Access the binary content file via webhook during the import process.

Introduction

If an object is imported to yuuvis® Momentum, a binary content file can be assigned in addition to the object's metadata. The storage of the binary content file is managed by the REPOSITORY service. Afterwards, the metadata are stored in a separate database and indexed for search.
>> Basic Use Case Flows

As soon as the object import process is finished, the binary content file can be accessed as well. Especially, it can be analysed in order to set some content-related metadata properties for the corresponding object. The metadata update is possible, i.e., via POST or PATCH /api/dms/objects/{objectId} and triggers the creation of a new object version. However, in some use cases, it might be necessary to set metadata properties depending on an analysis of the corresponding binary content file already for the first version of the imported object. For this purpose, the binary content file can be accessed from a webhook that is called after storing the content and before storing the metadata. This tutorial describes an example solution using an internal endpoint of the REPOSITORY service.

Setting up the Webhook Service

The webhook entry point has to be located after storing the binary content file and before storing the metadata in the process chain of an object import. For this purpose, the type dms.request.objects.upsert.database-before is suitable.

The tutorial Preprocessing Metadata using Webhooks provides a general example on how to configure and set up your own webhook service. A more specific example controller class for a webhook service for our concrete use case is provided in the code block below. For each object imported with a binary content file, the MD5 digest of the corresponding content is calculated.

Especially in the case of a batch import, it is necessary to iterate over the individual objects as the repository can only retrieve the content of one object at a time.

Calculate MD5-Digest of binary content before import

@RestController
@RequestMapping("/api")
public class WebhookRestController
{    
    @PostMapping(value = "/process/checkcontent", produces = "application/json;charset=UTF-8", consumes = "application/json")
    public ResponseEntity<?> checkContent(@RequestBody final Map<String, Object> dmsApiObList, @RequestHeader HttpHeaders incomingHeaders) throws Exception
    {
        try
        {
            String authorization = incomingHeaders.getFirst(HttpHeaders.AUTHORIZATION);
            List<Map<String, Object>> apiObjectList = (List<Map<String, Object>>)dmsApiObList.get("objects");

            for (Map<String, Object> apiObject : apiObjectList)
            {
                String objectId = (String)getMap(getMap(apiObject, "properties"), "system:objectId").get("value");

                boolean hasContent = apiObject.get("contentStreams") != null && ((List)apiObject.get("contentStreams")).size() > 0;

                if (hasContent)
                {
                    Map<String, Object> requestObject = new LinkedHashMap<>();
                    LinkedList<Map<String, Object>> requestList = new LinkedList<>();
                    requestList.add(apiObject);
                    requestObject.put("objects", requestList);

                    // @formatter:off
                    String md5Digest = 
                        restTemplate.execute(
                            "http://repository/api/dms/objects/" + objectId, 
                            HttpMethod.POST, 
                            (ClientHttpRequest requestCallback) -> {
                              if (StringUtils.hasLength(authorization))
                              {
                                requestCallback.getHeaders().add(HttpHeaders.AUTHORIZATION, authorization);
                              }
                              requestCallback.getHeaders().setContentType(MediaType.APPLICATION_JSON);
                              requestCallback.getBody().write(this.objectMapper.writeValueAsString(requestObject).getBytes("UTF-8"));
                            }, 
                            new ResponseExtractor<String>()
                            {
                                @Override
                                public String extractData(ClientHttpResponse response) throws IOException
                                {
                                    if (response.getStatusCode().is2xxSuccessful())
                                    {
                                        // calculate MD5 Hash
                                        return DigestUtils.md5DigestAsHex(response.getBody());
                                    }
                                    throw new IllegalStateException("error in getting content: " + response.getRawStatusCode() + " " + response.getStatusText());
                                }
                            }   
                        );
                    // @formatter:on

                    System.out.println("for objectId[" + objectId + "] the md5-digest of content is[" + md5Digest + "]");
                }
            }
        }
        catch (Throwable e)
        {

            return new ResponseEntity<>(e.getMessage(), HttpStatus.UNPROCESSABLE_ENTITY);
        }

        // just return input no changes
        return new ResponseEntity<Map<String, Object>>(dmsApiObList, HttpStatus.OK);
    }
}

Accessing the binary content from a WebHook

Introduction

Setting up the Webhook Service