tethys.backend/app/Controllers/Http/Oai/OaiController.ts

import type { HttpContext } from '@adonisjs/core/http';
// import { RequestContract } from '@ioc:Adonis/Core/Request';
import { Request } from '@adonisjs/core/http';
import { XMLBuilder } from 'xmlbuilder2/lib/interfaces.js';
import { create } from 'xmlbuilder2';
import dayjs, { Dayjs } from 'dayjs';
import utc from 'dayjs/plugin/utc.js';
import timezone from 'dayjs/plugin/timezone.js';
import { readFileSync } from 'fs';
import { StatusCodes } from 'http-status-codes';
import SaxonJS from 'saxon-js';
// import { Xslt, xmlParse } from 'xslt-processor'
import { OaiErrorCodes, OaiModelError } from '#app/exceptions/OaiErrorCodes';
import { OaiModelException, BadOaiModelException } from '#app/exceptions/OaiModelException';
import Dataset from '#models/dataset';
import Collection from '#models/collection';
import { getDomain, preg_match } from '#app/utils/utility-functions';
import XmlModel from '#app/Library/XmlModel';
import logger from '@adonisjs/core/services/logger';
import ResumptionToken from '#app/Library/Oai/ResumptionToken';
// import Config from '@ioc:Adonis/Core/Config';
import config from '@adonisjs/core/services/config'
// import { inject } from '@adonisjs/fold';
import { inject } from '@adonisjs/core'
// import { TokenWorkerContract } from "MyApp/Models/TokenWorker";
import TokenWorkerContract from '#library/Oai/TokenWorkerContract';
import { ModelQueryBuilderContract } from '@adonisjs/lucid/types/model';


interface XslTParameter {
    [key: string]: any;
}

interface Dictionary {
    [index: string]: string;
}

interface ListParameter {
    cursor: number;
    totalIds: number;
    start: number;
    reldocIds: (number | null)[];
    metadataPrefix: string;
}

@inject()
export default class OaiController {
    private deliveringDocumentStates = ['published', 'deleted'];
    private sampleRegEx = /^[A-Za-zäüÄÜß0-9\-_.!~]+$/;
    private xsltParameter: XslTParameter;

    /**
     * Holds xml representation of document information to be processed.
     *
     * @var xmlbuilder.XMLDocument | null  Defaults to null.
     */
    private xml: XMLBuilder;
    private proc;

    
    constructor(public tokenWorker: TokenWorkerContract) {
        // Load the XSLT file
        this.proc = readFileSync('public/assets2/datasetxml2oai.sef.json');
        dayjs.extend(utc);
        dayjs.extend(timezone);
    }

    public async index({ response, request }: HttpContext): Promise<void> {
        this.xml = create({ version: '1.0', encoding: 'UTF-8', standalone: true }, '<root></root>');

        // this.proc = new XSLTProcessor();
        // const stylesheet = readFileSync(__dirname + "/datasetxml2oai.sef.json");
        const xsltParameter: XslTParameter = (this.xsltParameter = {});

        let oaiRequest: Dictionary = {};
        if (request.method() === 'POST') {
            oaiRequest = request.body();
        } else if (request.method() === 'GET') {
            oaiRequest = request.qs();
        } else {
            xsltParameter['oai_error_code'] = 'unknown';
            xsltParameter['oai_error_message'] = 'Only POST and GET methods are allowed for OAI-PMH.';
        }

        let earliestDateFromDb;
        // const oaiRequest: OaiParameter = request.body;
        try {
            const firstPublishedDataset: Dataset | null = await Dataset.earliestPublicationDate();
            firstPublishedDataset != null &&
                (earliestDateFromDb = firstPublishedDataset.server_date_published.toFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"));
            this.xsltParameter['earliestDatestamp'] = earliestDateFromDb;
            // start the request
            await this.handleRequest(oaiRequest, request);
        } catch (error) {
            if (error instanceof OaiModelException) {
                const code = error.oaiCode;
                let oaiErrorCode: string | undefined = 'Unknown oai error code ' + code;
                if (OaiModelError.has(error.oaiCode) && OaiModelError.get(code) !== undefined) {
                    oaiErrorCode = OaiModelError.get(error.oaiCode);
                }
                this.xsltParameter['oai_error_code'] = oaiErrorCode;
                this.xsltParameter['oai_error_message'] = error.message;
            } else {
                //     // return next(error); // passing to default express middleware error handler
                this.xsltParameter['oai_error_code'] = 'unknown';
                this.xsltParameter['oai_error_message'] = 'An internal error occured.';
            }
        }

        const xmlString = this.xml.end({ prettyPrint: true });

        let xmlOutput; // = xmlString;
        try {
            const result = await SaxonJS.transform({
                // stylesheetFileName: `${config.TMP_BASE_DIR}/data-quality/rules/iati.sef.json`,
                stylesheetText: this.proc,
                destination: 'serialized',
                // sourceFileName: sourceFile,
                sourceText: xmlString,
                stylesheetParams: xsltParameter,
                // logLevel: 10,
            });
            xmlOutput = result.principalResult;
        } catch (error) {
            return response.status(500).json({
                message: 'An error occurred while creating the user',
                error: error.message,
            });
        }

        response
            .header('Content-Type', 'application/xml; charset=utf-8')
            .header('Access-Control-Allow-Origin', '*')
            .header('Access-Control-Allow-Methods', 'GET,POST');
        response.status(StatusCodes.OK).send(xmlOutput);
    }

    protected async handleRequest(oaiRequest: Dictionary, request: Request) {
        // Setup stylesheet
        // $this->loadStyleSheet('datasetxml2oai-pmh.xslt');

        // Set response time
        const now: Dayjs = dayjs();
        this.xsltParameter['responseDate'] = now.format('YYYY-MM-DDTHH:mm:ss[Z]');
        this.xsltParameter['unixTimestamp'] = now.unix();

        // set OAI base url
        const baseDomain = process.env.OAI_BASE_DOMAIN || 'localhost';
        this.xsltParameter['baseURL'] = baseDomain + '/oai';
        this.xsltParameter['repURL'] = request.protocol() + '://' + request.hostname();
        this.xsltParameter['downloadLink'] = request.protocol() + '://' + request.hostname() + '/file/download/';
        this.xsltParameter['doiLink'] = 'https://doi.org/';
        this.xsltParameter['doiPrefix'] = 'info:eu-repo/semantics/altIdentifier/doi/';

        if (oaiRequest['verb']) {
            const verb = oaiRequest['verb'];
            this.xsltParameter['oai_verb'] = verb;
            if (verb === 'Identify') {
                this.handleIdentify();
            } else if (verb === 'ListMetadataFormats') {
                this.handleListMetadataFormats();
            } else if (verb == 'GetRecord') {
                await this.handleGetRecord(oaiRequest);
            } else if (verb == 'ListRecords') {
                await this.handleListRecords(oaiRequest);
            } else if (verb == 'ListIdentifiers') {
                await this.handleListIdentifiers(oaiRequest);
            } else if (verb == 'ListSets') {
                await this.handleListSets();
            } else {
                this.handleIllegalVerb();
            }
        } else {
            // // try {
            // //     console.log("Async code example.")
            // const err = new PageNotFoundException("verb not found");
            // throw err;
            // // } catch (error) { // manually catching
            // //     next(error); // passing to default middleware error handler
            // // }
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'The verb provided in the request is illegal.',
                OaiErrorCodes.BADVERB,
            );
        }
    }

    protected handleIdentify() {
        const email = process.env.OAI_EMAIL || 'repository@geosphere.at';
        const repositoryName = 'Tethys RDR';
        const repIdentifier = 'tethys.at';
        const sampleIdentifier = 'oai:' + repIdentifier + ':1'; //$this->_configuration->getSampleIdentifier();

        // Dataset::earliestPublicationDate()->server_date_published->format('Y-m-d\TH:i:s\Z') : null;
        // earliestDateFromDb!= null && (this.xsltParameter['earliestDatestamp'] = earliestDateFromDb?.server_date_published);

        // set parameters for oai-pmh.xslt
        this.xsltParameter['email'] = email;
        this.xsltParameter['repositoryName'] = repositoryName;
        this.xsltParameter['repIdentifier'] = repIdentifier;
        this.xsltParameter['sampleIdentifier'] = sampleIdentifier;
        // $this->proc->setParameter('', 'earliestDatestamp', $earliestDateFromDb);

        this.xml.root().ele('Datasets');
    }

    protected handleListMetadataFormats() {
        this.xml.root().ele('Datasets');
    }

    protected async handleListSets() {
        const repIdentifier = 'tethys.at';
        this.xsltParameter['repIdentifier'] = repIdentifier;
        const datasetElement = this.xml.root().ele('Datasets');

        const sets: { [key: string]: string } = {
            'open_access': 'Set for open access licenses',
            'openaire_data': "OpenAIRE",
            'doc-type:ResearchData': 'Set for document type ResearchData',
            ...(await this.getSetsForDatasetTypes()),
            ...(await this.getSetsForCollections()),
            // ... await this.getSetsForProjects(),
        } as Dictionary;

        for (const [key, value] of Object.entries(sets)) {
            const setElement = datasetElement.ele('Rdr_Sets');
            setElement.att('Type', key);
            setElement.att('TypeName', value);
        }
    }

    protected async handleGetRecord(oaiRequest: Dictionary) {
        const repIdentifier = 'tethys.at';
        this.xsltParameter['repIdentifier'] = repIdentifier;

        const dataId = this.validateAndGetIdentifier(oaiRequest);
        const dataset = await Dataset.query()
            .where('publish_id', dataId)
            .preload('xmlCache')
            .preload('collections', (builder) => {
                builder.preload('collectionRole');
            })
            .first();

        if (!dataset || !dataset.publish_id) {
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'The value of the identifier argument is unknown or illegal in this repository.',
                OaiErrorCodes.IDDOESNOTEXIST,
            );
        }

        const metadataPrefix = this.validateAndGetMetadataPrefix(oaiRequest);
        this.xsltParameter['oai_metadataPrefix'] = metadataPrefix;
        // do not deliver datasets which are restricted by document state defined in deliveringStates
        this.validateDatasetState(dataset);

        // add xml elements
        const datasetNode = this.xml.root().ele('Datasets');
        await this.createXmlRecord(dataset, datasetNode);
    }

    protected async handleListIdentifiers(oaiRequest: Dictionary) {
        !this.tokenWorker.isConnected && (await this.tokenWorker.connect());

        const maxIdentifier: number = config.get('oai.max.listidentifiers', 100);
        await this.handleLists(oaiRequest, maxIdentifier);
    }

    protected async handleListRecords(oaiRequest: Dictionary) {
        !this.tokenWorker.isConnected && (await this.tokenWorker.connect());

        const maxRecords: number = config.get('oai.max.listrecords', 100);
        await this.handleLists(oaiRequest, maxRecords);
    }

    private async handleLists(oaiRequest: Dictionary, maxRecords: number) {
        maxRecords = maxRecords || 100;
        const repIdentifier = 'tethys.at';
        this.xsltParameter['repIdentifier'] = repIdentifier;
        const datasetNode = this.xml.root().ele('Datasets');

        // list initialisation
        const numWrapper: ListParameter = {
            cursor: 0,
            totalIds: 0,
            start: maxRecords + 1,
            reldocIds: [],
            metadataPrefix: '',
        };

        // resumptionToken is defined
        if ('resumptionToken' in oaiRequest) {
            await this.handleResumptionToken(oaiRequest, maxRecords, numWrapper);
        } else {
            // no resumptionToken is given
            await this.handleNoResumptionToken(oaiRequest, numWrapper);
        }

        // handling of document ids
        const restIds = numWrapper.reldocIds as number[];
        const workIds = restIds.splice(0, maxRecords) as number[]; // array_splice(restIds, 0, maxRecords);

        // no records returned
        if (workIds.length == 0) {
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'The combination of the given values results in an empty list.',
                OaiErrorCodes.NORECORDSMATCH,
            );
        }

        const datasets: Dataset[] = await Dataset.query()
            .whereIn('publish_id', workIds)
            .preload('xmlCache')
            .preload('collections', (builder) => {
                builder.preload('collectionRole');
            })
            .orderBy('publish_id');

        for (const dataset of datasets) {
            await this.createXmlRecord(dataset, datasetNode);
        }

        // store the further Ids in a resumption-file
        const countRestIds = restIds.length; //84
        if (countRestIds > 0) {
            const token = new ResumptionToken();
            token.startPosition = numWrapper.start; //101
            token.totalIds = numWrapper.totalIds; //184
            token.documentIds = restIds; //101 -184
            token.metadataPrefix = numWrapper.metadataPrefix;

            // $tokenWorker->storeResumptionToken($token);
            const res: string = await this.tokenWorker.set(token);

            // set parameters for the resumptionToken-node
            // const res = token.ResumptionId;
            this.setParamResumption(res, numWrapper.cursor, numWrapper.totalIds);
        }
    }

    private async handleResumptionToken(oaiRequest: Dictionary, maxRecords: number, numWrapper: ListParameter) {
        const resParam = oaiRequest['resumptionToken']; //e.g. "158886496600000"
        const token = await this.tokenWorker.get(resParam);

        if (!token) {
            throw new OaiModelException(StatusCodes.INTERNAL_SERVER_ERROR, 'cache is outdated.', OaiErrorCodes.BADRESUMPTIONTOKEN);
        }

        numWrapper.cursor = token.startPosition - 1; //startet dann bei Index 10
        numWrapper.start = token.startPosition + maxRecords;
        numWrapper.totalIds = token.totalIds;
        numWrapper.reldocIds = token.documentIds;
        numWrapper.metadataPrefix = token.metadataPrefix;

        this.xsltParameter['oai_metadataPrefix'] = numWrapper.metadataPrefix;
    }

    private async handleNoResumptionToken(oaiRequest: Dictionary, numWrapper: ListParameter) {
        // no resumptionToken is given
        if ('metadataPrefix' in oaiRequest) {
            numWrapper.metadataPrefix = oaiRequest['metadataPrefix'];
        } else {
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'The prefix of the metadata argument is unknown.',
                OaiErrorCodes.BADARGUMENT,
            );
        }
        this.xsltParameter['oai_metadataPrefix'] = numWrapper.metadataPrefix;

        let finder: ModelQueryBuilderContract<typeof Dataset, Dataset> = Dataset.query();
        // add server state restrictions
        finder.whereIn('server_state', this.deliveringDocumentStates);
        if ('set' in oaiRequest) {
            const set = oaiRequest['set'] as string;
            const setArray = set.split(':');

            if (setArray[0] == 'data-type') {
                if (setArray.length == 2 && setArray[1]) {
                    finder.where('type', setArray[1]);
                }
            } else if (setArray[0] == 'open_access') {
                const openAccessLicences = ['CC-BY-4.0', 'CC-BY-SA-4.0'];
                finder.andWhereHas('licenses', (query) => {
                    query.whereIn('name', openAccessLicences);
                });
            } else if (setArray[0] == 'ddc') {
                if (setArray.length == 2 && setArray[1] != '') {
                    finder.andWhereHas('collections', (query) => {
                        query.where('number', setArray[1]);
                    });
                }
            }
        }

        // const timeZone = "Europe/Vienna"; // Canonical time zone name
        // &from=2020-09-03&until2020-09-03
        // &from=2020-09-11&until=2021-05-11
        if ('from' in oaiRequest && 'until' in oaiRequest) {
            const from = oaiRequest['from'] as string;
            let fromDate = dayjs(from); //.tz(timeZone);
            const until = oaiRequest['until'] as string;
            let untilDate = dayjs(until); //.tz(timeZone);
            if (!fromDate.isValid() || !untilDate.isValid()) {
                throw new OaiModelException(StatusCodes.INTERNAL_SERVER_ERROR, 'Date Parameter is not valid.', OaiErrorCodes.BADARGUMENT);
            }
            fromDate = dayjs.tz(from, 'Europe/Vienna');
            untilDate = dayjs.tz(until, 'Europe/Vienna');

            if (from.length != until.length) {
                throw new OaiModelException(
                    StatusCodes.INTERNAL_SERVER_ERROR,
                    'The request has different granularities for the from and until parameters.',
                    OaiErrorCodes.BADARGUMENT,
                );
            }
            fromDate.hour() == 0 && (fromDate = fromDate.startOf('day'));
            untilDate.hour() == 0 && (untilDate = untilDate.endOf('day'));

            finder.whereBetween('server_date_published', [fromDate.format('YYYY-MM-DD HH:mm:ss'), untilDate.format('YYYY-MM-DD HH:mm:ss')]);
        } else if ('from' in oaiRequest && !('until' in oaiRequest)) {
            const from = oaiRequest['from'] as string;
            let fromDate = dayjs(from);
            if (!fromDate.isValid()) {
                throw new OaiModelException(
                    StatusCodes.INTERNAL_SERVER_ERROR,
                    'From date parameter is not valid.',
                    OaiErrorCodes.BADARGUMENT,
                );
            }
            fromDate = dayjs.tz(from, 'Europe/Vienna');
            fromDate.hour() == 0 && (fromDate = fromDate.startOf('day'));

            const now = dayjs();
            if (fromDate.isAfter(now)) {
                throw new OaiModelException(
                    StatusCodes.INTERNAL_SERVER_ERROR,
                    'Given from date is greater than now. The given values results in an empty list.',
                    OaiErrorCodes.NORECORDSMATCH,
                );
            } else {
                finder.andWhere('server_date_published', '>=', fromDate.format('YYYY-MM-DD HH:mm:ss'));
            }
        } else if (!('from' in oaiRequest) && 'until' in oaiRequest) {
            const until = oaiRequest['until'] as string;
            let untilDate = dayjs(until);
            if (!untilDate.isValid()) {
                throw new OaiModelException(
                    StatusCodes.INTERNAL_SERVER_ERROR,
                    'Until date parameter is not valid.',
                    OaiErrorCodes.BADARGUMENT,
                );
            }
            untilDate = dayjs.tz(until, 'Europe/Vienna');
            untilDate.hour() == 0 && (untilDate = untilDate.endOf('day'));

            const firstPublishedDataset: Dataset = (await Dataset.earliestPublicationDate()) as Dataset;
            const earliestPublicationDate = dayjs(firstPublishedDataset.server_date_published.toISO()); //format("YYYY-MM-DDThh:mm:ss[Z]"));
            if (earliestPublicationDate.isAfter(untilDate)) {
                throw new OaiModelException(
                    StatusCodes.INTERNAL_SERVER_ERROR,
                    `earliestDatestamp is greater than given until date. 
                The given values results in an empty list.`,
                    OaiErrorCodes.NORECORDSMATCH,
                );
            } else {
                finder.andWhere('server_date_published', '<=', untilDate.format('YYYY-MM-DD HH:mm:ss'));
            }
        }

        let reldocIdsDocs = await finder.select('publish_id').orderBy('publish_id');
        numWrapper.reldocIds = reldocIdsDocs.map((dat) => dat.publish_id);
        numWrapper.totalIds = numWrapper.reldocIds.length; //212
    }

    private setParamResumption(res: string, cursor: number, totalIds: number) {
        const tomorrow = dayjs().add(1, 'day').format('YYYY-MM-DDThh:mm:ss[Z]');
        this.xsltParameter['dateDelete'] = tomorrow;
        this.xsltParameter['res'] = res;
        this.xsltParameter['cursor'] = cursor;
        this.xsltParameter['totalIds'] = totalIds;
    }

    private validateAndGetIdentifier(oaiRequest: Dictionary): number {
        // Identifier references metadata Urn, not plain Id!
        // Currently implemented as 'oai:foo.bar.de:{docId}' or 'urn:nbn...-123'
        if (!('identifier' in oaiRequest)) {
            throw new BadOaiModelException('The prefix of the identifier argument is unknown.');
        }
        const dataId = Number(this.getDocumentIdByIdentifier(oaiRequest.identifier));
        if (isNaN(dataId)) {
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'The value of the identifier argument is illegal in this repository.',
                OaiErrorCodes.BADARGUMENT,
            );
        }
        return dataId;
    }

    private validateAndGetMetadataPrefix(oaiRequest: Dictionary): string {
        let metadataPrefix = '';
        if ('metadataPrefix' in oaiRequest) {
            metadataPrefix = oaiRequest['metadataPrefix'];
        } else {
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'The prefix of the metadata argument is unknown.',
                OaiErrorCodes.BADARGUMENT,
            );
        }
        return metadataPrefix;
    }

    private validateDatasetState(dataset: Dataset): void {
        if (dataset.server_state == null || !this.deliveringDocumentStates.includes(dataset.server_state)) {
            throw new OaiModelException(
                StatusCodes.INTERNAL_SERVER_ERROR,
                'Document is not available for OAI export!',
                OaiErrorCodes.NORECORDSMATCH,
            );
        }
    }

    private async createXmlRecord(dataset: Dataset, datasetNode: XMLBuilder) {
        const domNode = await this.getDatasetXmlDomNode(dataset);

        if (domNode) {
            // add frontdoor url and data-type
            dataset.publish_id && this.addLandingPageAttribute(domNode, dataset.publish_id.toString());
            this.addSpecInformation(domNode, 'data-type:' + dataset.type);

            if (dataset.collections) {
                for (const coll of dataset.collections) {
                    const collRole = coll.collectionRole;
                    this.addSpecInformation(domNode, collRole.oai_name + ':' + coll.number);
                }
            }

            datasetNode.import(domNode);
        }
    }

    private async getDatasetXmlDomNode(dataset: Dataset) {
        const xmlModel = new XmlModel(dataset);
        // xmlModel.setModel(dataset);
        xmlModel.excludeEmptyFields();
        xmlModel.caching = true;
        // const cache = dataset.xmlCache ? dataset.xmlCache : null;
        // dataset.load('xmlCache');
        if (dataset.xmlCache) {
            xmlModel.xmlCache = dataset.xmlCache;
        }

        // return cache.getDomDocument();
        const domDocument: XMLBuilder | null = await xmlModel.getDomDocument();
        return domDocument;
    }

    private addSpecInformation(domNode: XMLBuilder, information: string) {
        domNode.ele('SetSpec').att('Value', information);
    }

    private addLandingPageAttribute(domNode: XMLBuilder, dataid: string) {
        const baseDomain = process.env.OAI_BASE_DOMAIN || 'localhost';
        const url = 'https://' + getDomain(baseDomain) + '/dataset/' + dataid;
        // add attribute du dataset xml element
        domNode.att('landingpage', url);
    }

    private getDocumentIdByIdentifier(oaiIdentifier: string): string {
        const identifierParts: string[] = oaiIdentifier.split(':'); // explode(":", $oaiIdentifier);
        const dataId: string = identifierParts[2];
        // switch (identifierParts[0]) {
        //     case 'oai':
        //         if (isset($identifierParts[2])) {
        //             $dataId = $identifierParts[2];
        //         }
        //         break;
        //     default:
        //         throw new OaiModelException(
        //             'The prefix of the identifier argument is unknown.',
        //             OaiModelError::BADARGUMENT
        //         );
        //         break;
        // }

        // if (empty($dataId) or !preg_match('/^\d+$/', $dataId)) {
        //     throw new OaiModelException(
        //         'The value of the identifier argument is unknown or illegal in this repository.',
        //         OaiModelError::IDDOESNOTEXIST
        //     );

        return dataId;
    }

    private async getSetsForCollections(): Promise<Dictionary> {
        const sets: { [key: string]: string } = {} as Dictionary;

        const collections = await Collection.query()
            .select('name', 'number', 'role_id')
            .whereHas('collectionRole', (query) => {
                query.where('visible_oai', true);
            })
            .preload('collectionRole');

        collections.forEach((collection) => {
            // if collection has a collection role (classification like ddc):
            if (collection.number) {
                // collection.load('collectionRole');
                const setSpec = collection.collectionRole?.oai_name + ':' + collection.number;
                sets[setSpec] = `Set ${collection.number} '${collection.name}'`;
            }
        });
        return sets;
    }

    private async getSetsForDatasetTypes(): Promise<Dictionary> {
        const sets: { [key: string]: string } = {} as Dictionary;

        const datasets: Array<Dataset> = await Dataset.query().select('type').where('server_state', 'published');

        datasets.forEach((dataset) => {
            if (dataset.type && false == preg_match(this.sampleRegEx, dataset.type)) {
                const msg = `Invalid SetSpec (data-type='${dataset.type}').
                Allowed characters are [${this.sampleRegEx}].`;
                // Log::error("OAI-PMH: $msg");
                logger.error(`OAI-PMH: ${msg}`);
                return;
            }
            const setSpec = 'data-type:' + dataset.type;
            sets[setSpec] = `Set for document type '${dataset.type}'`;
        });
        return sets;
    }

    private handleIllegalVerb() {
        this.xsltParameter['oai_error_code'] = 'badVerb';
        this.xsltParameter['oai_error_message'] = 'The verb provided in the request is illegal.';
    }
}