[examples/openspending] - openspending v0.2 (#907)

* [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

examples/openspending/content/help/search.md

@@ -0,0 +1,93 @@
+---
+section: help
+lead: true
+title: Full-text search API
+authors:
+- Neil Ashton
+---
+OpenSpending supports full-text search as a research tool for
+everyone who wants to investigate the spending information kept
+in our database.
+
+It is important to note, however, that search is always performed
+on individual entries. More abstract concepts (e.g. "all
+health spending in a country over a given year") would mostly be the
+result of adding up many individual entries. If your use case
+requires that you access such concepts, you may want to look at
+the [aggregation API](../aggregate) instead.
+
+#### Basic call and parameters
+
+    GET /api/2/search?q=<query>
+
+Calls will return a set of fully JSON serialized entries, query
+statistics, and, depending on the other parameters, other data such as
+facets.
+
+The following parameters are recognized:
+
+* ``q``
+  Query string. Will usually search a composite text field but can
+  be limited to a specific field (i.e. a dimension, attribute, or measure)
+  with ``field:value``. Boolean operators such as OR, AND, and ±term can also be used.
+
+* ``dataset``
+  Specifies a dataset name to search in. While searching across multiple
+  datasets is supported, this parameter can be used to limit the scope and
+  increase performance. It can be used multiple times or multiple
+  dataset names can be separated with pipe symbols.
+
+* ``category``
+  The dataset category can be used to filter datasets by their type,
+  e.g. limiting the output to only transactional expenditure (and
+  excluding any budget items). Valid values include ``budget``,
+  ``spending``, and ``other``.
+
+* ``stats``
+  Includes solr statistics on measures, namely the average, mean, and
+  standard deviations. This is generated through the indexed data and
+   can differ marginally from the
+  results of the aggregator due to floating point inaccuracies.
+  Note that aggregations
+  across datasets with different currencies (or even the same currency
+  across different years) are possible but must be avoided.
+
+* ``filter``
+  Apply a simple filter of the format ``field:value``. Multiple filters
+  can be joined through pipes, e.g. ``fieldA:value|fieldB:value``.
+
+* ``page``
+  Page number for paginated results. Defaults to ``1``.
+
+* ``pagesize``
+  Size of a page for paginated results. Defaults to ``10000``.
+
+* ``facet_field``
+  A field to facet the search by, i.e. give all the distinct values of
+  the field in the result set with the count of how often each occurred.
+
+* ``facet_page``, ``facet_pagesize``
+  Works analogously to the ``page`` and ``pagesize`` parameters but applies
+  to facets instead.
+
+* ``expand_facet_dimensions``
+  When a compound dimension name is used for a facet, this will return a
+  full representation of this dimension value for each value.
+
+If an error is detected, the system will return a simple JSON response
+with a list of ``errors`` describing the fault.
+
+### Solr query syntax
+
+OpenSpending uses Apache Solr for full-text indexing. Some search
+parameters are passed directly to Solr:
+
+    GET /api/2/search?q=money%20measure:[min%20TO%20max]&fq=dimension:value
+
+Some useful resources to explore the query language of Solr include:
+
+* [Solr Common Query Parameters](http://wiki.apache.org/solr/CommonQueryParameters)
+* [Lucene Query Parser Syntax](http://lucene.apache.org/java/3_4_0/queryparsersyntax.html)
+* [Solr Query Syntax](http://wiki.apache.org/solr/SolrQuerySyntax) (Advanced)
+
+**Up**: [OpenSpending API](../)