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<?php
/**
 * 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.
 *
 * @copyright Copyright 2007-2011 Servigistics, Inc. (http://servigistics.com)
 * @license http://solr-php-client.googlecode.com/svn/trunk/COPYING New BSD
 * @version $Id: Service.php 59 2011-02-08 20:38:59Z donovan.jimenez $
 *
 * @package Apache
 * @subpackage Solr
 * @author Donovan Jimenez <djimenez@conduit-it.com>
 */

// See Issue #1 (http://code.google.com/p/solr-php-client/issues/detail?id=1)
// Doesn't follow typical include path conventions, but is more convenient for users
require_once(dirname(__FILE__) . '/Exception.php');
require_once(dirname(__FILE__) . '/HttpTransportException.php');
require_once(dirname(__FILE__) . '/InvalidArgumentException.php');

require_once(dirname(__FILE__) . '/Document.php');
require_once(dirname(__FILE__) . '/Response.php');

require_once(dirname(__FILE__) . '/HttpTransport/Interface.php');

/**
 * Starting point for the Solr API. Represents a Solr server resource and has
 * methods for pinging, adding, deleting, committing, optimizing and searching.
 *
 * Example Usage:
 * <code>
 * ...
 * $solr = new Apache_Solr_Service(); //or explicitly new Apache_Solr_Service('localhost', 8180, '/solr')
 *
 * if ($solr->ping())
 * {
 *              $solr->deleteByQuery('*:*'); //deletes ALL documents - be careful :)
 *
 *              $document = new Apache_Solr_Document();
 *              $document->id = uniqid(); //or something else suitably unique
 *
 *              $document->title = 'Some Title';
 *              $document->content = 'Some content for this wonderful document. Blah blah blah.';
 *
 *              $solr->addDocument($document);  //if you're going to be adding documents in bulk using addDocuments
 *                                                                              //with an array of documents is faster
 *
 *              $solr->commit(); //commit to see the deletes and the document
 *              $solr->optimize(); //merges multiple segments into one
 *
 *              //and the one we all care about, search!
 *              //any other common or custom parameters to the request handler can go in the
 *              //optional 4th array argument.
 *              $solr->search('content:blah', 0, 10, array('sort' => 'timestamp desc'));
 * }
 * ...
 * </code>
 *
 * @todo Investigate using other HTTP clients other than file_get_contents built-in handler. Could provide performance
 * improvements when dealing with multiple requests by using HTTP's keep alive functionality
 */
class Apache_Solr_Service
{
        /**
         * SVN Revision meta data for this class
         */
        const SVN_REVISION = '$Revision: 59 $';

        /**
         * SVN ID meta data for this class
         */
        const SVN_ID = '$Id: Service.php 59 2011-02-08 20:38:59Z donovan.jimenez $';

        /**
         * Response writer we'll request - JSON. See http://code.google.com/p/solr-php-client/issues/detail?id=6#c1 for reasoning
         */
        const SOLR_WRITER = 'json';

        /**
         * NamedList Treatment constants
         */
        const NAMED_LIST_FLAT = 'flat';
        const NAMED_LIST_MAP = 'map';

        /**
         * Search HTTP Methods
         */
        const METHOD_GET = 'GET';
        const METHOD_POST = 'POST';

        /**
         * Servlet mappings
         */
        const PING_SERVLET = 'admin/ping';
        const UPDATE_SERVLET = 'update';
        const SEARCH_SERVLET = 'select';
        const THREADS_SERVLET = 'admin/threads';
        const EXTRACT_SERVLET = 'update/extract';

        /**
         * Server identification strings
         *
         * @var string
         */
        protected $_host, $_port, $_path;

        /**
         * Whether {@link Apache_Solr_Response} objects should create {@link Apache_Solr_Document}s in
         * the returned parsed data
         *
         * @var boolean
         */
        protected $_createDocuments = true;

        /**
         * Whether {@link Apache_Solr_Response} objects should have multivalue fields with only a single value
         * collapsed to appear as a single value would.
         *
         * @var boolean
         */
        protected $_collapseSingleValueArrays = true;

        /**
         * How NamedLists should be formatted in the output.  This specifically effects facet counts. Valid values
         * are {@link Apache_Solr_Service::NAMED_LIST_MAP} (default) or {@link Apache_Solr_Service::NAMED_LIST_FLAT}.
         *
         * @var string
         */
        protected $_namedListTreatment = self::NAMED_LIST_MAP;

        /**
         * Query delimiters. Someone might want to be able to change
         * these (to use &amp; instead of & for example), so I've provided them.
         *
         * @var string
         */
        protected $_queryDelimiter = '?', $_queryStringDelimiter = '&', $_queryBracketsEscaped = true;

        /**
         * Constructed servlet full path URLs
         *
         * @var string
         */
        protected $_pingUrl, $_updateUrl, $_searchUrl, $_threadsUrl;

        /**
         * Keep track of whether our URLs have been constructed
         *
         * @var boolean
         */
        protected $_urlsInited = false;

        /**
         * HTTP Transport implementation (pluggable)
         *
         * @var Apache_Solr_HttpTransport_Interface
         */
        protected $_httpTransport = false;

        /**
         * Escape a value for special query characters such as ':', '(', ')', '*', '?', etc.
         *
         * NOTE: inside a phrase fewer characters need escaped, use {@link Apache_Solr_Service::escapePhrase()} instead
         *
         * @param string $value
         * @return string
         */
        static public function escape($value)
        {
                //list taken from http://lucene.apache.org/java/docs/queryparsersyntax.html#Escaping%20Special%20Characters
                $pattern = '/(\+|-|&&|\|\||!|\(|\)|\{|}|\[|]|\^|"|~|\*|\?|:|\\\)/';
                $replace = '\\\$1';

                return preg_replace($pattern, $replace, $value);
        }

        /**
         * Escape a value meant to be contained in a phrase for special query characters
         *
         * @param string $value
         * @return string
         */
        static public function escapePhrase($value)
        {
                $pattern = '/("|\\\)/';
                $replace = '\\\$1';

                return preg_replace($pattern, $replace, $value);
        }

        /**
         * Convenience function for creating phrase syntax from a value
         *
         * @param string $value
         * @return string
         */
        static public function phrase($value)
        {
                return '"' . self::escapePhrase($value) . '"';
        }

        /**
         * Constructor. All parameters are optional and will take on default values
         * if not specified.
         *
         * @param string $host
         * @param string $port
         * @param string $path
         * @param Apache_Solr_HttpTransport_Interface $httpTransport
         */
        public function __construct($host = 'localhost', $port = 8180, $path = '/solr/', $httpTransport = false)
        {
                $this->setHost($host);
                $this->setPort($port);
                $this->setPath($path);

                $this->_initUrls();

                if ($httpTransport)
                {
                        $this->setHttpTransport($httpTransport);
                }

                // check that our php version is >= 5.1.3 so we can correct for http_build_query behavior later
                $this->_queryBracketsEscaped = version_compare(phpversion(), '5.1.3', '>=');
        }

        /**
         * Return a valid http URL given this server's host, port and path and a provided servlet name
         *
         * @param string $servlet
         * @return string
         */
        protected function _constructUrl($servlet, $params = array())
        {
                if (count($params))
                {
                        //escape all parameters appropriately for inclusion in the query string
                        $escapedParams = array();

                        foreach ($params as $key => $value)
                        {
                                $escapedParams[] = urlencode($key) . '=' . urlencode($value);
                        }

                        $queryString = $this->_queryDelimiter . implode($this->_queryStringDelimiter, $escapedParams);
                }
                else
                {
                        $queryString = '';
                }

                return 'http://' . $this->_host . ':' . $this->_port . $this->_path . $servlet . $queryString;
        }

        /**
         * Construct the Full URLs for the three servlets we reference
         */
        protected function _initUrls()
        {
                //Initialize our full servlet URLs now that we have server information
                $this->_extractUrl = $this->_constructUrl(self::EXTRACT_SERVLET);
                $this->_pingUrl = $this->_constructUrl(self::PING_SERVLET);
                $this->_searchUrl = $this->_constructUrl(self::SEARCH_SERVLET);
                $this->_threadsUrl = $this->_constructUrl(self::THREADS_SERVLET, array('wt' => self::SOLR_WRITER ));
                $this->_updateUrl = $this->_constructUrl(self::UPDATE_SERVLET, array('wt' => self::SOLR_WRITER ));

                $this->_urlsInited = true;
        }

        protected function _generateQueryString($params)
        {
                // use http_build_query to encode our arguments because its faster
                // than urlencoding all the parts ourselves in a loop
                //
                // because http_build_query treats arrays differently than we want to, correct the query
                // string by changing foo[#]=bar (# being an actual number) parameter strings to just
                // multiple foo=bar strings. This regex should always work since '=' will be urlencoded
                // anywhere else the regex isn't expecting it
                //
                // NOTE: before php 5.1.3 brackets were not url encoded by http_build query - we've checked
                // the php version in the constructor and put the results in the instance variable. Also, before
                // 5.1.2 the arg_separator parameter was not available, so don't use it
                if ($this->_queryBracketsEscaped)
                {
                        $queryString = http_build_query($params, null, $this->_queryStringDelimiter);
                        return preg_replace('/%5B(?:[0-9]|[1-9][0-9]+)%5D=/', '=', $queryString);
                }
                else
                {
                        $queryString = http_build_query($params);
                        return preg_replace('/\\[(?:[0-9]|[1-9][0-9]+)\\]=/', '=', $queryString);
                }
        }

        /**
         * Central method for making a get operation against this Solr Server
         *
         * @param string $url
         * @param float $timeout Read timeout in seconds
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If a non 200 response status is returned
         */
        protected function _sendRawGet($url, $timeout = FALSE)
        {
                $httpTransport = $this->getHttpTransport();

                $httpResponse = $httpTransport->performGetRequest($url, $timeout);
                $solrResponse = new Apache_Solr_Response($httpResponse, $this->_createDocuments, $this->_collapseSingleValueArrays);

                if ($solrResponse->getHttpStatus() != 200)
                {
                        throw new Apache_Solr_HttpTransportException($solrResponse);
                }

                return $solrResponse;
        }

        /**
         * Central method for making a post operation against this Solr Server
         *
         * @param string $url
         * @param string $rawPost
         * @param float $timeout Read timeout in seconds
         * @param string $contentType
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If a non 200 response status is returned
         */
        protected function _sendRawPost($url, $rawPost, $timeout = FALSE, $contentType = 'text/xml; charset=UTF-8')
        {
                $httpTransport = $this->getHttpTransport();

                $httpResponse = $httpTransport->performPostRequest($url, $rawPost, $contentType, $timeout);
                $solrResponse = new Apache_Solr_Response($httpResponse, $this->_createDocuments, $this->_collapseSingleValueArrays);

                if ($solrResponse->getHttpStatus() != 200)
                {
                        throw new Apache_Solr_HttpTransportException($solrResponse);
                }

                return $solrResponse;
        }

        /**
         * Returns the set host
         *
         * @return string
         */
        public function getHost()
        {
                return $this->_host;
        }

        /**
         * Set the host used. If empty will fallback to constants
         *
         * @param string $host
         *
         * @throws Apache_Solr_InvalidArgumentException If the host parameter is empty
         */
        public function setHost($host)
        {
                //Use the provided host or use the default
                if (empty($host))
                {
                        throw new Apache_Solr_InvalidArgumentException('Host parameter is empty');
                }
                else
                {
                        $this->_host = $host;
                }

                if ($this->_urlsInited)
                {
                        $this->_initUrls();
                }
        }

        /**
         * Get the set port
         *
         * @return integer
         */
        public function getPort()
        {
                return $this->_port;
        }

        /**
         * Set the port used. If empty will fallback to constants
         *
         * @param integer $port
         *
         * @throws Apache_Solr_InvalidArgumentException If the port parameter is empty
         */
        public function setPort($port)
        {
                //Use the provided port or use the default
                $port = (int) $port;

                if ($port <= 0)
                {
                        throw new Apache_Solr_InvalidArgumentException('Port is not a valid port number');
                }
                else
                {
                        $this->_port = $port;
                }

                if ($this->_urlsInited)
                {
                        $this->_initUrls();
                }
        }

        /**
         * Get the set path.
         *
         * @return string
         */
        public function getPath()
        {
                return $this->_path;
        }

        /**
         * Set the path used. If empty will fallback to constants
         *
         * @param string $path
         */
        public function setPath($path)
        {
                $path = trim($path, '/');

                $this->_path = '/' . $path . '/';

                if ($this->_urlsInited)
                {
                        $this->_initUrls();
                }
        }

        /**
         * Get the current configured HTTP Transport
         *
         * @return HttpTransportInterface
         */
        public function getHttpTransport()
        {
                // lazy load a default if one has not be set
                if ($this->_httpTransport === false)
                {
                        require_once(dirname(__FILE__) . '/HttpTransport/FileGetContents.php');

                        $this->_httpTransport = new Apache_Solr_HttpTransport_FileGetContents();
                }

                return $this->_httpTransport;
        }

        /**
         * Set the HTTP Transport implemenation that will be used for all HTTP requests
         *
         * @param Apache_Solr_HttpTransport_Interface
         */
        public function setHttpTransport(Apache_Solr_HttpTransport_Interface $httpTransport)
        {
                $this->_httpTransport = $httpTransport;
        }

        /**
         * Set the create documents flag. This determines whether {@link Apache_Solr_Response} objects will
         * parse the response and create {@link Apache_Solr_Document} instances in place.
         *
         * @param boolean $createDocuments
         */
        public function setCreateDocuments($createDocuments)
        {
                $this->_createDocuments = (bool) $createDocuments;
        }

        /**
         * Get the current state of teh create documents flag.
         *
         * @return boolean
         */
        public function getCreateDocuments()
        {
                return $this->_createDocuments;
        }

        /**
         * Set the collapse single value arrays flag.
         *
         * @param boolean $collapseSingleValueArrays
         */
        public function setCollapseSingleValueArrays($collapseSingleValueArrays)
        {
                $this->_collapseSingleValueArrays = (bool) $collapseSingleValueArrays;
        }

        /**
         * Get the current state of the collapse single value arrays flag.
         *
         * @return boolean
         */
        public function getCollapseSingleValueArrays()
        {
                return $this->_collapseSingleValueArrays;
        }

        /**
         * Get the current default timeout setting (initially the default_socket_timeout ini setting)
         * in seconds
         *
         * @return float
         *
         * @deprecated Use the getDefaultTimeout method on the HTTP transport implementation
         */
        public function getDefaultTimeout()
        {
                return $this->getHttpTransport()->getDefaultTimeout();
        }

        /**
         * Set the default timeout for all calls that aren't passed a specific timeout
         *
         * @param float $timeout Timeout value in seconds
         *
         * @deprecated Use the setDefaultTimeout method on the HTTP transport implementation
         */
        public function setDefaultTimeout($timeout)
        {
                $this->getHttpTransport()->setDefaultTimeout($timeout);
        }

        /**
         * Set how NamedLists should be formatted in the response data. This mainly effects
         * the facet counts format.
         *
         * @param string $namedListTreatment
         * @throws Apache_Solr_InvalidArgumentException If invalid option is set
         */
        public function setNamedListTreatment($namedListTreatment)
        {
                switch ((string) $namedListTreatment)
                {
                        case Apache_Solr_Service::NAMED_LIST_FLAT:
                                $this->_namedListTreatment = Apache_Solr_Service::NAMED_LIST_FLAT;
                                break;

                        case Apache_Solr_Service::NAMED_LIST_MAP:
                                $this->_namedListTreatment = Apache_Solr_Service::NAMED_LIST_MAP;
                                break;

                        default:
                                throw new Apache_Solr_InvalidArgumentException('Not a valid named list treatement option');
                }
        }

        /**
         * Get the current setting for named list treatment.
         *
         * @return string
         */
        public function getNamedListTreatment()
        {
                return $this->_namedListTreatment;
        }

        /**
         * Set the string used to separate the path form the query string.
         * Defaulted to '?'
         *
         * @param string $queryDelimiter
         */
        public function setQueryDelimiter($queryDelimiter)
        {
                $this->_queryDelimiter = $queryDelimiter;
        }

        /**
         * Set the string used to separate the parameters in thequery string
         * Defaulted to '&'
         *
         * @param string $queryStringDelimiter
         */
        public function setQueryStringDelimiter($queryStringDelimiter)
        {
                $this->_queryStringDelimiter = $queryStringDelimiter;
        }

        /**
         * Call the /admin/ping servlet, can be used to quickly tell if a connection to the
         * server is able to be made.
         *
         * @param float $timeout maximum time to wait for ping in seconds, -1 for unlimited (default is 2)
         * @return float Actual time taken to ping the server, FALSE if timeout or HTTP error status occurs
         */
        public function ping($timeout = 2)
        {
                $start = microtime(true);
                
                $httpTransport = $this->getHttpTransport();

                $httpResponse = $httpTransport->performHeadRequest($this->_pingUrl, $timeout);
                $solrResponse = new Apache_Solr_Response($httpResponse, $this->_createDocuments, $this->_collapseSingleValueArrays);

                if ($solrResponse->getHttpStatus() == 200)
                {
                        return microtime(true) - $start;
                }
                else
                {
                        return false;
                }
        }

        /**
         * Call the /admin/threads servlet and retrieve information about all threads in the
         * Solr servlet's thread group. Useful for diagnostics.
         *
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function threads()
        {
                return $this->_sendRawGet($this->_threadsUrl);
        }

        /**
         * Raw Add Method. Takes a raw post body and sends it to the update service.  Post body
         * should be a complete and well formed "add" xml document.
         *
         * @param string $rawPost
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function add($rawPost)
        {
                return $this->_sendRawPost($this->_updateUrl, $rawPost);
        }

        /**
         * Add a Solr Document to the index
         *
         * @param Apache_Solr_Document $document
         * @param boolean $allowDups
         * @param boolean $overwritePending
         * @param boolean $overwriteCommitted
         * @param integer $commitWithin The number of milliseconds that a document must be committed within, see @{link http://wiki.apache.org/solr/UpdateXmlMessages#The_Update_Schema} for details.  If left empty this property will not be set in the request.
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function addDocument(Apache_Solr_Document $document, $allowDups = false, $overwritePending = true, $overwriteCommitted = true, $commitWithin = 0)
        {
                $dupValue = $allowDups ? 'true' : 'false';
                $pendingValue = $overwritePending ? 'true' : 'false';
                $committedValue = $overwriteCommitted ? 'true' : 'false';
                
                $commitWithin = (int) $commitWithin;
                $commitWithinString = $commitWithin > 0 ? " commitWithin=\"{$commitWithin}\"" : '';
                
                $rawPost = "<add allowDups=\"{$dupValue}\" overwritePending=\"{$pendingValue}\" overwriteCommitted=\"{$committedValue}\"{$commitWithinString}>";
                $rawPost .= $this->_documentToXmlFragment($document);
                $rawPost .= '</add>';

                return $this->add($rawPost);
        }

        /**
         * Add an array of Solr Documents to the index all at once
         *
         * @param array $documents Should be an array of Apache_Solr_Document instances
         * @param boolean $allowDups
         * @param boolean $overwritePending
         * @param boolean $overwriteCommitted
         * @param integer $commitWithin The number of milliseconds that a document must be committed within, see @{link http://wiki.apache.org/solr/UpdateXmlMessages#The_Update_Schema} for details.  If left empty this property will not be set in the request.
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function addDocuments($documents, $allowDups = false, $overwritePending = true, $overwriteCommitted = true, $commitWithin = 0)
        {
                $dupValue = $allowDups ? 'true' : 'false';
                $pendingValue = $overwritePending ? 'true' : 'false';
                $committedValue = $overwriteCommitted ? 'true' : 'false';

                $commitWithin = (int) $commitWithin;
                $commitWithinString = $commitWithin > 0 ? " commitWithin=\"{$commitWithin}\"" : '';

                $rawPost = "<add allowDups=\"{$dupValue}\" overwritePending=\"{$pendingValue}\" overwriteCommitted=\"{$committedValue}\"{$commitWithinString}>";

                foreach ($documents as $document)
                {
                        if ($document instanceof Apache_Solr_Document)
                        {
                                $rawPost .= $this->_documentToXmlFragment($document);
                        }
                }

                $rawPost .= '</add>';

                return $this->add($rawPost);
        }

        /**
         * Create an XML fragment from a {@link Apache_Solr_Document} instance appropriate for use inside a Solr add call
         *
         * @return string
         */
        protected function _documentToXmlFragment(Apache_Solr_Document $document)
        {
                $xml = '<doc';

                if ($document->getBoost() !== false)
                {
                        $xml .= ' boost="' . $document->getBoost() . '"';
                }

                $xml .= '>';

                foreach ($document as $key => $value)
                {
                        $key = htmlspecialchars($key, ENT_QUOTES, 'UTF-8');
                        $fieldBoost = $document->getFieldBoost($key);

                        if (is_array($value))
                        {
                                foreach ($value as $multivalue)
                                {
                                        $xml .= '<field name="' . $key . '"';

                                        if ($fieldBoost !== false)
                                        {
                                                $xml .= ' boost="' . $fieldBoost . '"';

                                                // only set the boost for the first field in the set
                                                $fieldBoost = false;
                                        }

                                        $multivalue = htmlspecialchars($multivalue, ENT_NOQUOTES, 'UTF-8');

                                        $xml .= '>' . $multivalue . '</field>';
                                }
                        }
                        else
                        {
                                $xml .= '<field name="' . $key . '"';

                                if ($fieldBoost !== false)
                                {
                                        $xml .= ' boost="' . $fieldBoost . '"';
                                }

                                $value = htmlspecialchars($value, ENT_NOQUOTES, 'UTF-8');

                                $xml .= '>' . $value . '</field>';
                        }
                }

                $xml .= '</doc>';

                // replace any control characters to avoid Solr XML parser exception
                return $this->_stripCtrlChars($xml);
        }

        /**
         * Replace control (non-printable) characters from string that are invalid to Solr's XML parser with a space.
         *
         * @param string $string
         * @return string
         */
        protected function _stripCtrlChars($string)
        {
                // See:  http://w3.org/International/questions/qa-forms-utf-8.html
                // Printable utf-8 does not include any of these chars below x7F
                return preg_replace('@[\x00-\x08\x0B\x0C\x0E-\x1F]@', ' ', $string);
        }

        /**
         * Send a commit command.  Will be synchronous unless both wait parameters are set to false.
         *
         * @param boolean $expungeDeletes Defaults to false, merge segments with deletes away
         * @param boolean $waitFlush Defaults to true,  block until index changes are flushed to disk
         * @param boolean $waitSearcher Defaults to true, block until a new searcher is opened and registered as the main query searcher, making the changes visible
         * @param float $timeout Maximum expected duration (in seconds) of the commit operation on the server (otherwise, will throw a communication exception). Defaults to 1 hour
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function commit($expungeDeletes = false, $waitFlush = true, $waitSearcher = true, $timeout = 3600)
        {
                $expungeValue = $expungeDeletes ? 'true' : 'false';
                $flushValue = $waitFlush ? 'true' : 'false';
                $searcherValue = $waitSearcher ? 'true' : 'false';

                $rawPost = '<commit expungeDeletes="' . $expungeValue . '" waitFlush="' . $flushValue . '" waitSearcher="' . $searcherValue . '" />';

                return $this->_sendRawPost($this->_updateUrl, $rawPost, $timeout);
        }

        /**
         * Raw Delete Method. Takes a raw post body and sends it to the update service. Body should be
         * a complete and well formed "delete" xml document
         *
         * @param string $rawPost Expected to be utf-8 encoded xml document
         * @param float $timeout Maximum expected duration of the delete operation on the server (otherwise, will throw a communication exception)
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function delete($rawPost, $timeout = 3600)
        {
                return $this->_sendRawPost($this->_updateUrl, $rawPost, $timeout);
        }

        /**
         * Create a delete document based on document ID
         *
         * @param string $id Expected to be utf-8 encoded
         * @param boolean $fromPending
         * @param boolean $fromCommitted
         * @param float $timeout Maximum expected duration of the delete operation on the server (otherwise, will throw a communication exception)
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function deleteById($id, $fromPending = true, $fromCommitted = true, $timeout = 3600)
        {
                $pendingValue = $fromPending ? 'true' : 'false';
                $committedValue = $fromCommitted ? 'true' : 'false';

                //escape special xml characters
                $id = htmlspecialchars($id, ENT_NOQUOTES, 'UTF-8');

                $rawPost = '<delete fromPending="' . $pendingValue . '" fromCommitted="' . $committedValue . '"><id>' . $id . '</id></delete>';

                return $this->delete($rawPost, $timeout);
        }

        /**
         * Create and post a delete document based on multiple document IDs.
         *
         * @param array $ids Expected to be utf-8 encoded strings
         * @param boolean $fromPending
         * @param boolean $fromCommitted
         * @param float $timeout Maximum expected duration of the delete operation on the server (otherwise, will throw a communication exception)
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function deleteByMultipleIds($ids, $fromPending = true, $fromCommitted = true, $timeout = 3600)
        {
                $pendingValue = $fromPending ? 'true' : 'false';
                $committedValue = $fromCommitted ? 'true' : 'false';

                $rawPost = '<delete fromPending="' . $pendingValue . '" fromCommitted="' . $committedValue . '">';

                foreach ($ids as $id)
                {
                        //escape special xml characters
                        $id = htmlspecialchars($id, ENT_NOQUOTES, 'UTF-8');

                        $rawPost .= '<id>' . $id . '</id>';
                }

                $rawPost .= '</delete>';

                return $this->delete($rawPost, $timeout);
        }

        /**
         * Create a delete document based on a query and submit it
         *
         * @param string $rawQuery Expected to be utf-8 encoded
         * @param boolean $fromPending
         * @param boolean $fromCommitted
         * @param float $timeout Maximum expected duration of the delete operation on the server (otherwise, will throw a communication exception)
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function deleteByQuery($rawQuery, $fromPending = true, $fromCommitted = true, $timeout = 3600)
        {
                $pendingValue = $fromPending ? 'true' : 'false';
                $committedValue = $fromCommitted ? 'true' : 'false';

                // escape special xml characters
                $rawQuery = htmlspecialchars($rawQuery, ENT_NOQUOTES, 'UTF-8');

                $rawPost = '<delete fromPending="' . $pendingValue . '" fromCommitted="' . $committedValue . '"><query>' . $rawQuery . '</query></delete>';

                return $this->delete($rawPost, $timeout);
        }

        /**
         * Use Solr Cell to extract document contents. See {@link http://wiki.apache.org/solr/ExtractingRequestHandler} for information on how
         * to use Solr Cell and what parameters are available.
         *
         * NOTE: when passing an Apache_Solr_Document instance, field names and boosts will automatically be prepended by "literal." and "boost."
         * as appropriate. Any keys from the $params array will NOT be treated this way. Any mappings from the document will overwrite key / value
         * pairs in the params array if they have the same name (e.g. you pass a "literal.id" key and value in your $params array but you also
         * pass in a document isntance with an "id" field" - the document's value(s) will take precedence).
         *
         * @param string $file Path to file to extract data from
         * @param array $params optional array of key value pairs that will be sent with the post (see Solr Cell documentation)
         * @param Apache_Solr_Document $document optional document that will be used to generate post parameters (literal.* and boost.* params)
         * @param string $mimetype optional mimetype specification (for the file being extracted)
         *
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_InvalidArgumentException if $file, $params, or $document are invalid.
         */
        public function extract($file, $params = array(), $document = null, $mimetype = 'application/octet-stream')
        {
                // check if $params is an array (allow null for default empty array)
                if (!is_null($params))
                {
                        if (!is_array($params))
                        {
                                throw new Apache_Solr_InvalidArgumentException("\$params must be a valid array or null");
                        }
                }
                else
                {
                        $params = array();
                }
                
                // if $file is an http request, defer to extractFromUrl instead
                if (substr($file, 0, 7) == 'http://' || substr($file, 0, 8) == 'https://')
                {
                        return $this->extractFromUrl($file, $params, $document, $mimetype);
                }
                
                // read the contents of the file
                $contents = @file_get_contents($file);

                if ($contents !== false)
                {
                        // add the resource.name parameter if not specified
                        if (!isset($params['resource.name']))
                        {
                                $params['resource.name'] = basename($file);
                        }

                        // delegate the rest to extractFromString
                        return $this->extractFromString($contents, $params, $document, $mimetype);
                }
                else
                {
                        throw new Apache_Solr_InvalidArgumentException("File '{$file}' is empty or could not be read");
                }
        }
        
        /**
         * Use Solr Cell to extract document contents. See {@link http://wiki.apache.org/solr/ExtractingRequestHandler} for information on how
         * to use Solr Cell and what parameters are available.
         *
         * NOTE: when passing an Apache_Solr_Document instance, field names and boosts will automatically be prepended by "literal." and "boost."
         * as appropriate. Any keys from the $params array will NOT be treated this way. Any mappings from the document will overwrite key / value
         * pairs in the params array if they have the same name (e.g. you pass a "literal.id" key and value in your $params array but you also
         * pass in a document isntance with an "id" field" - the document's value(s) will take precedence).
         *
         * @param string $data Data that will be passed to Solr Cell
         * @param array $params optional array of key value pairs that will be sent with the post (see Solr Cell documentation)
         * @param Apache_Solr_Document $document optional document that will be used to generate post parameters (literal.* and boost.* params)
         * @param string $mimetype optional mimetype specification (for the file being extracted)
         *
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_InvalidArgumentException if $file, $params, or $document are invalid.
         *
         * @todo Should be using multipart/form-data to post parameter values, but I could not get my implementation to work. Needs revisisted.
         */
        public function extractFromString($data, $params = array(), $document = null, $mimetype = 'application/octet-stream')
        {
                // check if $params is an array (allow null for default empty array)
                if (!is_null($params))
                {
                        if (!is_array($params))
                        {
                                throw new Apache_Solr_InvalidArgumentException("\$params must be a valid array or null");
                        }
                }
                else
                {
                        $params = array();
                }

                // make sure we receive our response in JSON and have proper name list treatment
                $params['wt'] = self::SOLR_WRITER;
                $params['json.nl'] = $this->_namedListTreatment;

                // check if $document is an Apache_Solr_Document instance
                if (!is_null($document) && $document instanceof Apache_Solr_Document)
                {
                        // iterate document, adding literal.* and boost.* fields to $params as appropriate
                        foreach ($document as $field => $fieldValue)
                        {
                                // check if we need to add a boost.* parameters
                                $fieldBoost = $document->getFieldBoost($field);

                                if ($fieldBoost !== false)
                                {
                                        $params["boost.{$field}"] = $fieldBoost;
                                }

                                // add the literal.* parameter
                                $params["literal.{$field}"] = $fieldValue;
                        }
                }

                // params will be sent to SOLR in the QUERY STRING
                $queryString = $this->_generateQueryString($params);

                // the file contents will be sent to SOLR as the POST BODY - we use application/octect-stream as default mimetype
                return $this->_sendRawPost($this->_extractUrl . $this->_queryDelimiter . $queryString, $data, false, $mimetype);
        }
        
        /**
         * Use Solr Cell to extract document contents. See {@link http://wiki.apache.org/solr/ExtractingRequestHandler} for information on how
         * to use Solr Cell and what parameters are available.
         *
         * NOTE: when passing an Apache_Solr_Document instance, field names and boosts will automatically be prepended by "literal." and "boost."
         * as appropriate. Any keys from the $params array will NOT be treated this way. Any mappings from the document will overwrite key / value
         * pairs in the params array if they have the same name (e.g. you pass a "literal.id" key and value in your $params array but you also
         * pass in a document isntance with an "id" field" - the document's value(s) will take precedence).
         *
         * @param string $url URL
         * @param array $params optional array of key value pairs that will be sent with the post (see Solr Cell documentation)
         * @param Apache_Solr_Document $document optional document that will be used to generate post parameters (literal.* and boost.* params)
         * @param string $mimetype optional mimetype specification (for the file being extracted)
         *
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_InvalidArgumentException if $url, $params, or $document are invalid.
         */
        public function extractFromUrl($url, $params = array(), $document = null, $mimetype = 'application/octet-stream')
        {
                // check if $params is an array (allow null for default empty array)
                if (!is_null($params))
                {
                        if (!is_array($params))
                        {
                                throw new Apache_Solr_InvalidArgumentException("\$params must be a valid array or null");
                        }
                }
                else
                {
                        $params = array();
                }

                $httpTransport = $this->getHttpTransport();
                
                // read the contents of the URL using our configured Http Transport and default timeout
                $httpResponse = $httpTransport->performGetRequest($url);
                
                // check that its a 200 response
                if ($httpResponse->getStatusCode() == 200)
                {
                        // add the resource.name parameter if not specified
                        if (!isset($params['resource.name']))
                        {
                                $params['resource.name'] = $url;
                        }

                        // delegate the rest to extractFromString
                        return $this->extractFromString($httpResponse->getBody(), $params, $document, $mimetype);
                }
                else
                {
                        throw new Apache_Solr_InvalidArgumentException("URL '{$url}' returned non 200 response code");
                }
        }

        /**
         * Send an optimize command.  Will be synchronous unless both wait parameters are set
         * to false.
         *
         * @param boolean $waitFlush
         * @param boolean $waitSearcher
         * @param float $timeout Maximum expected duration of the commit operation on the server (otherwise, will throw a communication exception)
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         */
        public function optimize($waitFlush = true, $waitSearcher = true, $timeout = 3600)
        {
                $flushValue = $waitFlush ? 'true' : 'false';
                $searcherValue = $waitSearcher ? 'true' : 'false';

                $rawPost = '<optimize waitFlush="' . $flushValue . '" waitSearcher="' . $searcherValue . '" />';

                return $this->_sendRawPost($this->_updateUrl, $rawPost, $timeout);
        }

        /**
         * Simple Search interface
         *
         * @param string $query The raw query string
         * @param int $offset The starting offset for result documents
         * @param int $limit The maximum number of result documents to return
         * @param array $params key / value pairs for other query parameters (see Solr documentation), use arrays for parameter keys used more than once (e.g. facet.field)
         * @param string $method The HTTP method (Apache_Solr_Service::METHOD_GET or Apache_Solr_Service::METHOD::POST)
         * @return Apache_Solr_Response
         *
         * @throws Apache_Solr_HttpTransportException If an error occurs during the service call
         * @throws Apache_Solr_InvalidArgumentException If an invalid HTTP method is used
         */
        public function search($query, $offset = 0, $limit = 10, $params = array(), $method = self::METHOD_GET)
        {
                // ensure params is an array
                if (!is_null($params))
                {
                        if (!is_array($params))
                        {
                                // params was specified but was not an array - invalid
                                throw new Apache_Solr_InvalidArgumentException("\$params must be a valid array or null");
                        }
                }
                else
                {
                        $params = array();
                }
                
                // construct our full parameters

                // common parameters in this interface
                $params['wt'] = self::SOLR_WRITER;
                $params['json.nl'] = $this->_namedListTreatment;

                $params['q'] = $query;
                $params['start'] = $offset;
                $params['rows'] = $limit;

                $queryString = $this->_generateQueryString($params);

                if ($method == self::METHOD_GET)
                {
                        return $this->_sendRawGet($this->_searchUrl . $this->_queryDelimiter . $queryString);
                }
                else if ($method == self::METHOD_POST)
                {
                        return $this->_sendRawPost($this->_searchUrl, $queryString, FALSE, 'application/x-www-form-urlencoded; charset=UTF-8');
                }
                else
                {
                        throw new Apache_Solr_InvalidArgumentException("Unsupported method '$method', please use the Apache_Solr_Service::METHOD_* constants");
                }
        }
}