This is the request for items:
POST _bulk
{"index":{"_index":"orly-test","_type":"doc","_id":"item_39"}}
{"resulttype":"Item","model":"Item","modelid":39,"featured":false,"public":true,"created":"2018-06-22T16:36:13+00:00","updated":"2020-04-07T16:04:44+00:00","title":"1\u0414\u043e\u043a\u043b\u0430\u0434\u043d\u044b\u0435 \u0437\u0430\u043f\u0438\u0441\u043a\u0438 \u043e\u0431 \u0430\u0433\u0435\u043d\u0442\u0443\u0440\u043d\u043e-\u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u043e\u0439 \u0440\u0430\u0431\u043e\u0442\u0435 \u043e\u0440\u0433\u0430\u043d\u043e\u0432 \u041d\u041a\u0412\u0414: \u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u044b\u0435 \u0434\u0430\u043d\u043d\u044b\u0435 \u043e \u0442\u0440\u043e\u0446\u043a\u0438\u0441\u0442\u0430\u0445 \u0438 \u043f\u0440\u0430\u0432\u044b\u0445 \u0441\u0438\u043e\u043d\u0438\u0441\u0442\u0430\u0445","collection":"1\u0421\u0411\u0423, \u041a\u0438\u0435\u0432, \u0424. 16: \u0421\u0435\u043a\u0440\u0435\u0442\u0430\u0440\u0438\u0430\u0442 \u0413\u041f\u0423-\u041a\u0413\u0411 \u0423\u0421\u0421\u0420","itemtype":"Text","element":{"identifier":"sbu_kv_16_34_30-1935","source":"1\u041e\u0413\u0410 \u0421\u0411\u0423, \u041a\u0438\u0435\u0432, \u0444.16, \u0434.34 ","ispartof":"1\u041e\u0442\u0440\u0430\u0441\u043b\u0435\u0432\u043e\u0439 \u0433\u043e\u0441\u0443\u0434\u0430\u0440\u0441\u0442\u0432\u0435\u043d\u043d\u044b\u0439 \u0430\u0440\u0445\u0438\u0432 \u0421\u043b\u0443\u0436\u0431\u044b \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0423\u043a\u0440\u0430\u0438\u043d\u044b, \u041a\u0438\u0435\u0432, \u0424.16: \u0441\u0435\u043a\u0440\u0435\u0442\u0430\u0440\u0438\u0430\u0442 \u0413\u041f\u0423-\u041a\u0413\u0411 \u0423\u0421\u0421\u0420 ","title":"1\u0414\u043e\u043a\u043b\u0430\u0434\u043d\u044b\u0435 \u0437\u0430\u043f\u0438\u0441\u043a\u0438 \u043e\u0431 \u0430\u0433\u0435\u043d\u0442\u0443\u0440\u043d\u043e-\u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u043e\u0439 \u0440\u0430\u0431\u043e\u0442\u0435 \u043e\u0440\u0433\u0430\u043d\u043e\u0432 \u041d\u041a\u0412\u0414: \u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u044b\u0435 \u0434\u0430\u043d\u043d\u044b\u0435 \u043e \u0442\u0440\u043e\u0446\u043a\u0438\u0441\u0442\u0430\u0445 \u0438 \u043f\u0440\u0430\u0432\u044b\u0445 \u0441\u0438\u043e\u043d\u0438\u0441\u0442\u0430\u0445","temporalcoverage":"1935 ","extent":"1491 \u043b. (\u043f\u043e\u0434\u0431\u043e\u0440\u043a\u0430 \u201278 \u0441.)","contributor":"Benyamin Lukin"},"elements":[{"displayName":"Identifier","name":"identifier"},{"displayName":"Source","name":"source"},{"displayName":"Is Part Of","name":"ispartof"},{"displayName":"Title","name":"title"},{"displayName":"Temporal Coverage","name":"temporalcoverage"},{"displayName":"Extent","name":"extent"},{"displayName":"Contributor","name":"contributor"}],"tags":["\u0417\u0430\u043f\u043e\u0440\u043e\u0436\u044c\u0435 (\u0410\u043b\u0435\u043a\u0441\u0430\u043d\u0434\u0440\u043e\u0432\u0441\u043a)","\u041a\u0438\u0435\u0432","\u041a\u043e\u043d\u0441\u0442\u0430\u043d\u0442\u0438\u043d\u043e\u0432\u043a\u0430","\u041e\u0434\u0435\u0441\u0441\u0430","\u0420\u043e\u0432\u043d\u043e (R\u00f3wne)","\u0425\u0430\u0440\u044c\u043a\u043e\u0432","\u0427\u0435\u0440\u043d\u0438\u0433\u043e\u0432"]}
The request for files:
POST _bulk
{"index":{"_index":"orly-test","_type":"doc","_id":"file_40"}}
{"resulttype":"File","model":"File","modelid":40,"featured":false,"public":false,"created":"2018-06-22T16:36:20+00:00","updated":"2020-04-07T16:04:44+00:00","title":null,"item_id":39,"filename":"54822b6858b46c3a802a3b135ef67fc2.pdf","original_filename":"original_filename","size":17582964,"mime_type":"application\/pdf","element":{"text":"1\u0413\u0410\u041b\u0423\u0417\u0415\u0412\u0418\u0419 \u0414\u0415\u0420\u0416\u0410\u0412\u041d\u0418\u0419 \u0410\u0420\u04251\u0412\n\u0421\u041b\u0423\u0416\u0411\u0418 \u0411\u0415\u0417\u041f\u0415\u041a\u0418 \u0423\u041a\u0420\u0410\u0428\u0418\n\n\u042d \u0415!\u0425(!\u0432 \u0418\u0417 : 5 .\u00ab\u0441\u0422\u042f\u043a\n\n\u0421\u0415\u041a\u0420\u0415\u0422\u0410\u04201\u0410\u0422 \u0414\u041f\u0423 \u0423\u0421\u0420\u0420 - \u041a\u0414\u0411 \u0423\u0420\u0421\u0420\n\n\u0428\u0424\u041e\u0420\u041c\u0410\u0429\u0419\u041d1\u041f\u041e\u04121\u0414\u041e\u041c\u041b\u0415\u041d\u041d\u042f \u041f\u0420\u041e\n\u041e\u041f\u0415\u0420\u0410\u0422\u0418\u0412\u041d\u041e-\u0421\u041b1\u0414\u0427\u0423 \u0420\u041e\u0411\u041e\u0422\u0423 \u0421\u0422\u0420\u0423\u041a\u0422\u0423\u0420\u041d\u0418\u0425\n\u0428\u0414\u0420\u041e\u0417\u04141\u041b1\u0412 \u0423\u0414\u0411 \u041d\u041a\u0412\u0421 \u0423\u0420\u0421\u0420, \u041f\u0415\u0420\u041b\u042e\u0421\u0422\u0420\u0410\u04261\u042e\n\u041a\u041e\u0420\u0415\u0421\u041f\u041e\u041d\u0414\u0415\u041d\u0426\u041f \u0422\u0410 \u0412\u0418\u042f\u0412\u041b\u0415\u041d\u041d\u042f"},"elements":[{"displayName":"Text","name":"text"}]}
The text for files is very big, so I have truncated it a lot for this example. In the requests the maximum size for bulk is 500.