Issue 230 in couchdb-python: Document Update Handler (update_doc) support for PUT and POST

[couchdb...@googlecode.com]

Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 230 by te...@prosauce.org: Document Update Handler (update_doc)
support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

couchdb/client.py:
def update_doc(self, name, docid=None, **options):
"""Calls server side update handler.

:param name: the name of the update handler function in the format
``designdoc/updatename``.
:param docid: optional ID of a document to pass to the update
handler.
:param options: optional query string parameters.
:return: (headers, body) tuple, where headers is a dict of headers
returned from the list function and body is a readable
file-like instance
"""
path = _path_from_name(name, '_update')
if docid is None:
func = self.resource(*path).post
else:
path.append(docid)
func = self.resource(*path).put
_, headers, body = func(**options)
return headers, body

The Document Update Handlers API reference
(http://docs.couchdb.org/en/latest/ddocs.html#update-functions) mentions
support for both PUT and POST. For larger updates (>650bytes) PUT is not
appropriate (HTTP 414, request too long, concerns). The module should
prefer POST or include a kwarg to allow the caller to decide the verb.

Thanks!

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[couchdb...@googlecode.com]

Comment #1 on issue 230 by kxepal: Document Update Handler (update_doc)

support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

Actually, the update handlers supports any method except GET (that's
artificial restriction on query server side).

However, semantically only POST and PUT methods matters and there is no any
restrictions on their payload size.

Is there some proxy-server in front of your CouchDB?

[couchdb...@googlecode.com]

Comment #2 on issue 230 by te...@prosauce.org: Document Update Handler

(update_doc) support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

Cool on the any method but GET comment, good to know!

And cool on the no restriction on payload size. :) Regardless of my setup,
you are right, objects are commonly length-restricted when proxies are
used. Though there are additional concerns like request/access logging,
which would prefer larger content in the body.

The issue does not reflect a specific setup, it is a common-practices
suggestion. The flexibility of verb usage, by the caller, is desired.

Thanks!

[couchdb...@googlecode.com]

Comment #3 on issue 230 by kxepal: Document Update Handler (update_doc)

support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

Suddenly, you have to fix your proxy setup because CouchDB uses RESTful
HTTP API where request method's makes a sense.

Fixing this issue for update handlers will not fix the similar for
attachments - they are big and may be stored only with PUT method, so you
will still have problems due to proxy server.

[couchdb...@googlecode.com]

Comment #4 on issue 230 by te...@prosauce.org: Document Update Handler

(update_doc) support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

I agree with you that PUT "traditionally" makes sense in a RESTful world to
update objects (and POST to create). Forgive me if I'm asking you to commit
RESTful sin by allowing an update with POST, haha. ;)

POST in some scenarios does make sense to update objects (i.e., I POST to
add content, I POST to add sub-content, I POST a change). In this case,
CouchDB supports POST to update documents via the Document Update Handler
API.

I'm not a web developer and admittedly not the person to
argue/defend/describe REST implementations. Though I am a user of your
module and would greatly appreciate mainline support that corroborates the
CouchDB documentation. I've listed a few examples of why it may be
preferred for some users. If they are not sufficient I am unfortunately at
a loss.

[couchdb...@googlecode.com]

Comment #5 on issue 230 by kxepal: Document Update Handler (update_doc)

support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

Sure, but I'm trying to tell you that fixing update_doc method for using
POST method instead of PUT because you have proxy-server issues wouldn't
help you with any other CouchDB API requests that required PUT-only
requests like:

- Document updates
- Attachments storing
- Database security setup
- Replication
- On fly configuration updates

So this fix would be just a workaround of your network issues, not a fix of
CouchDB API misusing.

[couchdb...@googlecode.com]

Comment #6 on issue 230 by te...@prosauce.org: Document Update Handler

(update_doc) support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

You're right, and in my case the issue is not the PUT vs. POST, but the
handling of the expanded kwargs.

The following seem equivalent:

PUT update_doc(..., body=options)
POST update_doc(..., **options)

PUT, with the expanded options tacks on the variables to the query string.
POST, with the expanded options adds them as HTTP request content. Long
request objects + query strings is trouble, long request contents is not.

My error is an oversight in the expected behavior of update_doc(...,
**options). Since you're using POST and PUT (for new and updates
respectively), there was some ambiguity about the behavior of the update
variables. I'm not sure if this requires any action on the part of
python-couchdb, though it would be nice if the API took the same action
(updates within HTTP request body) when using update_doc.

Thanks!

[couchdb...@googlecode.com]

Comment #7 on issue 230 by jzy...@gmail.com: Document Update Handler

(update_doc) support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

FWIW, I have a slightly different application that would benefit from being
able to specify the method. As you say, the update handler will accept any
method except for GET. Even though the documentation only mentions POST &
PUT, COUCHDB-1779 describes using update handlers to implement PATCH until
it is available as part of the CouchDB REST API. I'm working on a project
where we will use DELETE against the update handler to flag a document as
deleted, but otherwise preserve its contents (basically a Trash folder).

[couchdb...@googlecode.com]

Comment #8 on issue 230 by djc.ochtman: Document Update Handler

(update_doc) support for PUT and POST
http://code.google.com/p/couchdb-python/issues/detail?id=230

This issue has been migrated to GitHub. Please continue discussion here:

https://github.com/djc/couchdb-python/issues/230