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REST in practice - PHPTwente meetup

Joshua Thijssen
March 07, 2013
170

REST in practice - PHPTwente meetup

Joshua Thijssen

March 07, 2013
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  1. Joshua Thijssen Freelance consultant, developer and trainer @ NoxLogic Development

    in PHP, Python, Perl, C, Java. Lead developer of Saffire. Blog: http://adayinthelifeof.nl Email: [email protected] Twitter: @jaytaph
  2. 4 ➡ Quick REST recap ➡ Common “myths” ➡ Common

    “mistakes” ➡ How to do stuff @Todo:
  3. Restful constraints 7 ➡ Client / Server ➡ Stateless ➡

    Cacheable ➡ Layered system ➡ Code on demand (optional) ➡ Uniform interface
  4. Uniform interface 8 ➡ Identification through representations of resources ➡

    Manipulation through representations ➡ Self-descriptive messages ➡ Hypermedia as the engine of application state (HATEOAS)
  5. 11 http://martinfowler.com/articles/richardsonMaturityModel.html Level 0: Plain Old XML ➡ HTTP is

    tunnel protocol ➡ POST to single URL (or worse: GET) ➡ SOAP / XML-RPC
  6. 13 http://martinfowler.com/articles/richardsonMaturityModel.html Level 2: HTTP Verbs ➡ POST or PUT

    for creations ➡ GET for retrievals ➡ POST or PUT for updates ➡ DELETE for deletions ➡ PATCH for partial updates
  7. 14 http://martinfowler.com/articles/richardsonMaturityModel.html Level 3: Hypermedia controls ➡ HATEOAS ➡ Hypermedia

    as the engine of application state ➡ Using links to detect your next states ➡ One bookmark link to rule them all
  8. ➡ User has got multiple addresses ➡ Entity X/Y/Z is

    set to 42 26 Resource state Resource state never changes through GET (or other safe) methods!
  9. ➡ Which “stage” is the user in the checkout process?

    ➡ Which page is the user currently browsing ➡ Is the user currently logged in? ➡ Depends.... 27 Application state
  10. 28 “Per client” state should be saved by the client,

    not on the server. It’s called Representational STATE TRANSFER
  11. 30 PUT or POST? PUT when the resource URI is

    known POST when it’s not (server decides) PUT /user/jthijssen/talk/123 POST /user/jthijssen/talks
  12. 31 PUT /user/jthijssen/talk/123 POST /user/jthijssen/talks PUT = idempotent, POST is

    not! PUT /user/jthijssen/talk/123 PUT /user/jthijssen/talk/123 POST /user/jthijssen/talks POST /user/jthijssen/talks POST is the worst option for caching / scalability, but use it if you don’t know what to do.
  13. 32 url = data.link_rel(“talks”, user_id); rc = HTTP.post(url, data); url

    = MAIN_URL + “/” + user_id + “/talks”; rc = HTTP.post(url, data); Uri can change: server, uri, protocol, port etc.. If you need to “construct” an URI, you are doing it wrong
  14. Watch out with visibility 34 <xml version=”1.0” encoding=”utf-8”> <persons> <person>

    <name>Joshua Thijssen</name> <phone type=”cell”>0612345678</phone> <link rel=”address” href=”/users/jthijssen/address”> </person> ... <persons>
  15. Watch out with visibility 35 <xml version=”1.0” encoding=”utf-8”> <persons> <person>

    <name>Joshua Thijssen</name> <phone type=”cell”>0612345678</phone> <address> <street>Mainstreet 1234</street> <postalcode>1234AB</postalcode> <city>Amsterdam</city> <country>Netherlands</country> </address> <link rel=”address” href=”/users/jthijssen/address”> </person> ... </persons>
  16. ➡ Degrades resource visibility since they contain overlapping data ➡

    Use caching proxies! (maybe ESI???) ➡ Each client needs a different composite. 37
  17. ➡ HTTP 1xx : Do I got info for you!

    ➡ HTTP 2xx : We’re cool.. ➡ HTTP 3xx : Take a look there.. ➡ HTTP 4xx : your bad! ➡ HTTP 5xx : my bad! 40
  18. ➡ Sometimes hard: ➡ 405 Method not allowed ➡ 501

    Not implemented ➡ Who is to blame? (tip: blame client!) 41
  19. ➡ Use a hypermedia format (xhtml / atom) ➡ JSON

    is NOT a hypermedia format ➡ JSON-LD http://json-ld.org/ ➡ HAL http://stateless.co/hal_specification.html 43
  20. 50 Cookie: 0xEncryptedData Client Server “This information is of no

    concern to you. Just bring it with you every time.. ”
  21. 51 “This information is of no concern to you. Just

    bring it with you every time.. ” Are we still stateless? Does the server use the client as an (extended) file storage? Why doesn’t the client have any say in what to send?
  22. ➡ Authenticate / Authorize per request. ➡ Caching is possible,

    just don’t rely on it. ➡ If you need state, make sure it’s resource state, not session/application state. 52
  23. 56

  24. 58 /restaurants/top1000?page=5 <xml version=”1.0” encoding=”utf-8”> <restaurants> <restaurant>...</restaurant> <restaurant>...</restaurant> <link rel=”first”

    href=”/restaurants/top10?page=1”> <link rel=”self” href=”/restaurants/top10?page=5”> <link rel=”previous” href=”/restaurants/top10?page=4”> <link rel=”next” href=”/restaurants/top10?page=6”> <link rel=”last” href=”/restaurants/top10?page=25”> </restaurants>
  25. 62 /distance/amsterdam;brussels /distance/brussels;amsterdam HTTP/1.1 303 See other Location: /distance/amsterdam;brussels Parameters,

    order does not matter: One cache system: http://cyberroadie.wordpress.com/2012/01/05/varnish-reordering-query-string/
  26. 64 POST /blogs HTTP/1.1 Content-type: application/vnd.myblog.article+xml ; version=1.0 <?xml version="1.0"

    encoding="UTF-8" ?> <article> <title>My blogpost</title> <author>John Doe</author> <content>This is the content for my blog article</content> </article> Synchronous updates HTTP/1.1 201 Created Location: /blog/20010101-myblogpost
  27. 65 POST /blogs HTTP/1.1 Content-type: application/vnd.myblog.article+xml ; version=1.0 <?xml version="1.0"

    encoding="UTF-8" ?> <article> <title>My blogpost</title> <author>John Doe</author> <content>This is the content for my blog article</content> </article> Asynchronous updates HTTP/1.1 202 Accepted Location: /queue/621252
  28. 66 GET /queue/621252 HTTP/1.1 HTTP/1.1 200 OK <?xml version="1.0" encoding="UTF-8"

    ?> <queue> <status>Pending</status> <eta>10 minutes</eta> <link rel="cancel" href="/queue/621252"/> </queue> Asynchronous updates - waiting in queue
  29. 67 GET /queue/621252 HTTP/1.1 HTTP/1.1 200 OK <?xml version="1.0" encoding="UTF-8"

    ?> <queue> <status>In progress</status> <eta>3 minutes, 25 seconds</eta> </queue> Asynchronous updates - in progress
  30. 68 GET /queue/621252 HTTP/1.1 Asynchronous updates - done HTTP/1.1 303

    See Other Location: /blog/20010101-myblogarticle
  31. 70 Don’t make transactions through multiple resources. Breaks the state

    constraint (plus the rest of the the internet)
  32. 71 POST /account/1234?amount=-100 TransIDX: 55A50611FE HTTP/1.1 202 Accepted POST /account/4567?amount=+100

    TransIDX: 55A50611FE HTTP/1.1 202 Accepted POST /commit TransIDX: 55A50611FE Nope! This is state!
  33. 76 POST /transactions/55A50611FE POST /transactions/55A50611FE/commit POST /transactions/55A50611FE/rollback POST /transactions/55A50611FE/snapshot POST

    /transactions/55A50611FE/rollback/1 So, define services: POST /booking <xml> <amount currency=”USD”>10.000.000</amount> <from_account>12.34.56.789, my bank</from_account> <to_account>X5252P25, Cayman Islands</to_account> </xml>
  34. 77 ➡ If you do REST, don’t break the constraints.

    ➡ Be realistic about the constraints ➡ XML-RPC, HTTP-services (even SOAP) are valid for their uses. This stuff is hard!
  35. 78 ➡ Take into account that you probably are not

    building the next Twitter API. ➡ If you follow the REST constraints, at least your API can scale.
  36. Techademy Workshopdag 81 Aanmeldingen: [email protected] Workshopdag: Varnish + PHP Speedups

    vrijdag 22 maart - Apeldoorn php5.[34] + http essentials, gearman + activemq, solr + solarium, html5+css3, mongodb + caching, scrum, git+github+travisCI, phpdocumentor
  37. Thank you 82 Find me on twitter: @jaytaph Find me

    for development or training: www.noxlogic.nl Find me on email: [email protected] Find me for blogs: www.adayinthelifeof.nl