WIP XLSX export

src/main/java/tech/ailef/dbadmin/external/controller/DataExportController.java

@@ -1,12 +1,21 @@
 package tech.ailef.dbadmin.external.controller;
 
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+
 import java.io.StringWriter;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.apache.commons.csv.CSVFormat;
 import org.apache.commons.csv.CSVPrinter;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.ResponseEntity;
@@ -23,6 +32,7 @@ import tech.ailef.dbadmin.external.dbmapping.DbAdminRepository;
 import tech.ailef.dbadmin.external.dbmapping.DbField;
 import tech.ailef.dbadmin.external.dbmapping.DbObject;
 import tech.ailef.dbadmin.external.dbmapping.DbObjectSchema;
+import tech.ailef.dbadmin.external.dto.DataExportFormat;
 import tech.ailef.dbadmin.external.dto.QueryFilter;
 import tech.ailef.dbadmin.external.exceptions.DbAdminException;
 import tech.ailef.dbadmin.external.misc.Utils;
@@ -39,32 +49,87 @@ public class DataExportController {
 
 	@GetMapping("/{className}")
 	@ResponseBody
-	public ResponseEntity<byte[]> export(@PathVariable String className,
+	public ResponseEntity<byte[]> export(@PathVariable String className, @RequestParam(required = false) String query,
-			@RequestParam(required=false) String query,
+			@RequestParam(required = false) String format, @RequestParam MultiValueMap<String, String> otherParams) {
-			@RequestParam MultiValueMap<String, String> otherParams) {
+
+		if (format == null)
+			format = "CSV";
+		DataExportFormat exportFormat = null;
+		try {
+			exportFormat = DataExportFormat.valueOf(format.toUpperCase());
+		} catch (IllegalArgumentException e) {
+			throw new DbAdminException("Unsupported export format: " + format);
+		}
+
+		List<String> fieldToInclude = otherParams.getOrDefault("fields[]", new ArrayList<>());
 
 		DbObjectSchema schema = dbAdmin.findSchemaByClassName(className);
 
+		List<DbField> fields = schema.getSortedFields().stream().filter(f -> fieldToInclude.contains(f.getName()))
+				.collect(Collectors.toList());
+
 		Set<QueryFilter> queryFilters = Utils.computeFilters(schema, otherParams);
 
 		List<DbObject> results = repository.search(schema, query, queryFilters);
 
-		String result = toCsv(results, schema.getSortedFields());
+		switch (exportFormat) {
-		return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION,
+		case CSV:
+			return ResponseEntity.ok()
+					.header(HttpHeaders.CONTENT_DISPOSITION,
 							"attachment; filename=\"export_" + schema.getJavaClass().getSimpleName() + ".csv\"")
-				.body(result.getBytes());
+					.body(toCsv(results, fields).getBytes());
+		case XLSX:
+			return ResponseEntity.ok()
+					.header(HttpHeaders.CONTENT_DISPOSITION,
+					"attachment; filename=\"export_" + schema.getJavaClass().getSimpleName() + ".xlsx\"")
+					.body(toXlsx(results, fields));
+		case JSON:
+			throw new DbAdminException("JSON TODO");
+		default:
+			throw new DbAdminException("Unable to detect export format");
+		}
+
+	}
+
+	private byte[] toXlsx(List<DbObject> items, List<DbField> fields) {
+		Workbook workbook = new XSSFWorkbook();
+
+		Sheet sheet = workbook.createSheet("SchemaName");
+
+		int rowIndex = 0;
+		for (DbObject item : items) {
+			Row row = sheet.createRow(rowIndex++);
+			int cellIndex = 0;
+			for (DbField field : fields) {
+				Cell cell = row.createCell(cellIndex++);
+				if (field.isForeignKey()) {
+					DbObject linkedItem = item.traverse(field);
+					cell.setCellValue(linkedItem.getPrimaryKeyValue() + " (" + linkedItem.getDisplayName() + ")");
+				} else {
+					cell.setCellValue(item.get(field).getFormattedValue());
+				}				
+			}
+		}
+		// lets write the excel data to file now
+		ByteArrayOutputStream fos = new ByteArrayOutputStream();
+		try {
+			workbook.write(fos);
+			fos.close();
+		} catch (IOException e) {
+			throw new DbAdminException("Error writing XLSX file");
+		}
+		return fos.toByteArray();
 	}
 
 	private String toCsv(List<DbObject> items, List<DbField> fields) {
-		if (items.isEmpty()) return "";
+		if (items.isEmpty())
+			return "";
 
 		StringWriter sw = new StringWriter();
 
 		String[] header = fields.stream().map(f -> f.getName()).toArray(String[]::new);
 
-	    CSVFormat csvFormat = CSVFormat.DEFAULT.builder()
+		CSVFormat csvFormat = CSVFormat.DEFAULT.builder().setHeader(header).build();
-	        .setHeader(header)
-	        .build();
 
 		try (final CSVPrinter printer = new CSVPrinter(sw, csvFormat)) {
 			for (DbObject item : items) {

src/main/java/tech/ailef/dbadmin/external/dto/DataExportFormat.java

@@ -0,0 +1,5 @@
+package tech.ailef.dbadmin.external.dto;
+
+public enum DataExportFormat {
+	CSV, XLSX, JSON;
+}