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;
@@ -40,6 +43,7 @@ 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.exception.SolidifyHttpErrorException;
 import ch.unige.solidify.rest.FacetPage;
@@ -82,7 +86,7 @@ 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,
@@ -114,20 +118,42 @@ 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)));
+
+    // build the responseBody as stream
+    StreamingResponseBody responseBody = outputStream -> {
+      int numberOfBytesToWrite;
+      byte[] data = new byte[1024];
+      while ((numberOfBytesToWrite = is.read(data, 0, data.length)) != -1) {
+        outputStream.write(data, 0, numberOfBytesToWrite);
+      }
+      is.close();
+    };
+
+    return new ResponseEntity(responseBody, headers, HttpStatus.OK);
+
   }
 
 
-  public HttpHeaders getHeaders(ExportFormat format) {
+  private 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;
+      case XML -> {
+        headers.setContentType(MediaType.APPLICATION_XML);
+        headers.setContentDispositionFormData("attachment", "bibliography.xml");
+      }
+      case JSON -> {
+        headers.setContentType(MediaType.APPLICATION_JSON);
+        headers.setContentDispositionFormData("attachment", "bibliography.json");
+      }
+      case CSV -> {
+        headers.setContentType(MediaType.TEXT_PLAIN);
+        headers.setContentDispositionFormData("attachment", "bibliography.txt");
+      }
     }
     return headers;
   }

[Florent Poittevin]

Utiliser plutôt buildDownloadResponseEntity