[yatsyk]

Custom backend means no synchronisation and no advantages over postgres.

Do you propose to create proxy that parses query and estimates complexity? I think this task at least as hard as implementing couchdb myself (actually harder)

Is there any secure open source code with pouchdb/couchdb integrations?

[daleharvey]

Your backend can be a reverse proxy that authenticates requests then passes them off to CouchDB (or PouchDB, since that also runs on the server). I have an example up @ https://github.com/daleharvey/noted. The server is 200 lines and does signup / email authentication etc.

[yatsyk]

This server can't prevent authenticated user from uploading huge document of running expensive query.

[Volundr]

Any reverse proxy can limit the the size of a document upload. Even just plain NGINX can do that. Just set the client max body size.

As for queries, it kind of depends on your model. Mango queries are pretty limited (no joins, no arbitrary filters), so it's not necessarily as easy as you think to write one that hosed performance. A client could of course write one that doesn't use an index, which may or may not be a concern.

An easy option if it is though is just don't expose the `_find` endpoint, which effectively limits your users to the map/reduce queries you've written (unless you give them admin they don't have the ability to create their own).

[daleharvey]

A popular model is for the clients to run the queries locally, the server doesnt need to expose any query endpoints, only the ones necessary for replication.

[yatsyk]

Is it any documents that describes secure couchdb architecture? Most of the articles I find are limited to authentication and basic permissions.

[Volundr]

What kind of document are you looking for here? There is [1], but yeah, that covers access controls. As do the MongoDB [2] and Postgres [3] documents.

I feel like your thinking about Couch as exposing your entire PostgreSQL DB to the internet, whereas with couch, a common model is to have a single database per user. In the Postgres model, providing the end user with any direct access is a nightmare, because every other users data is in there and I have to keep other users from viewing/modifying it. In Couch, you give them access to their database and only their database, that's how you isolate users.

[1]https://docs.couchdb.org/en/stable/intro/security.html

[2]https://docs.mongodb.com/manual/security/

[3]https://www.postgresql.org/docs/7.0/security.htm [3]

[daleharvey]

I wasnt worried about that since it is a basic proof of concept, adding that would make it ~210 lines of code.

[newfeatureok]

There are plenty of proxies that do that with some config like nginx. Even if you were using a relational database with a backend you’d still have to solve the same problem.

[yatsyk]

If I use backend I can create all validation logic in application server. But in this case no automatic synchronisation.

One of the major selling point of couchdb is replication protocol for client-server data syncing. When you design product with posgress you don't allow to execute raw sql queries from clients without any application server. But looks like it is recommended way to update data in couchdb world if you want to have synchronisation. I can't understand how can this architecture be secure?

[lhuser123]

Couchdb has options for controlling which documents are replicated. This may help depending on your use case.

[SahAssar]

nginx couldn't solve the "execute expensive query" though right, only limit max size. I guess you could do a request timeout + blacklist, but that would also be hard to do right, since at heavy load some proper clients might get blacklisted.