fixes neo4j-contrib#1276: Add streaming support to export JSON and Gr…

…aphML

docs/asciidoc/export/exportJson.adoc

@@ -24,8 +24,11 @@ include::../../../build/generated-documentation/apoc.export.json.csv[]
 
 .Config
 
+[opts=header]
 |===
-| writeNodeProperties | true/false, if true export properties too.
+| name | type | default | description
+| writeNodeProperties | boolean | false | if true export properties too.
+| stream | boolean | false | stream the json directly to the client into the `data` field
 |===
 
 [NOTE]

docs/asciidoc/export/graphml.adoc

@@ -63,6 +63,7 @@ The output of `labels()` function is not sorted, use it in combination with `apo
 | cypherFormat | create | In export to cypher script, define the cypher format (for example use `MERGE` instead of `CREATE`). Possible values are: "create", "updateAll", "addStructure", "updateStructure".
 | bulkImport | true | In export it creates files for Neo4j Admin import
 | separateHeader | false | In export it creates two file one for header and one for data
+| stream | false | stream the xml directly to the client into the `data` field
 |===
 
 Values for the `quotes` configuration:

src/main/java/apoc/export/csv/ExportCSV.java

@@ -9,6 +9,7 @@
 import apoc.result.ProgressInfo;
 import apoc.util.QueueBasedSpliterator;
 import apoc.util.Util;
+import org.apache.commons.lang3.StringUtils;
 import org.neo4j.cypher.export.DatabaseSubGraph;
 import org.neo4j.cypher.export.SubGraph;
 import org.neo4j.graphdb.GraphDatabaseService;
@@ -88,7 +89,7 @@ private void preventBulkImport(ExportConfig config) {
     }
 
     private Stream<ProgressInfo> exportCsv(@Name("file") String fileName, String source, Object data, ExportConfig exportConfig) throws Exception {
-        checkWriteAllowed(exportConfig);
+        if (StringUtils.isNotBlank(fileName)) checkWriteAllowed(exportConfig);
         ProgressInfo progressInfo = new ProgressInfo(fileName, source, "csv");
         progressInfo.batchSize = exportConfig.getBatchSize();
         ProgressReporter reporter = new ProgressReporter(null, null, progressInfo);

src/main/java/apoc/export/cypher/ExportCypher.java

@@ -7,6 +7,7 @@
 import apoc.result.ProgressInfo;
 import apoc.util.QueueBasedSpliterator;
 import apoc.util.Util;
+import org.apache.commons.lang3.StringUtils;
 import org.neo4j.cypher.export.CypherResultSubGraph;
 import org.neo4j.cypher.export.DatabaseSubGraph;
 import org.neo4j.cypher.export.SubGraph;
@@ -96,7 +97,7 @@ public Stream<DataProgressInfo> schema(@Name(value = "file",defaultValue = "") S
     }
 
     private Stream<DataProgressInfo> exportCypher(@Name("file") String fileName, String source, SubGraph graph, ExportConfig c, boolean onlySchema) throws IOException {
-        if (fileName != null) checkWriteAllowed(c);
+        if (StringUtils.isNotBlank(fileName)) checkWriteAllowed(c);
 
         ProgressInfo progressInfo = new ProgressInfo(fileName, source, "cypher");
         progressInfo.batchSize = c.getBatchSize();

src/main/java/apoc/export/cypher/FileManagerFactory.java

@@ -82,15 +82,23 @@ public StringExportCypherFileManager(boolean separatedFiles) {
         @Override
         public PrintWriter getPrintWriter(String type) throws IOException {
             if (this.separatedFiles) {
-                return new PrintWriter(writers.compute(type, (key, writer) -> writer == null ? new StringWriter() : writer));
+                return new PrintWriter(getStringWriter(type));
             } else {
-                return new PrintWriter(writers.compute(type.equals("csv") ? type : "cypher", (key, writer) -> writer == null ? new StringWriter() : writer));
+                switch (type) {
+                    case "csv":
+                    case "json":
+                    case "graphml":
+                        break;
+                    default:
+                        type = "cypher";
+                }
+                return new PrintWriter(getStringWriter(type));
             }
         }
 
         @Override
         public StringWriter getStringWriter(String type) {
-            return writers.get(type);
+            return writers.computeIfAbsent(type, (key) -> new StringWriter());
         }
 
         @Override

src/main/java/apoc/export/graphml/ExportGraphML.java

@@ -1,11 +1,16 @@
 package apoc.export.graphml;
 
+import apoc.Pools;
+import apoc.export.cypher.ExportFileManager;
+import apoc.export.cypher.FileManagerFactory;
 import apoc.export.util.ExportConfig;
 import apoc.export.util.NodesAndRelsSubGraph;
 import apoc.export.util.ProgressReporter;
 import apoc.result.ProgressInfo;
 import apoc.util.FileUtils;
+import apoc.util.QueueBasedSpliterator;
 import apoc.util.Util;
+import org.apache.commons.lang3.StringUtils;
 import org.neo4j.cypher.export.CypherResultSubGraph;
 import org.neo4j.cypher.export.DatabaseSubGraph;
 import org.neo4j.cypher.export.SubGraph;
@@ -14,17 +19,22 @@
 import org.neo4j.graphdb.Relationship;
 import org.neo4j.graphdb.Result;
 import org.neo4j.helpers.collection.Iterables;
-import org.neo4j.procedure.*;
+import org.neo4j.procedure.Context;
+import org.neo4j.procedure.Description;
+import org.neo4j.procedure.Mode;
+import org.neo4j.procedure.Name;
+import org.neo4j.procedure.Procedure;
+import org.neo4j.procedure.TerminationGuard;
 
-import javax.xml.stream.XMLStreamException;
 import java.io.PrintWriter;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 import static apoc.util.FileUtils.checkWriteAllowed;
-import static apoc.util.FileUtils.getPrintWriter;
 
 /**
  * @author mh
@@ -34,6 +44,9 @@ public class ExportGraphML {
     @Context
     public GraphDatabaseService db;
 
+    @Context
+    public TerminationGuard terminationGuard;
+
     @Procedure(name = "apoc.import.graphml",mode = Mode.WRITE)
     @Description("apoc.import.graphml(file,config) - imports graphml file")
     public Stream<ProgressInfo> file(@Name("file") String fileName, @Name("config") Map<String, Object> config) throws Exception {
@@ -90,14 +103,41 @@ public Stream<ProgressInfo> query(@Name("query") String query, @Name("file") Str
         return exportGraphML(fileName, source, graph, c);
     }
 
-    private Stream<ProgressInfo> exportGraphML(@Name("file") String fileName, String source, SubGraph graph, ExportConfig config) throws Exception, XMLStreamException {
-        if (fileName != null) checkWriteAllowed();
+    private Stream<ProgressInfo> exportGraphML(@Name("file") String fileName, String source, SubGraph graph, ExportConfig exportConfig) throws Exception {
+        if (StringUtils.isNotBlank(fileName)) checkWriteAllowed(exportConfig);
         ProgressReporter reporter = new ProgressReporter(null, null, new ProgressInfo(fileName, source, "graphml"));
-        PrintWriter printWriter = getPrintWriter(fileName, null);
         XmlGraphMLWriter exporter = new XmlGraphMLWriter();
-        exporter.write(graph, printWriter, reporter, config);
-        printWriter.flush();
-        printWriter.close();
-        return reporter.stream();
+        ExportFileManager cypherFileManager = FileManagerFactory.createFileManager(fileName, false, exportConfig.streamStatements());
+        final PrintWriter graphMl = cypherFileManager.getPrintWriter("graphml");
+        if (exportConfig.streamStatements()) {
+            long timeout = exportConfig.getTimeoutSeconds();
+            final ArrayBlockingQueue<ProgressInfo> queue = new ArrayBlockingQueue<>(1000);
+            ProgressReporter reporterWithConsumer = reporter.withConsumer(
+                    (pi) -> {
+                        Util.put(queue, pi == ProgressInfo.EMPTY ? ProgressInfo.EMPTY : new ProgressInfo(pi).drain(cypherFileManager.getStringWriter("graphml")), timeout);
+                        closeWriter(graphMl);
+                    }
+            );
+            Util.inTxFuture(Pools.DEFAULT, db, () -> {
+                exporter.write(graph, graphMl, reporterWithConsumer, exportConfig);
+                return true;
+            });
+            QueueBasedSpliterator<ProgressInfo> spliterator = new QueueBasedSpliterator<>(queue, ProgressInfo.EMPTY, terminationGuard, timeout);
+            return StreamSupport.stream(spliterator, false);
+        } else {
+            exporter.write(graph, graphMl, reporter, exportConfig);
+            closeWriter(graphMl);
+            return reporter.stream();
+        }
     }
+
+    private void closeWriter(PrintWriter writer) {
+        writer.flush();
+        try {
+            writer.close();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
 }

src/main/java/apoc/export/graphml/XmlGraphMLWriter.java

@@ -36,6 +36,7 @@ public void write(SubGraph graph, Writer writer, Reporter reporter, ExportConfig
             reporter.update(0, 1, props);
         }
         writeFooter(xmlWriter);
+        reporter.done();
     }
 
     private void writeKey(XMLStreamWriter writer, SubGraph ops, ExportConfig config) throws Exception {

src/main/java/apoc/export/json/ExportJson.java

@@ -1,12 +1,15 @@
 package apoc.export.json;
 
+import apoc.Pools;
 import apoc.export.cypher.ExportFileManager;
 import apoc.export.cypher.FileManagerFactory;
 import apoc.export.util.ExportConfig;
 import apoc.export.util.NodesAndRelsSubGraph;
 import apoc.export.util.ProgressReporter;
 import apoc.result.ProgressInfo;
+import apoc.util.QueueBasedSpliterator;
 import apoc.util.Util;
+import org.apache.commons.lang3.StringUtils;
 import org.neo4j.cypher.export.DatabaseSubGraph;
 import org.neo4j.cypher.export.SubGraph;
 import org.neo4j.graphdb.GraphDatabaseService;
@@ -17,20 +20,25 @@
 import org.neo4j.procedure.Description;
 import org.neo4j.procedure.Name;
 import org.neo4j.procedure.Procedure;
+import org.neo4j.procedure.TerminationGuard;
 
-import java.io.PrintWriter;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 import static apoc.util.FileUtils.checkWriteAllowed;
 
 public class ExportJson {
     @Context
     public GraphDatabaseService db;
 
+    @Context
+    public TerminationGuard terminationGuard;
+
     public ExportJson(GraphDatabaseService db) {
         this.db = db;
     }
@@ -72,20 +80,34 @@ public Stream<ProgressInfo> query(@Name("query") String query, @Name("file") Str
         return exportJson(fileName, source,result,config);
     }
 
-    private Stream<ProgressInfo> exportJson(@Name("file") String fileName, String source, Object data, Map<String,Object> config) throws Exception {
-        ExportConfig c = new ExportConfig(config);
-        checkWriteAllowed(c);
+    private Stream<ProgressInfo> exportJson(String fileName, String source, Object data, Map<String,Object> config) throws Exception {
+        ExportConfig exportConfig = new ExportConfig(config);
+        if (StringUtils.isNotBlank(fileName)) checkWriteAllowed(exportConfig);
         ProgressReporter reporter = new ProgressReporter(null, null, new ProgressInfo(fileName, source, "json"));
         JsonFormat exporter = new JsonFormat(db);
-
-        ExportFileManager cypherFileManager = FileManagerFactory.createFileManager(fileName, false, c.streamStatements());
-
-        try (PrintWriter printWriter = cypherFileManager.getPrintWriter("json")) {
-            if (data instanceof SubGraph)
-                exporter.dump(((SubGraph)data),cypherFileManager,reporter,c);
-            if (data instanceof Result)
-                exporter.dump(((Result)data),printWriter,reporter,c);
+        ExportFileManager cypherFileManager = FileManagerFactory.createFileManager(fileName, false, exportConfig.streamStatements());
+        if (exportConfig.streamStatements()) {
+            long timeout = exportConfig.getTimeoutSeconds();
+            final ArrayBlockingQueue<ProgressInfo> queue = new ArrayBlockingQueue<>(1000);
+            ProgressReporter reporterWithConsumer = reporter.withConsumer(
+                    (pi) -> Util.put(queue, pi == ProgressInfo.EMPTY ? ProgressInfo.EMPTY : new ProgressInfo(pi).drain(cypherFileManager.getStringWriter("json")), timeout)
+            );
+            Util.inTxFuture(Pools.DEFAULT, db, () -> {
+                dump(data, exportConfig, reporterWithConsumer, exporter, cypherFileManager);
+                return true;
+            });
+            QueueBasedSpliterator<ProgressInfo> spliterator = new QueueBasedSpliterator<>(queue, ProgressInfo.EMPTY, terminationGuard, timeout);
+            return StreamSupport.stream(spliterator, false);
+        } else {
+            dump(data, exportConfig, reporter, exporter, cypherFileManager);
+            return reporter.stream();
         }
-        return reporter.stream();
+    }
+
+    private void dump(Object data, ExportConfig c, ProgressReporter reporter, JsonFormat exporter, ExportFileManager cypherFileManager) throws Exception {
+        if (data instanceof SubGraph)
+            exporter.dump(((SubGraph)data),cypherFileManager,reporter,c);
+        if (data instanceof Result)
+            exporter.dump(((Result)data),cypherFileManager,reporter,c);
     }
 }

src/main/java/apoc/export/json/JsonFormat.java

@@ -11,7 +11,12 @@
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.util.MinimalPrettyPrinter;
 import org.neo4j.cypher.export.SubGraph;
-import org.neo4j.graphdb.*;
+import org.neo4j.graphdb.GraphDatabaseService;
+import org.neo4j.graphdb.Node;
+import org.neo4j.graphdb.Path;
+import org.neo4j.graphdb.Relationship;
+import org.neo4j.graphdb.Result;
+import org.neo4j.graphdb.Transaction;
 
 import java.io.IOException;
 import java.io.Reader;
@@ -34,12 +39,15 @@ public ProgressInfo load(Reader reader, Reporter reporter, ExportConfig config)
     }
 
     private ProgressInfo dump(Writer writer, Reporter reporter, Consumer<JsonGenerator> consumer) throws Exception {
-        try (Transaction tx = db.beginTx(); JsonGenerator jsonGenerator = getJsonGenerator(writer);) {
-
+        try (Transaction tx = db.beginTx();
+             JsonGenerator jsonGenerator = getJsonGenerator(writer)) {
             consumer.accept(jsonGenerator);
-
+            jsonGenerator.flush();
             tx.success();
+            reporter.done();
             return reporter.getTotal();
+        } finally {
+            writer.close();
         }
     }
 
@@ -56,7 +64,7 @@ public ProgressInfo dump(SubGraph graph, ExportFileManager writer, Reporter repo
         return dump(writer.getPrintWriter("json"), reporter, consumer);
     }
 
-    public ProgressInfo dump(Result result, Writer writer, Reporter reporter, ExportConfig config) throws Exception {
+    public ProgressInfo dump(Result result, ExportFileManager writer, Reporter reporter, ExportConfig config) throws Exception {
         Consumer<JsonGenerator> consumer = (jsonGenerator) -> {
             try {
                 String[] header = result.columns().toArray(new String[result.columns().size()]);
@@ -69,14 +77,14 @@ public ProgressInfo dump(Result result, Writer writer, Reporter reporter, Export
                 throw new RuntimeException(e);
             }
         };
-        return dump(writer, reporter, consumer);
+        return dump(writer.getPrintWriter("json"), reporter, consumer);
     }
 
     private JsonGenerator getJsonGenerator(Writer writer) throws IOException {
-        JsonFactory jsonF = new JsonFactory();
-        JsonGenerator jsonGenerator = jsonF.createGenerator(writer);
-        jsonGenerator.setCodec(JsonUtil.OBJECT_MAPPER);
-        jsonGenerator.setPrettyPrinter(new MinimalPrettyPrinter("\n"));
+        JsonGenerator jsonGenerator = new JsonFactory()
+                .createGenerator(writer)
+                .setCodec(JsonUtil.OBJECT_MAPPER)
+                .setPrettyPrinter(new MinimalPrettyPrinter("\n"));
         return jsonGenerator;
     }
 
@@ -158,7 +166,6 @@ private void write(Reporter reporter, JsonGenerator jsonGenerator, ExportConfig
                 JsonFormatSerializer.DEFAULT.serializeProperty(jsonGenerator, keyName, value, writeKey);
                 reporter.update(0, 0, 1);
                 break;
-
         }
     }