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dustin / go-couch

CouchDB API
MIT License
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Support Sync Gateway style sequences #1

Open tleyden opened 11 years ago

tleyden commented 11 years ago

CouchDB style sequence: 4356 (numeric only)

Sync Gateway style sequence: *:4356 (the "*" means something related to the channels, which I can't remember off the top of my head)

I've got a workaround/fix, will send a pull request.

tleyden commented 11 years ago

Hmm, just realized that my workaround will break all existing code because the changes function is changed from:

type ChangeHandler func(r io.Reader) int64

to

type ChangeHandler func(r io.Reader) string

@snej can you remind me what exactly the string part of the sequence means? Also, if something is following the changes feed, I take it it will need to preserve this string part when requesting since=??

I'm asking because in couch-go the expectation is that the sequence is numeric-only and the code would need to be changed in order to accommodate strings.

tleyden commented 11 years ago

Here's what I changed to make it work against Sync Gateway:

https://github.com/tleyden/go-couch/commit/a8d50160edbc9956bab0b1d567d3615f003a4e95

not going to submit a pull request since there might be a cleaner way to solve this.

snej commented 11 years ago

CouchDB sequence IDs are opaque — the correct type to use is probably interface{}, not int64 or string.

The only thing you can validly do with a received sequence ID is send it in the since parameter of a future changes feed request. You can't even safely compare IDs for equality, since some implementations (like Cloudant) can represent the same sequence in different ways when called at different times.

It sounds like you do need to break existing code.

tleyden commented 10 years ago

More Sync Gateway <-> Go-Couch incompatibilities: https://github.com/couchbase/sync_gateway/issues/190#issuecomment-30987039