AtomODataWriter - Code Metrics - Inspection of "Hook target resource set wrappers up to singleton..." - Algo-Web/POData - Measure and Improve Code Quality continuously with Scrutinizer

Test Setup Failed
Push — master ( 2bb3c0...689644 )

by Alex
created 2017-06-18 06:19 UTC
AtomODataWriter F

↳ Parent: Project
Complexity

Total Complexity
Size/Duplication

Total Lines	815
Duplicated Lines	3.31 %
Coupling/Cohesion

Components	1
Dependencies	13
Importance

Changes	2
Bugs	0	Features	1
Metric	Value
wmc	71
c	2
b	0
f	1
lcom	1
cbo	13
dl	27
loc	815
rs	3.9024
24 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	13	2
A	canHandle()	0	8	3
B	write()	0	24	6
A	writeURL()	0	9	1
B	writeUrlCollection()	0	35	4
B	writeFeed()	0	39	5
A	writeEntry()	0	16	2
C	writeBeginEntry()	27	117	8
B	writeLink()	0	25	4
B	writeProperties()	0	21	5
A	beforeWriteValue()	0	14	2
B	preWriteProperties()	0	42	2
B	beginWriteProperty()	0	29	5
A	postWriteProperties()	0	9	2
B	writeBagContent()	0	24	3
A	writeNullValue()	0	13	3
A	getOutput()	0	6	1
B	serializeException()	0	32	2
A	writeNodeValue()	0	8	1
A	writeNodeAttributeValue()	0	13	1
B	writeLinkNode()	0	29	4
B	writeBaseUriAndDefaultNamespaces()	0	25	1
B	writeServiceDocument()	0	28	3
A	writeServiceDocumentNode()	0	13	1
How to fix Duplicated Code Complexity

Duplicated Code

Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
If you have the same expression in different places: Extract expression to a method
If you have the same method in different sub-classes: Extract method, and pull up field to the parent class
If you have the same code in unrelated classes: Consider extracting the code to a new class, and injecting that class
Complex Class

Tip: Before tackling complexity, make sure that you eliminate any duplication first. This often can reduce the size of classes significantly.
Complex classes like AtomODataWriter often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use AtomODataWriter, and based on these observations, apply Extract Interface, too.
<?php

namespace POData\Writers\Atom;

use Carbon\Carbon as Carbon;
use POData\Common\MimeTypes;
use POData\Common\ODataConstants;
use POData\Common\ODataException;
use POData\Common\Version;
use POData\ObjectModel\ODataBagContent;
use POData\ObjectModel\ODataEntry;
use POData\ObjectModel\ODataFeed;
use POData\ObjectModel\ODataLink;
use POData\ObjectModel\ODataProperty;
use POData\ObjectModel\ODataPropertyContent;
use POData\ObjectModel\ODataURL;
use POData\ObjectModel\ODataURLCollection;
use POData\Providers\ProvidersWrapper;
use POData\Writers\IODataWriter;

/**
 * Class AtomODataWriter.
 */
class AtomODataWriter implements IODataWriter
{
    /**
     * Writer to which output (CSDL Document) is sent.
     *
     * @var \XMLWriter
     */
    public $xmlWriter;

    /**
     * The service base uri.
     *
     * @var string
     */
    protected $baseUri;

    /**
     * Construct a new instance of AtomODataWriter.
     *
     * @param string $absoluteServiceUri The absolute service Uri
     */
    public function __construct($absoluteServiceUri)
    {
        $final = substr($absoluteServiceUri, -1);
        if ('/' != $final) {
            $absoluteServiceUri .= '/';
        }
        $this->baseUri = $absoluteServiceUri;

        $this->xmlWriter = new \XMLWriter();
        $this->xmlWriter->openMemory();
        $this->xmlWriter->startDocument('1.0', 'UTF-8', 'yes');
        $this->xmlWriter->setIndent(4);
    }

    /**
     * Determines if the given writer is capable of writing the response or not.
     *
     * @param Version $responseVersion the OData version of the response
     * @param string  $contentType     the Content Type of the response
     *
     * @return bool true if the writer can handle the response, false otherwise
     */
    public function canHandle(Version $responseVersion, $contentType)
    {
        $parts = explode(';', $contentType);

        //first 2 parts are for service documents, second part is for Resources
        //TODO: i'm not sold about this first part not being constrained to v1 (or maybe v2)..but it's how WS DS works. See #94
        return in_array(MimeTypes::MIME_APPLICATION_XML, $parts) || in_array(MimeTypes::MIME_APPLICATION_ATOMSERVICE, $parts) || in_array(MimeTypes::MIME_APPLICATION_ATOM, $parts);
    }

    /**
     * Write the given OData model in a specific response format.
     *
     * @param ODataURL|ODataURLCollection|ODataPropertyContent|ODataFeed|ODataEntry $model Object of requested content
     *
     * @return AtomODataWriter
     */
    public function write($model)
    {
        if ($model instanceof ODataURL) {
            return $this->writeURL($model);
        }

        if ($model instanceof ODataURLCollection) {
            return $this->writeURLCollection($model);
        }

        if ($model instanceof ODataPropertyContent) {
            return $this->writeProperties($model, true);
        }

        if ($model instanceof ODataFeed) {
            return $this->writeFeed($model, true);
        }

        if ($model instanceof ODataEntry) {
            return $this->writeEntry($model, true);
        }

        return $this;
    }

    /**
     * @param ODataURL $url the url to write
     *
     * @return AtomODataWriter
     */
    protected function writeURL(ODataURL $url)
    {
        $this->xmlWriter->startElement(ODataConstants::ATOM_URI_ELEMENT_NAME);
        $this->xmlWriter->writeAttribute(ODataConstants::XMLNS_NAMESPACE_PREFIX, ODataConstants::ODATA_NAMESPACE);
        $this->xmlWriter->text($url->url);
        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Begin write odata links.
     *
     * @param ODataURLCollection $urls Object of ODataUrlCollection to start writing collection of url
     *
     * @return AtomODataWriter
     */
    public function writeUrlCollection(ODataURLCollection $urls)
    {
        $this->xmlWriter->startElement(ODataConstants::ATOM_LINKS_ELEMENT_NAME);
        $this->xmlWriter->writeAttribute(
            ODataConstants::XMLNS_NAMESPACE_PREFIX,
            ODataConstants::ODATA_NAMESPACE
        );
        $this->xmlWriter->endAttribute();
        if ($urls->count != null) {
            $this->xmlWriter->writeAttributeNs(
                ODataConstants::XMLNS_NAMESPACE_PREFIX,
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                null,
                ODataConstants::ODATA_METADATA_NAMESPACE
            );
            $this->xmlWriter->endAttribute();
            $this->xmlWriter->startElementNs(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ROWCOUNT_ELEMENT,
                null
            );
            $this->xmlWriter->text($urls->count);
            $this->xmlWriter->endElement();
        }
        foreach ($urls->urls as $url) {
            $this->writeNodeValue(ODataConstants::ATOM_URI_ELEMENT_NAME, $url->url);
        }

        if ($urls->nextPageLink != null) {
            $this->writeLinkNode($urls->nextPageLink, false);
        }
        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Begin write OData Feed.
     *
     * @param ODataFeed $feed       Object of OData feed to start writing feed
     * @param bool      $isTopLevel indicates if this is the top level feed in the response
     *
     * @return AtomODataWriter
     */
    protected function writeFeed(ODataFeed $feed, $isTopLevel = false)
    {
        $this->xmlWriter->startElement(ODataConstants::ATOM_FEED_ELEMENT_NAME);
        if ($isTopLevel) {
            $this->writeBaseUriAndDefaultNamespaces();
        }

        $this
            ->writeNodeAttributeValue(
                ODataConstants::ATOM_TITLE_ELELMET_NAME,
                ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME,
                MimeTypes::MIME_TEXTTYPE,
                $feed->title
            )
            ->writeNodeValue(ODataConstants::ATOM_ID_ELEMENT_NAME, $feed->id)
            ->writeNodeValue(ODataConstants::ATOM_UPDATED_ELEMENT_NAME, date(DATE_ATOM))
            ->writeLinkNode($feed->selfLink, false);

        if ($feed->rowCount != null) {
            $this->xmlWriter->startElementNs(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ROWCOUNT_ELEMENT,
                null
            );
            $this->xmlWriter->text($feed->rowCount);
            $this->xmlWriter->endElement();
        }

        foreach ($feed->entries as $entry) {
            $this->writeEntry($entry);
        }

        if ($feed->nextPageLink != null) {
            $this->writeLinkNode($feed->nextPageLink, false);
        }
        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Write top level entry.
     *
     * @param ODataEntry $entry      Object of ODataEntry
     * @param bool       $isTopLevel
     *
     * @return AtomODataWriter
     */
    protected function writeEntry(ODataEntry $entry, $isTopLevel = false)
    {
        $this->writeBeginEntry($entry, $isTopLevel);
        foreach ($entry->links as $link) {
            $this->writeLink($link);
        }

        $this
            ->preWriteProperties($entry)
            ->writeProperties($entry->propertyContent)
            ->postWriteProperties($entry);

        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Start writing a entry.
     *
     * @param ODataEntry $entry      Entry to write
     * @param bool       $isTopLevel
     *
     * @return AtomODataWriter
     */
    protected function writeBeginEntry(ODataEntry $entry, $isTopLevel)
    {
        $this->xmlWriter->startElement(ODataConstants::ATOM_ENTRY_ELEMENT_NAME);
        if ($isTopLevel) {
            $this->writeBaseUriAndDefaultNamespaces();
        }

        if (!is_null($entry->eTag)) {

            $this->xmlWriter->startAttributeNs(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ATOM_ETAG_ATTRIBUTE_NAME,
                null
            );
            $this->xmlWriter->text($entry->eTag);
            $this->xmlWriter->endAttribute();
        }

        $this
            ->writeNodeValue(ODataConstants::ATOM_ID_ELEMENT_NAME, $entry->id)
            ->writeNodeAttributeValue(
                ODataConstants::ATOM_TITLE_ELELMET_NAME,
                ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME,
                MimeTypes::MIME_TEXTTYPE,
                $entry->title
            )
            ->writeNodeValue(ODataConstants::ATOM_UPDATED_ELEMENT_NAME, date(DATE_ATOM));

        $this->xmlWriter->startElement(ODataConstants::ATOM_AUTHOR_ELEMENT_NAME);
        $this->xmlWriter->startElement(ODataConstants::ATOM_NAME_ELEMENT_NAME);
        $this->xmlWriter->endElement();
        $this->xmlWriter->endElement();


        $this->xmlWriter->startElement(ODataConstants::ATOM_LINK_ELEMENT_NAME);
        $this->xmlWriter->startAttribute(ODataConstants::ATOM_LINK_RELATION_ATTRIBUTE_NAME);
        $this->xmlWriter->text(ODataConstants::ATOM_EDIT_RELATION_ATTRIBUTE_VALUE);
        $this->xmlWriter->endAttribute();
        $this->xmlWriter->startAttribute(ODataConstants::ATOM_TITLE_ELELMET_NAME);
        $this->xmlWriter->text($entry->title);
        $this->xmlWriter->endAttribute();
        $this->xmlWriter->startAttribute(ODataConstants::ATOM_HREF_ATTRIBUTE_NAME);
        if (is_string($entry->editLink)) {
            $this->xmlWriter->text($entry->editLink);
        } else {
            $this->xmlWriter->text($entry->editLink->url);
        }
        $this->xmlWriter->endAttribute();

        $this->xmlWriter->endElement();


        if ($entry->isMediaLinkEntry) {
            $this->xmlWriter->startElement(ODataConstants::ATOM_LINK_ELEMENT_NAME);
            if ($entry->mediaLink->eTag != null) {

                $this->xmlWriter->startAttributeNs(
                    ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                    ODataConstants::ATOM_ETAG_ATTRIBUTE_NAME,
                    null
                );
                $this->xmlWriter->text($entry->mediaLink->eTag);
                $this->xmlWriter->endAttribute();
            }
            $this->xmlWriter->startAttribute(
                ODataConstants::ATOM_LINK_RELATION_ATTRIBUTE_NAME
            );
            $this->xmlWriter->text(ODataConstants::ATOM_EDIT_MEDIA_RELATION_ATTRIBUTE_VALUE);
            $this->xmlWriter->endAttribute();

            $this->xmlWriter->startAttribute(ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME);
            $this->xmlWriter->text($entry->mediaLink->contentType);
            $this->xmlWriter->endAttribute();

            $this->xmlWriter->startAttribute(ODataConstants::ATOM_TITLE_ELELMET_NAME);
            $this->xmlWriter->text($entry->mediaLink->name);
            $this->xmlWriter->endAttribute();

            $this->xmlWriter->startAttribute(ODataConstants::ATOM_HREF_ATTRIBUTE_NAME);
            $this->xmlWriter->text($entry->mediaLink->editLink);
            $this->xmlWriter->endAttribute();
            $this->xmlWriter->endElement();


            foreach ($entry->mediaLinks as $mediaLink) {
                $this->xmlWriter->startElement(ODataConstants::ATOM_LINK_ELEMENT_NAME);
                if ($mediaLink->eTag != null) {

                    $this->xmlWriter->startAttributeNs(
                        ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                        ODataConstants::ATOM_ETAG_ATTRIBUTE_NAME,
                        null
                    );
                    $this->xmlWriter->text($mediaLink->eTag);
                    $this->xmlWriter->endAttribute();
                }
                $this->xmlWriter->startAttribute(ODataConstants::ATOM_LINK_RELATION_ATTRIBUTE_NAME);
                $this->xmlWriter->text(
                    'http://schemas.microsoft.com/ado/2007/08/dataservices/mediaresource/'
                    .$mediaLink->name
                );
                $this->xmlWriter->endAttribute();

                $this->xmlWriter->startAttribute(ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME);
                $this->xmlWriter->text($mediaLink->contentType);
                $this->xmlWriter->endAttribute();

                $this->xmlWriter->startAttribute(ODataConstants::ATOM_TITLE_ELELMET_NAME);
                $this->xmlWriter->text($mediaLink->name);
                $this->xmlWriter->endAttribute();

                $this->xmlWriter->startAttribute(ODataConstants::ATOM_HREF_ATTRIBUTE_NAME);
                $this->xmlWriter->text($mediaLink->editLink);
                $this->xmlWriter->endAttribute();
                $this->xmlWriter->endElement();
            }
        }

        return $this;
    }

    /**
     * @param ODataLink $link Link to write
     *
     * @return AtomODataWriter
     */
    protected function writeLink(ODataLink $link)
    {
        $this->writeLinkNode($link, $link->isExpanded);

        if ($link->isExpanded) {
            $this->xmlWriter->startElementNS(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ATOM_INLINE_ELEMENT_NAME,
                null
            );

            if (!is_null($link->expandedResult)) {
                if ($link->isCollection) {
                    $this->writeFeed($link->expandedResult);
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
                } else {
                    $this->writeEntry($link->expandedResult);
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
                }
            }

            $this->xmlWriter->endElement();
            $this->xmlWriter->endElement();
        }

        return $this;
    }

    /**
     * Write the given collection of properties.
     * (properties of an entity or complex type).
     *
     * @param ODataPropertyContent $properties Collection of properties
     * @param bool                 $topLevel   indicates if this property content is the top level response to be written
     *
     * @return AtomODataWriter
     */
    protected function writeProperties(ODataPropertyContent $properties, $topLevel = false)
    {
        foreach ($properties->properties as $property) {
            $this->beginWriteProperty($property, $topLevel);

            if ($property->value == null) {
                $this->writeNullValue($property);
            } elseif ($property->value instanceof ODataPropertyContent) {
                $this->writeProperties($property->value, false);
            } elseif ($property->value instanceof ODataBagContent) {
                $this->writeBagContent($property->value);
            } else {
                $value = $this->beforeWriteValue($property->value, $property->typeName);
                $this->xmlWriter->text($value);
            }

            $this->xmlWriter->endElement();
        }

        return $this;
    }

    /**
     * XML write a basic data type (string, number, boolean, null).
     *
     * @param string $value value to be written
     * @param string $type  data type of the value
     *
     * @return string
     */
    protected function beforeWriteValue($value, $type = null)
    {
        switch ($type) {
            case 'Edm.DateTime':
                $dateTime = new Carbon($value, new \DateTimeZone('UTC'));
                $result = $dateTime->format('Y-m-d\TH:i:s');
                break;

            default:
                $result = $value;
        }

        return $result;
    }

    /**
     * Write the node which hold the entity properties as child.
     *
     * @param ODataEntry $entry ODataEntry object for pre writing properties
     *
     * @return AtomODataWriter
     */
    public function preWriteProperties(ODataEntry $entry)
    {
        $this->xmlWriter->startElement(ODataConstants::ATOM_CATEGORY_ELEMENT_NAME);
        $this->xmlWriter->writeAttribute(
            ODataConstants::ATOM_CATEGORY_TERM_ATTRIBUTE_NAME,
            $entry->type
        );
        $this->xmlWriter->writeAttribute(
            ODataConstants::ATOM_CATEGORY_SCHEME_ATTRIBUTE_NAME,
            ODataConstants::ODATA_SCHEME_NAMESPACE
        );
        $this->xmlWriter->endElement();
        $this->xmlWriter->startElement(ODataConstants::ATOM_CONTENT_ELEMENT_NAME);
        if ($entry->isMediaLinkEntry) {
            $this->xmlWriter->writeAttribute(
                ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME,
                $entry->mediaLink->contentType
            );
            $this->xmlWriter->writeAttribute(
                ODataConstants::ATOM_CONTENT_SRC_ATTRIBUTE_NAME,
                $entry->mediaLink->srcLink
            );
            $this->xmlWriter->endElement();
            $this->xmlWriter->startElementNS(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ATOM_PROPERTIES_ELEMENT_NAME,
                null
            );
        } else {
            $this->xmlWriter->writeAttribute(
                ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME,
                MimeTypes::MIME_APPLICATION_XML
            );
            $this->xmlWriter->startElementNS(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ATOM_PROPERTIES_ELEMENT_NAME,
                null
            );
        }

        return $this;
    }

    /**
     * Write a property.
     *
     * @param ODataProperty $property   Property to be written
     * @param bool          $isTopLevel is link top level or not
     *
     * @return AtomODataWriter
     */
    protected function beginWriteProperty(ODataProperty $property, $isTopLevel)
    {
        $this->xmlWriter->startElementNS(
            ODataConstants::ODATA_NAMESPACE_PREFIX,
            $property->name,
            null
        );
        if ($property->typeName != null) {
            $this->xmlWriter->startAttributeNs(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME,
                null
            );
            $this->xmlWriter->text($property->typeName);
        }
        if ($isTopLevel) {
            $this->xmlWriter->startAttribute(ODataConstants::XMLNS_NAMESPACE_PREFIX);
            $this->xmlWriter->text(ODataConstants::ODATA_METADATA_NAMESPACE);
            $this->xmlWriter->startAttributeNs(ODataConstants::XMLNS_NAMESPACE_PREFIX, ODataConstants::ODATA_NAMESPACE_PREFIX, null);
            $this->xmlWriter->text(ODataConstants::ODATA_NAMESPACE);
            $this->xmlWriter->startAttributeNs(ODataConstants::XMLNS_NAMESPACE_PREFIX, ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX, null);
            $this->xmlWriter->text(ODataConstants::ODATA_METADATA_NAMESPACE);
        }
        if ($property->typeName != null || $isTopLevel) {
            $this->xmlWriter->endAttribute();
        }

        return $this;
    }

    /**
     * Write after last property.
     *
     * @param ODataEntry $entry Entry object to post writing properties
     *
     * @return AtomODataWriter
     */
    public function postWriteProperties(ODataEntry $entry)
    {
        if (!$entry->isMediaLinkEntry) {
            $this->xmlWriter->endElement();
        }
        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Begin an item in a collection.
     *
     * @param ODataBagContent $bag Bag property object to begin write property
     *
     * @return AtomODataWriter
     */
    protected function writeBagContent(ODataBagContent $bag)
    {
        foreach ($bag->propertyContents as $content) {
            if ($content instanceof ODataPropertyContent) {
                $this->xmlWriter->startElementNs(
                    ODataConstants::ODATA_NAMESPACE_PREFIX,
                    ODataConstants::COLLECTION_ELEMENT_NAME,
                    null
                );
                $this->writeProperties($content);
                $this->xmlWriter->endElement();
            } else {  //probably just a primitive string
                    $this->xmlWriter->startElementNs(
                        ODataConstants::ODATA_NAMESPACE_PREFIX,
                        ODataConstants::COLLECTION_ELEMENT_NAME,
                        null
                    );
                $this->xmlWriter->text($content);
                $this->xmlWriter->endElement();
            }
        }

        return $this;
    }

    /**
     * Write null value.
     *
     * @param ODataProperty $property ODataProperty object to write null value
     *                                according to property type
     *
     * @return AtomODataWriter
     */
    protected function writeNullValue(ODataProperty $property)
    {
        if (!(($property instanceof ODataBagContent) || ($property instanceof ODataPropertyContent))) {
            $this->xmlWriter->writeAttributeNs(
                ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
                ODataConstants::ATOM_NULL_ATTRIBUTE_NAME,
                null,
                ODataConstants::XML_TRUE_LITERAL
            );
        }

        return $this;
    }

    /**
     * Get the final result as string.
     *
     * @return string output of requested data in Atom format
     */
    public function getOutput()
    {
        $this->xmlWriter->endDocument();

        return $this->xmlWriter->outputMemory(true);
    }

    /**
     * Serialize the exception.
     *
     * @param ODataException $exception               Exception to serialize
     * @param bool           $serializeInnerException if set to true,
     *                                                serialize the inner exception if $exception is an ODataException
     *
     * @return string
     */
    public static function serializeException(ODataException $exception, $serializeInnerException)

    {
        $xmlWriter = new \XMLWriter();
        $xmlWriter->openMemory();
        $xmlWriter->startDocument('1.0', 'UTF-8', 'yes');
        $xmlWriter->setIndent(4);

        $xmlWriter->startElement(ODataConstants::XML_ERROR_ELEMENT_NAME);
        //$xmlWriter->writeAttributeNs(
        //    ODataConstants::XMLNS_NAMESPACE_PREFIX,
        //    ODataConstants::XML_NAMESPACE_PREFIX,
        //    ODataConstants::XML_NAMESPACE,
        //    null
        //);
        $xmlWriter->writeAttribute(
            ODataConstants::XMLNS_NAMESPACE_PREFIX,
            ODataConstants::ODATA_METADATA_NAMESPACE
        );
        $xmlWriter->endAttribute();
        $xmlWriter->startElement(ODataConstants::XML_ERROR_CODE_ELEMENT_NAME);
        if (null != $exception->getStatusCode()) {
            $xmlWriter->text($exception->getStatusCode());
        }
        $xmlWriter->endElement();
        $xmlWriter->startElement(ODataConstants::XML_ERROR_MESSAGE_ELEMENT_NAME);
        $xmlWriter->text($exception->getMessage());
        $xmlWriter->endElement();
        $xmlWriter->endElement();
        $xmlWriter->endDocument();

        return $xmlWriter->outputMemory(true);
    }

    /**
     * Function to create element only contain value without argument.
     *
     * @param string $node  Element name
     * @param string $value Element value
     *
     * @return AtomODataWriter
     */
    public function writeNodeValue($node, $value)
    {
        $this->xmlWriter->startElement($node);
        $this->xmlWriter->text($value);
        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Function to create element with one attribute and value.
     *
     * @param string $node           Element name
     * @param string $attribute      Attribute name
     * @param string $attributeValue Attribute value
     * @param string $nodeValue      Element value
     *
     * @return AtomODataWriter
     */
    public function writeNodeAttributeValue(
        $node,
        $attribute,
        $attributeValue,
        $nodeValue
    ) {
        $this->xmlWriter->startElement($node);
        $this->xmlWriter->writeAttribute($attribute, $attributeValue);
        $this->xmlWriter->text($nodeValue);
        $this->xmlWriter->endElement();

        return $this;
    }

    /**
     * Function to create link element with arguments.
     *
     * @param ODataLink $link       Link object to make link element
     * @param bool      $isExpanded Is link expanded or not
     *
     * @return AtomODataWriter
     */
    protected function writeLinkNode(ODataLink $link, $isExpanded)
    {
        $this->xmlWriter->startElement(ODataConstants::ATOM_LINK_ELEMENT_NAME);
        $this->xmlWriter->writeAttribute(
            ODataConstants::ATOM_LINK_RELATION_ATTRIBUTE_NAME,
            $link->name
        );
        if ($link->type != null) {
            $this->xmlWriter->writeAttribute(
                ODataConstants::ATOM_TYPE_ATTRIBUTE_NAME,
                $link->type
            );
        }
        if ($link->title != null) {
            $this->xmlWriter->writeAttribute(
                ODataConstants::ATOM_TITLE_ELELMET_NAME,
                $link->title
            );
        }
        $this->xmlWriter->writeAttribute(
            ODataConstants::ATOM_HREF_ATTRIBUTE_NAME,
            $link->url
        );
        if (!$isExpanded) {
            $this->xmlWriter->endElement();
        }

        return $this;
    }

    /**
     * Function to write base uri and default namespaces for top level elements.
     *
     * @return AtomODataWriter
     */
    public function writeBaseUriAndDefaultNamespaces()
    {
        $this->xmlWriter->writeAttribute(
            ODataConstants::XML_BASE_ATTRIBUTE_NAME_WITH_PREFIX,
            $this->baseUri
        );
        $this->xmlWriter->writeAttributeNs(
            ODataConstants::XMLNS_NAMESPACE_PREFIX,
            ODataConstants::ODATA_NAMESPACE_PREFIX,
            null,
            ODataConstants::ODATA_NAMESPACE
        );
        $this->xmlWriter->writeAttributeNs(
            ODataConstants::XMLNS_NAMESPACE_PREFIX,
            ODataConstants::ODATA_METADATA_NAMESPACE_PREFIX,
            null,
            ODataConstants::ODATA_METADATA_NAMESPACE
        );
        $this->xmlWriter->writeAttribute(
            ODataConstants::XMLNS_NAMESPACE_PREFIX,
            ODataConstants::ATOM_NAMESPACE
        );

        return $this;
    }

    /**
     * XML prefix for the Atom namespace.
     *
     * @var string
     */
    const ATOM_NAMESPACE_PREFIX = 'atom';

    /**
     * XML prefix for the Atom Publishing Protocol namespace.
     *
     * @var string
     */
    const APP_NAMESPACE_PREFIX = 'app';

    /**
     * @param ProvidersWrapper $providers
     *
     * @return IODataWriter
     */
    public function writeServiceDocument(ProvidersWrapper $providers)
    {
        $writer = $this->xmlWriter;
        $writer->startElementNs(null, ODataConstants::ATOM_PUBLISHING_SERVICE_ELEMENT_NAME, ODataConstants::APP_NAMESPACE);
        $writer->writeAttributeNs(ODataConstants::XML_NAMESPACE_PREFIX, ODataConstants::XML_BASE_ATTRIBUTE_NAME, null, $this->baseUri);
        $writer->writeAttributeNs(ODataConstants::XMLNS_NAMESPACE_PREFIX, self::ATOM_NAMESPACE_PREFIX, null, ODataConstants::ATOM_NAMESPACE);
        //$writer->writeAttributeNs(ODataConstants::XMLNS_NAMESPACE_PREFIX, self::APP_NAMESPACE_PREFIX, null, ODataConstants::APP_NAMESPACE);


        $writer->startElement(ODataConstants::ATOM_PUBLISHING_WORKSPACE_ELEMNT_NAME);
        $writer->startElementNs(self::ATOM_NAMESPACE_PREFIX, ODataConstants::ATOM_TITLE_ELELMET_NAME, null);
        $writer->text(ODataConstants::ATOM_PUBLISHING_WORKSPACE_DEFAULT_VALUE);
        $writer->endElement();
        foreach ($providers->getResourceSets() as $resourceSetWrapper) {
            $name = $resourceSetWrapper->getName();
            $this->writeServiceDocumentNode($writer, $name);
        }
        foreach ($providers->getSingletons() as $single) {
            $name = $single->getName();
            //start collection node
            $this->writeServiceDocumentNode($writer, $name);
        }

        //End workspace and service nodes
        $writer->endElement();
        $writer->endElement();

        return $this;
    }

    /**
     * @param $writer
     * @param $name
     */
    private function writeServiceDocumentNode(&$writer, $name)
    {
        //start collection node
        $writer->startElement(ODataConstants::ATOM_PUBLISHING_COLLECTION_ELEMENT_NAME);
        $writer->writeAttribute(ODataConstants::ATOM_HREF_ATTRIBUTE_NAME, $name);
        //start title node
        $writer->startElementNs(self::ATOM_NAMESPACE_PREFIX, ODataConstants::ATOM_TITLE_ELELMET_NAME, null);
        $writer->text($name);
        //end title node
        $writer->endElement();
        //end collection node
        $writer->endElement();
    }
}

Algo-Web / POData
