Aleks DrozdovEnterprise Architect

What is an API and what might the Discovery API mean for services contributing data to

Discovery

Agenda

• API and Data• Discovery architecture• Getting data into Discovery• Discovery data structure• Discovery API (Scenarios)• Next steps

API and Data

Application Programming InterfaceA language and message format used by an application program to communicate with the operating system or some other control program such as a database management system (DBMS) or communications protocol.

Personal computer Application Operating SystemUI API

Web API

• When used in the context of web development, an API is typically defined as a set of Hypertext Transfer Protocol (HTTP) request messages.

• Response messages, which is usually in an Extensible Markup Language (XML) or JavaScript Object Notation (JSON) format.

• While "Web API" is virtually a synonym for web service, the recent trend (so-called Web 2.0) has been moving away from Simple Object Access Protocol (SOAP) based services towards more direct Representational State Transfer (REST) style communications. Source: Wikipedia

Personal computer Application Discovery SystemWeb

browserAPI

Data

• Explosion in the amount of data

• It is common to mashup data from a number of sources

• User contributed data

• Since ‘80s processor speed increas of 360• RAM price – from $1000/MB to $25/GB• Reduction in RAM size

1956 disk drive-5MB-Refrigerator size-250 pounds

Discovery Architecture

Discovery Architecture

System User Interface

Object Data Store

Datasets and datatransformations

Getting data into Discovery

Data import - databases

Relational (SQL) databases

Nonrelational Object Data Store

Data denormalisation/Transformation

Text input

EXCEL TXT CSV

XML

XML XML XML

Data import – user

Discovery data model

Information Asset

Information Asset

Information Asset

Information Asset

Collection<InformationAsset>

Information Asset

Information Asset

Information Asset

Collection<InformationAsset>

Series

Piece

Item

Core of the Discovery is an Information Asset object. Information Asset models The National Archives data in the hierarchical way and uses Collections and parent-child relationship. Properties of the Information Asset object don’t change across different data sets and hierarchies. Different data sources are using different schemas, which can lead to missing properties in the Information Assets. Still, the structure of the Information Asset stays unchanged. The main challenge in the design Information Asset object is to find minimum common set of properties which will work across all data sources.

Information Asset

Discovery data - Search

Discovery data - Browse

Discovery data - Detailshttp://discovery.nationalarchives.gov.uk/SearchUI/details?Uri=C10127419

Discovery API

Uri Method Description

informationasset/{id} GET Service at http://discovery.nationalarchives.gov.uk/DiscoveryAPI/[xml][json]informationasset/{ID}

children/{id}/{page} GET Service at http://discovery.nationalarchives.gov.uk/DiscoveryAPI/[xml][json]children/{ID}/{PAGE}

totalchildren/{id} GET Service at http://discovery.nationalarchives.gov.uk/DiscoveryAPI/[xml][json]totalchildren/{ID}

parent/{id} GET Service at http://discovery.nationalarchives.gov.uk/DiscoveryAPI/[xml][json]Parent/{ID}

siblings/{id}/{PAGE} GET Service at http://discovery.nationalarchives.gov.uk/DiscoveryAPI/[xml][json]siblings/{ID}/{PAGE}

search/{PAGE}?{query} GET Service at http://discovery.nationalarchives.gov.uk/DiscoveryAPI/[xml][json]search//{PAGE}/

query={QUERY};all={ALLWORDS};exact={EXACTPHRASE};collection={DEPARTMENTS}&startDate={STARTDATE}&endDate={ENDDATE};formerRef={FORMERREFERENCE}

Operations at http://discovery.nationalarchives.gov.uk/Discover

yAPI

Documentation:http://discovery.nationalarchives.gov.uk/SearchUI/api.htm

Information Asset C10127419

http://discovery.nationalarchives.gov.uk/DiscoveryAPI/xml/informationasset/C10127419

API XML response

{ "assetView" : { "IAID" : "C10127419", "SourceLevelId" : 7, "ParentIAID" : "C2389021", "Reference" : "1", "CatalogueId" : -5596696, "Language" : "English", "LegalStatus" : "Public Record(s)", "FormerReferenceDep" : "", "FormerReferencePro" : "", "Title" : "", "MapDesignation" : "", "CreatorName" : [ ], "CoveringDates" : "1853 October 8", "PhysicalDescriptionExtent" : "", "PhysicalDescriptionForm" : "", "Dimensions" : "", "MapScaleNumber" : 0, "PhysicalCondition" : "", "HeldBy" : [ { "Corporate_Body_Name_Text" : "The National Archives, Kew" } ],

<IAID>C10127419</IAID> <SourceLevelId>7</SourceLevelId> <ParentIAID>C2389021</ParentIAID> <Reference>1</Reference> <CatalogueId>-5596696</CatalogueId> <Language>English</Language> <LegalStatus>Public Record(s)</LegalStatus> <FormerReferenceDep/> <FormerReferencePro/> <Title/> <MapDesignation/> <CoveringDates>1853 October 8</CoveringDates> <PhysicalDescriptionExtent/> <PhysicalDescriptionForm/> <Dimensions/> <MapScaleNumber>0</MapScaleNumber> <PhysicalCondition/> <HeldBy> <HeldBy> <Corporate_Body_Name_Text>The National Archives, Kew</Corporate_Body_Name_Text> </HeldBy> </HeldBy>

XML JSON

Scenarios

Scenario – navigating hierarchy

<SearchResultList> <AssetView> <IAID>C3735</IAID> <CitableReference>C 203</CitableReference> <Title>Chancery: Petty Bag Office: Various Certificates</Title> <Description>Chancery: Petty Bag Office: Various Certificates. Miscellaneous returns and certificates in the custody of the Petty Bag Office, including inquisitions and presentments by jurors concerning the killing, sale or eating of meat in Lent; records of the appointment of collectors of subsidies, possibly connected with their own tax liabilities; documents relating to the sequestration of estates of delinquents; certificates confirming the surrender of offices; certificates recording the oath of allegiance, supremacy and abjuration sworn by attornies; certificates naming those who failed to swear the oaths required by the Security of the Sovereign Act 1714; certificates concerning concealed deaths under the Cestui que Vie Act 1707; certificates attesting that members of Parliament met the property qualification required by the Parliament Act 1710.</Description> <Places /> <People /> <Subjects> <string>C10106 Taxation</string> <string>C10039 Food and drink</string> </Subjects> <StartDate>01-01-1558</StartDate> <EndDate>31-12-1839</EndDate> <References /> <URLParams>066/1/C43/C598/C3735</URLParams> <Department>C</Department> </AssetView>

http://discovery.nationalarchives.gov.uk/DiscoveryAPI/xml/search/1/query=C%20203

Search for Information Asset

Scenario – navigating hierarchy

109

http://discovery.nationalarchives.gov.uk/DiscoveryAPI/xml/totalchildren/C3775

Get total number of children

Scenario – navigating hierarchy

<InformationAssetIdentity> <ObjectId>4f24d14055e0f1922313380a</ObjectId> <IAID>C3413406</IAID> <ParentIAID>C3735</ParentIAID> <SourceLevelId>6</SourceLevelId> <ReferenceComponent>1</ReferenceComponent> <Title>Description available at other catalogue level</Title> <PhysicalDescription> </PhysicalDescription> <CoveringDates /> <HasChildren>true</HasChildren> <ChildrenTotal>0</ChildrenTotal> <ContextPath /> </InformationAssetIdentity>

http://discovery.nationalarchives.gov.uk/DIscoveryAPI/xml/children/C3735/1

Get all children

Scenario - search

Build API request

http://discovery.nationalarchives.gov.uk/DiscoveryAPI/xml/search/1/query=witchcraft

Send request to API

Receive list of results

Page through results

Retrieve Information Asset data

http://discovery.nationalarchives.gov.uk/DiscoveryAPI/xml/search/2/query=witchcraft

<TotalResults>53</TotalResults> <SearchResultList> <AssetView> <IAID>C2341588</IAID> <CitableReference>DO 119/1373</CitableReference> <Title>Ritual murder and &lt;span class="highlight"&gt;witchcraft&lt;/span&gt;; Rex vs Chiefs Bereng and Gabashane and others</Title> <Description>High Commissioner for South Africa, and High Commissioner for Basutoland, the Bechuanaland Protectorate and Swaziland, and UK High Commissioner for the Union of South Africa: Correspondence. Basutoland. Ritual murder and &lt;span class="highlight"&gt;witchcraft&lt;/span&gt;; Rex vs Chiefs Bereng and Gabashane and others.</Description> <Places /> <People /> <Subjects> <string>C10125 Africa</string> <string>C10117 Witchcraft</string> <string>C10023 Crime</string> </Subjects> <StartDate>01-01-1949</StartDate> <EndDate>31-12-1949</EndDate> <References> <string>9657 II</string> </References> <URLParams>066/1/C86/C495/C6128/C51353/0/C2341588</URLParams> <Department>DO</Department> </AssetView>

http://discovery.nationalarchives.gov.uk/DiscoveryAPI/xml/informationasset/C2341588

Next steps

Discovery Platform

External Data

Data Import API

Data Export API

External Data

External Data

Data sharing and reuse

User participation API

Thank you!

http://discovery.nationalarchives.gov.uk

http://discovery.nationalarchives.gov.uk/DiscoveryAPI

adrozdov@nationalarchives.gov.uk