ManagedResourceStore < Main

ManagedResourceStore

ManagedResourceStore : public

Title	ManagedResourceStore : public
Author(s)	LiXizhi
Date	2008/2/25
File	script/kids/3DMapSystemApp/localserver/ManagedResourceStore.lua

Description

A ManagedResourceStore represents a set of entries in the WebCacheDB and allows the set to be managed as a group. The identifying properties of a LocalServer are its domain, name, required_cookie, and server_type.

Sample Code

NPL.load("(gl)script/kids/3DMapSystemApp/localserver/ManagedResourceStore .lua");

Member Functions

ManagedResourceStore:new

------------------------------------------
 ManagedResourceStore  : public <localserver>
------------------------------------------
local ManagedResourceStore = commonlib.inherit(Map3DSystem.localserver.localserver, {
   -- type of WebCacheDB.ServerType
   server_type_ = WebCacheDB.ServerType.MANAGED_RESOURCE_STORE,

   -- default policy
   Cache_policy = Map3DSystem.localserver.CachePolicy:new("access plus 1 month"),
}

);

commonlib.setfield("Map3DSystem.localserver.ManagedResourceStore", ManagedResourceStore);

syntax

function ManagedResourceStore:new(o)

parameters

o

ManagedResourceStore:CreateOrOpen

public member functions:

Initializes an instance and inserts rows in the Servers and Versions table of the DB if needed

syntax

function ManagedResourceStore:CreateOrOpen(security_origin, name, required_cookie)

parameters

security
origin
name
required
cookie

ManagedResourceStore:Open

Initializes an instance from its server_id. Will not insert rows into the Servers or Versions table of the DB. If the expected rows are not present in the Servers and Versions table, this method fails and returns false.

syntax

function ManagedResourceStore:Open(server_id)

parameters

server
id

ManagedResourceStore:GetManifestUrl

Get the manifest url for this store

param manifest :_url: string
return __ : the manifest url (maybe ""), it returns nil if failed.

syntax

function ManagedResourceStore:GetManifestUrl(manifest_url)

parameters

manifest	_url: string
url

ManagedResourceStore:SetManifestUrl

Sets the manifest url for this store

param manifest :_url: string

syntax

function ManagedResourceStore:SetManifestUrl(manifest_url)

parameters

manifest	_url: string
url

ManagedResourceStore:HasVersion

returns if the application has a version in the desired state or a version string.

param state : it int, it is VersionReadyState, if string, it is the version string.

syntax

function ManagedResourceStore:HasVersion(state)

parameters

state	it int, it is VersionReadyState, if string, it is the version string.

ManagedResourceStore:GetUpdateInfo

Retrieves the update info for this store

param return : status, last_time, manifest_date_header, update_error

syntax

function ManagedResourceStore:GetUpdateInfo()

ManagedResourceStore:SetUpdateInfo

Sets the update info for this applicaiton

syntax

function ManagedResourceStore:SetUpdateInfo(status, last_time, manifest_date_header, update_error)

parameters

status
last
time
manifest
date
header
update
error

creating instances of local servers

Title	creating instances of local servers
Author(s)	LiXizhi
Date	2008/2/27
File	script/kids/3DMapSystemApp/localserver/factory.lua

Description

Sample Code

NPL.load("(gl)script/kids/3DMapSystemApp/localserver/factory.lua");
local store = Map3DSystem.localserver.CreateStore("WebserviceStore_sample", 2)
local store = Map3DSystem.localserver.CreateStore("ResourceStore_sample", 1)
local store = Map3DSystem.localserver.CreateStore("ManagedResourceStore_sample", 0)

Member Functions

Map3DSystem.localserver.GetStore

get the loaded store. if the store is not loaded,it will return nil. To CreateGet a store, use CreateStore() instead.

syntax

function Map3DSystem.localserver.GetStore(name)

parameters

name

cache policy

Title	cache policy
Author(s)	LiXizhi
Date	2008/3/2
File	script/kids/3DMapSystemApp/localserver/cache_policy.lua

Description

In NPL local server, there is a single cache policy which is slight different from standard HTTP cache (The official version is here: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9

)

NPL local server caching policy

The cache policy by NPL local server (and represented by this CachePolicy class) is stated below:

find the entry in the local server. If a completed entry is found, it is always returned immediately, regardless of whether it has expired or not.
if no entry is found or the entry expired, a new entry will be fetched via remote server and updated in the local server.
When a entry is updated in the store, it will be returned to all callback functions registered to it.

Note1: It means that the same request might be returned twice. The first time is the local version at the time of call; and the second time is when the entry is just updated via the server. The second call is skipped if the server can verify that the content has not changed and only update the last access time in the local store. Note2: If the relative expire time is 0, the first call is ignored. Note3: If the relative expire time is larger than a year, the second call is always ignored. Note4: This same policy applies to ResourceStore, ManagedResourceStore, and WebserviceStore.For WebserviceStore, only access base time type is permitted. The server policy can be overwritten by local server policy, local server policy can be overwritten by per function policy

To increase efficiency, one can create several different cache policy objects and share them for all local stores and related function calls.

Sample Code

NPL.load("(gl)script/kids/3DMapSystemApp/localserver/cache_policy.lua");
local cache_policy = Map3DSystem.localserver.CachePolicy:new("access plus 1 month");
cache_policy:IsExpired(ParaGlobal.GetSysDateTime()-80000);

-- there are some premade policies, which can be retrieve from Map3DSystem.localserver.CachePolicies, see below
local cp = Map3DSystem.localserver.CachePolicies["never"];
local cp = Map3DSystem.localserver.CachePolicies["always"];
local cp = Map3DSystem.localserver.CachePolicies["1 hour"];
local cp = Map3DSystem.localserver.CachePolicies["1 day"];

Member Functions

CachePolicy:new

--------------------------
 CachePolicy class
--------------------------

local CachePolicy = {
   -- The base time is either the last modification time of the file, or the time of the client's access to the document.
   -- 0 means that the file's last modification time should be used as the base time, 
   -- 1 means the client's access time should be used.
   -- nil Expiration is not enabled. 
   BaseTime = 1,
   -- Time in seconds to expire relative to BaseTime. e.g. 2592000 is a month, which is good for asset and images.  604800 is a week which is good for profile and content pages. 
   ExpireTime = 604800,
}

;

commonlib.setfield("Map3DSystem.localserver.CachePolicy", CachePolicy);

create the object and init from initCode. format of initCode, please see Init() function.

syntax

function CachePolicy:new(initCode)

parameters

initCode

CachePolicy:Init

[[ Extacts the policy base time type expire time from an input string.

param initCode : string: it has the following syntax

" [plus] { }*" where is one of: access, now (equivalent to 'access'), modification The plus keyword is optional should be an integer value, and is one of: years months weeks days hours minutes seconds For example, any of the following can be used to make entries expire 1 month after being accessed: - "access plus 1 month" - "access plus 4 weeks" - "access plus 30 days" The expiry time can be fine-tuned by adding several ' ' clauses: - "access plus 1 month 15 days 2 hours" - "modification plus 5 hours 3 minutes"

return __ : Returns true if successful.

]]

syntax

function CachePolicy:Init(initCode)

parameters

| initCode | string: it has the following syntax " [plus] { }*" where is one of: access, now (equivalent to 'access'), modification The plus keyword is optional should be an integer value, and is one of: years months weeks days hours minutes seconds For example, any of the following can be used to make entries expire 1 month after being accessed: - "access plus 1 month" - "access plus 4 weeks" - "access plus 30 days" The expiry time can be fine-tuned by adding several ' ' clauses: - "access plus 1 month 15 days 2 hours" - "modification plus 5 hours 3 minutes" |

CachePolicy:IsExpired

whether time is expired.

param Basetime : the base time in second
return __ : true if input time is expired

syntax

function CachePolicy:IsExpired(Basetime)

parameters

Basetime	the base time in second

CachePolicy:IsCacheEnabled

return whether : cache is enabled. i.e. self.ExpireTime is not 0.

syntax

function CachePolicy:IsCacheEnabled()

parameters

return	cache is enabled. i.e. self.ExpireTime is not 0.

CachePolicy:IsCacheAlwaysUsed

return whether : cache is always used. i.e. self.ExpireTime over 1 year.

syntax

function CachePolicy:IsCacheAlwaysUsed()

parameters

return	cache is always used. i.e. self.ExpireTime over 1 year.

Topic revision: r1 - 2008-02-29 - LiXizhi