14974edcbf
* [examples/openspending] - openspending v0.2 * [examples/openspending][m] - fix build * [examples/openspending][xs] - fix build * [examples/openspending][xs] - add prebuild step * [examples/openspending][m] - fix requested by demenech * [examples/openspending][sm] - remove links + fix bug
94 lines
3.4 KiB
Markdown
94 lines
3.4 KiB
Markdown
---
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section: help
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lead: true
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title: Full-text search API
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authors:
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- Neil Ashton
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---
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OpenSpending supports full-text search as a research tool for
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everyone who wants to investigate the spending information kept
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in our database.
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It is important to note, however, that search is always performed
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on individual entries. More abstract concepts (e.g. "all
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health spending in a country over a given year") would mostly be the
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result of adding up many individual entries. If your use case
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requires that you access such concepts, you may want to look at
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the [aggregation API](../aggregate) instead.
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#### Basic call and parameters
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GET /api/2/search?q=<query>
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Calls will return a set of fully JSON serialized entries, query
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statistics, and, depending on the other parameters, other data such as
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facets.
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The following parameters are recognized:
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* ``q``
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Query string. Will usually search a composite text field but can
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be limited to a specific field (i.e. a dimension, attribute, or measure)
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with ``field:value``. Boolean operators such as OR, AND, and ±term can also be used.
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* ``dataset``
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Specifies a dataset name to search in. While searching across multiple
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datasets is supported, this parameter can be used to limit the scope and
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increase performance. It can be used multiple times or multiple
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dataset names can be separated with pipe symbols.
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* ``category``
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The dataset category can be used to filter datasets by their type,
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e.g. limiting the output to only transactional expenditure (and
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excluding any budget items). Valid values include ``budget``,
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``spending``, and ``other``.
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* ``stats``
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Includes solr statistics on measures, namely the average, mean, and
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standard deviations. This is generated through the indexed data and
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can differ marginally from the
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results of the aggregator due to floating point inaccuracies.
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Note that aggregations
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across datasets with different currencies (or even the same currency
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across different years) are possible but must be avoided.
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* ``filter``
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Apply a simple filter of the format ``field:value``. Multiple filters
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can be joined through pipes, e.g. ``fieldA:value|fieldB:value``.
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* ``page``
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Page number for paginated results. Defaults to ``1``.
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* ``pagesize``
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Size of a page for paginated results. Defaults to ``10000``.
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* ``facet_field``
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A field to facet the search by, i.e. give all the distinct values of
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the field in the result set with the count of how often each occurred.
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* ``facet_page``, ``facet_pagesize``
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Works analogously to the ``page`` and ``pagesize`` parameters but applies
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to facets instead.
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* ``expand_facet_dimensions``
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When a compound dimension name is used for a facet, this will return a
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full representation of this dimension value for each value.
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If an error is detected, the system will return a simple JSON response
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with a list of ``errors`` describing the fault.
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### Solr query syntax
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OpenSpending uses Apache Solr for full-text indexing. Some search
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parameters are passed directly to Solr:
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GET /api/2/search?q=money%20measure:[min%20TO%20max]&fq=dimension:value
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Some useful resources to explore the query language of Solr include:
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* [Solr Common Query Parameters](http://wiki.apache.org/solr/CommonQueryParameters)
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* [Lucene Query Parser Syntax](http://lucene.apache.org/java/3_4_0/queryparsersyntax.html)
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* [Solr Query Syntax](http://wiki.apache.org/solr/SolrQuerySyntax) (Advanced)
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**Up**: [OpenSpending API](../)
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