Using a LDAP Directory Server for Environmental Data

Using a LDAP Directory Server for Environmental Data Discovery Donald Denbo NOAA-PMEL/UW-JISAO Presented by Eugene Burger NOAA-PMEL/UW-JISAO http: //www. epic. noaa. gov/cdp January 15, 2002 18 th AMS International Conference on IIPS

Objective Develop a data discovery service that enables users to find data sets available from on-line Data Servers based on geographic region, observed quantities, or keyword. January 15, 2002 18 th AMS International Conference on IIPS 2

Design Goals w w Expandable, extensible, and scalable Use standards when possible (LDAPv 3) Platform independent Automated population of directory directly from data servers w Tools to aid in the creation of queries w Work both with applications and web servers January 15, 2002 18 th AMS International Conference on IIPS 3

Approach n n Extend existing LDAP objects and parameters to create Data. Server and Data. Collection objects. Develop application to retrieve metadata from Data Server and XML configuration file then merge/update directory entries. Enhance Web Server and Desktop Application to directly access LDAP Directory Server. Develop monitor application to continuously test availability of Data Server and its data collections and appropriately modify directory entry. January 15, 2002 18 th AMS International Conference on IIPS 4

Architecture Directory service has three major components. w Directory server and the flow of information w The schema (relationship between directory objects and parameters) w LDAP query construction January 15, 2002 18 th AMS International Conference on IIPS 5

Directory Server w Directory information updated directly from remote data servers. w Queries can be made from both desktop client and Web client. Queries follow the LDAP protocol. w Data server and data collection information can be easily updated. Only Directory Server address needs to be hard-coded into client. January 15, 2002 18 th AMS International Conference on IIPS 6

Update Availability Status Directory Server Desktop Client Create and Update Entries Directory Search Data Server Monitor Web Client Data Test Availability of Data Server Web Server Data Servers January 15, 2002 18 th AMS International Conference on IIPS 7

Directory Schema w Directory information is structured as a “tree”. w “dataserver” object contains data server location, name, owner, etc. w “datacollection” object contains data collection name, description, temporal and spatial ranges, keywords, owner, etc. January 15, 2002 18 th AMS International Conference on IIPS 8

Directory Schema o=cdp. noaa. gov ou=CDPServers ou=EPICCTDServer ou=NODCServer ou=People ou=TAOServer ou=Groups ou=UHSLServer cid=North. Pacific cid=Hourly. SL cid=South. Pacific cid=Daily. SL cid=Alaska January 15, 2002 cid=Monthly. SL 18 th AMS International Conference on IIPS 9

Query Construction w LDAP queries have a “Reverse Polish” flavor. n For example, &(keyword=atlantic)(keyword=salinity) is requesting a keyword match of atlantic and salinity. w Java. CC parser developed to translate user friendly entry to LDAP query. For example, Temperature AND salinity AND (pacific OR atlantic) is translated to &(|(keyword=atlantic)(keyword=pacific))(&(keyword=salinity) (keyword=temperature)) January 15, 2002 18 th AMS International Conference on IIPS 10

Graphical Query Entry January 15, 2002 18 th AMS International Conference on IIPS 11

Keyword List w Keyword list downloaded from directory server w Popup used to aid the user in constructing a query January 15, 2002 18 th AMS International Conference on IIPS 12

Future Directions w Add directory-side parsing and comparisons of date -range strings. w Add directory-side parsing and intersection checking of Latitude-Longitude domain bounds. January 15, 2002 18 th AMS International Conference on IIPS 13