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Using an API

Adam Culp
August 08, 2012

Using an API

Talk about API basics and also more details on actually using an API and programming for it.

Adam Culp

August 08, 2012
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  1. Using an API  Tools  HTTPie  CURL 

    Charles – http://www.charlesproxy.com  Firebug – https://getfirebug.com
  2. Using an API  HTTPie  Great for debugging APIs

    rather than using cURL  http://www.httpie.org  Free  Requires Python POST /books HTTP/1.1 HOST: example.com Content-Type: application/hal+json Accept-Encoding: identity, deflate, compress, gzip Accept: application/hal+json User-Agent: HTTPie/0.2.0 { “author”: “Stoyan Stefanov”,
  3. Using an API  Charles  http://charlesproxy.com  Great for

    debugging AJAX and Flash AMF requests  Worth the $50 license fee, but (at least on Ubuntu) you can use it free, though it shuts down after 30 minutes.
  4. Using an API  cURL  Great to use via

    PHP, but for command line use HTTPie.  Firebug  Great for debugging from Firefox.  Others  I hear IE has an OK debugging tool like Firebug.  I have also heard Chrome has a great Firebug'ish tool also.
  5. Using an API  What is an API?  Application

    programming interface  A specification intended to be used as an interface by software components to communicate with each other. - wikipedia
  6. Using an API  API types (popular)  SOAP –

    Simple Object Access Protocol  REST – Representational State Transfer  (RFC 2616)  Javascript  Screen scrape
  7. Using an API  SOAP basics  Relies on XML

    as its message format.  Uses HTTP, SMTP, TCP, or JMS for transport, but usually HTTP.  Generally uses a WSDL (Web Services Description Language) configuration file making it easier to build for or connect to the API.  Cross platform and cross language.  Very structured – each action is defined (addUser, getUsers, getNewUsersSince, etc.)
  8. Using an API  Javascript basics  Client side execution

     Communication from client to server  Usually methods are defined on server side (getThis, addThat, etc.)  Perception of interactivity (desktop feel)  Can be asynchronous  Used by Google Maps and others
  9. Using an API  Screen scrape basics  Not a

    true client/server api.  Relies on regular expression matching of content.  Usually done over HTTP using cURL.  Breaks when server content changes.  Must download all content, so may be slow and resource intensive.
  10. Using an API  REST basics (main focus for this

    talk)  Client-Server  Stateless – each request is complete and self contained (struggle with sessions and cookies)  Cacheable  Layered – client cannot tell if using end-server, allows load balancers, caches, logging, auth.  Uniform interface – decoupled from architecture  Methods – GET, POST, PUT, DELETE, HEAD, OPTIONS, TRACE, CONNECT
  11. Using an API  REST safe methods  No side

    effects on the server  GET & HEAD should make no other action than to retrieve.  Allows user agents to represent POST, PUT, and DELETE special. (most browsers do not support PUT and DELETE out of the box)
  12. Using an API  Idempotence  Operations that can be

    applied multiple times without changing the result. (Ex.- N>0 identical requests would have the same output)  GET, HEAD, PUT, and DELETE share this property  OPTIONS and TRACE are inherently idempotent.
  13. Using an API  GET  Safe and idempotent 

    No effect on the server GET /books/9790482c HTTP/1.1 Host: example.com Accept-Encoding: identity, deflate, compress, gzip Accept: application/hal+json User-Agent: HTTPie/0.2.0
  14. Using an API  GET response HTTP/1.1 200 OK Date:

    Wed, 08 Aug 2012 09:32:42 GMT Server: Apache/2.2.22 (Ubuntu) X-Powered-By: PHP/5.3.10-1ubuntu3.2 ETag: “9790482c-1” Last-Modified: Wed, 08 Aug 2012 04:14:30 GMT Content-Length: 254 Content-Type: application/hal+json { “_links”: { “self”: { “href”: “http://example.com/books/9790482c” } }, “author”: “Luke Welling, Laura Thomson”, “id”: “9790482c”, “isbn10”: “0672329166”,
  15. Using an API  POST  Not safe  Not

    idempotent (same post multiple times could have different effects on server)  Used to create resource  Is often used to also update a resource, though PUT is more for updating.
  16. Using an API  POST example POST /books HTTP/1.1 HOST:

    example.com Content-Type: application/hal+json Accept-Encoding: identity, deflate, compress, gzip Accept: application/hal+json User-Agent: HTTPie/0.2.0 { “author”: “Stoyan Stefanov”, “isbn10”: “1449320198”, “isbn13”: “9781449320195”, “publisher”: “O'Reilly Media”, “title”: “Javascript for PHP Developers”, “year”: 2012 }
  17. Using an API  Created Response HTTP/1.1 201 Created Date:

    Sun, 29 Jul 2012 23:26:49 GMT Server: Apache/2.2.22 (Ubuntu) X-Powered-By: PHP/5.3.10-1ubuntu3.2 Location: http://example.com/books/decd0562 Etag: “decd0562-1” Last-Modified: Sun, 29 Jul 2012 23:26:49 GMT Content-Length: 239 Content-Type: application/hal+json { “_links”: { “self”: { “href”: “http://example.com/books/decd0562” } }, “author”: “Stoyan Stefanov”, “id”: “decd0562”, “isbn10”: “1449320198”,
  18. Using an API  PUT  Not safe  But

    is idempotent  Primarily an update action, but can also be used to create though POST should be used for that.
  19. Using an API  Sample PUT PUT /books/decd0562 HTTP/1.1 HOST:

    example.com Content-Type: application/hal+json Accept-Encoding: identity, deflate, compress, gzip If-Match: “decd0562-1” Accept: application/hal+json User-Agent: HTTPie/0.2.0 { “_links”: { “self”: { “href”: “http://example.com/books/decd0562” } } “author”: “Stoyan Stefanov”, “isbn10”: “1449320198”,
  20. Using an API  Update response HTTP/1.1 201 OK Date:

    Sun, 29 Jul 2012 23:26:49 GMT Server: Apache/2.2.22 (Ubuntu) X-Powered-By: PHP/5.3.10-1ubuntu3.2 Location: http://example.com/books/decd0562 Etag: “decd0562-2” Last-Modified: Sun, 29 Jul 2012 23:26:49 GMT Content-Length: 270 Content-Type: application/hal+json { “_links”: { “self”: { “href”: “http://example.com/books/decd0562” } }, “author”: “Stoyan Stefanov”, “id”: “decd0562”, “isbn10”: “1449320198”,
  21. Using an API  DELETE  Not safe  Is

    idempotent  Does not mean to remove the resource, but does mean to remove from public view. DELETE /books/decd0562 HTTP/1.1 Host: example.com Accept-Encoding: identity, deflate, compress, gzip Accept: application/hal+json User-Agent: HTTPie/0.2.0 If-Match: “decd0562-2”
  22. Using an API  DELETE response HTTP/1.1 204 No Content

    Date: Mon, 30 Jul 2012 00:01:44 GMT Server: Apache/2.2.22 (Ubuntu) X-Powered-By: PHP/5.3.10-1ubuntu3.2 Content-Length: 0 Content-Type: application/hal+json
  23. Using an API  HEAD  Same as GET, but

    doesn't return the body  An example of use would be to check content length before actually requesting it.
  24. Using an API  Status codes  Informational (1xx) 

    Successful (2xx)  Redirection (3xx)  Client error (4xx)  Server error (5xx)
  25. Using an API  Common usage  Most developers aren't

    building an API  Using for sites and application content  Leverage resources/services (Google Maps)  Cut development time, add functionality
  26. Using an API  Resources for great APIs available 

    Mashery.com  https://developer.mashery.com/apis  Apigee.com  https://apigee.com/providers  Google  https://developers.google.com Let's take a look!!!
  27. Using an API  Documention tools  Mashery http://mashery.github.com 

    I/O Docs – interactive API documentation  I/O Alfred – Alfred app to use some APIs  I/O Wraps – API client library generator  Oauth Signature Tool  Oauth 1.0 JS Testing Tool  AppMobi Sample Apps
  28. Using an API  Documentation tools  apigee  Providers

    list  “Console” to experiment with APIs  “Console To-Go” to add your own API  Usergrid – Backend as a service to get mobile apps running quickly.  O-Auth api
  29. Using an API  Resources  http://www.charlesproxy.com  https://getfirebug.com 

    http://www.httpie.org  https://developer.mashery.com/apis  https://apigee.com/providers  https://developers.google.com
  30. Using an API  Thank You Adam Culp @adamculp http://geekyboy.com

    Please rate this talk at: http://joind.in/6739