How to connect SproutCore to CouchDB in Mac OSX - couchdb

Question

I am using SproutCore to query a CouchDB database on Mac OSX (10.6.7), from a tutorial on NetTuts+ premium. The database name is microblog. The query resolve to this string:
"http://localhost:5984/microblog/_design/posts/_view/posts?descending=true"
If I type this query directly in the browser's address bar, I get a nice json answer. But through the SproutCore app, I get an error message:
405 Method Not Allowed
Why is that? would that be because SC is running out of :4020 and CouchDB out of :5984 ? Any ideas?

Answer 1

Because of Javascript cross-domain regulations you are not allowed to query any arbitrary URL from your browser. If you loaded your sproutcore page from localhost:4020, it's forbidden to contact any other host or port on the same host.
To overcome this problem you usually make your sproutcore host proxy to the backend. You can do this by including a proxy statement like the following in your sproutcore buildfile
proxy "/microblog", :to => "localhost:5984"
which will forward all request going to localhost:4020/microblog to your backend localhost:5984/microblog. As you can imagine this might lead to problems where you can't set the url in your sc application to the desired value, the common case might be that your sc application is also named "microblog" the above proxy directive would then cause your sc application url being overridden.
To fix that problem you can use another url in your sc application to contact the backend, e.g. /db and then use the url parameter in the proxy directive to rewrite the target url:
proxy "/db", :to => "localhost:5984", :url => "microblog"
All requests to localhost:4020/db will then be forwarded to localhost:5984/microblog and will no longer interfere with your sc application on localhost:4020/microblog.