NEPHP '12: Create a RESTful API


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  • Thank you _____________Today I’m going to be talking about creating a RESTful API with PHP. Not just any RESTful API, but an Epic one.
  • Even if you are developing a closed API…I hope everyone considers open APIs.All this roles up into one concept. “The platform play.” So if you need something to go back to your boss or your investors with… that’s the thing. You’re making a platform play.
  • There are multiple patterns for APIs. There are a couple more lesser used ones but the two big ones are REST and RPC.Within those patterns you can use one or more formats to transfer your data.
  • Rest stands for Representational State Transfer incase you missed it in Neal’s presentation. As mentioned yesterday, the largest example of REST in the wild is HTTP.Luckily for us, CakePHP is usually layered on-top of HTTP so it inherits all the RESTful mechanisms.REST has a concept called resources (a specific user or comment are two examples).They are also called nouns which are acted on by verbs.There are five verbs in HTTP. We will focus on three.Finally, one last important thing… CakePHP makes REST easy.
  • The app that I will be using as an example today is the simplest app that I could think of.It is a URL shortening services that allows you to authenticate and thus be able to delete and edit URLs that you yourself shortened, and also basic CRUD.
  • There are two models. The user model, which is pretty standard for a CakePHP project, and the urls model which I have on the screen.A full URL shortened can, of course, get much more complicated than that. But for today I’m keeping it basic.
  • Once you’ve baked your model and what not you can open up your router and map the resource. This will register all the routes you need for REST in one call.You can still do it manually if you want but you don’t have to.These are the six routes registered when you map a resource.
  • Before we begin developing views we’ll haveto tell PHP to recognize file extensions and switch the views and layouts accordingly.We do this by turning on parseExtensions in the routes.php file and including the RequestHandler component in the app_controller.The RequestHandler component is what actually switches the views. It also includes helpers automatically in the view if a helper has the same name as the extension (like XML) and parses incoming POSTed XML and assigns it to the data property of the controller.
  • One rule to live by is to never write or delete data on anything that is not a POST, PUT, or DELETE request.The main purpose of this rule is to protect against Cross Site Request Forgeries or CSRF attacks which are every difficult to defend against otherwise.Say that the add method accepted GET requests. Someone could then simply embed an image on a page with the add URL as a source and execute a add() as any user who visits the site.
  • We now need to create a couple views.The Json view is the first and the one that I like the most. Because it is simple and easy to understand.It is fast thanks to native PHP support, and also very wide-spread.What you see here is the entire view for the view action in the urls controller.Notice the path to the view. The RequestHandler will tell Cake to look in the json folder for the appropriate view.
  • We can also easily support JsonP or Json with padding.JsonP specifies a Javascript callback function to execute with the results of a request.It allows for cross domain requests because you can trigger it via a simple script-include and function calls works across domains so the callback will work just fine.One important note is that it is only for GET requests. So, as I said earlier, it shouldn’t be able to write or delete data.JsonP can be handle generically in the layout. Notice the layout path.A JsonP request always takes the callback via a query parameter. So your app controller can read in the callback then set it for use in the view. The layout then reads it sand wraps the output in it is necessary.
  • Now for the XML view. And I can hear the boos now.XML does have some benefits. It is strongly typed, human readable, and has lots of existing tools available.Like Json, the view is pretty self-explanatory. Note the xml sub-directory in the view path.
  • One of the best parts about using parseExtensions and RequestHandler is you can literally have as many views as you want into the data.I listed just some of them here.
  • Erik’s talk.
  • If you did the ACL stuff Erik was talking about…Little difficult. Default behavior is redirectController, model, and object
  • Maintenance mode
  • NEPHP '12: Create a RESTful API

    1. 1. and Conquering the World Andrew Curioso
    2. 2.  Cre·ate[kree-eyt] verb1. to cause to come into being, as something unique that would not naturally evolve or that is not made by ordinary processes.2. to evolve from ones own thought or imagination, as a work of art or an invention. Source:
    3. 3.  Ep·ic [ep-ik] adjective1. noting or pertaining to a long poetic composition, usually centered upon a hero, in which a series of great achievements or events is narrated in elevated style: Homers Iliad is an epic poem.2. resembling or suggesting such poetry: an epic novel on the founding of the country.3. heroic; majestic; impressively great: the epic events of the war.4. of unusually great size or extent: a crime wave of epic proportions. Source:
    4. 4.  Rest[rest] noun1. the refreshing quiet or repose of sleep: a good nights rest.2. refreshing ease or inactivity after exertion or labor: to allow an hour for rest.3. relief or freedom, especially from anything that wearies, troubles, or disturbs.4. a period or interval of inactivity, repose, solitude, or tranquility: to go away for a rest.5. mental or spiritual calm; tranquility.6. Representational State Transfer Source:
    5. 5.  Rest [rest] noun1. the refreshing quiet or repose of sleep: a good nights rest.2. refreshing ease or inactivity after exertion or labor: to allow an hour for rest.3. relief or freedom, especially from anything that wearies, troubles, or disturbs.4. a period or interval of inactivity, repose, solitude, or tranquility: to go away for a rest.5. mental or spiritual calm; tranquility.6. Representational State Transfer Source: Common Knowledge
    6. 6.  A·P·I [ey-pee-ahy] noun1. Application Programming Interface. A contract between two applications that allows them to communicate effectively. Source: Andrew Curioso
    7. 7.  Con·quer[kong-ker] verb1. to acquire by force of arms; win in war: to conquer a foreign land.2. to overcome by force; subdue: to conquer an enemy.3. to gain, win, or obtain by effort, personal appeal, etc.: conquer the hearts of his audience.4. to gain a victory over; surmount; master; overcome: to conquer disease and poverty; to conquer ones fear. Source: Andrew Curioso
    8. 8.  World [wurld] noun1. the earth or globe, considered as a planet.2. ( often initial capital letter ) a particular division of the earth: the Western world.3. the earth or a part of it, with its inhabitants, affairs, etc., during a particular period: the ancient world.4. humankind; the human race; humanity: The world must eliminate war and poverty.5. the public generally: The whole world knows it. Source: Andrew Curioso
    9. 9.  World [wurld] noun1. The ecosystem around your startup or cause into which you drag your family, friends, investors, and anyone who will listen. Source: Andrew Curioso
    10. 10.  Internal only (closed)  External (open)  Multiple consumers  Everything +  Scalable  Growth ▪ Mash-ups! Semi-Private ▪ Innovation ▪ Evangelists  Partner Integration  “The Platform Play”
    11. 11. PATTERNS PROTOCOLS / FORMATS Representation State  XML Transfer (REST)  JSON Remote Procedure Calls  YAML (RPC)  AMF  Etc...
    12. 12.  Representational State Transfer Resource based (nouns) 5 verbs  GET   POST  DELETE  Easy in PHP
    13. 13. 1. Client / Server2. Stateless3. Cacheable4. Layered5. Uniform Interface6. ???
    14. 14.  URL shortening website  User authentication (simple)  Create, read, update, and delete (CRUD)
    15. 15.  id user_id users urls url created modified
    16. 16. Verb URL ActionGET /urls.json List URLsGET /urls/123.json Resource for URL with id 123POST /urls.json Shorten a new URLPUT /urls/123.json Edit the URL with the ID 123DELETE /urls/123.json Delete the URL with the ID 123POST /urls/123.json Also edit the URL with the ID 123
    17. 17. <?php if ( $_SERVER[REQUEST_METHOD] == POST ) { ... }?>
    18. 18.  Only you can prevent CSRF  Only POST and PUT should write data  Only POST and DELETE should delete data  Check Referrer  Per request tokens
    19. 19.  HTTP Accepts Mime Types
    20. 20.  Simple Fast Wide-spread Mime: application/json<?php echo json_encode( $urlObject);?>
    21. 21.  P w/ padding  Uses callback  Cross domain  Mime: application/javascriptif ( array_key_exists(callback’, $_GET) ) $callbackFunc = $_GET[callback];else $callbackFunc = false;if ( $callbackFunc !== false ) echo $callbackFunc.(;echojson_encode( $urlObject );if ( $callbackFunc )echo );?>
    22. 22.  Strongly Typed Human readable Lots of existing tools Mime: application/xml<?php...?>
    23. 23. HUMAN READABLE BINARY  AMF  Microsoft Excel HTML  PDF YAML  JPEG / PNG CSV  Etc… Serialized PHP Etc…
    24. 24. Createcurl –d “” –d “” –X DELETE
    25. 25. WE HAVE WE’RE MISSING Request handling  Error handling RESTful Output Formats  Pagination  XML  Authentication  Json / JsonP  Authorization  Documentation
    26. 26.  Success  Error (continued)  200 OK *  405 Method Not Allowed *  201 Created *  409 Conflict  303 See Other *  410 Gone  500 Internal Server Error * Error  501 Not Implemented  401 Unauthorized *  503 Service Unavailable  402 Payment Required  403 Forbidden *  404 Not Found *
    27. 27.  If not a POST request  405 Method Not Allowed Already existed  303 See Other Save success  201 Created Failure  500 Internal Server Error with explanation
    28. 28.  If not a POST or PUT request  405 Method Not Allowed Invalid ID  404 File Not Found Success  200 OK Failure  500 Internal Server Error with explanation
    29. 29.  If not a POST or DELETE request  405 Method Not Allowed Invalid ID  404 File Not Found Success  200 OK Failure  500 Internal Server Error with explanation
    30. 30.  User is not allowed to access resource  403 Forbidden User is not logged in  401 Unauthorized
    31. 31.  Same format Descriptive  Human  Computer Comprehensive
    32. 32. {"Error": { "code" : 404, "description" : "File Not Found"}}
    33. 33.  Return meta-information  Rate limiting  Pagination  Expiration / cache  Etc.
    34. 34.  Uses HTTP headers App defined “used to” start with “X-”header(“X-Current-Page:”.$currentPage);header(“X-Total: ”.$total);header(“X-Per-Page: ”.$perPage);
    35. 35. SOME PLATFORMS (LIKE MANYWEB BROWSERS) FORTUNATELY… Do not support:  You can/should do this:  DELETE  PUT _method=DELETE
    36. 36. DELETE /urls/123.json HTTP1.1 POST /urls/123.json HTTP1.1Host: Host: _method=DELETE
    37. 37. BAD No Authentication GOOD Basic BETTERForm and Cookie Digest BEST Oauth Shared Secret
    38. 38.  There are no shortcuts One or more:  All Users (public)  Owner  Shared User  Moderator  Administrator
    39. 39.  Vocabularies / Schemas  DTD or schema files Examples  Code  I/O Community Feedback WSDL 2.0
    40. 40.  PHP rocks with REST SOAP is heavy AMF is light but requires Flash But, if you still want to, you can
    41. 41. User Gateway REST API POST REST request REST request Response Aka the Façade Pattern
    42. 42.  Built-in to HTTP  Expires  Last-Modified  Cache-Control  Etag ▪ If-None-Match Stateless
    43. 43.  Hypermedia as the Engine of Application State Roy Thomas Fielding
    44. 44.  REST constraints Documentation Security Unit tests
    45. 45.  Contact:   @AndrewCurioso on Twitter 