how to disable / turn-off / refresh couchdb caching

问题

I have a list that has some basic authentication on a document. The issue I am having is that the list is caching so the user will not see they have access unless I update the revision id. How do you show a non-cached list?

if (req.userCtx.name === doc.permissions.owner) {
    return 'you have permission';   
}
else {
    return 'you do not';
}

How I would imagine it done is by passing no-cache or update the ETAG or something of that sort in the header, but nothing seems to work. Here is an attempt I have that sends a new date in the head every time to make it not cache, but this doesn't work.

var date = new Date().getTime() + 'x';
start({code: 200, headers: {'Content-Type': 'text/html', 'date': date}});

Any ideas greatly appreciated!

By the way I am looking for a pure couch solution.

回答1:

So after a lot more digging I found this:

http://wiki.apache.org/couchdb/Formatting_with_Show_and_List#ETags

Cutting to the important parts:

ETags are handled by the List and Shows
version up to 1.2 your user must have a role, then they will get different ETags.
1.3 will introduce new ETags per user name.

Hope this helps someone.

回答2:

Fortunately CouchDB sources are available! I was able to find this algorithm in couch_mrview_show.erl:

show_etag(#httpd{user_ctx=UserCtx}=Req, Doc, DDoc, More) ->
    Accept = couch_httpd:header_value(Req, "Accept"),
    DocPart = case Doc of
        nil -> nil;
        Doc -> couch_httpd:doc_etag(Doc)
    end,
    couch_httpd:make_etag({couch_httpd:doc_etag(DDoc), DocPart, Accept,
        {UserCtx#user_ctx.name, UserCtx#user_ctx.roles}, More}).

Here we could see that Shows are cached unless one of the following things changed:

Design doc, which contain the show function
The doc which is used to render the show
'Accept' HTTP request header
Username (it means that show is rendered at least once for each user)
Set of user roles in user context

来源：https://stackoverflow.com/questions/14947825/how-to-disable-turn-off-refresh-couchdb-caching

标签

caching

couchdb