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https://issues.apache.org/jira/browse/COUCHDB-280?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chris Anderson closed COUCHDB-280.
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Resolution: Fixed
closed in r751813
> relative links between resources provided by design docs
> --------------------------------------------------------
>
> Key: COUCHDB-280
> URL: https://issues.apache.org/jira/browse/COUCHDB-280
> Project: CouchDB
> Issue Type: Improvement
> Reporter: Chris Anderson
> Assignee: Chris Anderson
> Fix For: 0.9
>
> Attachments: relative-design-paths.diff
>
>
> In an earlier thread we discussed the costs and benefits of changing CouchDB
> so that all the resources provided by a design doc are rooted in the design
> doc.
> Under the current system, there is no way to link among HTML files attached
> to a design docs, the HTML output of show and list functions, and view
> queries. The only way to link between these resources is by hard-coding the
> design doc name in your link. By giving the resources provided by design docs
> a common root, one can link between them using hrefs like
> "../../_show/sname/docid".
> The current system never posed a problem before, because design docs only
> provided one type of resource. However, going forward I can see that design
> docs could continue to provide new, unanticipated resources. Jason Davies has
> proposed an _update resource, which would be a JavaScript (or other language)
> function that can accept request with non-JSON bodies (for instance POSTed
> XML from a webhook service) and convert them to JSON for storage.
> The advantages to decomposing the traditional "accept a request, do whatever
> you want, send a reply" app-server model into discrete functions are
> numerous, the main one being that developers can support custom non-JSON
> content-types, while still interacting with the database in a manner where
> side-effects and memory / runtime characteristics are controlled.
> Show and list break non-JSON rendering down into the right sized granules for
> safe, cacheable idempotent requests. But because we we can't link between
> them (and design doc attachments) using normal html links (the links must be
> computed on the server) they aren't enough to provide a hypermedia interface
> for CouchDB. Hypermedia is above what CouchDB has been shooting for, but we
> are so close now that it seems silly not to go the "rest" of the way.
> If it were just the tradeoffs between relative links (good) and slightly
> uglier urls (bad) I'd be roughly +0 on this change. But a consequence of
> giving design doc resources a common root is that the applications the define
> can then be proxied with a URL rewriter. The means that (if written
> correctly) an application with paths like:
> /db/_design/foo/_view/bar?limit=10
> /db/_design/foo/_show/docid
> /db/_design/foo/index.html
> can be proxied so that the "/db/_design/foo" part of the URL is added by the
> proxy, so that all clients see is:
> /_view/bar?limit=10
> /_show/docid
> /index.html
> This also nicely limits end-client access, so that they may only interact
> with the database using resources provided by the design doc. I consider this
> an edge-case for deployment but the fact that we can cleanly support makes me
> think we're on the right track with the change to a common root for design
> doc resources.
> For more details about these URL path interactions, see the earlier thread:
> http://mail-archives.apache.org/mod_mbox/couchdb-dev/200902.mbox/%3ce282921e0902242116n2cd207c4x7a9d0feced3f1...@mail.gmail.com%3e
> I've implemented a patch (attached to this ticket) that makes it so that
> views, shows, lists, and design doc attachments are all rooted under the
> design doc.
> It works by adding a section to the ini file, like this (which we could use
> to easily add new resource, like the _update mentioned above):
> [httpd_design_handlers]
> _view = {couch_httpd_view, handle_view_req}
> _show = {couch_httpd_show, handle_doc_show_req}
> _list = {couch_httpd_show, handle_view_list_req}
> the _design handler itself is just an http_db_handler.
> Points of discussion:
> If we want to change the names of any of: _view, _show, _list, or _design now
> is a good time to do it. We've been over the names _list and _show many
> times, and while they aren't perfect, they are short, and more-or-less
> descriptive of what they do.
> The code is robust about changes to the _design db handler's name. That is,
> we could continue to call them design docs, and store them with ids like
> "_design/name", while changing the resource root so that the above set of
> URLs could be something like (modulo an attachments handler, "_files" here,
> for clarity):
> /db/_baz/foo/_view/bar?limit=10
> /db/_baz/foo/_show/docid
> /db/_baz/foo/_files/index.html
> Before we commit / before 0.9.0:
> This patch is a big enough change that I think we should vote on it before I
> commit it. However, I'd like to get it in before 0.9.0 to avoid future
> confusion where trunk is incompatible with API clients and applications
> designed to run on our latest release.
> Sincerely,
> Chris
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