How to redirect all new PUT /db/doc REST calls to updates handler?

[fangq]

I want to thank @janl and @rnewson for answering my question posted at #5493.

as a follow up to that question - if I want to reinforce change-logs and creation/update timestamps in my databases, one thing is to implement something, such as adding relevant keys and maintain a change-log in the doc, in the updates handler. However, I can only add these keys if someone posts updated docs via the update handler in the design doc, such as

curl -X PUT https://example.com:port/dbname/_design/ddoc/_updates/handlername/docname -d @"newdoc.json"

however, if someone posts a new version of doc via the PUT /db/doc API, then, this update handler won't be used.

If I want to reinforce this by using update-handler as the only way to upload/update docs, I will need to redirect PUT request towards /db/doc to the update handler URL. If this is running on my Apache server, I can do this using .htaccess and RewriteRule, but it appears that CouchDB does not use .htaccess.

is there another way to perform this URL redirect?

[benel]

Hi @fangq.

Disclaimer: I'm a mere user. Nothing authoritative here.

You could check the documentation of CouchDB _rewrite API. But please note that this feature is deprecated and will be removed in CouchDB 4.

A more "lasting" option would be to put this rewrite rule into your reverse proxy setting. A section in CouchDB documentation is dedicated to reverse proxies.

[rnewson]

update handlers exist for clients incapable of performing logic or data manipulation, and that's basically nothing these days. Do your document construction and validation on the client. You can use a validate_doc_update function on couchdb as an inescapable check on what is written to the database. so;

1. ensure all requests meet your requirements in your own code (or intermediate proxy).
2. use a validate_doc_update function in your couchdb database to ensure they are met (though also ensure this function is idempotent, in practice this means not comparing the request to the current time)