[BACKLOG-42356] Check if the file already exists before saving

extensions/src/main/java/org/pentaho/platform/web/http/api/resources/FileResource.java

@@ -102,6 +102,7 @@
 import java.io.OutputStream;
 import java.io.StringReader;
 import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.nio.channels.IllegalSelectorException;
 import java.security.GeneralSecurityException;
@@ -490,6 +491,39 @@ public Response doGetFileOrDir( @PathParam ( "pathId" ) String pathId ) {
       return buildStatusResponse( Response.Status.FORBIDDEN );
     }
   }
+  /**
+   * Checks if a file exists at the specified path in the repository.
+   *
+   * <p><b>Example Request:</b><br />
+   *    GET pentaho/api/repo/exists?pathId=%2Fhome%2Fuser%2Ftest_file.wtr
+   * </p>
+   *
+   * @param pathId Encoded path of the repository file to check. Must be URL-encoded.
+   *
+   * @return A jax-rs Response object with the appropriate status code
+   */
+
+  @GET
+  @Path( "/exists" )
+  @StatusCodes( {
+          @ResponseCode( code = 200, condition = "Successfully finds the file." ),
+          @ResponseCode( code = 404, condition = "Invalid Input." ),
+          @ResponseCode( code = 404, condition = "Failed to find the file." ),
+          @ResponseCode( code = 500, condition = "For any other exceptions." )
+  } )
+  public Response doesFileExists( @QueryParam ( "pathId" ) String pathId ) {
+    try {
+      boolean fileExists = fileService.doesExist( URLDecoder.decode( pathId, "UTF-8" ) );
+      if ( !fileExists ) {
+        return buildStatusResponse( Response.Status.NOT_FOUND );
+      }
+    } catch ( UnsupportedEncodingException e ) {
+      return buildStatusResponse( Response.Status.BAD_REQUEST );
+    } catch ( Exception e ) {
+      return buildStatusResponse( Response.Status.INTERNAL_SERVER_ERROR );
+    }
+    return buildOkResponse();
+  }
 
   // Overloaded this method to try and minimize calls to the repo
   // Had to unmap this method since browsers ask for resources with Accepts="*/*" which will default to this method

extensions/src/test/java/org/pentaho/platform/web/http/api/resources/FileResourceTest.java

@@ -69,6 +69,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.net.URLDecoder;
 import java.nio.channels.IllegalSelectorException;
 import java.security.GeneralSecurityException;
 import java.security.InvalidParameterException;
@@ -715,6 +716,33 @@ public void testDoIsParameterizable() throws Exception {
     verify( mockAttribElement, times( 1 ) ).attributeValue( "value" );
   }
 
+  @Test
+  public void testDoesFileExists() throws Exception {
+    // Test Case 1: File exists, expect 200 (OK)
+    String validPathId = "validPathId";
+    doReturn( true ).when( fileResource.fileService ).doesExist( URLDecoder.decode(
+            validPathId, "UTF-8" ) );
+
+    Response response = fileResource.doesFileExists( validPathId );
+    assertEquals( Response.Status.OK.getStatusCode(), response.getStatus() );
+
+    // Test Case 2: File does not exist, expect 404 ( not found)
+    String invalidPathId = "invalidPathId";
+    doReturn( false ).when( fileResource.fileService ).doesExist( URLDecoder.decode(
+            invalidPathId, "UTF-8" ) );
+
+    response = fileResource.doesFileExists( invalidPathId );
+    assertEquals( Response.Status.NOT_FOUND.getStatusCode(), response.getStatus() );
+
+    // Test Case 3: Unexpected exception occurs, expect 500 (internal server error)
+    String pathIdForError = "pathForError";
+    doThrow( new RuntimeException( "Unexpected error" ) ).when( fileResource.fileService ).doesExist( URLDecoder.decode(
+            pathIdForError, "UTF-8" ) );
+
+    response = fileResource.doesFileExists( pathIdForError );
+    assertEquals( Response.Status.INTERNAL_SERVER_ERROR.getStatusCode(), response.getStatus( ) );
+  }
+
   @Test
   public void testDoIsParameterizableError() throws Exception {