We believe in Persistent Identifiers. We believe in defence in depth. Today we’re excited to announce an upgrade to our data resilience strategy.
Defence in depth means layers of security and resilience, and that means layers of backups. For some years now, our last line of defence has been a reliable, tried-and-tested technology. One that’s been around for a while. Yes, I’m talking about the humble 5¼ inch floppy disk.
Recording data citations supports data reuse and aids research integrity and reproducibility. Crossref makes it easy for our members to submit data citations to support the scholarly record.
TL;DR Citations are essential/core metadata that all members should submit for all articles, conference proceedings, preprints, and books. Submitting data citations to Crossref has long been possible. And it’s easy, you just need to:
Include data citations in the references section as you would for any other citation Include a DOI or other persistent identifier for the data if it is available - just as you would for any other citation Submit the references to Crossref through the content registration process as you would for any other record And your data citations will flow through all the normal processes that Crossref applies to citations.
At Crossref, we care a lot about the completeness and quality of metadata. Gathering robust metadata from across the global network of scholarly communication is essential for effective co-creation of the research nexus and making the inner workings of academia traceable and transparent. We invest time in community initiatives such as Metadata 20/20 and Better Together webinars. We encourage members to take time to look up their participation reports, and our team can support you if you’re looking to understand and improve any aspects of metadata coverage of your content.
What’s in the metadata matters because it is So.Heavily.Used.
You might be tired of hearing me say it but that doesn’t make it any less true. Our open APIs now see over 1 billion queries per month. The metadata is ingested, displayed and redistributed by a vast, global array of systems and services that in whole or in part are often designed to point users to relevant content. It’s also heavily used by researchers, who author the content that is described in the metadata they analyze.
Notification callback is a service you can use to notify you when a submission log, either in the test or production admin tool, is available for a metadata, batch query, or Cited-by query submission. Notification is provided in the form of a HTTP(S) URL where the log can be retrieved. If the notification callback service is enabled, you will no longer receive submission log emails.
How the notification callback service works
The callback will be an HTTP(S) request to a URL (notify-url) provided by the member with all data relayed via HTTPS headers. The notification specifies the availability of the result, some context of the request, and an HTTP(S) URL from which to get the result. The submission log may then be retrieved using the HTTP(S) URL.
The headers use the simple name and value structure; that is, the value has no additional structure that divides it into parts. To ensure that all Unicode values can be accommodated all header values will be UTF-8 encoded.
When the notify-url is used the following HTTPS headers are provided:
CROSSREF-NOTIFY-ENDPOINT: the notify-endpoint (required) is just the name used to identify the specific notification (more on this below)
CROSSREF-EXTERNAL-ID: the id given by the member with regards to the request. For metadata deposits, for example, it is the value of the doi_batch_id element (Optional)
CROSSREF-INTERNAL-ID: the id given by us with regards to the request (Optional)
CROSSREF-RETRIEVE-URL: the URL for the member to use to retrieve the request’s result. Since the HTTPS header value is UTF-8 encoded, the URL will contain no URI encodings. For example, an Á will not be encoded as %C3%81
CROSSREF-SERVICE-DATE: the date and time stamp of the service request. Learn more about format specification in RFC 2616.
CROSSREF-RETRIEVE-URL-EXPIRATION-DATE: the timestamp after which service result is no longer available at the given retrieve-url.
Setting up an endpoint
You’ll need to set up and register an endpoint to receive callbacks.
your endpoint info (notify-endpoint and notify-url) – the notify-endpoint is just a name to identify the specific notification. The notify-endpoint should be something you can recognize so when you receive responses that include the endpoint name, it is easy to know which of the callback feeds it is coming from. Thenotify-url has to be the actual URL of your callback receiver, as that is where the notification callback transmits to via http/https.
the services you’re activating the service for (metadata submissions, batch querying, Cited-by alerts)
the username and/or DOI prefix you’ll be using.
Make sure you inform us of any changes to your endpoint: if a message fails to send we will retry for up to a week after which you will no longer be able to receive it.
Example of a notification
For the submission 1368966558 the notification would be as follows (new lines have been added between header name and header value to improve readability):
The notification callback service can be queried for past callbacks. The query is implemented as an HTTPSservice.(Access control and limits to end-points and time frames TBD).
The query takes 3 criteria, the notify-endpoints, an inclusive from timestamp, and an exclusive until timestamp. All timestamps use the ISO 8061 format YYYY-MM-DD’T’hh:mm:ss’Z, for example, 2014-07-23T14:43:01Z.
The query results in a JSON array of callbacks. For example, querying for the single endpoint “1CFA094C-4876-497E-976B-6A6404652FC2” returns:
A flat structure is used to aid processing the result as a stream. There is no order defined.
The audit item is a record of attempted callbacks. It details the notify-endpoint’s notify-url used at the time of the callback, the timestamp of the callback, and the HTTPS status of the callback. If more than one attempt has been tried then the audit array will contain multiple elements; there is no order defined.
The usr and pwd are your Crossref username and password. The ENDPOINT value is a notify-endpoint or a space separated set of notify-endpoints.
Glossary of notification callback service terms
notify-url: the URL that the member provides and is used to notify them of the availability of a service request’s result. How the URL is provided to us will depend on the service.
notify-endpoint: an opaque token used to select a notify-url. The token will be anonymous and difficult to guess. The notify-endpoint is provided by the member. The notify-endpoint is associated with one notify-url (many notify-endpoints can be associated with the same notify-url).
retrieve-url: the URL that we provides that is used by the member to get the service request result.
notify-payload: the data that specifies what service request this notification is for. This payload will use HTTPS headers so as to be HTTPS method-neutral (such as POST, PUT).
retrieve-payload: the service result. Each service will define its own result content-type (that is very much like what would be sent in email today).
notification-authentication: This is the method of authentication we will use with the notify-url. Credentials are provided by the member.
retrieval-authentication: This is the method of authentication the member will use with the retrieve-url. The account credentials are provided by us.
Page owner: Isaac Farley | Last updated 2023-February-23