Web Services and REST

Introduction
• Web sites are normally accessed by a browser guided by a person
• But we have seen that programs can also access a web site, return one or

more pages, and scrape the site for information
• Web Services is the idea of offering the capabilities/information on a web

site via a programming interface, so application programs can more readily
access the information on the site

• Web Services are APIs for accessing a website’s information across the
Internet

Introduction (cont’d)
• The implementation of Web Services is roughly divided into three

categories:
– Big Web Services which involve XML messages that are communicated by the

Simple Object Access Protocol (SOAP); the API is formally described using the
Web Services Description Language (WSDL). These services are normally used
for server-to-server communication, using additional protocols like XML Security
and XML Encryption.

– REST (Representational State Transfer) Services which use HTTP methods
PUT, GET, POST and DELETE.

– Cloud Services which provide cloud storage, application hosting, content
delivery, and other hosting services.

• All three types of Web Services provide access through APIs.
• The rest of the slides will cover REST Services and Cloud Services

REST Services
• Many web sites are now offering their facilities through REST Web Services
• REST Services can be used to access sites that perform the following

functions:
– Web Search (e.g. Google Custom Search)
– Geolocation (e.g. Google Maps Geolocation API)
– Photo Sharing (e.g. SmugMug’s Flickr)
– Social Networking (e.g. Facebook, Twitter)
– Mapping (e.g. Google Maps, Bing Maps)

• Access is provided using one or both of these methods:
– Direct URL, returning a response in one or more formats (XML, JSON, PHP)
– Library-based APIs, embedded in JavaScript, Java, C#, Objective-C and other

source and binary library formats
• Many of these services now require or include OAuth user authentication

– Oauth is a standard for clients to access server resources on behalf of a resource owner
– E.g. see http://en.wikipedia.org/wiki/OAuth

• Many of these services limit daily usage by a single website, and require
payment when the thresholds are breached

Cloud Services
• Cloud Services covers a variety of hosting services:

– Application Hosting (e.g. AWS, Google App Engine, FireHost, Microsoft Azure)
– Backup and Storage ( e.g. AWS)
– Content Delivery (e.g. Netflix hosted by AWS)
– E-commerce (Amazon.com e-commerce)
– Media Hosting (e.g. Microsoft Azure, RackSpace, Streaming Media Hosting)
– DNS Protection Services (e.g., CloudFlare)
– Consumer Cloud Storage (e.g. Apple iCloud Drive, Dropbox, Microsoft OneDrive,

Google Drive)
• Access is provided using one or both of these methods:

– Dashboard
– Library-based APIs, embedded in Java, C#, Objective-C and other binary library

formats
• All these services are commercial services that require monthly payments
• The consumer cloud services provide limited, free basic storage

REST (Representational State Transfer)

• REST is a style of software architecture for distributed hypermedia systems (i.e.
the Web)
– Initially proposed by Roy Fielding in a 2000 doctoral dissertation
– See: http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm
– The World Wide Web is an example of REST

• There are three fundamental aspects of the REST Design Pattern
– 1. client, 2. servers and 3. resources
– Resources are typically represented as documents
– Systems that follow Fielding’s REST principles are often referred to as
RESTful;

Resources
Every distinguishable entity is a resource

URLs
Every resource is uniquely

identified by a URL
Simple Operations
(PUT,GET,POST,DELETE)

6© Ellis Horowitz Marco Papa 2006-2021

REST versus Other Approaches

• REST
– Software architectural style for distributed hypermedia systems like WWW
– Quickly gained popularity through its simplicity

• SOAP
– Protocol for exchanging XML-based message, normally using HTTP
– Much more robust way to make requests, but more robust than most APIs need
– More complicated to use

• XML-RPC
– RPC protocol with XML as an encoding and HTTP as a transport
– More complex than REST but much simpler than SOAP

• JSON-RPC
– RPC protocol encoded in JSON instead of XML
– Very simple protocol (and very similar to XML-RPC)

7© Ellis Horowitz Marco Papa 2006-2021

REST as Lightweight Web Services
• Much like Web Services, a REST service is:

– Platform-independent (you don’t care if the server is Unix, the client is
a Mac, or anything else),

– Language-independent (C# can talk to Java, etc.),
– Standards-based (runs on top of HTTP), and
– Can be used in the presence of firewalls (port 80/443 always open)

• Like Web Services, REST offers no built-in security features, encryption,
session management, QoS guarantees, etc. But also as with Web Services,
these can be added by building on top of HTTP:
– For security, username/password tokens are often used.
– For encryption, REST can be used on top of HTTPS (secure sockets).

• One thing that is not part of a good REST design is cookies:
– The “ST” in “REST” stands for “State Transfer”, and indeed, in a good

REST design operations are self-contained, and each request carries
with it (transfers) all the information (state) that the server needs in
order to complete it.

REST & the HTML Web
(Get book list, get book details, order book)

User

GET /books/ HTTP/1.1

HTTP/1.1 200 OK
Content-Type: text/html
…

Moby Dick
XML QuickRef

Web
Server

GET /books/1234 HTTP/1.1

HTTP/1.1 200 OK
Content-Type: text/html
…

Moby Dick

Buy!

POST /order?id=1234 HTTP/1.1
Content-type: application/x-www-form-urlencoded
…order form data…

HTTP/1.1 200 OK
…

Order

View
list of books

V
iew

book details
O

rder book

Books

Orders

REST & the XML Web
(get book list, get book details)

Web
Service

G
et list of books

G
et book details

GET /books/ HTTP/1.1

HTTP/1.1 200 OK
Content-type: text/xml
…

GET /books/1234/ HTTP/1.1

HTTP/1.1 200 OK
Content-type: text/xml
…

Moby Dick
…other book data…

REST & the XML Web (2)
(order book)

POST /orders/ HTTP/1.1
…

… …

Web
Service

O
rder B

ook

HTTP/1.1 201 Created
Location: http://…/abcd/

Rather than web pages being returned
xml files are returned

REST & the JSON Web
(get book list, get book details)

GET /books/ HTTP/1.1

HTTP/1.1 200 OK

Content-type: text/json

{ “books”: {

“book”: [

{ “href”: “http://…/1234/” },

{ “href”: “http://…/5678/” }

]
}

}

GET /books/1234/ HTTP/1.1

HTTP/1.1 200 OK

Content-type: text/json

{
“book”: {

“title”: “Moby Dick”,

. . . other book data

“order”: { “href”: “http://…/orders” }

}
}

JSON objects are returned

REST & the JSON Web (2)
(order book)

POST /orders/ HTTP/1.1
{

“order”: {

“bookId”: { “-href”: “http://…/books/1234” },

“payment”: ” … “,

“shipping”: ” … ”

}
}

HTTP/1.1 201 Created

location: http://…/abcd

More Complex REST Requests
• REST can easily handle more complex requests, including multiple parameters.
• All types of HTTP requests: GET, POST, PUT, PATCH, DELETE, COPY, HEAD,

OPTIONS, LINK, UNLINK, PURGE
• In most cases, you’ll just use HTTP GET parameters in the URL.
• For example:
http://www.acme.com/phonebook/UserDetails?firstName=John&lastName=Doe

• If you need to pass long parameters, or binary ones, you’d normally use HTTP POST
requests, and include the parameters in the POST body.

• As a rule,
1. GET requests should be for read-only queries; they should not change the state

of the server and its data.
2. For creation, updating, and deleting data, use POST requests. POST can also be

used for read-only queries, as noted above, when complex params are required.’
3. PUT, DELETE are also used for updating and deleting items.

• “Legacy” REST services might use XML in their responses.
• Newer REST Services use JSON in their responses.
• Postman can be used to test any of the HTTP requests.

Postman
• Postman is a tool for API testing
• Platforms include Chrome add-on, MacOS, Windows and Linux native apps
• Download page available at:

https://www.getpostman.com/apps

• Free version comes with the following support:
– Unlimited Postman collections, variables, environments, & collection runs
– Postman Workspaces
– Postman Help Center & Community Support
– API Documentation (1000 Monthly document views)
– Mock Servers (1000 Monthly mock server calls)
– Postman API (1000 Monthly API calls)
– API Monitoring (100 Monthly calls)

• Postman Pro and Postman Enterprise provide additional feature on a monthly
subscription.

REST Server Responses
• A server response in REST used to be an XML file; for example, ACME Boomerang
Used by Coyote in Zoom at the Top, 1962

17.32 http://www.acme.com/parts/3322

ACME Dehydrated Boulders
Used by Coyote in Scrambled Aches, 1957

19.95 http://www.acme.com/parts/783

• However, other formats can also be used; REST is not bound to XML in any way.
JSON is the response format recently used the most. Possible formats include CSV.

• One option that is not acceptable as a REST response format, except in very specific
cases is HTML, or any other format which is meant for human consumption and is not
easily processed by clients.

• The specific exception is, of course, when the REST service is documented to return
a human-readable document; and when viewing the entire WWW as a RESTful
application, we find that HTML is in fact the most common REST response format.

Flickr

• Photo-sharing community with APIs provide viewing and uploading access
• Request formats: REST, XML-RCP, SOAP
• Response Formats: REST, XML-RPC, SOAP, JSON, PHP. Supports

JSONP.
• API Developer Kits available for 15 languages including ActionScript

(Flash), Java (Android), .NET, Objective-C (iOS)
• Comprehensive number of API methods for authentication, blogs, contacts,

favorites, galleries, people, photos
• Example Query:

– https://api.flickr.com/services/rest/?method=flickr.photos.getRecent&api
_key=f2cc26448280a762143ba4a865795ab4&format=json

– (remove format parameter for XML results)
– https required since June 2014

Flickr Sample JSON Result

jsonFlickrApi({“photos”:{“page”:1, “pages”:10, “perpage”:100, “total”:1000, “photo”:[{“id”:”6879393174″,
“owner”:”50010354@N05″, “secret”:”cf784500dd”, “server”:”7080″, “farm”:8,
“title”:”wjk_20110611_0092.jpg”, “ispublic”:1, “isfriend”:0, “isfamily”:0}, {“id”:”6879393274″,
“owner”:”31403543@N03″, “secret”:”af280ab218″, “server”:”6231″, “farm”:7, “title”:”Imagen 415″,
“ispublic”:1, “isfriend”:0, “isfamily”:0}, {“id”:”6879393306″, “owner”:”66286618@N05″,
“secret”:”7fc731bc3d”, “server”:”6237″, “farm”:7, “title”:”IMG_6241-1″, “ispublic”:1, “isfriend”:0,
“isfamily”:0}, {“id”:”6879393338″, “owner”:”28935680@N03″, “secret”:”ec7444d9b6″,
“server”:”7237″, “farm”:8, “title”:”IMG_6756″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879393352″, “owner”:”32752988@N06″, “secret”:”be56f5751c”, “server”:”6046″, “farm”:7,
“title”:”AED_4586″, “ispublic”:1, “isfriend”:0, “isfamily”:0}, {“id”:”6879393370″,
“owner”:”29083790@N00″, “secret”:”ec89570135″, “server”:”6219″, “farm”:7, “title”:”IMG_6546″,
“ispublic”:1, “isfriend”:0, “isfamily”:0}, {“id”:”6879393402″, “owner”:”50702313@N08″,
“secret”:”18ecdd7871″, “server”:”7191″, “farm”:8, “title”:”Group A 3″, “ispublic”:1, “isfriend”:0,
“isfamily”:0}, {“id”:”6879393418″, “owner”:”8502118@N08″, “secret”:”082968f6a9″,
“server”:”6220″, “farm”:7, “title”:”Buff-necked Ibis (Theristicus caudatus)”, “ispublic”:1, “isfriend”:0,
“isfamily”:0}, {“id”:”6879393440″, “owner”:”51425572@N04″, “secret”:”bc5f816ffb”,
“server”:”6219″, “farm”:7, “title”:”P2115768″, “ispublic”:1, “isfriend”:0, “isfamily”:0}, […]})

Partial Flickr Sample JSON Result With Formatting

jsonFlickrApi({“photos”:{“page”:1, “pages”:10, “perpage”:100, “total”:1000,
“photo”:[
{“id”:”6879682760″, “owner”:”8348059@N02″, “secret”:”1ac6c7e2c4″, “server”:”6220″, “farm”:7,
“title”:”DSC_0619″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879682762″, “owner”:”35772789@N02″, “secret”:”db5dffb91d”, “server”:”6117″, “farm”:7,
“title”:”Dianna Romo 5″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879682776″, “owner”:”8091633@N05″, “secret”:”302174b53e”, “server”:”6118″, “farm”:7,
“title”:”DSC_4259″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879682778″, “owner”:”58641881@N08″, “secret”:”c028082788″, “server”:”7212″, “farm”:8,
“title”:”DSC_0777″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879682790″, “owner”:”32045507@N06″, “secret”:”d80d372bd2″, “server”:”6093″, “farm”:7,
“title”:”IMG_9136″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879682792″, “owner”:”76919580@N08″, “secret”:”57e8d1cf8d”, “server”:”7277″, “farm”:8,
“title”:”DSC01410″, “ispublic”:1, “isfriend”:0, “isfamily”:0},
{“id”:”6879682796″, “owner”:”50838701@N04″, “secret”:”a3431e27e9″, “server”:”6042″, “farm”:7,
“title”:”eP3274587″, “ispublic”:1, “isfriend”:0, “isfamily”:0},

Microsoft Bing Maps REST Services

• Bing Maps REST Services: https://docs.microsoft.com/en-us/bingmaps/rest-services/
• The Bing Spatial Data Services are REST-based services that offer three key

functionalities: batch geocoding, point of interest (POI) data, and the ability to store and
expose your spatial data.

• Used for performing tasks such as geocoding, reverse-geocoding, routing and static
imagery.

• REST Request URLs:
– Find a location by Address:
http://dev.virtualearth.net/REST/v1/Locations/CA/adminDistrict/postalCode/locality/address

Line?includeNeighborhood=includeNeighborhood&maxResults=maxResults&key=Bing
MapsKey

– Find a location by Query:
http://dev.virtualearth.net/REST/v1/Locations/1%20Microsoft%20Way%20Redmond
%20WA%2098052?o=xml&key=BingMapsKey
– Find a location by Point:
!””#$%%&'()(*+”,-.’-+”!)/'”%0123%(4%1.'(-“*5/%6*7″8#5*/”79:;)<=>:4?@44A)BC;CC?:;)<=:=:? @44A)BC;B?@44A)BCDAD?:;)<=::B?@44A)BCDDCEF'G9H*/IJ-#7K'G © Ellis Horowitz Marco Papa 2006-2021 21 https://docs.microsoft.com/en-us/bingmaps/rest-services/ http://dev.virtualearth.net/REST/v1/Locations/CA/adminDistrict/postalCode/locality/addressLine?includeNeighborhood=includeNeighborhood&maxResults=maxResults&key=BingMapsKey http://dev.virtualearth.net/REST/v1/Locations/1%20Microsoft%20Way%20Redmond%20%20WA%2098052?o=xml&key=BingMapsKey http://dev.virtualearth.net/REST/v1/Locations/1%20Microsoft%20Way%20Redmond%20%20WA%2098052?o=xml&key=BingMapsKey http://dev.virtualearth.net/REST/v1/Elevation/List?points=35.89431,-110.72522,35.89393,%20-110.72578,35.89374,-110.72606,35.89337,-110.72662&key=BingMapsKey http://dev.virtualearth.net/REST/v1/Elevation/List?points=35.89431,-110.72522,35.89393,%20-110.72578,35.89374,-110.72606,35.89337,-110.72662&key=BingMapsKey Microsoft REST Services (cont’d) • Request Parameters: See complete list at: https://docs.microsoft.com/en-us/bingmaps/rest-services/common-parameters-and-types – Response formats: XML, JSON (output=JSON), JSONP (jsonp=callback), and PHP • Response fields (Location Data) defined at: https://docs.microsoft.com/en-us/bingmaps/rest-services/common-response-description © Ellis Horowitz Marco Papa 2006-2021 22 https://docs.microsoft.com/en-us/bingmaps/rest-services/common-parameters-and-types https://docs.microsoft.com/en-us/bingmaps/rest-services/common-response-description Amazon Web Services • Among them are – Amazon Associates Web Services (see next slides) – Amazon Elastic Compute Cloud (or EC2) • allows users to rent computers on which to run their own computer applications. EC2 allows scalable deployment of applications by providing a web service through which a user can boot an Amazon Machine Image to create a virtual machine, which Amazon calls an "instance", containing any software desired. • A user can create, launch, and terminate server instances as needed, paying by the hour for active servers, hence the term "elastic". – Amazon primarily charges customers in two ways: • On-demand pricing. Example: EC2 Linux, t2.nano $0.0058 per hour https://aws.amazon.com/ec2/pricing/on-demand/ • Spot Instances pricing. Example: linux, m4.large $0.019 per Hour https://aws.amazon.com/ec2/spot/pricing/ • Reserved Instances pricing. https://aws.amazon.com/ec2/pricing/reserved-instances/pricing/ • Dedicated Hosts pricing. https://aws.amazon.com/ec2/dedicated-hosts/pricing/ – See http://en.wikipedia.org/wiki/Amazon_Elastic_Compute_Cloud for details © Ellis Horowitz Marco Papa 2006-2021 23 https://aws.amazon.com/ec2/pricing/on-demand/ https://aws.amazon.com/ec2/spot/pricing/ https://aws.amazon.com/ec2/pricing/reserved-instances/pricing/ https://aws.amazon.com/ec2/dedicated-hosts/pricing/ http://en.wikipedia.org/wiki/Amazon_Elastic_Compute_Cloud © Ellis Horowitz Marco Papa 2006-2021 24 Amazon Associates Web Services • Amazon offers web services to 3 types of users: – Associates: third-party site owners wishing to build more effective sponsored affiliate links to Amazon products, thus increasing their referral fees – Vendors: sellers on the Amazon platform looking to manage inventory and receive batch product data feeds – Developers: third-party developers building Amazon-driven functionality into their applications • Amazon Web Services provides software developers direct access to Amazon's technology platform and product data. • Developers can build businesses by creating Web sites and Web applications that use Amazon products, charging and delivery mechanisms. • Using Web services, you can now enable your Web site visitors to add products to Amazon.com shopping carts, wedding registries, baby registries and wish lists directly from your site. • http://aws.amazon.com/ © Ellis Horowitz Marco Papa 2006-2021 25 Amazon Associates Web Services Data Flow Amazon results can be returned either as XML files or as SOAP messages Data XML/HTTP stands for REST © Ellis Horowitz Marco Papa 2006-2021 26 Amazon Web Services Data Model Below is a graphical listing of the elements of the Amazon Web Services data model. The graphic represents the logical structure of AWS data. Google APIs • Available at: – http://developers.google.com/products • APIs available for: – Android – App Engine – Chrome – Games – Google Maps – Google Apps – Google Play – Commerce – YouTube – Etc. • Develop, Grow, and Earn © Ellis Horowitz Marco Papa 2006-2021 27 http://developers.google.com/products Google App Engine • Google App Engine lets you run Web Applications / Web Services on GCP. – There are no servers to maintain: You just upload your application (like AWS) • You can serve your app from your own domain name or you can serve your app using a free name on the appspot.com domain. – You can limit access to members of your organization. • Google App Engine supports apps written in several programming languages 1. Java environment, including the JVM, and Java servlets. 2. PHP 3. Python. App Engine also features two dedicated Python runtime environments, each of which includes a fast Python interpreter and the Python standard library. 4. Go. App Engine provides a Go runtime that runs natively compiled Go code. 5. Node.js & Ruby. Included in the “flexible environment”. • Download App Engine SDKs at: https://cloud.google.com/appengine/downloads • You only pay for what you use and there are no set-up costs and no recurring fees • Free daily limits are quite high: 657K API calls (URLFetch API) , 200h connect time, 5GB storage) • See: https://cloud.google.com/appengine/pricing © Ellis Horowitz Marco Papa 2006-2021 28 https://cloud.google.com/appengine/downloads https://cloud.google.com/appengine/pricing Google App Engine Free Quota • See: https://cloud.google.com/appengine/quotas © Ellis Horowitz Marco Papa 2006-2021 29 https://cloud.google.com/appengine/quotas Google Custom Search • Enables searching over a website or a collection of websites • Places a Google search box on a website that allows users to search the site • Search results can be customized to match the design of the site – Google form to be filled out to create the custom search box http://cse.google.com/ • Create a search engine – Google Custom Search enables you to create a search engine for your website, your blog, or a collection of websites. You can configure your engine to search both web pages and images • Search experience for users – Site search for your website – Topical search engine – Use structured data with Custom Search • See: https://developers.google.com/custom-search/ • Documentation on implementing a “search box”: https://developers.google.com/custom- search/docs/tutorial/implementingsearchbox © Ellis Horowitz Marco Papa 2006-2021 30 http://cse.google.com/ https://developers.google.com/custom-search/ https://developers.google.com/custom-search/docs/tutorial/implementingsearchbox Google API Example: Google Maps API • We will use the JavaScript API for Google maps https://developers.google.com/maps/ documentation/javascript • We will use their API, V. 3, click on "Get Started" • First step: obtain an API key by click on “GET A KEY” • Second step: return to https://developers.google.com/maps/ documentation/javascript/tutorial and examine the sample code Note: Google Maps API material not required. Skip to Slide 42, Apple iCloud for developers. 31© Ellis Horowitz Marco Papa 2006-2021 Activate Google Maps JavaScript API v3 32© Ellis Horowitz Marco Papa 2006-2021 Obtaining an API Key Select Project Returning a key result 33© Ellis Horowitz Marco Papa 2006-2021 Simple Maps Example

for many more details about this example see
https://developers.google.com/maps/documentati
on/javascript/tutorial

Changing the Map’s Center Point

• Use Geocoding API to
find the
latitude/longitude of a
local address
• Use a geocoding service

at:
https://developers.googl
e.com/maps/documenta
tion/geocoding/start
• For an address we will

use the CS dept
• The result is the lat/long

Simple Map with Lat/Long Change

Changing the Zoom Level

• the zoom level controls the distance
above the map

• higher values cause the zoom to close in
• set the zoom value to 16 and the

resulting map is produced

ROADMAP

Adding a Marker to the Map
• But where is the CS dept.? we need to add a marker
• we see an example of a marker at

https://developers.google.com/maps/documentation/javascript/examples/marker-simple
function initialize() {

var myLatLng = {lat: 34.020, lng: -118.290};

var mapOptions = { zoom: 4, center: myLatlng }

var map = new google.maps.Map(document.getElementById(‘map-
canvas’), mapOptions);

var marker = new google.maps.Marker({

position: myLatlng,

map: map,

title: ‘CS Dept’

});

}

google.maps.event.addDomListener(window, ‘load’, initialize);

Change the Map Type

one can alter the map type by adding the line:
mapTypeId: ‘satellite’; or
map.setMapTypeId(‘terrain’);

there are 4 map types:
HYBRID
ROADMAP
SATELLITE
TERRAIN

Add a Marker with Tool Tip

Adding a Popup Info Window to the Marker

Apple iCloud For Developers

• Apple’s iCloud service places all information captured on any Apple
device into the cloud, making it immediately available to all other
Apple devices

• 5GB (free) – 50GB, 200GB, 1TB plans available at:
– http://www.apple.com/icloud/
– https://developer.apple.com/icloud/index.html

• iCloud APIs available for iOS 5 through 13 and OS X 10.9+
– CloudKit framework
– Storage API for Documents
– Storage API for key-value data storage
– Storage API for Core Data
– Fallback Store (iOS 7+)
– Account Changes (iOS 7+)
– Manage iCloud Content (iOS 7+)
– Xcode debugging (Xcode 5+)
– iPhone simulator support (iOS 7+)

REST Best Practices
• 1. Provide a URI for each resource that you want exposed.
• 2. Prefer URIs that are logical over URIs that are physical. For example prefer
http://www.boeing.com/airplanes/747
Over:
http://www.boeing.com/airplanes/747.html
• Logical URIs allow the resource implementation to change without impacting client applications
• 3. As a corollary to (2) use nouns in the logical URI, not verbs. Resources are “things“ not “actions”
• 4. Make all HTTP GETs side-effect free.
• 5. Use links in your responses to requests. Doing so connects your response with other data. It enables

client applications to be self-propelled. That is, the response itself contains info about “what’s the next
step to take”.

• 6. Minimize the use of query strings. For example, prefer
http://www.parts-depot.com/parts/00345
Over
http://www.parts-depot.com/parts?part-id=00345
• 7. Use the slash “/” to represent a parent-child, whole-part relationship
• 8. Use a “gradual unfolding methodology” for exposing data to clients. That is, a resource

representation should provide links to obtain more details.
• 9. Always implement a service using HTTP GET when the purpose of the service is to allow a client to

retrieve a resource representation, i.e. don’t use HTTP POST

Moby Dick

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