flowable/flowable-engine · error · FlowableIllegalArgumentException

Multipart request with file content is required

Error message

Multipart request with file content is required

What it means

Thrown by PUT /repository/models/{modelId}/source-extra when the request is multipart but contains no file parts (getFileMap().size() == 0). The resource takes the first file part and stores it as the extra editor source, so at least one file is mandatory.

Source

Thrown at modules/flowable-rest/src/main/java/org/flowable/rest/service/api/repository/ModelSourceExtraResource.java:88

    })
    @ApiResponses(value = {
            @ApiResponse(code = 204, message = "Indicates the model was found and the extra source has been updated."),
            @ApiResponse(code = 404, message = "Indicates the requested model was not found.")
    })
    @PutMapping(value = "/repository/models/{modelId}/source-extra", consumes = "multipart/form-data")
    @ResponseStatus(HttpStatus.NO_CONTENT)
    public void setModelSource(@ApiParam(name = "modelId") @PathVariable String modelId, HttpServletRequest request) {
        Model model = getModelFromRequest(modelId);
        try {

            if (!(request instanceof MultipartHttpServletRequest)) {
                throw new FlowableIllegalArgumentException("Multipart request is required");
            }

            MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;

            if (multipartRequest.getFileMap().size() == 0) {
                throw new FlowableIllegalArgumentException("Multipart request with file content is required");
            }

            MultipartFile file = multipartRequest.getFileMap().values().iterator().next();

            repositoryService.addModelEditorSourceExtra(model.getId(), file.getBytes());

        } catch (Exception e) {
            throw new FlowableException("Error adding model editor source extra", e);
        }
    }

}

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Include an actual file part in the form (curl -F 'file=@extra.xml')
2. Verify the file path exists and is readable on the client machine
3. Inspect the request with a proxy to confirm the file part appears in the body
4. Check the HTTP client's multipart builder marks the part as a file, not a text field

Example fix

// before
curl -X PUT -F 'description=extra source' .../models/id/source-extra
// after
curl -X PUT -F 'file=@extra.xml' -F 'description=extra source' .../models/id/source-extra

if (!java.nio.file.Files.exists(path)) throw new IllegalArgumentException("file part missing/unreadable: " + path);

try { setModelSource(modelId, request); } catch (FlowableIllegalArgumentException e) { log.error("multipart body had no file part", e); }

When it happens

Trigger: POSTing multipart/form-data with only text fields, empty file parts, or a malformed body where the parser finds no files; e.g. curl -F 'name=x' with no file=@ entry.

Common situations: Clients sending multipart with only metadata fields; scripting errors building the form; file paths that failed to resolve so the part was omitted; Content-Disposition not marked as a file part.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Multipart request is required
• Multipart request is required
• Multipart request with file content is required
• Multipart request is required
• Multipart request with file content is required

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/0a984c411270b3d5. Report an issue: GitHub.