chore[aou-1869]: refactor export bibliograpy endpoint

refactor controller to return a stream instead of string.

Closes: AOU-1869

AoU-Admin/src/main/java/ch/unige/aou/controller/admin/ExportMetadataController.java

@@ -23,7 +23,10 @@
 
 package ch.unige.aou.controller.admin;
 
-
+import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -32,15 +35,14 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.http.HttpEntity;
-import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
-import org.springframework.http.MediaType;
-import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;
 
+import ch.unige.solidify.controller.SolidifyController;
 import ch.unige.solidify.exception.SolidifyHttpErrorException;
 import ch.unige.solidify.rest.FacetPage;
 import ch.unige.solidify.rest.FacetRequest;
@@ -64,7 +66,7 @@ import ch.unige.aou.service.query.QueryBuilderService;
 @EveryonePermissions
 @ConditionalOnBean(AdminController.class)
 @RequestMapping(UrlPath.ADMIN_EXPORT_PUBLICATIONS)
-public class ExportMetadataController {
+public class ExportMetadataController extends SolidifyController {
 
   private final QueryBuilderService queryBuilderService;
   private final ExportMetadataService exportMetadataService;
@@ -72,7 +74,7 @@ public class ExportMetadataController {
   private final IndexResourceService<String, PublicationIndexEntry> indexResourceService;
   private final String indexName;
 
-  public ExportMetadataController(AouProperties aouProperties,QueryBuilderService queryBuilderService,
+  public ExportMetadataController(AouProperties aouProperties, QueryBuilderService queryBuilderService,
           IndexResourceService<String, PublicationIndexEntry> indexResourceService,
           ExportMetadataService exportMetadataService) {
     this.queryBuilderService = queryBuilderService;
@@ -82,14 +84,15 @@ public class ExportMetadataController {
   }
 
   @GetMapping(value = "/" + AouActionName.EXPORT)
-  public HttpEntity<String> getExportBibliography(
+  public HttpEntity<StreamingResponseBody> getExportBibliography(
           @RequestParam(name = "searches", required = false) String commaSeparatedSearchIds,
           @RequestParam(name = "publicationIds", required = false) String commaSeparatedPublicationIds,
           @RequestParam(name = "days", required = false) String searchFrom,
           @RequestParam(name = "format") String format) {
 
     ExportFormat exportFormat = ExportFormat.fromValue(format);
-    if (StringTool.isNullOrEmpty(commaSeparatedSearchIds) && StringTool.isNullOrEmpty(commaSeparatedPublicationIds) && StringTool.isNullOrEmpty(searchFrom)) {
+    if (StringTool.isNullOrEmpty(commaSeparatedSearchIds) && StringTool.isNullOrEmpty(commaSeparatedPublicationIds) && StringTool.isNullOrEmpty(
+            searchFrom)) {
       throw new SolidifyHttpErrorException(HttpStatus.BAD_REQUEST, "Either one search id or one publication id or a date is required");
     }
 
@@ -103,7 +106,8 @@ public class ExportMetadataController {
       publicationIds.addAll(Arrays.stream(commaSeparatedPublicationIds.split(",")).map(String::trim).toList());
     }
 
-    AouSearchCondition searchConditions = this.queryBuilderService.getSearchesOrPublicationsSearchCondition(searchFrom, searchIds, publicationIds);
+    AouSearchCondition searchConditions = this.queryBuilderService.getSearchesOrPublicationsSearchCondition(searchFrom, searchIds,
+            publicationIds);
 
     List<FacetRequest> facetRequests = new ArrayList<>(); // not interested in facets here
     List<SearchCondition> searchConditionList = this.queryBuilderService.replaceAliasesByIndexField(List.of(searchConditions));
@@ -114,21 +118,27 @@ public class ExportMetadataController {
     if (!results.getContent().isEmpty()) {
       result = this.exportMetadataService.exportMetadata(exportFormat, results.getContent());
     }
-    HttpHeaders headers = this.getHeaders(exportFormat);
-    return new ResponseEntity<>(result, headers, HttpStatus.OK);
+
+    // convert the string result to Inputstream
+    InputStream is = new BufferedInputStream(new ByteArrayInputStream(result.getBytes(StandardCharsets.UTF_8)));
+
+    return this.buildDownloadResponseEntity(is, this.getFileName(exportFormat), this.getContentType(exportFormat), 0L);
+
   }
 
+  private String getFileName(ExportFormat format) {
+    return switch (format) {
+      case XML -> "bibliography.xml";
+      case JSON -> "bibliography.json";
+      case CSV -> "bibliography.csv";
+    };
+  }
 
-  public HttpHeaders getHeaders(ExportFormat format) {
-    HttpHeaders headers = new HttpHeaders();
-    switch (format) {
-      case XML: headers.setContentType(MediaType.APPLICATION_XML);
-          break;
-      case JSON: headers.setContentType(MediaType.APPLICATION_JSON);
-        break;
-      case CSV: headers.setContentType(MediaType.TEXT_PLAIN);
-        break;
-    }
-    return headers;
+  private String getContentType(ExportFormat format) {
+    return switch (format) {
+      case CSV -> "text/csv";
+      case XML -> "application/xml";
+      case JSON -> "application/json";
+    };
   }
 }