flowable/flowable-engine · error · FlowableIllegalArgumentException

Multipart request is required

Error message

Multipart request is required

What it means

POST /dmn-repository/deployments only accepts multipart/form-data. The handler checks whether the incoming HttpServletRequest is a Spring MultipartHttpServletRequest and throws FlowableIllegalArgumentException if not. This is a request-shape validation: the deployment API always requires uploaded file parts.

Source

Thrown at modules/flowable-dmn-rest/src/main/java/org/flowable/dmn/rest/service/api/repository/DmnDeploymentCollectionResource.java:159

    @ApiOperation(value = "Create a new decision deployment", nickname = "uploadDecisionDeployment", tags = {
            "Deployment" }, consumes = "multipart/form-data", produces = "application/json", notes = "The request body should contain data of type multipart/form-data. There should be exactly one file in the request, any additional files will be ignored. The deployment name is the name of the file-field passed in. If multiple resources need to be deployed in a single deployment, compress the resources in a zip and make sure the file-name ends with .bar or .zip.\n"
                    + "\n"
                    + "An additional parameter (form-field) can be passed in the request body with name tenantId. The value of this field will be used as the id of the tenant this deployment is done in.",
            code = 201)
    @ApiResponses(value = {
            @ApiResponse(code = 201, message = "Indicates the deployment was created."),
            @ApiResponse(code = 400, message = "Indicates there was no content present in the request body or the content mime-type is not supported for deployment. The status-description contains additional information.")
    })
    @ApiImplicitParams({
        @ApiImplicitParam(name="file", paramType = "form", dataType = "java.io.File")
    })
    @PostMapping(value = "/dmn-repository/deployments", produces = "application/json", consumes = "multipart/form-data")
    @ResponseStatus(HttpStatus.CREATED)
    public DmnDeploymentResponse uploadDeployment(@ApiParam(name = "tenantId") @RequestParam(value = "tenantId", required = false) String tenantId, HttpServletRequest request) {

        if (!(request instanceof MultipartHttpServletRequest)) {
            throw new FlowableIllegalArgumentException("Multipart request is required");
        }
        
        if (restApiInterceptor != null) {
            restApiInterceptor.executeNewDeploymentForTenantId(tenantId);
        }

        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();

        try {
            DmnDeploymentBuilder deploymentBuilder = dmnRepositoryService.createDeployment();
            String fileName = file.getOriginalFilename();
            if (StringUtils.isEmpty(fileName) || !DmnResourceUtil.isDmnResource(fileName)) {

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Send the request as multipart/form-data with the .dmn file as a file part (curl -F 'file=@decision.dmn').
2. Ensure the client library attaches files as form-data parts, not as a JSON body.
3. Verify multipart support is enabled (spring.servlet.multipart.enabled=true in Spring Boot).
4. Confirm no intermediary proxy rewrites the Content-Type or body.

Example fix

// before
curl -X POST -H 'Content-Type: application/json' -d '{"file":"decision.dmn"}' http://host/flowable-dmn/dmn-repository/deployments
// after
curl -X POST -F 'file=@decision.dmn' http://host/flowable-dmn/dmn-repository/deployments

const ct = request.headers['content-type'] || '';
if (!ct.includes('multipart/form-data')) throw new Error('must send multipart/form-data');

try { return await deploy(file); }
catch (e) { if (e.status === 400 && /Multipart request/.test(e.message)) { console.error('send multipart/form-data with a file part'); } throw e; }

When it happens

Trigger: Sending POST /dmn-repository/deployments with Content-Type application/json, application/x-www-form-urlencoded, or missing multipart parts, so Spring never wraps the request as multipart.

Common situations: REST clients forgetting to set 'Content-Type: multipart/form-data' (or the boundary), curl calls using -d instead of -F, proxies/gateways stripping the multipart wrapper, or the servlet multipart support not being enabled in Spring Boot config.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Multipart request is required
• No variable name was found in request body.
• Multipart request with file content is required
• No file content was found in request body.
• No variable name was found in request body.

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/a49330a317fb57ff. Report an issue: GitHub.