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        }
128    }
129
130    /**
131     * appends a {@link OsmPrimitive} id to the list of ids which will be fetched from the server.
132     *
133     * @param ds the {@link DataSet} to which the primitive belongs
134     * @param id the primitive id
135     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
136     * {@link OsmPrimitiveType#RELATION RELATION}
137     * @return this
138     */
139    public MultiFetchServerObjectReader append(DataSet ds, long id, OsmPrimitiveType type) {
140        OsmPrimitive p = ds.getPrimitiveById(id, type);
141        switch(type) {
142        case NODE:
143            return appendNode((Node) p);
144        case WAY:
145            return appendWay((Way) p);
146        case RELATION:
147            return appendRelation((Relation) p);
148        }
149        return this;
150    }
151
152    /**
153     * appends a {@link Node} id to the list of ids which will be fetched from the server.
154     *
155     * @param node  the node (ignored, if null)
156     * @return this
157     */
158    public MultiFetchServerObjectReader appendNode(Node node) {
159        if (node == null) return this;
160        remember(node.getPrimitiveId());
161        return this;
162    }
163
164    /**
165     * 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.
166     *
167     * @param way the way (ignored, if null)
168     * @return this
169     */
170    public MultiFetchServerObjectReader appendWay(Way way) {
171        if (way == null) return this;
172        if (way.isNew()) return this;
173        for (Node node: !recursesDown() ? way.getNodes() : Collections.<Node>emptyList()) {
174            if (!node.isNew()) {
175                remember(node.getPrimitiveId());
176            }
177        }
178        remember(way.getPrimitiveId());
179        return this;
180    }
181
182    /**
183     * appends a {@link Relation} id to the list of ids which will be fetched from the server.
184     *
185     * @param relation  the relation (ignored, if null)
186     * @return this
187     */
188    protected MultiFetchServerObjectReader appendRelation(Relation relation) {
189        if (relation == null) return this;
190        if (relation.isNew()) return this;
191        remember(relation.getPrimitiveId());
192        for (RelationMember member : !recursesDown() ? relation.getMembers() : Collections.<RelationMember>emptyList()) {
193            if (OsmPrimitiveType.from(member.getMember()).equals(OsmPrimitiveType.RELATION)) {
194                // avoid infinite recursion in case of cyclic dependencies in relations
195                //
196                if (relations.contains(member.getMember().getId())) {
197                    continue;
198                }
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            }
219        }
220        return this;
221    }
222
223    /**
224     * appends a list of {@link OsmPrimitive} to the list of ids which will be fetched from the server.
225     *
226     * @param primitives  the list of primitives (ignored, if null)
227     * @return this
228     *
229     * @see #append(OsmPrimitive)
230     */
231    public MultiFetchServerObjectReader append(Collection<? extends OsmPrimitive> primitives) {
232        if (primitives == null) return this;
233        for (OsmPrimitive primitive : primitives) {
234            append(primitive);
235        }
236        return this;
237    }
238
239    /**
240     * extracts a subset of max {@link #MAX_IDS_PER_REQUEST} ids from <code>ids</code> and
241     * replies the subset. The extracted subset is removed from <code>ids</code>.
242     *
243     * @param ids a set of ids
244     * @return the subset of ids
245     */
246    protected Set<Long> extractIdPackage(Set<Long> ids) {
247        Set<Long> pkg = new HashSet<>();
248        if (ids.isEmpty())
249            return pkg;
250        if (ids.size() > MAX_IDS_PER_REQUEST) {
251            Iterator<Long> it = ids.iterator();
252            for (int i = 0; i < MAX_IDS_PER_REQUEST; i++) {
253                pkg.add(it.next());
254            }
255            ids.removeAll(pkg);
256        } else {
257            pkg.addAll(ids);
258            ids.clear();
259        }
260        return pkg;
261    }
262
263    /**
264     * builds the Multi Get request string for a set of ids and a given {@link OsmPrimitiveType}.
265     *
266     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
267     * {@link OsmPrimitiveType#RELATION RELATION}
268     * @param idPackage  the package of ids
269     * @return the request string
270     */
271    protected String buildRequestString(final OsmPrimitiveType type, Set<Long> idPackage) {
272        return type.getAPIName() + "s?" + type.getAPIName() + "s=" + Utils.join(",", idPackage);
273    }
274
275    @Override
276    protected String getBaseUrl() {
277        return super.getBaseUrl();
278    }
279
280    protected void rememberNodesOfIncompleteWaysToLoad(DataSet from) {
281        for (Way w: from.getWays()) {
282            if (w.hasIncompleteNodes()) {
283                for (Node n: w.getNodes()) {
284                    if (n.isIncomplete()) {
285                        nodes.add(n.getId());
286                    }
287                }
288            }
289        }
290    }
291
292    /**
293     * merges the dataset <code>from</code> to {@link #outputDataSet}.
294     *
295     * @param from the other dataset
296     */
297    protected void merge(DataSet from) {
298        final DataSetMerger visitor = new DataSetMerger(outputDataSet, from);
299        visitor.merge();
300    }
301
302    /**
303     * fetches a set of ids of a given {@link OsmPrimitiveType} from the server
304     *
305     * @param ids the set of ids
306     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
307     * {@link OsmPrimitiveType#RELATION RELATION}
308     * @param progressMonitor progress monitor
309     * @throws OsmTransferException if an error occurs while communicating with the API server
310     */
311    protected void fetchPrimitives(Set<Long> ids, OsmPrimitiveType type, ProgressMonitor progressMonitor) throws OsmTransferException {
312        String msg = "";
313        final String baseUrl = getBaseUrl();
314        switch (type) {
315            case NODE:     msg = tr("Fetching a package of nodes from ''{0}''",     baseUrl); break;
316            case WAY:      msg = tr("Fetching a package of ways from ''{0}''",      baseUrl); break;
317            case RELATION: msg = tr("Fetching a package of relations from ''{0}''", baseUrl); break;
318        }
319        progressMonitor.setTicksCount(ids.size());
320        progressMonitor.setTicks(0);
321        // The complete set containing all primitives to fetch
322        Set<Long> toFetch = new HashSet<>(ids);
323        // Build a list of fetchers that will  download smaller sets containing only MAX_IDS_PER_REQUEST (200) primitives each.
324        // we will run up to MAX_DOWNLOAD_THREADS concurrent fetchers.
325        int threadsNumber = Main.pref.getInteger("osm.download.threads", OsmApi.MAX_DOWNLOAD_THREADS);
326        threadsNumber = Math.min(Math.max(threadsNumber, 1), OsmApi.MAX_DOWNLOAD_THREADS);
327        final ExecutorService exec = Executors.newFixedThreadPool(
328                threadsNumber, Utils.newThreadFactory(getClass() + "-%d", Thread.NORM_PRIORITY));
329        CompletionService<FetchResult> ecs = new ExecutorCompletionService<>(exec);
330        List<Future<FetchResult>> jobs = new ArrayList<>();
331        while (!toFetch.isEmpty()) {
332            jobs.add(ecs.submit(new Fetcher(type, extractIdPackage(toFetch), progressMonitor)));
333        }
334        // Run the fetchers
335        for (int i = 0; i < jobs.size() && !isCanceled(); i++) {
336            progressMonitor.subTask(msg + "... " + progressMonitor.getTicks() + '/' + progressMonitor.getTicksCount());
337            try {
338                FetchResult result = ecs.take().get();
339                if (result.missingPrimitives != null) {
340                    missingPrimitives.addAll(result.missingPrimitives);
341                }
342                if (result.dataSet != null && !isCanceled()) {
343                    rememberNodesOfIncompleteWaysToLoad(result.dataSet);
344                    merge(result.dataSet);
345                }
346            } catch (InterruptedException | ExecutionException e) {
347                Main.error(e);
348            }
349        }
350        exec.shutdown();
351        // Cancel requests if the user chose to
352        if (isCanceled()) {
353            for (Future<FetchResult> job : jobs) {
354                job.cancel(true);
355            }
356        }
357    }
358
359    /**
360     * invokes one or more Multi Gets to fetch the {@link OsmPrimitive}s and replies
361     * the dataset of retrieved primitives. Note that the dataset includes non visible primitives too!
362     * In contrast to a simple Get for a node, a way, or a relation, a Multi Get always replies
363     * the latest version of the primitive (if any), even if the primitive is not visible (i.e. if
364     * visible==false).
365     *
366     * Invoke {@link #getMissingPrimitives()} to get a list of primitives which have not been
367     * found on  the server (the server response code was 404)
368     *
369     * @return the parsed data
370     * @throws OsmTransferException if an error occurs while communicating with the API server
371     * @see #getMissingPrimitives()
372     *
373     */
374    @Override
375    public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
376        int n = nodes.size() + ways.size() + relations.size();
377        progressMonitor.beginTask(trn("Downloading {0} object from ''{1}''",
378                "Downloading {0} objects from ''{1}''", n, n, OsmApi.getOsmApi().getBaseUrl()));
379        try {
380            missingPrimitives = new HashSet<>();
381            if (isCanceled()) return null;
382            fetchPrimitives(ways, OsmPrimitiveType.WAY, progressMonitor);
383            if (isCanceled()) return null;
384            fetchPrimitives(nodes, OsmPrimitiveType.NODE, progressMonitor);
385            if (isCanceled()) return null;
386            fetchPrimitives(relations, OsmPrimitiveType.RELATION, progressMonitor);
387            if (outputDataSet != null) {
388                outputDataSet.deleteInvisible();
389            }
390            return outputDataSet;
391        } finally {
392            progressMonitor.finishTask();
393        }
394    }
395
396    /**
397     * replies the set of ids of all primitives for which a fetch request to the
398     * server was submitted but which are not available from the server (the server
399     * replied a return code of 404)
400     *
401     * @return the set of ids of missing primitives
402     */
403    public Set<PrimitiveId> getMissingPrimitives() {
404        return missingPrimitives;
405    }
406
407    /**
408     * Whether this reader fetches nodes when loading ways, or members when loading relations.
409     *
410     * @return {@code true} if the reader recurses down
411     */
412    protected boolean recursesDown() {
413        return false;
414    }
415
416    /**
417     * The class holding the results given by {@link Fetcher}.
418     * It is only a wrapper of the resulting {@link DataSet} and the collection of {@link PrimitiveId} that could not have been loaded.
419     */
420    protected static class FetchResult {
421
422        /**
423         * The resulting data set
424         */
425        public final DataSet dataSet;
426
427        /**
428         * The collection of primitive ids that could not have been loaded
429         */
430        public final Set<PrimitiveId> missingPrimitives;
431
432        /**
433         * Constructs a {@code FetchResult}
434         * @param dataSet The resulting data set
435         * @param missingPrimitives The collection of primitive ids that could not have been loaded
436         */
437        public FetchResult(DataSet dataSet, Set<PrimitiveId> missingPrimitives) {
438            this.dataSet = dataSet;
439            this.missingPrimitives = missingPrimitives;
440        }
441    }
442
443    /**
444     * The class that actually download data from OSM API.
445     * Several instances of this class are used by {@link MultiFetchServerObjectReader} (one per set of primitives to fetch).
446     * The inheritance of {@link OsmServerReader} is only explained by the need to have a distinct OSM connection by {@code Fetcher} instance.
447     * @see FetchResult
448     */
449    protected class Fetcher extends OsmServerReader implements Callable<FetchResult> {
450
451        private final Set<Long> pkg;
452        private final OsmPrimitiveType type;
453        private final ProgressMonitor progressMonitor;
454
455        /**
456         * Constructs a {@code Fetcher}
457         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
458         * {@link OsmPrimitiveType#RELATION RELATION}
459         * @param idsPackage The set of primitives ids to fetch
460         * @param progressMonitor The progress monitor
461         */
462        public Fetcher(OsmPrimitiveType type, Set<Long> idsPackage, ProgressMonitor progressMonitor) {
463            this.pkg = idsPackage;
464            this.type = type;
465            this.progressMonitor = progressMonitor;
466        }
467
468        @Override
469        public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
470            // This method is implemented because of the OsmServerReader inheritance, but not used,
471            // as the main target of this class is the call() method.
472            return fetch(progressMonitor).dataSet;
473        }
474
475        @Override
476        public FetchResult call() throws Exception {
477            return fetch(progressMonitor);
478        }
479
480        /**
481         * fetches the requested primitives and updates the specified progress monitor.
482         * @param progressMonitor the progress monitor
483         * @return the {@link FetchResult} of this operation
484         * @throws OsmTransferException if an error occurs while communicating with the API server
485         */
486        protected FetchResult fetch(ProgressMonitor progressMonitor) throws OsmTransferException {
487            try {
488                return multiGetIdPackage(type, pkg, progressMonitor);
489            } catch (OsmApiException e) {
490                if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
491                    Main.info(tr("Server replied with response code 404, retrying with an individual request for each object."));
492                    return singleGetIdPackage(type, pkg, progressMonitor);
493                } else {
494                    throw e;
495                }
496            }
497        }
498
499        @Override
500        protected String getBaseUrl() {
501            return MultiFetchServerObjectReader.this.getBaseUrl();
502        }
503
504        /**
505         * invokes a Multi Get for a set of ids and a given {@link OsmPrimitiveType}.
506         * The retrieved primitives are merged to {@link #outputDataSet}.
507         *
508         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
509         * {@link OsmPrimitiveType#RELATION RELATION}
510         * @param pkg the package of ids
511         * @param progressMonitor progress monitor
512         * @return the {@link FetchResult} of this operation
513         * @throws OsmTransferException if an error occurs while communicating with the API server
514         */
515        protected FetchResult multiGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
516                throws OsmTransferException {
517            String request = buildRequestString(type, pkg);
518            FetchResult result = null;
519            try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
520                if (in == null) return null;
521                progressMonitor.subTask(tr("Downloading OSM data..."));
522                try {
523                    result = new FetchResult(OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(pkg.size(), false)), null);
524                } catch (Exception e) {
525                    throw new OsmTransferException(e);
526                }
527            } catch (IOException ex) {
528                Main.warn(ex);
529            }
530            return result;
531        }
532
533        /**
534         * invokes a Multi Get for a single id and a given {@link OsmPrimitiveType}.
535         * The retrieved primitive is merged to {@link #outputDataSet}.
536         *
537         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
538         * {@link OsmPrimitiveType#RELATION RELATION}
539         * @param id the id
540         * @param progressMonitor progress monitor
541         * @return the {@link DataSet} resulting of this operation
542         * @throws OsmTransferException if an error occurs while communicating with the API server
543         */
544        protected DataSet singleGetId(OsmPrimitiveType type, long id, ProgressMonitor progressMonitor) throws OsmTransferException {
545            String request = buildRequestString(type, Collections.singleton(id));
546            DataSet result = null;
547            try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
548                if (in == null) return null;
549                progressMonitor.subTask(tr("Downloading OSM data..."));
550                try {
551                    result = OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(1, false));
552                } catch (Exception e) {
553                    throw new OsmTransferException(e);
554                }
555            } catch (IOException ex) {
556                Main.warn(ex);
557            }
558            return result;
559        }
560
561        /**
562         * invokes a sequence of Multi Gets for individual ids in a set of ids and a given {@link OsmPrimitiveType}.
563         * The retrieved primitives are merged to {@link #outputDataSet}.
564         *
565         * This method is used if one of the ids in pkg doesn't exist (the server replies with return code 404).
566         * If the set is fetched with this method it is possible to find out which of the ids doesn't exist.
567         * Unfortunately, the server does not provide an error header or an error body for a 404 reply.
568         *
569         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
570         * {@link OsmPrimitiveType#RELATION RELATION}
571         * @param pkg the set of ids
572         * @param progressMonitor progress monitor
573         * @return the {@link FetchResult} of this operation
574         * @throws OsmTransferException if an error occurs while communicating with the API server
575         */
576        protected FetchResult singleGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
577                throws OsmTransferException {
578            FetchResult result = new FetchResult(new DataSet(), new HashSet<PrimitiveId>());
579            String baseUrl = OsmApi.getOsmApi().getBaseUrl();
580            for (long id : pkg) {
581                try {
582                    String msg = "";
583                    switch (type) {
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                    }
588                    progressMonitor.setCustomText(msg);
589                    result.dataSet.mergeFrom(singleGetId(type, id, progressMonitor));
590                } catch (OsmApiException e) {
591                    if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
592                        Main.info(tr("Server replied with response code 404 for id {0}. Skipping.", Long.toString(id)));
593                        result.missingPrimitives.add(new SimplePrimitiveId(id, type));
594                    } else {
595                        throw e;
596                    }
597                }
598            }
599            return result;
600        }
601    }
602}