DASH is Harvard's digital repository for scholarly articles, theses and dissertatinos, and other Harvard-affiliate generated literature. Harvard Library makes the bibliographic data openly available for all uses, with a standard set of APIs.
DASH supports two standard APIs for extracting article information: opensearch and OAI-PMH.
As of the November 9, 2009 (1.1.8) release, DASH includes an OpenSearch interface. OpenSearch is a RESTful Web service that performs a query and returns search results as RSS or ATOM feeds. It provides complete, unmediated access to the full power of DSpace's Lucene search engine; the UI places inherent limitations on the queries you can construct.
The URL of an OpenSearch request starts with http://dash.harvard.edu/open-search/ (the trailing "/" is required). All parameters are specified as query arguments after that:
||Lucene query string (see below)|
|format||Output format, must be one of: atom, rss, or one of the supported specific format versions, e.g. atom_1.0, rss_1.0, rss_2.0. No default.|
|scope||Search is restricted to a collection or community with the indicated handle|
|rpp||Number indicating the number of results per page (i.e. per request). Default is 10. Specifying 0 invokes the default, so to get all results use an improbably large rpp, e.g. 500.|
|start||Number of the page to start with (if paginating results)|
|sort_by||Index of sorting criteria (same as DSpace advanced search values). Must match a sort-option index in the DSpace configuration. Currently they are: 0 - by relevance (default) 1 - by title 2 - by date of issue 3 - by date of accession (i.e. submit date)|
|order||Ordering of sorted entries, either ascending or descending. Only effective when sort_by is nonzero.|
Lucene Query Syntax
The query string specifies what field (index) to match with a value. It also supports Boolean combinations, ranges, proximity, and other advanced features. The value of the query parameter must be in the Lucene query language (suitably escaped for inclusion in a URL, of course).
DASH is configured with the following indexes. Not all of them appear on the Advanced Search page.
|OpenSearch/Lucene name||Advanced Search||Description|
|default||Full Text||All metadata indexes and extracted text.|
|author||Author||Keyword in author name, wildcards and phrases acceptable.|
|author_authority||n/a||Authority key value of a Harvard-affiliated author.|
|title||Title||Keyword or phrase in title of article or journal.|
|subject||Keyword||Subject keywords (dc.subject.* fields)|
|abstract||Abstract||Keyword or phrase in the dc.description.abstract metadata field.|
|fasDepartment||FAS Department||Keyword or phrase matching FAS Department name|
|identifier||Identifier||Any of the identifiers such as DOIs and URLs associated with the work, including the published version, other sources, and the DASH NRS identifier.|
|issued||Issue Date||Date of issue (original publication), as full date.|
|issued.year||n/a||Year only of the date of issue.|
|accessioned||n/a||Date of accession, i.e. when the submission is entered into the archive.|
|accessioned.year||n/a||Year only of the date of accession.|
- When matching FAS departments, search for an unambiguous phrase, e.g. fasDepartment:"Molecular and Cellular Biology", not just fasDepartment:biology.
- Specify search terms in lower case to match case-insensitively.
- Full dates are specified as YYYYMMDD, e.g. 20091031. See the Lucene Query Language for further details about specifying ranges, etc.
- To match a Harvard author by authority key, go to the DASH UI and choose "Browse by Harvard Author" from the Options menu. Find your author, and copy the URL it links to. That URL will contain query arguments including a value for "authority", this is the authority key you have to look for. For example:
This gets an Atom feed for all of the articles by Stuart Shieber, using his Harvard-affiliated authority identification. They are ordered by descending issue date so newest papers appear first, although the year granularity may present a problem.
This shows all articles from the department of Molecular and Cellular Biology:
We provide OAI-PMH access in conformity with its open standard.
As a DASH-specific example, here's an OAI-PMH url configured to show all articles in the Graduate School of Education collection ("set=hdl_1_3345928") for a
specified date range:
The resulting XML file contains metadata about each article and a url for the dash abstract page.