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        }
150        return this;
151    }
152
153    /**
154     * appends a {@link Node} id to the list of ids which will be fetched from the server.
155     *
156     * @param node  the node (ignored, if null)
157     * @return this
158     */
159    public MultiFetchServerObjectReader appendNode(Node node) {
160        if (node == null) return this;
161        remember(node.getPrimitiveId());
162        return this;
163    }
164
165    /**
166     * 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.
167     *
168     * @param way the way (ignored, if null)
169     * @return this
170     */
171    public MultiFetchServerObjectReader appendWay(Way way) {
172        if (way == null) return this;
173        if (way.isNew()) return this;
174        for (Node node: !recursesDown() ? way.getNodes() : Collections.<Node>emptyList()) {
175            if (!node.isNew()) {
176                remember(node.getPrimitiveId());
177            }
178        }
179        remember(way.getPrimitiveId());
180        return this;
181    }
182
183    /**
184     * appends a {@link Relation} id to the list of ids which will be fetched from the server.
185     *
186     * @param relation  the relation (ignored, if null)
187     * @return this
188     */
189    protected MultiFetchServerObjectReader appendRelation(Relation relation) {
190        if (relation == null) return this;
191        if (relation.isNew()) return this;
192        remember(relation.getPrimitiveId());
193        for (RelationMember member : !recursesDown() ? relation.getMembers() : Collections.<RelationMember>emptyList()) {
194            if (OsmPrimitiveType.from(member.getMember()).equals(OsmPrimitiveType.RELATION)) {
195                // avoid infinite recursion in case of cyclic dependencies in relations
196                //
197                if (relations.contains(member.getMember().getId())) {
198                    continue;
199                }
200            }
201            if (!member.getMember().isIncomplete()) {
202                append(member.getMember());
203            }
204        }
205        return this;
206    }
207
208    /**
209     * appends an {@link OsmPrimitive} to the list of ids which will be fetched from the server.
210     * @param primitive the primitive
211     * @return this
212     */
213    public MultiFetchServerObjectReader append(OsmPrimitive primitive) {
214        if (primitive != null) {
215            switch (OsmPrimitiveType.from(primitive)) {
216                case NODE: return appendNode((Node) primitive);
217                case WAY: return appendWay((Way) primitive);
218                case RELATION: return appendRelation((Relation) primitive);
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    @Override
277    protected String getBaseUrl() {
278        return super.getBaseUrl();
279    }
280
281    protected void rememberNodesOfIncompleteWaysToLoad(DataSet from) {
282        for (Way w: from.getWays()) {
283            if (w.hasIncompleteNodes()) {
284                for (Node n: w.getNodes()) {
285                    if (n.isIncomplete()) {
286                        nodes.add(n.getId());
287                    }
288                }
289            }
290        }
291    }
292
293    /**
294     * merges the dataset <code>from</code> to {@link #outputDataSet}.
295     *
296     * @param from the other dataset
297     */
298    protected void merge(DataSet from) {
299        final DataSetMerger visitor = new DataSetMerger(outputDataSet, from);
300        visitor.merge();
301    }
302
303    /**
304     * fetches a set of ids of a given {@link OsmPrimitiveType} from the server
305     *
306     * @param ids the set of ids
307     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
308     * {@link OsmPrimitiveType#RELATION RELATION}
309     * @param progressMonitor progress monitor
310     * @throws OsmTransferException if an error occurs while communicating with the API server
311     */
312    protected void fetchPrimitives(Set<Long> ids, OsmPrimitiveType type, ProgressMonitor progressMonitor) throws OsmTransferException {
313        String msg;
314        final String baseUrl = getBaseUrl();
315        switch (type) {
316            case NODE:     msg = tr("Fetching a package of nodes from ''{0}''",     baseUrl); break;
317            case WAY:      msg = tr("Fetching a package of ways from ''{0}''",      baseUrl); break;
318            case RELATION: msg = tr("Fetching a package of relations from ''{0}''", baseUrl); break;
319            default: throw new AssertionError();
320        }
321        progressMonitor.setTicksCount(ids.size());
322        progressMonitor.setTicks(0);
323        // The complete set containing all primitives to fetch
324        Set<Long> toFetch = new HashSet<>(ids);
325        // Build a list of fetchers that will  download smaller sets containing only MAX_IDS_PER_REQUEST (200) primitives each.
326        // we will run up to MAX_DOWNLOAD_THREADS concurrent fetchers.
327        int threadsNumber = Main.pref.getInteger("osm.download.threads", OsmApi.MAX_DOWNLOAD_THREADS);
328        threadsNumber = Math.min(Math.max(threadsNumber, 1), OsmApi.MAX_DOWNLOAD_THREADS);
329        final ExecutorService exec = Executors.newFixedThreadPool(
330                threadsNumber, Utils.newThreadFactory(getClass() + "-%d", Thread.NORM_PRIORITY));
331        CompletionService<FetchResult> ecs = new ExecutorCompletionService<>(exec);
332        List<Future<FetchResult>> jobs = new ArrayList<>();
333        while (!toFetch.isEmpty()) {
334            jobs.add(ecs.submit(new Fetcher(type, extractIdPackage(toFetch), progressMonitor)));
335        }
336        // Run the fetchers
337        for (int i = 0; i < jobs.size() && !isCanceled(); i++) {
338            progressMonitor.subTask(msg + "... " + progressMonitor.getTicks() + '/' + progressMonitor.getTicksCount());
339            try {
340                FetchResult result = ecs.take().get();
341                if (result.missingPrimitives != null) {
342                    missingPrimitives.addAll(result.missingPrimitives);
343                }
344                if (result.dataSet != null && !isCanceled()) {
345                    rememberNodesOfIncompleteWaysToLoad(result.dataSet);
346                    merge(result.dataSet);
347                }
348            } catch (InterruptedException | ExecutionException e) {
349                Main.error(e);
350            }
351        }
352        exec.shutdown();
353        // Cancel requests if the user chose to
354        if (isCanceled()) {
355            for (Future<FetchResult> job : jobs) {
356                job.cancel(true);
357            }
358        }
359    }
360
361    /**
362     * invokes one or more Multi Gets to fetch the {@link OsmPrimitive}s and replies
363     * the dataset of retrieved primitives. Note that the dataset includes non visible primitives too!
364     * In contrast to a simple Get for a node, a way, or a relation, a Multi Get always replies
365     * the latest version of the primitive (if any), even if the primitive is not visible (i.e. if
366     * visible==false).
367     *
368     * Invoke {@link #getMissingPrimitives()} to get a list of primitives which have not been
369     * found on  the server (the server response code was 404)
370     *
371     * @return the parsed data
372     * @throws OsmTransferException if an error occurs while communicating with the API server
373     * @see #getMissingPrimitives()
374     *
375     */
376    @Override
377    public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
378        int n = nodes.size() + ways.size() + relations.size();
379        progressMonitor.beginTask(trn("Downloading {0} object from ''{1}''",
380                "Downloading {0} objects from ''{1}''", n, n, OsmApi.getOsmApi().getBaseUrl()));
381        try {
382            missingPrimitives = new HashSet<>();
383            if (isCanceled()) return null;
384            fetchPrimitives(ways, OsmPrimitiveType.WAY, progressMonitor);
385            if (isCanceled()) return null;
386            fetchPrimitives(nodes, OsmPrimitiveType.NODE, progressMonitor);
387            if (isCanceled()) return null;
388            fetchPrimitives(relations, OsmPrimitiveType.RELATION, progressMonitor);
389            if (outputDataSet != null) {
390                outputDataSet.deleteInvisible();
391            }
392            return outputDataSet;
393        } finally {
394            progressMonitor.finishTask();
395        }
396    }
397
398    /**
399     * replies the set of ids of all primitives for which a fetch request to the
400     * server was submitted but which are not available from the server (the server
401     * replied a return code of 404)
402     *
403     * @return the set of ids of missing primitives
404     */
405    public Set<PrimitiveId> getMissingPrimitives() {
406        return missingPrimitives;
407    }
408
409    /**
410     * Whether this reader fetches nodes when loading ways, or members when loading relations.
411     *
412     * @return {@code true} if the reader recurses down
413     */
414    protected boolean recursesDown() {
415        return false;
416    }
417
418    /**
419     * The class holding the results given by {@link Fetcher}.
420     * It is only a wrapper of the resulting {@link DataSet} and the collection of {@link PrimitiveId} that could not have been loaded.
421     */
422    protected static class FetchResult {
423
424        /**
425         * The resulting data set
426         */
427        public final DataSet dataSet;
428
429        /**
430         * The collection of primitive ids that could not have been loaded
431         */
432        public final Set<PrimitiveId> missingPrimitives;
433
434        /**
435         * Constructs a {@code FetchResult}
436         * @param dataSet The resulting data set
437         * @param missingPrimitives The collection of primitive ids that could not have been loaded
438         */
439        public FetchResult(DataSet dataSet, Set<PrimitiveId> missingPrimitives) {
440            this.dataSet = dataSet;
441            this.missingPrimitives = missingPrimitives;
442        }
443    }
444
445    /**
446     * The class that actually download data from OSM API.
447     * Several instances of this class are used by {@link MultiFetchServerObjectReader} (one per set of primitives to fetch).
448     * The inheritance of {@link OsmServerReader} is only explained by the need to have a distinct OSM connection by {@code Fetcher} instance.
449     * @see FetchResult
450     */
451    protected class Fetcher extends OsmServerReader implements Callable<FetchResult> {
452
453        private final Set<Long> pkg;
454        private final OsmPrimitiveType type;
455        private final ProgressMonitor progressMonitor;
456
457        /**
458         * Constructs a {@code Fetcher}
459         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
460         * {@link OsmPrimitiveType#RELATION RELATION}
461         * @param idsPackage The set of primitives ids to fetch
462         * @param progressMonitor The progress monitor
463         */
464        public Fetcher(OsmPrimitiveType type, Set<Long> idsPackage, ProgressMonitor progressMonitor) {
465            this.pkg = idsPackage;
466            this.type = type;
467            this.progressMonitor = progressMonitor;
468        }
469
470        @Override
471        public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
472            // This method is implemented because of the OsmServerReader inheritance, but not used,
473            // as the main target of this class is the call() method.
474            return fetch(progressMonitor).dataSet;
475        }
476
477        @Override
478        public FetchResult call() throws Exception {
479            return fetch(progressMonitor);
480        }
481
482        /**
483         * fetches the requested primitives and updates the specified progress monitor.
484         * @param progressMonitor the progress monitor
485         * @return the {@link FetchResult} of this operation
486         * @throws OsmTransferException if an error occurs while communicating with the API server
487         */
488        protected FetchResult fetch(ProgressMonitor progressMonitor) throws OsmTransferException {
489            try {
490                return multiGetIdPackage(type, pkg, progressMonitor);
491            } catch (OsmApiException e) {
492                if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
493                    Main.info(tr("Server replied with response code 404, retrying with an individual request for each object."));
494                    return singleGetIdPackage(type, pkg, progressMonitor);
495                } else {
496                    throw e;
497                }
498            }
499        }
500
501        @Override
502        protected String getBaseUrl() {
503            return MultiFetchServerObjectReader.this.getBaseUrl();
504        }
505
506        /**
507         * invokes a Multi Get for a set of ids and a given {@link OsmPrimitiveType}.
508         * The retrieved primitives are merged to {@link #outputDataSet}.
509         *
510         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
511         * {@link OsmPrimitiveType#RELATION RELATION}
512         * @param pkg the package of ids
513         * @param progressMonitor progress monitor
514         * @return the {@link FetchResult} of this operation
515         * @throws OsmTransferException if an error occurs while communicating with the API server
516         */
517        protected FetchResult multiGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
518                throws OsmTransferException {
519            String request = buildRequestString(type, pkg);
520            FetchResult result = null;
521            try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
522                if (in == null) return null;
523                progressMonitor.subTask(tr("Downloading OSM data..."));
524                try {
525                    result = new FetchResult(OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(pkg.size(), false)), null);
526                } catch (IllegalDataException e) {
527                    throw new OsmTransferException(e);
528                }
529            } catch (IOException ex) {
530                Main.warn(ex);
531            }
532            return result;
533        }
534
535        /**
536         * invokes a Multi Get for a single id and a given {@link OsmPrimitiveType}.
537         * The retrieved primitive is merged to {@link #outputDataSet}.
538         *
539         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
540         * {@link OsmPrimitiveType#RELATION RELATION}
541         * @param id the id
542         * @param progressMonitor progress monitor
543         * @return the {@link DataSet} resulting of this operation
544         * @throws OsmTransferException if an error occurs while communicating with the API server
545         */
546        protected DataSet singleGetId(OsmPrimitiveType type, long id, ProgressMonitor progressMonitor) throws OsmTransferException {
547            String request = buildRequestString(type, Collections.singleton(id));
548            DataSet result = null;
549            try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
550                if (in == null) return null;
551                progressMonitor.subTask(tr("Downloading OSM data..."));
552                try {
553                    result = OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(1, false));
554                } catch (IllegalDataException e) {
555                    throw new OsmTransferException(e);
556                }
557            } catch (IOException ex) {
558                Main.warn(ex);
559            }
560            return result;
561        }
562
563        /**
564         * invokes a sequence of Multi Gets for individual ids in a set of ids and a given {@link OsmPrimitiveType}.
565         * The retrieved primitives are merged to {@link #outputDataSet}.
566         *
567         * This method is used if one of the ids in pkg doesn't exist (the server replies with return code 404).
568         * If the set is fetched with this method it is possible to find out which of the ids doesn't exist.
569         * Unfortunately, the server does not provide an error header or an error body for a 404 reply.
570         *
571         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
572         * {@link OsmPrimitiveType#RELATION RELATION}
573         * @param pkg the set of ids
574         * @param progressMonitor progress monitor
575         * @return the {@link FetchResult} of this operation
576         * @throws OsmTransferException if an error occurs while communicating with the API server
577         */
578        protected FetchResult singleGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
579                throws OsmTransferException {
580            FetchResult result = new FetchResult(new DataSet(), new HashSet<PrimitiveId>());
581            String baseUrl = OsmApi.getOsmApi().getBaseUrl();
582            for (long id : pkg) {
583                try {
584                    String msg;
585                    switch (type) {
586                        case NODE:     msg = tr("Fetching node with id {0} from ''{1}''",     id, baseUrl); break;
587                        case WAY:      msg = tr("Fetching way with id {0} from ''{1}''",      id, baseUrl); break;
588                        case RELATION: msg = tr("Fetching relation with id {0} from ''{1}''", id, baseUrl); break;
589                        default: throw new AssertionError();
590                    }
591                    progressMonitor.setCustomText(msg);
592                    result.dataSet.mergeFrom(singleGetId(type, id, progressMonitor));
593                } catch (OsmApiException e) {
594                    if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
595                        Main.info(tr("Server replied with response code 404 for id {0}. Skipping.", Long.toString(id)));
596                        result.missingPrimitives.add(new SimplePrimitiveId(id, type));
597                    } else {
598                        throw e;
599                    }
600                }
601            }
602            return result;
603        }
604    }
605}