Metadata is one of the most important tools needed to communicate with each other about science and scholarship. It tells the story of research that travels throughout systems and subjects and even to future generations. We have metadata for organising and describing content, metadata for provenance and ownership information, and metadata is increasingly used as signals of trust.
Following our panel discussion on the same subject at the ALPSP University Press Redux conference in May 2024, in this post we explore the idea that metadata, once considered important mostly for discoverability, is now a vital element used for evidence and the integrity of the scholarly record.
For the third year in a row, Crossref hosted a roundtable on research integrity prior to the Frankfurt book fair. This year the event looked at Crossmark, our tool to display retractions and other post-publication updates to readers.
Since the start of 2024, we have been carrying out a consultation on Crossmark, gathering feedback and input from a range of members. The roundtable discussion was a chance to check and refine some of the conclusions we’ve come to, and gather more suggestions on the way forward.
https://0-doi-org.lib.rivier.edu/10.13003/ief7aibi
In our previous blog post in this series, we explained why no metadata matching strategy can return perfect results. Thankfully, however, this does not mean that it’s impossible to know anything about the quality of matching. Indeed, we can (and should!) measure how close (or far) we are from achieving perfection with our matching. Read on to learn how this can be done!
How about we start with a quiz?
We’re in year two of the Resourcing Crossref for Future Sustainability (RCFS) research. This report provides an update on progress to date, specifically on research we’ve conducted to better understand the impact of our fees and possible changes.
Crossref is in a good financial position with our current fees, which haven’t increased in 20 years. This project is seeking to future-proof our fees by:
Making fees more equitable Simplifying our complex fee schedule Rebalancing revenue sources In order to review all aspects of our fees, we’ve planned five projects to look into specific aspects of our current fees that may need to change to achieve the goals above.
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
if configuring the notification callback service for Cited-by alerts, you’ll need to provide us with the email address that was used to set your fl_query alerts
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 HTTPS service (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.
A note on trusting Let’s Encrypt
We use Let’s Encrypt, a global Certificate Authority, to enable secure HTTPS connections. Please ensure your local certificate library is updated to include the letsencrypt root certificate before requesting a notification callback for your account/prefix.
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-November-29