simple-oai-pmh/xml_creater.php

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<?php
/**
* \file
* \brief functions and class related to generating XML response file.
*
* Example usage:
*
* \code
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* $par_array = array("verb"=>"ListRecords","resumptionToken"=>"9CD1DA87F59C3E960871F4F3C9D093887C17D174");
* // Example 1: Error response
* $error_array[] = oai_error("badVerb","Rubish");
* $error_array[] = oai_error("sameVerb");
* $e = new ANDS_Error_XML($par_array,$error_array);
* $e->display();
*
* // Example 2: Normal response without error codes
* $par_array = array("verb"=>"ListRecords","resumptionToken"=>"9CD1DA87F59C3E960871F4F3C9D093887C17D174");
* $test = new ANDS_Response_XML($par_array);
* $record_node = $test->create_record();
* $test->create_header("function: identifier string",gmdate("Y-m-d\TH:i:s\Z"),"collection",$record_node);
* $test->create_metadata($record_node);
* $test->display();
* \endcode
*
* \see http://www.openarchives.org/OAI/openarchivesprotocol.html#ErrorConditions
*/
/*
http://www.openarchives.org/OAI/openarchivesprotocol.html#ErrorConditions
badArgument:
The request includes illegal arguments, is missing required arguments, includes a repeated argument, or values for arguments have an illegal syntax. Applied to all verbs.
badResumptionToken:
The value of the resumptionToken argument is invalid or expired. Applied to: ListIdentifiers, ListRecords, ListSets
badVerb:
Value of the verb argument is not a legal OAI-PMH verb, the verb argument is missing, or the verb argument is repeated. N/A
cannotDisseminateFormat:
The metadata format identified by the value given for the metadataPrefix argument is not supported by the item or by the repository. Applied to GetRecord, ListIdentifiers, ListRecords
idDoesNotExist:
The value of the identifier argument is unknown or illegal in this repository. Applied to GetRecord, ListMetadataFormats
noRecordsMatch:
The combination of the values of the from, until, set and metadataPrefix arguments results in an empty list. Applied to ListIdentifiers, ListRecords
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noMetadataFormats:
There are no metadata formats available for the specified item. Applied to ListMetadataFormats.
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noSetHierarchy:
The repository does not support sets. Applied to ListSets, ListIdentifiers, ListRecords
*/
/** utility funciton to mapping error codes to readable messages */
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function oai_error($code, $argument = '', $value = '') {
switch ($code) {
case 'badArgument' :
$text = "Attribute '{$argument}' is not allowed to appear in element 'request'.";
break;
case 'badGranularity' :
$text = "The value '{$value}' of attribute '{$argument}' on element 'request' is not valid with respect to its type, 'UTCdatetimeType'.";
$code = 'badArgument';
break;
case 'badResumptionToken' :
$text = "The resumptionToken '{$value}' does not exist or has already expired.";
break;
case 'badRequestMethod' :
$text = "The request method '{$argument}' is unknown.";
$code = 'badVerb';
break;
case 'badVerb' :
$text = "The value '{$argument}' of attribute 'verb' on element 'request' is not valid with respect to its type, 'verbType'";
break;
case 'cannotDisseminateFormat' :
$text = "The metadata format '{$value}' given by {$argument} is not supported by this repository.";
break;
case 'exclusiveArgument' :
$text = 'The usage of resumptionToken as an argument allows no other arguments.';
$code = 'badArgument';
break;
case 'idDoesNotExist' :
$text = "The value '{$value}' of the identifier does not exist in this repository.";
if (!is_valid_uri($value)) {
$code = 'badArgument';
$text .= ' Invalidated URI has been detected.';
}
break;
case 'missingArgument' :
$text = "The required argument '{$argument}' is missing in the request.";
$code = 'badArgument';
break;
case 'noRecordsMatch' :
$text = 'The combination of the given values results in an empty list.';
break;
case 'noMetadataFormats' :
$text = 'There are no metadata formats available for the specified item.';
break;
case 'noVerb' :
$text = 'The request does not provide any verb.';
$code = 'badVerb';
break;
case 'noSetHierarchy' :
$text = 'This repository does not support sets.';
break;
case 'sameArgument' :
$text = 'Do not use the same argument more than once.';
$code = 'badArgument';
break;
case 'sameVerb' :
$text = 'Do not use verb more than once.';
$code = 'badVerb';
break;
case 'notImp' :
$text = 'Not yet implemented.';
$code = 'debug';
break;
default:
$text = "Unknown error: code: '{$code}', argument: '{$argument}', value: '{$value}'";
$code = 'badArgument';
}
return $code."|".$text;
}
/**
* A wraper of DOMDocument for data provider
*/
class ANDS_XML {
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public $doc; /**< Type: DOMDocument. Handle of current XML Document object */
/**
* Constructs an ANDS_XML object.
*
* @param $par_array Type: array.
* Array of request parameters for creating an ANDS_XML object.
* \see create_request.
*/
function __construct($par_array) {
$this->doc = new DOMDocument("1.0","UTF-8");
// oai_node equals to $this->doc->documentElement;
$oai_node = $this->doc->createElement("OAI-PMH");
$oai_node->setAttribute("xmlns","http://www.openarchives.org/OAI/2.0/");
$oai_node->setAttribute("xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance");
$oai_node->setAttribute("xsi:schemaLocation","http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd");
$this->addChild($oai_node,"responseDate",gmdate("Y-m-d\TH:i:s\Z"));
$this->doc->appendChild($oai_node);
$this->create_request($par_array);
}
/**
* Add a child node to a parent node on a XML Doc: a worker function.
*
* @param $mom_node
* Type: DOMNode. The target node.
*
* @param $name
* Type: string. The name of child nade is being added
*
* @param $value
* Type: string. Text for the adding node if it is a text node.
*
* @return DOMElement $added_node
* The newly created node, can be used for further expansion.
* If no further expansion is expected, return value can be igored.
*/
function addChild($mom_node,$name, $value='') {
$added_node = $this->doc->createElement($name,$value);
$added_node = $mom_node->appendChild($added_node);
return $added_node;
}
/**
* Create an OAI request node.
*
* @param $par_array Type: array
* The attributes of a request node. They describe the verb of the request and other associated parameters used in the request.
* Keys of the array define attributes, and values are their content.
*/
function create_request($par_array) {
$request = $this->addChild($this->doc->documentElement,"request",MY_URI);
foreach($par_array as $key => $value) {
$request->setAttribute($key,$value);
}
}
/**
* Display a doc in a readable, well-formatted way for display or saving
*/
function display() {
$pr = new DOMDocument();
$pr->preserveWhiteSpace = false;
$pr->formatOutput = true;
$pr->loadXML($this->doc->saveXML());
echo $pr->saveXML();
}
}
/**
* Generate an XML response when a request cannot be finished
*
* It has only one derived member function
*/
class ANDS_Error_XML extends ANDS_XML {
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function __construct($par_array, $error_array) {
parent::__construct($par_array);
$oai_node = $this->doc->documentElement;
foreach($error_array as $e) {
list($code, $value) = explode("|", $e);
$node = $this->addChild($oai_node,"error",$value);
$node->setAttribute("code",$code);
}
}
}
/**
* Generate an XML response to a request if no error has occured
*
* This is the class to further develop to suits a publication need
*/
class ANDS_Response_XML extends ANDS_XML {
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public $verbNode; /**< Type: DOMElement. Verb node itself. */
protected $verb; /**< Type: string. The verb in the request */
function __construct($par_array) {
parent::__construct($par_array);
$this->verb = $par_array["verb"];
$this->verbNode = $this->addChild($this->doc->documentElement,$this->verb);
}
/** Add direct child nodes to verb node (OAI-PMH), e.g. response to ListMetadataFormats.
* Different verbs can have different required child nodes.
* \see create_record, create_header
* \see http://www.openarchives.org/OAI/2.0/openarchivesprotocol.htm.
*
* \param $nodeName Type: string. The name of appending node.
* \param $value Type: string. The content of appending node.
*/
function add2_verbNode($nodeName, $value=null) {
return $this->addChild($this->verbNode,$nodeName,$value);
}
/**
* Create an empty \<record\> node. Other nodes will be appended to it later.
*/
function create_record() {
return $this->add2_verbNode("record");
}
/** Headers are enclosed inside of \<record\> to the query of ListRecords, ListIdentifiers and etc.
*
* \param $identifier Type: string. The identifier string for node \<identifier\>.
* \param $timestamp Type: timestamp. Timestapme in UTC format for node \<datastamp\>.
* \param $ands_class Type: mix. Can be an array or just a string. Content of \<setSpec\>.
* \param $add_to_node Type: DOMElement. Default value is null.
* In normal cases, $add_to_node is the \<record\> node created previously. When it is null, the newly created header node is attatched to $this->verbNode.
* Otherwise it will be attatched to the desired node defined in $add_to_node.
*/
function create_header($identifier,$timestamp,$ands_class, $add_to_node=null) {
if(is_null($add_to_node)) {
$header_node = $this->add2_verbNode("header");
} else {
$header_node = $this->addChild($add_to_node,"header");
}
$this->addChild($header_node,"identifier",$identifier);
$this->addChild($header_node,"datestamp",$timestamp);
if (is_array($ands_class)) {
foreach ($ands_class as $setspec) {
$this->addChild($header_node,"setSpec",$setspec);
}
} else { $this->addChild($header_node,"setSpec",$ands_class); }
return $header_node;
}
/** Create metadata node for holding metadata. This is always added to \<record\> node.
*
* \param $mom_record_node DOMElement. A node acts as the parent node.
*
* @return $meta_node Type: DOMElement.
* The newly created registryObject node which will be used for further expansion.
* metadata node itself is maintained by internally by the Class.
*/
function create_metadata($mom_record_node) {
$meta_node = $this->addChild($mom_record_node,"metadata");
return $meta_node;
}
/** If there are too many records request could not finished a resumpToken is generated to let harvester know
*
* \param $token Type: string. A random number created somewhere?
* \param $expirationdatetime Type: string. A string representing time.
* \param $num_rows Type: integer. Number of records retrieved.
* \param $cursor Type: string. Cursor can be used for database to retrieve next time.
*/
function create_resumpToken($token, $expirationdatetime, $num_rows, $cursor=null) {
$resump_node = $this->addChild($this->verbNode,"resumptionToken",$token);
if(isset($expirationdatetime)) {
$resump_node->setAttribute("expirationDate",$expirationdatetime);
}
$resump_node->setAttribute("completeListSize",$num_rows);
$resump_node->setAttribute("cursor",$cursor);
}
}