Algo-Web / POData

     *

     * @return string|null

     */

    public function getStreamContentType($entity, $resourceStreamInfo)

    {

        $contentType = null;

        $this->_saveContentTypeAndETag();

        $opContext = $this->_service->getOperationContext();

        if (is_null($resourceStreamInfo)) {

            $this->_loadAndValidateStreamProvider();

            $contentType = $this->_streamProvider->getStreamContentType($entity, $opContext);

            if (is_null($contentType)) {

                throw new InvalidOperationException(

                    Messages::streamProviderWrapperGetStreamContentTypeReturnsEmptyOrNull()

                );

            }

        } else {

            $this->_loadAndValidateStreamProvider2();

            assert($this->_streamProvider instanceof IStreamProvider2);

            $contentType = $this->_streamProvider->getStreamContentType2($entity, $resourceStreamInfo, $opContext);

        }

        $this->_verifyContentTypeOrETagModified('IDSSP::getStreamContentType');

        return $contentType;

    }

    /**

     * Get the ETag of the stream associated with the entity specified.

     *

     * @return string Etag

     */

    public function getStreamETag($entity, $resourceStreamInfo)

    {

        $eTag = null;

        $this->_saveContentTypeAndETag();

        $opContext = $this->_service->getOperationContext();

        if (is_null($resourceStreamInfo)) {

            $this->_loadAndValidateStreamProvider();

            $eTag = $this->_streamProvider->getStreamETag($entity, $opContext);

        } else {

            $this->_loadAndValidateStreamProvider2();

            assert($this->_streamProvider instanceof IStreamProvider2);

            $eTag = $this->_streamProvider->getStreamETag2($entity, $resourceStreamInfo, $opContext);

        }

        $this->_verifyContentTypeOrETagModified('IDSSP::getStreamETag');

        if (!self::isETagValueValid($eTag, true)) {

            throw new InvalidOperationException(

                Messages::streamProviderWrapperGetStreamETagReturnedInvalidETagFormat()

            );

        }

        return $eTag;

    }

    /**

     * Gets the URI clients should use when making retrieve (ie. GET) requests