001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.io;
003
004import static org.openstreetmap.josm.tools.I18n.tr;
005import static org.openstreetmap.josm.tools.I18n.trn;
006
007import java.io.IOException;
008import java.io.InputStream;
009import java.net.HttpURLConnection;
010import java.util.ArrayList;
011import java.util.Collection;
012import java.util.Collections;
013import java.util.HashSet;
014import java.util.Iterator;
015import java.util.LinkedHashSet;
016import java.util.List;
017import java.util.Set;
018import java.util.concurrent.Callable;
019import java.util.concurrent.CompletionService;
020import java.util.concurrent.ExecutionException;
021import java.util.concurrent.ExecutorCompletionService;
022import java.util.concurrent.ExecutorService;
023import java.util.concurrent.Executors;
024import java.util.concurrent.Future;
025
026import org.openstreetmap.josm.Main;
027import org.openstreetmap.josm.data.osm.DataSet;
028import org.openstreetmap.josm.data.osm.DataSetMerger;
029import org.openstreetmap.josm.data.osm.Node;
030import org.openstreetmap.josm.data.osm.OsmPrimitive;
031import org.openstreetmap.josm.data.osm.OsmPrimitiveType;
032import org.openstreetmap.josm.data.osm.PrimitiveId;
033import org.openstreetmap.josm.data.osm.Relation;
034import org.openstreetmap.josm.data.osm.RelationMember;
035import org.openstreetmap.josm.data.osm.SimplePrimitiveId;
036import org.openstreetmap.josm.data.osm.Way;
037import org.openstreetmap.josm.gui.preferences.server.OverpassServerPreference;
038import org.openstreetmap.josm.gui.progress.NullProgressMonitor;
039import org.openstreetmap.josm.gui.progress.ProgressMonitor;
040import org.openstreetmap.josm.tools.Utils;
041
042/**
043 * Retrieves a set of {@link OsmPrimitive}s from an OSM server using the so called
044 * Multi Fetch API.
045 *
046 * Usage:
047 * <pre>
048 *    MultiFetchServerObjectReader reader = MultiFetchServerObjectReader()
049 *         .append(2345,2334,4444)
050 *         .append(new Node(72343));
051 *    reader.parseOsm();
052 *    if (!reader.getMissingPrimitives().isEmpty()) {
053 *        Main.info("There are missing primitives: " + reader.getMissingPrimitives());
054 *    }
055 *    if (!reader.getSkippedWays().isEmpty()) {
056 *       Main.info("There are skipped ways: " + reader.getMissingPrimitives());
057 *    }
058 * </pre>
059 */
060public class MultiFetchServerObjectReader extends OsmServerReader {
061    /**
062     * the max. number of primitives retrieved in one step. Assuming IDs with 7 digits,
063     * this leads to a max. request URL of ~ 1600 Bytes ((7 digits +  1 Separator) * 200),
064     * which should be safe according to the
065     * <a href="http://www.boutell.com/newfaq/misc/urllength.html">WWW FAQ</a>.
066     */
067    private static final int MAX_IDS_PER_REQUEST = 200;
068
069    private final Set<Long> nodes;
070    private final Set<Long> ways;
071    private final Set<Long> relations;
072    private Set<PrimitiveId> missingPrimitives;
073    private final DataSet outputDataSet;
074
075    /**
076     * Constructs a {@code MultiFetchServerObjectReader}.
077     */
078    protected MultiFetchServerObjectReader() {
079        nodes = new LinkedHashSet<>();
080        ways = new LinkedHashSet<>();
081        relations = new LinkedHashSet<>();
082        this.outputDataSet = new DataSet();
083        this.missingPrimitives = new LinkedHashSet<>();
084    }
085
086    /**
087     * Creates a new instance of {@link MultiFetchServerObjectReader} or {@link MultiFetchOverpassObjectReader}
088     * depending on the {@link OverpassServerPreference#useForMultiFetch preference}.
089     *
090     * @return a new instance
091     * @since 9241
092     */
093    public static MultiFetchServerObjectReader create() {
094        return create(OverpassServerPreference.useForMultiFetch());
095    }
096
097    /**
098     * Creates a new instance of {@link MultiFetchServerObjectReader} or {@link MultiFetchOverpassObjectReader}
099     * depending on the {@code fromMirror} parameter.
100     *
101     * @param fromMirror {@code false} for {@link MultiFetchServerObjectReader}, {@code true} for {@link MultiFetchOverpassObjectReader}
102     * @return a new instance
103     * @since 9241
104     */
105    static MultiFetchServerObjectReader create(final boolean fromMirror) {
106        if (fromMirror) {
107            return new MultiFetchOverpassObjectReader();
108        } else {
109            return new MultiFetchServerObjectReader();
110        }
111    }
112
113    /**
114     * Remembers an {@link OsmPrimitive}'s id. The id will
115     * later be fetched as part of a Multi Get request.
116     *
117     * Ignore the id if it represents a new primitives.
118     *
119     * @param id  the id
120     */
121    protected void remember(PrimitiveId id) {
122        if (id.isNew()) return;
123        switch(id.getType()) {
124        case NODE: nodes.add(id.getUniqueId()); break;
125        case WAY: ways.add(id.getUniqueId()); break;
126        case RELATION: relations.add(id.getUniqueId()); break;
127        default: throw new AssertionError();
128        }
129    }
130
131    /**
132     * appends a {@link OsmPrimitive} id to the list of ids which will be fetched from the server.
133     *
134     * @param ds the {@link DataSet} to which the primitive belongs
135     * @param id the primitive id
136     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
137     * {@link OsmPrimitiveType#RELATION RELATION}
138     * @return this
139     */
140    public MultiFetchServerObjectReader append(DataSet ds, long id, OsmPrimitiveType type) {
141        OsmPrimitive p = ds.getPrimitiveById(id, type);
142        switch(type) {
143        case NODE:
144            return appendNode((Node) p);
145        case WAY:
146            return appendWay((Way) p);
147        case RELATION:
148            return appendRelation((Relation) p);
149        default:
150            return this;
151        }
152    }
153
154    /**
155     * appends a {@link Node} id to the list of ids which will be fetched from the server.
156     *
157     * @param node  the node (ignored, if null)
158     * @return this
159     */
160    public MultiFetchServerObjectReader appendNode(Node node) {
161        if (node == null) return this;
162        remember(node.getPrimitiveId());
163        return this;
164    }
165
166    /**
167     * appends a {@link Way} id and the list of ids of nodes the way refers to the list of ids which will be fetched from the server.
168     *
169     * @param way the way (ignored, if null)
170     * @return this
171     */
172    public MultiFetchServerObjectReader appendWay(Way way) {
173        if (way == null) return this;
174        if (way.isNew()) return this;
175        for (Node node: !recursesDown() ? way.getNodes() : Collections.<Node>emptyList()) {
176            if (!node.isNew()) {
177                remember(node.getPrimitiveId());
178            }
179        }
180        remember(way.getPrimitiveId());
181        return this;
182    }
183
184    /**
185     * appends a {@link Relation} id to the list of ids which will be fetched from the server.
186     *
187     * @param relation  the relation (ignored, if null)
188     * @return this
189     */
190    protected MultiFetchServerObjectReader appendRelation(Relation relation) {
191        if (relation == null) return this;
192        if (relation.isNew()) return this;
193        remember(relation.getPrimitiveId());
194        for (RelationMember member : !recursesDown() ? relation.getMembers() : Collections.<RelationMember>emptyList()) {
195            // avoid infinite recursion in case of cyclic dependencies in relations
196            if (OsmPrimitiveType.from(member.getMember()).equals(OsmPrimitiveType.RELATION)
197                    && relations.contains(member.getMember().getId())) {
198                continue;
199            }
200            if (!member.getMember().isIncomplete()) {
201                append(member.getMember());
202            }
203        }
204        return this;
205    }
206
207    /**
208     * appends an {@link OsmPrimitive} to the list of ids which will be fetched from the server.
209     * @param primitive the primitive
210     * @return this
211     */
212    public MultiFetchServerObjectReader append(OsmPrimitive primitive) {
213        if (primitive != null) {
214            switch (OsmPrimitiveType.from(primitive)) {
215                case NODE: return appendNode((Node) primitive);
216                case WAY: return appendWay((Way) primitive);
217                case RELATION: return appendRelation((Relation) primitive);
218                default: break;
219            }
220        }
221        return this;
222    }
223
224    /**
225     * appends a list of {@link OsmPrimitive} to the list of ids which will be fetched from the server.
226     *
227     * @param primitives  the list of primitives (ignored, if null)
228     * @return this
229     *
230     * @see #append(OsmPrimitive)
231     */
232    public MultiFetchServerObjectReader append(Collection<? extends OsmPrimitive> primitives) {
233        if (primitives == null) return this;
234        for (OsmPrimitive primitive : primitives) {
235            append(primitive);
236        }
237        return this;
238    }
239
240    /**
241     * extracts a subset of max {@link #MAX_IDS_PER_REQUEST} ids from <code>ids</code> and
242     * replies the subset. The extracted subset is removed from <code>ids</code>.
243     *
244     * @param ids a set of ids
245     * @return the subset of ids
246     */
247    protected Set<Long> extractIdPackage(Set<Long> ids) {
248        Set<Long> pkg = new HashSet<>();
249        if (ids.isEmpty())
250            return pkg;
251        if (ids.size() > MAX_IDS_PER_REQUEST) {
252            Iterator<Long> it = ids.iterator();
253            for (int i = 0; i < MAX_IDS_PER_REQUEST; i++) {
254                pkg.add(it.next());
255            }
256            ids.removeAll(pkg);
257        } else {
258            pkg.addAll(ids);
259            ids.clear();
260        }
261        return pkg;
262    }
263
264    /**
265     * builds the Multi Get request string for a set of ids and a given {@link OsmPrimitiveType}.
266     *
267     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
268     * {@link OsmPrimitiveType#RELATION RELATION}
269     * @param idPackage  the package of ids
270     * @return the request string
271     */
272    protected String buildRequestString(final OsmPrimitiveType type, Set<Long> idPackage) {
273        return type.getAPIName() + "s?" + type.getAPIName() + "s=" + Utils.join(",", idPackage);
274    }
275
276    protected void rememberNodesOfIncompleteWaysToLoad(DataSet from) {
277        for (Way w: from.getWays()) {
278            if (w.hasIncompleteNodes()) {
279                for (Node n: w.getNodes()) {
280                    if (n.isIncomplete()) {
281                        nodes.add(n.getId());
282                    }
283                }
284            }
285        }
286    }
287
288    /**
289     * merges the dataset <code>from</code> to {@link #outputDataSet}.
290     *
291     * @param from the other dataset
292     */
293    protected void merge(DataSet from) {
294        final DataSetMerger visitor = new DataSetMerger(outputDataSet, from);
295        visitor.merge();
296    }
297
298    /**
299     * fetches a set of ids of a given {@link OsmPrimitiveType} from the server
300     *
301     * @param ids the set of ids
302     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
303     * {@link OsmPrimitiveType#RELATION RELATION}
304     * @param progressMonitor progress monitor
305     * @throws OsmTransferException if an error occurs while communicating with the API server
306     */
307    protected void fetchPrimitives(Set<Long> ids, OsmPrimitiveType type, ProgressMonitor progressMonitor) throws OsmTransferException {
308        String msg;
309        final String baseUrl = getBaseUrl();
310        switch (type) {
311            // CHECKSTYLE.OFF: SingleSpaceSeparator
312            case NODE:     msg = tr("Fetching a package of nodes from ''{0}''",     baseUrl); break;
313            case WAY:      msg = tr("Fetching a package of ways from ''{0}''",      baseUrl); break;
314            case RELATION: msg = tr("Fetching a package of relations from ''{0}''", baseUrl); break;
315            // CHECKSTYLE.ON: SingleSpaceSeparator
316            default: throw new AssertionError();
317        }
318        progressMonitor.setTicksCount(ids.size());
319        progressMonitor.setTicks(0);
320        // The complete set containing all primitives to fetch
321        Set<Long> toFetch = new HashSet<>(ids);
322        // Build a list of fetchers that will  download smaller sets containing only MAX_IDS_PER_REQUEST (200) primitives each.
323        // we will run up to MAX_DOWNLOAD_THREADS concurrent fetchers.
324        int threadsNumber = Main.pref.getInteger("osm.download.threads", OsmApi.MAX_DOWNLOAD_THREADS);
325        threadsNumber = Math.min(Math.max(threadsNumber, 1), OsmApi.MAX_DOWNLOAD_THREADS);
326        final ExecutorService exec = Executors.newFixedThreadPool(
327                threadsNumber, Utils.newThreadFactory(getClass() + "-%d", Thread.NORM_PRIORITY));
328        CompletionService<FetchResult> ecs = new ExecutorCompletionService<>(exec);
329        List<Future<FetchResult>> jobs = new ArrayList<>();
330        while (!toFetch.isEmpty()) {
331            jobs.add(ecs.submit(new Fetcher(type, extractIdPackage(toFetch), progressMonitor)));
332        }
333        // Run the fetchers
334        for (int i = 0; i < jobs.size() && !isCanceled(); i++) {
335            progressMonitor.subTask(msg + "... " + progressMonitor.getTicks() + '/' + progressMonitor.getTicksCount());
336            try {
337                FetchResult result = ecs.take().get();
338                if (result.missingPrimitives != null) {
339                    missingPrimitives.addAll(result.missingPrimitives);
340                }
341                if (result.dataSet != null && !isCanceled()) {
342                    rememberNodesOfIncompleteWaysToLoad(result.dataSet);
343                    merge(result.dataSet);
344                }
345            } catch (InterruptedException | ExecutionException e) {
346                Main.error(e);
347            }
348        }
349        exec.shutdown();
350        // Cancel requests if the user chose to
351        if (isCanceled()) {
352            for (Future<FetchResult> job : jobs) {
353                job.cancel(true);
354            }
355        }
356    }
357
358    /**
359     * invokes one or more Multi Gets to fetch the {@link OsmPrimitive}s and replies
360     * the dataset of retrieved primitives. Note that the dataset includes non visible primitives too!
361     * In contrast to a simple Get for a node, a way, or a relation, a Multi Get always replies
362     * the latest version of the primitive (if any), even if the primitive is not visible (i.e. if
363     * visible==false).
364     *
365     * Invoke {@link #getMissingPrimitives()} to get a list of primitives which have not been
366     * found on  the server (the server response code was 404)
367     *
368     * @return the parsed data
369     * @throws OsmTransferException if an error occurs while communicating with the API server
370     * @see #getMissingPrimitives()
371     *
372     */
373    @Override
374    public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
375        int n = nodes.size() + ways.size() + relations.size();
376        progressMonitor.beginTask(trn("Downloading {0} object from ''{1}''",
377                "Downloading {0} objects from ''{1}''", n, n, OsmApi.getOsmApi().getBaseUrl()));
378        try {
379            missingPrimitives = new HashSet<>();
380            if (isCanceled()) return null;
381            fetchPrimitives(ways, OsmPrimitiveType.WAY, progressMonitor);
382            if (isCanceled()) return null;
383            fetchPrimitives(nodes, OsmPrimitiveType.NODE, progressMonitor);
384            if (isCanceled()) return null;
385            fetchPrimitives(relations, OsmPrimitiveType.RELATION, progressMonitor);
386            if (outputDataSet != null) {
387                outputDataSet.deleteInvisible();
388            }
389            return outputDataSet;
390        } finally {
391            progressMonitor.finishTask();
392        }
393    }
394
395    /**
396     * replies the set of ids of all primitives for which a fetch request to the
397     * server was submitted but which are not available from the server (the server
398     * replied a return code of 404)
399     *
400     * @return the set of ids of missing primitives
401     */
402    public Set<PrimitiveId> getMissingPrimitives() {
403        return missingPrimitives;
404    }
405
406    /**
407     * Whether this reader fetches nodes when loading ways, or members when loading relations.
408     *
409     * @return {@code true} if the reader recurses down
410     */
411    protected boolean recursesDown() {
412        return false;
413    }
414
415    /**
416     * The class holding the results given by {@link Fetcher}.
417     * It is only a wrapper of the resulting {@link DataSet} and the collection of {@link PrimitiveId} that could not have been loaded.
418     */
419    protected static class FetchResult {
420
421        /**
422         * The resulting data set
423         */
424        public final DataSet dataSet;
425
426        /**
427         * The collection of primitive ids that could not have been loaded
428         */
429        public final Set<PrimitiveId> missingPrimitives;
430
431        /**
432         * Constructs a {@code FetchResult}
433         * @param dataSet The resulting data set
434         * @param missingPrimitives The collection of primitive ids that could not have been loaded
435         */
436        public FetchResult(DataSet dataSet, Set<PrimitiveId> missingPrimitives) {
437            this.dataSet = dataSet;
438            this.missingPrimitives = missingPrimitives;
439        }
440    }
441
442    /**
443     * The class that actually download data from OSM API.
444     * Several instances of this class are used by {@link MultiFetchServerObjectReader} (one per set of primitives to fetch).
445     * The inheritance of {@link OsmServerReader} is only explained by the need to have a distinct OSM connection by {@code Fetcher} instance.
446     * @see FetchResult
447     */
448    protected class Fetcher extends OsmServerReader implements Callable<FetchResult> {
449
450        private final Set<Long> pkg;
451        private final OsmPrimitiveType type;
452        private final ProgressMonitor progressMonitor;
453
454        /**
455         * Constructs a {@code Fetcher}
456         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
457         * {@link OsmPrimitiveType#RELATION RELATION}
458         * @param idsPackage The set of primitives ids to fetch
459         * @param progressMonitor The progress monitor
460         */
461        public Fetcher(OsmPrimitiveType type, Set<Long> idsPackage, ProgressMonitor progressMonitor) {
462            this.pkg = idsPackage;
463            this.type = type;
464            this.progressMonitor = progressMonitor;
465        }
466
467        @Override
468        public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
469            // This method is implemented because of the OsmServerReader inheritance, but not used,
470            // as the main target of this class is the call() method.
471            return fetch(progressMonitor).dataSet;
472        }
473
474        @Override
475        public FetchResult call() throws Exception {
476            return fetch(progressMonitor);
477        }
478
479        /**
480         * fetches the requested primitives and updates the specified progress monitor.
481         * @param progressMonitor the progress monitor
482         * @return the {@link FetchResult} of this operation
483         * @throws OsmTransferException if an error occurs while communicating with the API server
484         */
485        protected FetchResult fetch(ProgressMonitor progressMonitor) throws OsmTransferException {
486            try {
487                return multiGetIdPackage(type, pkg, progressMonitor);
488            } catch (OsmApiException e) {
489                if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
490                    Main.info(tr("Server replied with response code 404, retrying with an individual request for each object."));
491                    return singleGetIdPackage(type, pkg, progressMonitor);
492                } else {
493                    throw e;
494                }
495            }
496        }
497
498        @Override
499        protected String getBaseUrl() {
500            return MultiFetchServerObjectReader.this.getBaseUrl();
501        }
502
503        /**
504         * invokes a Multi Get for a set of ids and a given {@link OsmPrimitiveType}.
505         * The retrieved primitives are merged to {@link #outputDataSet}.
506         *
507         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
508         * {@link OsmPrimitiveType#RELATION RELATION}
509         * @param pkg the package of ids
510         * @param progressMonitor progress monitor
511         * @return the {@link FetchResult} of this operation
512         * @throws OsmTransferException if an error occurs while communicating with the API server
513         */
514        protected FetchResult multiGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
515                throws OsmTransferException {
516            String request = buildRequestString(type, pkg);
517            FetchResult result = null;
518            try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
519                if (in == null) return null;
520                progressMonitor.subTask(tr("Downloading OSM data..."));
521                try {
522                    result = new FetchResult(OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(pkg.size(), false)), null);
523                } catch (IllegalDataException e) {
524                    throw new OsmTransferException(e);
525                }
526            } catch (IOException ex) {
527                Main.warn(ex);
528            }
529            return result;
530        }
531
532        /**
533         * invokes a Multi Get for a single id and a given {@link OsmPrimitiveType}.
534         * The retrieved primitive is merged to {@link #outputDataSet}.
535         *
536         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
537         * {@link OsmPrimitiveType#RELATION RELATION}
538         * @param id the id
539         * @param progressMonitor progress monitor
540         * @return the {@link DataSet} resulting of this operation
541         * @throws OsmTransferException if an error occurs while communicating with the API server
542         */
543        protected DataSet singleGetId(OsmPrimitiveType type, long id, ProgressMonitor progressMonitor) throws OsmTransferException {
544            String request = buildRequestString(type, Collections.singleton(id));
545            DataSet result = null;
546            try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
547                if (in == null) return null;
548                progressMonitor.subTask(tr("Downloading OSM data..."));
549                try {
550                    result = OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(1, false));
551                } catch (IllegalDataException e) {
552                    throw new OsmTransferException(e);
553                }
554            } catch (IOException ex) {
555                Main.warn(ex);
556            }
557            return result;
558        }
559
560        /**
561         * invokes a sequence of Multi Gets for individual ids in a set of ids and a given {@link OsmPrimitiveType}.
562         * The retrieved primitives are merged to {@link #outputDataSet}.
563         *
564         * This method is used if one of the ids in pkg doesn't exist (the server replies with return code 404).
565         * If the set is fetched with this method it is possible to find out which of the ids doesn't exist.
566         * Unfortunately, the server does not provide an error header or an error body for a 404 reply.
567         *
568         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
569         * {@link OsmPrimitiveType#RELATION RELATION}
570         * @param pkg the set of ids
571         * @param progressMonitor progress monitor
572         * @return the {@link FetchResult} of this operation
573         * @throws OsmTransferException if an error occurs while communicating with the API server
574         */
575        protected FetchResult singleGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
576                throws OsmTransferException {
577            FetchResult result = new FetchResult(new DataSet(), new HashSet<PrimitiveId>());
578            String baseUrl = OsmApi.getOsmApi().getBaseUrl();
579            for (long id : pkg) {
580                try {
581                    String msg;
582                    switch (type) {
583                        // CHECKSTYLE.OFF: SingleSpaceSeparator
584                        case NODE:     msg = tr("Fetching node with id {0} from ''{1}''",     id, baseUrl); break;
585                        case WAY:      msg = tr("Fetching way with id {0} from ''{1}''",      id, baseUrl); break;
586                        case RELATION: msg = tr("Fetching relation with id {0} from ''{1}''", id, baseUrl); break;
587                        // CHECKSTYLE.ON: SingleSpaceSeparator
588                        default: throw new AssertionError();
589                    }
590                    progressMonitor.setCustomText(msg);
591                    result.dataSet.mergeFrom(singleGetId(type, id, progressMonitor));
592                } catch (OsmApiException e) {
593                    if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
594                        Main.info(tr("Server replied with response code 404 for id {0}. Skipping.", Long.toString(id)));
595                        result.missingPrimitives.add(new SimplePrimitiveId(id, type));
596                    } else {
597                        throw e;
598                    }
599                }
600            }
601            return result;
602        }
603    }
604}