Add basic RESTful API with support for searching and aggregate

statistics using a Solr backend

api/.htaccess

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+<IfModule mod_rewrite.c>
+    RewriteEngine On
+    RewriteCond %{REQUEST_URI} !dispatch\.php$
+    RewriteCond %{REQUEST_FILENAME} !-f
+    RewriteRule .* dispatch.php [L,QSA]
+</IfModule>

api/adapters/search.php

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+<?php
+
+interface SearchAdapter {
+
+	// Input methods
+	public function getQuery($exclude);
+	public function search($query, $start, $rows);
+
+	// Output methods
+	public function getNumResults();
+	public function getSingleResult();
+	public function getResults();
+	public function getAggregateResult($group);
+
+}

api/adapters/search/solr.php

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+<?php
+
+// load SolrPhpClient library
+require_once './lib/Apache/Solr/Service.php';
+
+class SearchAdapterSolr implements SearchAdapter {
+
+	/**
+	 * Config
+	 */
+	private $config = array(
+		'host'			=> 'localhost',
+		'port'			=> 8983,
+		'path'			=> '/solr',
+	);
+
+	/**
+	 * Members
+	 */
+	private $solr;
+	private $results;
+
+	/**
+	 * Initialise connection to Solr
+	 */
+    public function  __construct() {
+
+		$this->solr = new Apache_Solr_Service(
+			$this->config['host'],
+			$this->config['port'],
+			$this->config['path']
+		);
+
+		// Test we can connect to Solr
+		if (!$this->solr->ping()) {
+			throw new ResponseException('Could not connect to Solr server', Response::INTERNALSERVERERROR);
+		}
+
+	}
+
+	/**
+	 * Return GET search parameters in Lucene query syntax
+	 */
+	public function getQuery($exclude) {
+
+		$params = array();
+
+		foreach($_GET as $key => $value) {
+
+			if (in_array($key, $exclude)) {
+				continue;
+			}
+
+			$params[] = $key . ':' . $value;
+
+		}
+
+		if (count($params)) {
+			$query = implode(' AND ', $params);
+		} else {
+			$query = '*:*';
+		}
+
+		return $query;
+
+	}
+
+	/**
+	 * Execute search
+	 */
+	public function search($query, $start, $rows) {
+
+		try {
+			$this->results = $this->solr->search($query, $start, $rows);
+		} catch (Exception $e) {
+			throw new ResponseException('Solr failed with: "' . $e->getMessage() . '"', Response::INTERNALSERVERERROR);
+		}
+
+	}
+
+	/**
+	 * Get number of search results
+	 */
+	public function getNumResults() {
+		return (int)$this->results->response->numFound;
+	}
+
+	/**
+	 * Return a single observation
+	 */
+	public function getSingleResult() {
+		return $this->getObservation($this->results->response->docs[0]);
+	}
+
+	/**
+	 * Return a list of observations
+	 */
+	public function getResults() {
+
+		$observations = array();
+		foreach ($this->results->response->docs as $doc) {
+			$observations[] = $this->getObservation($doc);
+		}
+
+		return array(
+			'results' => $observations
+		);
+
+	}
+
+	/**
+	 * Return an aggregate result from a grouped query
+	 */
+	public function getAggregateResult($group) {
+
+		// Check group field exists
+		if (!isset($this->results->response->docs[0]->$group)) {
+			throw new ResponseException('Unknown group field: ' . $group, Response::BADREQUEST);
+		}
+
+		$data = array();
+
+		// Determine group field type
+		if ($group == 'value') {
+
+			$type = ObservationResource::GROUP_TYPE_MEASURE;
+
+		} else {
+
+			$type = ObservationResource::GROUP_TYPE_DIMENSION;
+			$data['results'] = array();
+
+		}
+
+		foreach ($this->results->response->docs as $doc) {
+
+			switch($type) {
+
+				case ObservationResource::GROUP_TYPE_MEASURE:
+					$data['value'] += $doc->value;
+					break;
+
+				case ObservationResource::GROUP_TYPE_DIMENSION:
+					if (isset($data['results'][$doc->$group])) {
+						$data['results'][$doc->$group] += $doc->value;
+					} else {
+						$data['results'][$doc->$group] = $doc->value;
+					}
+					break;
+
+			}
+
+		}
+
+		return $data;
+
+	}
+
+	/**
+	 * Helper method to create an array suitable for json_encode from
+	 * an Apache_Solr_Document object
+	 */
+	private function getObservation($result) {
+
+		$observation = array();
+		foreach ($result as $field => $value) {
+
+			// Ignore field names with underscores as these are assumed to
+			// be fields on a separate object that have been flattened for Solr
+			// e.g. only return "area" not "area_name", "area_location", etc
+			if (strpos($field, '_') === false) {
+				$observation[$field] = $value;
+			}
+
+		}
+
+		return $observation;
+
+	}
+
+}
+

api/dispatch.php

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+<?php
+
+// load Tonic library
+require_once './lib/tonic/tonic.php';
+
+// load Observation resource
+require_once './observation.php';
+
+// handle request
+$request = new Request();
+try {
+	$resource = $request->loadResource();
+    $response = $resource->exec($request);
+} catch (ResponseException $e) {
+	$response = $e->response($request);
+}
+$response->output();
+

api/lib/Apache/Solr/COPYING

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+Copyright (c) 2007-2011, Servigistics, Inc. 
+All rights reserved. 
+
+Redistribution and use in source and binary forms, with or without 
+modification, are permitted provided that the following conditions are met: 
+
+ * Redistributions of source code must retain the above copyright notice, 
+   this list of conditions and the following disclaimer. 
+ * Redistributions in binary form must reproduce the above copyright 
+   notice, this list of conditions and the following disclaimer in the 
+   documentation and/or other materials provided with the distribution. 
+ * Neither the name of Servigistics, Inc. nor the names of 
+   its contributors may be used to endorse or promote products derived from 
+   this software without specific prior written permission. 
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+POSSIBILITY OF SUCH DAMAGE.