Issue 17909: Autodetecting JSON encoding (original) (raw)

process

Status: closed Resolution: fixed
Dependencies: 12892 Superseder:
Assigned To: ncoghlan Nosy List: Julian, akira, berker.peksag, cvrebert, ezio.melotti, gsnedders, jleedev, martin.panter, matrixise, methane, miss-islington, ncoghlan, pitrou, python-dev, rhettinger, serhiy.storchaka, vstinner
Priority: normal Keywords: patch

Created on 2013-05-05 13:10 by serhiy.storchaka, last changed 2022-04-11 14:57 by admin. This issue is now closed.

Files
File name Uploaded Description Edit
json_detect_encoding_2.patch serhiy.storchaka,2014-05-15 12:38 review
json_detect_encoding_3.patch serhiy.storchaka,2016-06-22 16:57 review
Pull Requests
URL Status Linked Edit
PR 7366 merged Anthony Sottile,2018-06-03 23:24
PR 7474 merged miss-islington,2018-06-07 09:58
PR 7475 merged miss-islington,2018-06-07 09:59
Messages (13)
msg188442 - (view) Author: Serhiy Storchaka (serhiy.storchaka) * (Python committer) Date: 2013-05-05 13:10
RFC 4627 specifies a method to determine an encoding (one of UTF-8, UTF-16(BE|LE) or UTF-32(BE LE)) of encoded JSON text. The proposed preliminary patch (it doesn't include the documentation yet) allows load() and loads() functions accept bytes data when it is encoded with standard Unicode encoding. Also accepted data with BOM (this doesn't specified in RFC 4627, but is widely used). There is only one case where the method can give a misfire. Serialized string "\x00..." encoded in UTF-16LE may be erroneously detected as encoded in UTF-32LE. This case violates the two rules of RFC 4627: the string was serialized instead of a an object or an array, and the control character U+0000 was not escaped. The standard encoded JSON always detected correctly. This patch requires "surrogatepass" error handler for utf-16/32 (see and ).
msg218608 - (view) Author: Serhiy Storchaka (serhiy.storchaka) * (Python committer) Date: 2014-05-15 12:38
All dependencies for this issue are resolved now. Here is updated patch, synchronized with tip.
msg218616 - (view) Author: Chris Rebert (cvrebert) * Date: 2014-05-15 16:07
You'll need to also update the "Character Encodings" subsection of the json docs.
msg218640 - (view) Author: Akira Li (akira) * Date: 2014-05-16 02:39
Both json standard (ECMA-404) [1] and the new json rfc 7159 [2] do not mention the encoding detection. [1] http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf [2] https://tools.ietf.org/html/rfc7159#section-8.1 From the rfc: > JSON text SHALL be encoded in UTF-8, UTF-16, or UTF-32. The default encoding is UTF-8, and JSON texts that are encoded in UTF-8 are interoperable in the sense that they will be read successfully by the maximum number of implementations; there are many implementations that cannot successfully read texts in other encodings (such as UTF-16 and UTF-32). Implementations MUST NOT add a byte order mark to the beginning of a JSON text. In the interests of interoperability, implementations that parse JSON texts MAY ignore the presence of a byte order mark rather than treating it as an error.
msg218641 - (view) Author: Chris Rebert (cvrebert) * Date: 2014-05-16 04:20
I agree that the state of encoding detection in the new RFC seems unclear, given that the old RFC prefaced the part about the encoding detection with: > Since the first two characters of a JSON text will always be ASCII > characters But in the new RFC: > Appendix A. Changes from RFC 4627 [...] > o Changed the definition of "JSON text" so that it can be any JSON > value, removing the constraint that it be an object or array. Thus, > "ಠ_ಠ" whose 2nd character is decidedly non-ASCII, is now a valid JSON text (i.e. standalone JSON document). There seems to have been a thread about encoding detection in the RFC 7159 working group, but I don't have the time to read through it all: > Re: [Json] JSON: remove gap between Ecma-404 and IETF draft > http://www.ietf.org/mail-archive/web/json/current/msg01936.html It eventually leads to a dedicated sub-thread: > [Json] Encoding detection (Was: Re: JSON: remove gap between Ecma-404 and IETF draft) > http://www.ietf.org/mail-archive/web/json/current/msg01959.html
msg230053 - (view) Author: Martin Panter (martin.panter) * (Python committer) Date: 2014-10-27 01:06
If you adjusted the detect_encoding() logic according to Pete Cordell’s table at the bottom of <http://www.ietf.org/mail-archive/web/json/current/msg01959.html>, it might work for standalone strings. However since the RFC encourages UTF-8 for best interoperability, I wonder if any of this autodetection is necessary. It might be simpler to just assume UTF-8, or use the “utf-8-sig” codec. Or are there real cases where detecting UTF-16 or -32 would be useful?
msg273908 - (view) Author: Stéphane Wirtel (matrixise) * (Python committer) Date: 2016-08-30 10:36
Hi Serhiy, I have reviewed your patch, it seems to be ok.
msg275611 - (view) Author: Alyssa Coghlan (ncoghlan) * (Python committer) Date: 2016-09-10 10:07
Having hit the json.loads() problem recently when porting a project to Python 3, I'm keen to see this land for 3.6. Accodingly, assigning to myself to review and merge Serhiy's patch - if it proves necessary, we can tweak the details of the encoding detection during beta.
msg275612 - (view) Author: Roundup Robot (python-dev) (Python triager) Date: 2016-09-10 10:16
New changeset e9e1bf9ec2ac by Nick Coghlan in branch 'default': Issue #17909: Accept binary input in json.loads https://hg.python.org/cpython/rev/e9e1bf9ec2ac
msg275614 - (view) Author: Alyssa Coghlan (ncoghlan) * (Python committer) Date: 2016-09-10 10:18
Thanks for tackling this Serhiy! I removed issue 13916 from the dependency list, as while that's a reasonable suggestion, I don't think this fix is conditional on that change.
msg318918 - (view) Author: Inada Naoki (methane) * (Python committer) Date: 2018-06-07 09:58
New changeset bb6366bd7570ff3b74bc66095540bea78f31504e by INADA Naoki (Anthony Sottile) in branch 'master': bpo-17909: Document that json.load can accept a binary IO (GH-7366) https://github.com/python/cpython/commit/bb6366bd7570ff3b74bc66095540bea78f31504e
msg318920 - (view) Author: miss-islington (miss-islington) Date: 2018-06-07 10:17
New changeset f38ace61a39e64f5fde6f8f402e258177bdf7ff4 by Miss Islington (bot) in branch '3.7': bpo-17909: Document that json.load can accept a binary IO (GH-7366) https://github.com/python/cpython/commit/f38ace61a39e64f5fde6f8f402e258177bdf7ff4
msg318922 - (view) Author: miss-islington (miss-islington) Date: 2018-06-07 10:21
New changeset 21f2553482c3d6ec8beb8bfa0f1fb5d23c6a4c2f by Miss Islington (bot) in branch '3.6': bpo-17909: Document that json.load can accept a binary IO (GH-7366) https://github.com/python/cpython/commit/21f2553482c3d6ec8beb8bfa0f1fb5d23c6a4c2f
History
Date User Action Args
2022-04-11 14:57:45 admin set github: 62109
2018-06-07 10:21:22 miss-islington set messages: +
2018-06-07 10:17:20 miss-islington set nosy: + miss-islingtonmessages: +
2018-06-07 09:59:23 miss-islington set pull_requests: + <pull%5Frequest7098>
2018-06-07 09:58:24 miss-islington set pull_requests: + <pull%5Frequest7097>
2018-06-07 09:58:17 methane set nosy: + methanemessages: +
2018-06-03 23:24:31 Anthony Sottile set pull_requests: + <pull%5Frequest6992>
2016-09-10 10:24:12 ncoghlan set status: open -> closedstage: commit review -> resolved
2016-09-10 10:23:39 ncoghlan link issue22555 dependencies
2016-09-10 10:21:47 ncoghlan link issue10976 superseder
2016-09-10 10🔞20 ncoghlan set resolution: fixeddependencies: - disallow the "surrogatepass" handler for non utf-* encodingsmessages: +
2016-09-10 10:16:45 python-dev set nosy: + python-devmessages: +
2016-09-10 10:07:43 ncoghlan set assignee: serhiy.storchaka -> ncoghlanmessages: +
2016-08-30 10:38:52 matrixise set stage: patch review -> commit review
2016-08-30 10:36:24 matrixise set nosy: + matrixisemessages: +
2016-06-22 16:57:38 serhiy.storchaka set files: + json_detect_encoding_3.patchversions: + Python 3.6, - Python 3.5
2016-05-03 19:41:56 gsnedders set nosy: + gsnedders
2015-03-28 03:21:56 berker.peksag set nosy: + berker.peksag
2014-10-27 01:06:14 martin.panter set messages: +
2014-10-25 01:14:10 martin.panter set nosy: + martin.panter
2014-05-16 04:20:11 cvrebert set messages: +
2014-05-16 02:39:43 akira set nosy: + akiramessages: +
2014-05-15 16:07:28 cvrebert set messages: +
2014-05-15 12:39:43 serhiy.storchaka set files: - json_detect_encoding.patch
2014-05-15 12:38:58 serhiy.storchaka set files: + json_detect_encoding_2.patchmessages: +
2014-05-15 07:26:13 vstinner set nosy: + vstinner
2014-03-29 01:40:25 cvrebert set nosy: + cvrebert
2014-03-04 12:42:50 jleedev set nosy: + jleedev
2013-12-02 03🔞12 Julian set nosy: + Julian
2013-12-01 00:08:35 pitrou set versions: + Python 3.5, - Python 3.4
2013-11-30 11:07:13 pitrou set nosy: + ncoghlan
2013-08-10 14:31:38 serhiy.storchaka set stage: patch review
2013-05-05 13:11:10 serhiy.storchaka set dependencies: + UTF-16 and UTF-32 codecs should reject (lone) surrogates, disallow the "surrogatepass" handler for non utf-* encodings
2013-05-05 13:10:30 serhiy.storchaka create