Rest API endpoint for generating CSV file with data gathered from DB

Question

Stuck with composing CSV file from list of gathered data from db in reactive way.

My controller:

@RestController
@RequestMapping("/v1/foo")
@RequiredArgsConstructor
public class FooController {

    private final FooService paymentService;

    @GetMapping(value = "/export")
    @Validated
    public Mono<ResponseEntity> export(FooQuery query) {
        return fooService.export(query) // return Flux<Foo>
                             .collectList()
                             .map(foos -> ResponseEntity.ok()
                                                        .contentType(MediaType.valueOf("text/csv"))
                                                        // Somehow I need to generate CSV format resource and pass it to body(), but no clue how to do that.
                                                        .body(foos));
    }

}

How I can generate CSV format resource to pass it to body()?

Solution:

@GetMapping(value = "/export", produces = {"text/csv"})
    @Validated
    public Mono<ResponseEntity> export(FooQuery query) {
        return fooService.export(query) // return Flux<Foo>
                             .collectList()
                             .map(foos -> ResponseEntity.ok()
                                                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=export.csv")
                                                        .body("ffd;fdfddf;ddddd;")); 
                                                        // Need to convert List<Foo> to correct csv string that it'll work otherwise 406 NOT_ACCEPTABLE "Could not find acceptable representation"
    }

asfmlr · Accepted Answer · 2019-09-19 13:22:32Z

1

once you have the String csv Im using HttpServletResponse object instead the ResponseEntity like that:

 response.addHeader("Access-Control-Expose-Headers", "content-disposition, Content-Type");
            response.addHeader(HttpHeaders.CONTENT_DISPOSITION, "inline;filename=" + filename);
            response.setContentType("text/csv");
            OutputStream out = response.getOutputStream();
            out.write(csv.getBytes());
            out.flush();

answered Sep 19, 2019 at 13:22

asfmlr

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1 Comment

Viktor M. Over a year ago

One hint I got from your suggestion regarding added CONTENT_DISPOSITION, thanks.

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