Compatibility with PouchDB 7

[leonid-shevtsov]

I've seen #238, but it looked abandoned, and there was refactoring seemingly unrelated to PouchDB 7. I figured it's easier to start over. Sorry about that.

• upgrade dependencies to PouchDB 7
• drop dependency on deprecated pouchdb-ajax and pouchdb-promise
• for tests, replace deprecated (or just neglected?) pouchdb-memory build with pouchdb-browser and pouchdb-node.
• for the best integration with the ecosystem, we must use db.fetch, and not any other instance of fetch (such as an additional polyfill, or even imported from pouchdb-fetch). This will let this plugin cooperate with other plugins that might customize fetch behavior. So:
  • we shouldn't directly depend on the pouchdb-fetch package, since it's baked into pouchdb-browser and other builds.
• since fetch works with promises naturally, it's more appropriate to define the API in terms of promises as well. So to support the callback style, I've defined a toCallback helper which does roughly the opposite of toPromise and enables both the promise and the callback API styles.
• I've implemented fetchJSON - a wrapper around fetch that receives and returns JSONs. Then I've looked and, of course, pouchdb-adapter-http has a very similar function, but it's private. Perhaps some day we can extract and reuse it.
• tests have barely changed at all, as you can see.

Needless to say, this changeset is not compatible with PouchDB 6 anymore.

[leonid-shevtsov]

There are some issues in the tests:

• NodeJS tests are failing due to the wrong fetch-cookie version; either pouchdb-node will be updated, or we can make a custom build and use the correct fetch-cookie. Though until pouchdb-node is updated, pouchdb-authentication will still error against the official build, so maybe no sense in doing anything custom.
• PhantomJS probably needs a fetch polyfill
• and Sauce tests show some issues with running against a CouchDB instance. I've tested locally on Chrome + pouchdb-server and everything was green - I'll see if I can repro against CouchDB.

[jlami]

Can we use the api.fetch that pouchdb-adapter-http exposes?
https://github.com/pouchdb/pouchdb/blob/858660e9b37959d96eebf667ea9b8b1273f0d62c/packages/node_modules/pouchdb-adapter-http/src/index.js#L437
That one also supports 'overloading' so a user can give their own fetch function to modifiy the request.

We recently found out that we needed to overrule a signup request when logged in as a non-admin user to be able to prevent credentials from being included. I don't really see a way of doing this with your setup.

If we switched to api.fetch it might also prevent the need for getBasicAuthHeaders, since those seem to be handled there:
https://github.com/pouchdb/pouchdb/blob/858660e9b37959d96eebf667ea9b8b1273f0d62c/packages/node_modules/pouchdb-adapter-http/src/index.js#L169-L176

[leonid-shevtsov]

@jlami good point.

I was already using the fetch from pouchdb-adapter-http, which is available through PouchDB.fetch and in db.fetch, so it did support overloading

However, I did some digging and turns out, if you use db.fetch, you can pass it paths instead of URLs, and it will build the URL for you. And as you said, it also sets auth headers and enables cookies. This removes a lot of code from pouchdb-authentication.

Unfortunately this PR won't work until there's a new version of PouchDB released; this fix in particular is absolutely necessary.

[leonid-shevtsov]

I made a PR to pouchdb to expose the fetchJSON API so I can remove the implementation I made in this one.

pouchdb/pouchdb#7768

[mqtik]

Any updates on this?

[ptitjes]

Thank you @leonid-shevtsov. Sorry for the very late merge...

[leonid-shevtsov]

No worries! Thank you so much for merging.