level 3 ▪Http Verbsand multiple resource endpoints + options • Order a pizza • Get the pizza • Waiter gives info about the available toppings for the pizza • Informs you that they have other pizza types
- 50. RMM HTTP verbs+ URI+ Hypermedia = HATEOAS HTTP verbs + multiple URI single verb +multiple URI One Verb + one URI
- 51. WHY - Benefits ▪? ▪ ? ▪ ? ▪ ?
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