I've been staying out of the fray so far, but I want to (mostly) endorse
Paul's summary and suggestion. The hear tof my arguemnt is two simple
points:
[1] JSON only defines Number. It does not define separate integer and
floating point numbers.
[2] CouchDB promises to respond to HTTP requests to PUT and GET data,
and the return value is documented to be JSON.
These two points imply that CouchDB only knows about the kinds of data
structures that JSON defines and supports, and thus can/should make no
promises about the representation of numbers beyond what you can get
from JSON..
If an application depends on the distinction between integers and
floating point values, then it is up to the person writing the
application to make sure this distinction survives. As has already been
pointed out, they can accomplish that goal by storing all numbers as
(JSON) strings and using their application to decode/eval them. This
fix requires no changes to the CouchDB code.
I would not even change the encoder to deal with decimal points and
precision. I would advocate just making sure that the documentation is
clear on this point. In particular, it is probably necessary to
document (as a breaking change that may require people to rewrite some
of their applications) the fact that 1.2 may drop trailing zeros after
the decimal point.
You cannot really promise to support different types of numbers without
radically changing the CouchDB code. You would then have to continually
fight with JSON to get it to support something that is beyond its
capabilities. Maintenance would become a nightmare. Let's try to avoid
that road....
Kevin
On 2/13/2012 12:07 PM, Paul Joseph Davis (Commented) (JIRA) wrote:
[
https://issues.apache.org/jira/browse/COUCHDB-1407?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13207022#comment-13207022
]
Paul Joseph Davis commented on COUCHDB-1407:
--------------------------------------------
As mentioned on the dev@ thread, I'm pretty dead set against this approach.
While there seems to be some sort of general consensus that storing numbers as
uninterpreted bytes and repeating them back is the way to go it really misses
the entirety of the issue.
First, CouchDB has never claimed to pass numbers around while keeping byte
identical representations. This patch attempts to change that drastically with
a very large number of consequences that we haven't begun to investigate.
Secondly, if we were to actually consider going this route then we'd also be
obliged to start looking at every other place where we change representations
internally as well.
Thirdly, if we were to do that then we'd also have to get into all of the cases
where we're stricter than JSON specifically allows and then try and address all
of those issues as well.
Basically, how about we just fix the encoder to spit out a decimal point and an
appropriate amount of precision and then start documenting our round tripping
limitations.
JSON encoding of number changes
-------------------------------
Key: COUCHDB-1407
URL: https://issues.apache.org/jira/browse/COUCHDB-1407
Project: CouchDB
Issue Type: Bug
Components: HTTP Interface
Affects Versions: 1.2
Environment: Ubuntu 12.04 (alpha)
Reporter: Adam Lofts
Attachments: 0001-Only-validate-numbers-on-JSON-decoding.patch
JSON encoding of Number has changed from 1.0.2 to 1.2. JSON only defines Number
but this change causes issues in my app because python decodes the number as an
int in 1.2.
Test case:
PORT=5985
curl -X DELETE http://localhost:$PORT/test-floats/
curl -X PUT http://localhost:$PORT/test-floats/
curl -X PUT http://localhost:$PORT/test-floats/doc1 -H "Content-Type: application/json" -d "{
\"a\": 1.0 }"
curl http://localhost:$PORT/test-floats/doc1
Run against 1.0.2:
{"ok":true}
{"ok":true}
{"ok":true,"id":"doc1","rev":"1-78e61304147429d3d500aee7806fd26d"}
{"_id":"doc1","_rev":"1-78e61304147429d3d500aee7806fd26d","a":1.0}
Run against 1.2:
{"ok":true}
{"ok":true}
{"ok":true,"id":"doc1","rev":"1-78e61304147429d3d500aee7806fd26d"}
{"_id":"doc1","_rev":"1-78e61304147429d3d500aee7806fd26d","a":1}
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