Shindig Architectural Overview
Rajdeep Dua
Google Developer Relations
Nov ,2008.
1

Agenda
• Shindig Client and Server Components
• Javascript Client libraries and various containers
 OpenSocial Container
 Java script Container
• GET FRIENDS – Client side Collaboration
• GET FRIENDS - Server side Collaboration
Google Confidential and Proprietary 2

Shindig
• Apache Incubator Project
• Available in both Java and PHP Version
• Java version based on Servlet stack
• JSON backend in the reference implementation
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Shindig Client side
• Gadget Container – gadgets.js
• OpenSocial Container
• Restful Container – Part of OpenSocial 0.8 feature
Google Confidential and Proprietary 4

Shindig : Client Server Flow
Shindig Javascript Client
Gadgets.io Shindig Server
opensocial.Container:
FunctionObject
URL Parser and Mapper
XmlHttpRequest
extends
HTTP Service
Open Handler1
Social RestfulContainer: calls Handler2
Gadget FunctionObject
Handler3
JsonRpcContainer:
FunctionObject
calls
GadgetsContainer:
FunctionObject
Any HTTP Client
Google Confidential and Proprietary 5

Shindig Component Architecture
HTTP Server
Servlet Engine
Gadget Renderer
ConcatProxy Servlet
Servlet DataService
MakeRequest
JsonRpcServlet
Proxy Servlet
Rpc Servlet
Servlet
Js Servlet
Servlet
Gadget Open
Renderer Open Social Social
Open Social
Sample Server BeanJson
BeanXml
DataHandler Convertor
Container Side Convertor
implements
Object
People
s
Gadget Service
PersonHandler
Server
Activities JsonDB
Service OpenSocial Activities
Gadget
Spec Service Handler
Data Service AppData
Handler
Gadget
Features State
Gadget.xml File
and
jsLibraries
Google Confidential and Proprietary 6

Component Architecture –
Client side Gadget Container
Gadgets : Object gadgets.Container gadgets.Extensible
• gadgets.GadgetService() Function Object setDependencies()
• gadgets.DefaultUserPrefStore() Gadgets_
• gadgets.LayoutManager() ParentUrl_
• gadgets.Gadget() View_
• gadgets.Container() gadgetClass gadgets.IfrContainer
gadgetService • renderGadget()
gadgets.GadgetService gadgets.Gadget
gadgets.LayoutManager
Function Object Function Object
Function Object
_userPrefs
call inherits
gadgets.UserPrefStore call inherits
Function Object
gadgets.IfrGadgetService
inherits gadgets.StaticLayoutManager inherits
call call
gadgets.DefaultUserPrefStore
gadgets.IfrGadget
Google Confidential and Proprietary 7

OpenSocial client side container
1
opensocial.BodyType
opensocial.Container:
FunctionObject 0
0 0
opensocial.Person
• container_
n 0
• getEnvironment() 0 0 0
opensocial.Activity
• requestSendMessage(…)
• requestShareApp(..)
n
• requestCreateActivity(..) opensocial.Email
• newFetchPersonRequest(..)
n
• newFetchPeopleRequest(..)
opensocial.Phone
opensocial.Url
1
opensocial.enum.Smoker
1
opensocial.enum.Drinker
1
opensocial.enum.Presence
Google Confidential and Proprietary 8

Server Side Component Architecture
Servlet Class Diagram
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OpenSocial Client Side Flow
List of Friends
1. Create Request Object
2. Populate Request Parameters
3. Send the Request
Google Confidential and Proprietary 10

OpenSocial JS APIs – Collaboration Diagram
List of Friends Step 1
opensocial.Container.container makeIdSpec(
newDataRequest() _ : JsonRpcContainer 7
1 “VIEWER”)
7.1
new
8
Gadget Javascript
2 translate
newFetchPerson opensocial.IdSpec
6 IdSpec()
Request(“VIEWER”, new
ProfileDetails) JsonRpcRequest
9 new
4
newFetchPersonRequest() opensocial.DataRequest 3
\"/people/@viewer/@self?
fields=id, name, thumbnailUrl& RequestObject_=[]
startIndex=0 5
&count=20&
orderBy=topFriends& addDefaultProfileFields({})
filterBy=all\"
(to RequestObject_)
var req = opensocial.newDataRequest();
req.add( req.newFetchPersonRequest( opensocial.DataRequest.PersonId.VIEWER ) , 'viewer');
Google Confidential and Proprietary 11

OpenSocial JS APIs – Collaboration Diagram
List of Friends Step 2
new
RestFulRequestItem
opensocial.Container.container (X, “GET”,..)
_ :JsonRpcContainer
7.1
Gadget
Javascript opensocial.IdSpec
newFetchPeopleRequest(…) 14
/people/@viewer/@friends 13
userid =VIEWER
groupID =FRIENDS JsonRpcRequest
10 opensocial.DataRequest
newFetchPeopleRequest(
“VIEWER_FRIENDS”, undefined)
11
12
X =\"/people/@viewer/@ friends? fields=id,
name, thumbnailUrl& newFetchPeopleRequest( translateIdSpec(..)
startIndex=0&count=20&orderBy=topFriends & {userId=“VIEWER”, userId : VIEWER
filterBy=all\" groupId= ”FRIENDS”}) groupId: FRIENDS
req.add( req.newFetchPeopleRequest ( opensocial.DataRequest.Group.VIEWER_FRIENDS ),
'viewerFriends');
Google Confidential and Proprietary 12

OpenSocial JS APIs – Collaboration Diagram : GET
Request Object
RequestObject_=[]
Key Object
viewer { method = “GET”,
url = \"/people/@viewer/@self?
fields=id, name, thumbnailUrl&
startIndex=0&count=20&
orderBy= topFriends &
filterBy=all\"
}
viewerFriends { method = “GET”,
url = \"/people/@viewer/@friends?
fields=id, name, thumbnailUrl&
startIndex=0&count=20&
orderBy= topFriends &
filterBy=all\"
}
Google Confidential and Proprietary 13

OpenSocial JS APIs – Collaboration
Diagram Step 3 makeNonProxiedRequest( relativeUrl,
callback , .., “application/ json ” )
16
opensocial.Container.container
gadgets.io
_ : JsonRpcContainer
17
7.1
makeXhrRequest(…) 18
Gadget
Javascript sendRequest( opensocial.IdSpec new
16 14
RequestObject_, 13
<callback> ) JsonRpcRequest
XMLHttpRequest
10 opensocial.DataRequest
19 20
12 11
send(<callback>) Open(…) send(…)
15
relativeURL =\"/social/rest/jsonBatch?st=john.doe%3Ajohn.doe%3A7303%3Ashindig%3Ahttp%253A//hosting.gmodules.com/ig/gadgets/file/
104769461040349626058/list_of_friends.xml%3A0\" \"
req.send( onLoadFriends ) ;
Google Confidential and Proprietary 14

OpenSocial – Server Side flow
• List of Friends when it reaches the Server. It is a 4 Step Process
1. Call JsonRpcServletGet the Converter
2. Get the Appropriate Handler
3. Get the JSON Object from the DB
4. Populate Responses into a List
5. Stringify and return to the client
Google Confidential and Proprietary 15

List My Friends – Server Side Call fro m
the !
Step 1 : JsonRpcServlet’s doPost() l APIS!
O penSocia
Servlet Container
RpcRequestItem
dispatchBatch() new RpcRequestItem(..)
H b.i.a
O b doPost(..)
T b.i
S a
T
GET P
G Service(..)
a b.ii
JsonRpcServlet
S
d handleRequestItem(…)
e
g
r
e
v
t
e
r
Google Confidential and Proprietary 16

List My Friends – Server Side C all fro m
the !
APIS!
Step 2 :Get the People Handler Op e nSocial
Servlet Container
RpcRequestItem
H doPost(..) b.i.a
O b
T b.i
S a
getHandler(..)
T
GET P
G Service(..) b.ii.a HandlerDispatcher
a b.ii
JsonRpcServlet
S b.ii.b
d
e handleRequestItem(…) PeopleHandler
g
r
e
v
t
e
r
Google Confidential and Proprietary 17

List My Friends – Server Side C all fro m
the !
APIS!
Step 3 : Get the data from DB Op e nSocial
Servlet Container
RpcRequestItem
H doPost(..) b.i.a
O b
T b.i
S a
T
GET P
G Service(..) b.ii.a HandlerDispatcher
a b.ii
JsonRpcServlet
S b.ii.b
d
e handleRequestItem(…) PeopleHandler
g
r
e
v b.ii.b.1
t
e b.ii.b.1b
getAllPeople() getPeople(..)
r
BasicPeopleService
db:JsonObject
b.ii.b.1a getFriendIds.(.) 18
CASE: FRIENDS
Google Confidential and Proprietary 18

List My Friends – Server Side C all fro m
the !
APIS!
Step 4 :Populate List of Responses Op e nSocial
Servlet Container
RpcRequestItem
H doPost(..) b.i.a
O b
T b.i
S a
T
GET P
G Service(..) b.ii.a HandlerDispatcher
a b.ii
JsonRpcServlet
S b.ii.b
d
e PeopleHandler
g handleRequestItem(…)
r
e
v b.ii.b.1
t List<responses> b.ii.b.1b
e
r BasicPeopleService
db:JsonObject
b.ii.b.1a
19
Google Confidential and Proprietary 19

List My Friends – Server Side C all fro m
the !
APIS!
Step 5 :Send the response Op e nSocial
Servlet Container
RpcRequestItem
H doPost(..) b.i.a
O b
T b.i
S a
T
GET P
G Service(..) b.ii.a HandlerDispatcher
a b.ii
JsonRpcServlet
S b.ii.b
d c
e PeopleHandler
g handleRequestItem(…)
r
e
v b.ii.b.1
t List<responses> b.ii.b.1b
e
r BasicPeopleService
db:JsonObject
b.ii.b.1a
20
Google Confidential and Proprietary 20

OpenSocial – Server Side flow in case a REST Call
• List of Friends when it reaches the Server. It is a 5 Step Process
1. Call DataServiceServlet
2. Get the appropriate converter
3. Get the handler
4. Get the JSON Object from the DB
5. Stringify and return to the client
Call fro m the !
REST client!
Google Confidential and Proprietary 21

the !
Call fro m !
List My Friends – Server Side REST cli
ent
Step 1 : DataServiceServlet doPost()
URL : hUp://localhost:8080/social/rest/people/john.doe/@friends?st=a:a:a:a:a:a
DataServiceServlet
Servlet Container Fetcher
fetch(req)
token new BaseSecurityToken(..)
b.i.a.1
b.i.a.2
BasicSecurity
createToken() BaseSecurityToken
TokenDecoder
getSecuriyToken()
b.i.a
R H
T doPost(..) b.i
E
S T
T GET P
Service(..)
b.ii
DataServiceServlet
C S getConvertorforRequest(req)
L e
I r
E v handleSingleRequest(req, res, token, conv)
N e
b.iii
T r
Google Confidential and Proprietary 22

List My Friends – Server Side the !
Call fro m !
ent
Step 2 :Get the Converter REST cli
URL : hUp://localhost:8080/social/rest/people/john.doe/@friends?st=a:a:a:a:a:a
DataServiceServlet
Servlet Container Fetcher
b.i.a.1
b.i.a.2
BasicSecurity
TokenDecoder BaseSecurityToken
b.i.a getParameter(“param”)
R H
T doPost(..) b.i servletRequest
E
T b.ii.a
S
T GET P null
Service(..) BeanJson
b.ii.b
DataServiceServlet Converter
C S b.ii
L e
I r getConvertorforRequest(req)
E v handleSingleRequest(req, res, token, conv)
N e
b.iii
T r
Google Confidential and Proprietary 23

List My Friends – Server Side the !
Call fro m !
Step 3 :Get the Handler REST cli
ent
URL : hUp://localhost:8080/social/rest/people/john.doe/@friends?st=a:a:a:a:a:a
DataServiceServlet
Fetcher
handleGet in PeopleHandler
supports
Servlet Container
b.i.a.1
following PaUerns b.i.a.2
• /people/john.doe/@all
• /people/john.doe/@friends BasicSecurity
• /people/john.doe/@self TokenDecoder BaseSecurityToken
getSecuriyToken()
b.i.a
R H
T doPost(..) b.i servletRequest
E
T b.ii.a
S
T GET P null
Service(..) BeanJson
b.ii.b
DataServiceServlet Converter
C S b.ii
L e
I r getConvertorforRequest( req)
E v
N e
handleSingleRequest( b.iii.a getHUpMethodFromParameter(..)
b.iii
T r
req, res, token, conv) b.iii.b getHandler(“PeopleHandler”)
RequestItem
b.iii.c.2 InjectorImpl
handleRequestItem(..) b.iii.c b.iii.c.2.1
b.iii.c.3 PersonHandler
getRouteFromParameter(“..”)
b.iii.c.1
handleItem(request)
Google Confidential and Proprietary 24

List My Friends – Server Side the !
Call fro m !
Step 4 :Get the Data from DB ent
REST cli
URL : hUp://localhost:8080/social/rest/people/john.doe/@friends?st=a:a:a:a:a:a DataServiceServlet
Fetcher
b.i.a.1
Servlet Container b.i.a.2
BasicSecurity
getSecuriyToken() TokenDecoder BaseSecurityToken
R H b.i.a
T doPost(..) b.i servletRequest
E
T b.ii.a
S
T GET P
Service(..) BeanJson
b.ii.b
DataServiceServlet Converter
C S b.ii
L e
I r
b.iii.a
E v
e b.iii.b
N handleSingleRequest( b.iii RequestItem
T r
req, res, token, conv)
b.iii.c.2 InjectorImpl
handleRequestItem(..) b.iii.c b.iii.c.2.1
b.iii.c.3 PersonHandler
b.iii.c.1
b.iii.c.3.2
handleGet in PeopleHandler
supports b.iii.c.3.2b getPeople(..)
getAllPeople()
following PaUerns
• /people/john.doe/@all BasicPeopleService
db:JsonObject
• /people/john.doe/@friends getFriendIds.(.)
• /people/john.doe/@self b.iii.c.3.2a CASE: FRIENDS 25
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the !
List My Friends – Server Side Call fro m !
ent
REST cli
Step 5 :Convert to JSON String and Return
URL : hUp://localhost:8080/social/rest/people/john.doe/@friends?st=a:a:a:a:a:a DataServiceServlet
Fetcher
b.i.a.1
Servlet Container b.i.a.2
BasicSecurity
getSecuriyToken() TokenDecoder BaseSecurityToken
R H b.i.a
b doPost(..)
E a GET
T b.i servletRequest
T b.ii.a
S Service(..)
T P
BeanJson
b.ii.b
c DataServiceServlet Converter
C S b.ii
L e convertToString
(ResaulCollecbon<Person>)
I r
b.iii.a
E v b.iii.c.3.3
e b.iii.b
N handleSingleRequest( b.iii RequestItem
T r
req, res, token, conv)
b.iii.c.2 InjectorImpl
handleRequestItem(..) b.iii.c b.iii.c.2.1
b.iii.c.3 PersonHandler
b.iii.c.1
b.iii.c.3.2
handleGet in PeopleHandler
supports b.iii.c.3.2b getPeople(..)
following PaUerns
• /people/john.doe/@all BasicPeopleService
db:JsonObject
• /people/john.doe/@friends
• /people/john.doe/@self b.iii.c.3.2a 26
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Re-Cap
• Shindig is implemented in 2 languages ( Java, PHP, Others soon)
• Java version on top of Servlet stack
• Multiple entry points for various “kinds” of calls
• Client Side architecture - containers – Gadget and OpenSocial
• Handlers and Converters take care of call semantics
• REST and Json RPC calls share infrastructure in the backend
Google Confidential and Proprietary 27

Summary
• Shindig built on premise of reusability without major modifications
• It’s a moving target which is tending towards stable code base as
we close in on 0.8 spec
• Its Open source and “you” are encouraged to take up features and
implement them
Google Confidential and Proprietary 28