Thursday, June 7, 2018

SNAC Lookups Updated in xEAC and EADitor

Since the Social Networks and Archival Context has migrated to a new platform, it has published a JSON-based REST API, which they have well-documented. Although EADitor and xEAC have had lookup mechanisms to link personal, corporate, and family entities from SNAC to EAD and EAC-CPF records since 2014 (see here), the lookup mechanisms in the XForms-based backends to these platforms interacted with an unpublicized web service that provided an XML response for simple queries.

With the advent of these new SNAC APIs and JSON processing within the XForms 2.0 spec (present in Orbeon since 2016), I have finally gotten around to overhauling the lookups in both EADitor and xEAC. Following documentation for the Search API, the XForms Submission process now submits (via PUT) an instance that conforms to the required JSON model. The @serialization attribute is set to "application/json" in the submission, and the JSON response from SNAC is serialized back into XML following the XForms 2.0 specification. Side note: the JSON->XML serialization differs between XForms 2.0 and XSLT/XPath 3.0, and so there should be more communication between these groups to standardize JSON->XML across all XML technologies.

The following XML instance is transformed into API-compliant JSON upon submission.


<xforms:instance id="query-json" exclude-result-prefixed="#all">
 <json type="object" xmlns="">
  <command>search</command>
  <term/>
  <entity_type/>
  <start>0</start>
  <count>10</count>
 </json>
</xforms:instance>


The submission is as follows:


<xforms:submission id="query-snac" ref="instance('query-json')" 
    action="http://api.snaccooperative.org" method="put" replace="instance" 
    instance="snac-response" serialization="application/json">
 <xforms:header>
  <xforms:name>User-Agent</xforms:name>
  <xforms:value>XForms/xEAC</xforms:value>
 </xforms:header>
 <xforms:message ev:event="xforms-submit-error" level="modal">Error transfroming 
into JSON and/or interacting with the SNAC
  API.</xforms:message>
</xforms:submission> 

The SNAC URIs are placed into the entityIds within the cpfDescription/identity in EAC-CPF or as the @authfilenumber for a persname, corpname, or famname in EAD.

The next task to to build APIs into xEAC for pushing data (biographical data, skos:exactMatch URIs, and related archival resources) directly into SNAC. By tomorrow, all (or nearly all) of the authorities in the ANS Archives will be linked to SNAC URIs.

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