[jira] [Commented] (COUCHDB-2295) Connection hangs on document update for multipart/related and transfer encoding chunked request

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/COUCHDB-2295?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15932202#comment-15932202 ] 

ASF GitHub Bot commented on COUCHDB-2295:
-----------------------------------------

GitHub user stevebest opened an issue:

    https://github.com/apache/couchdb-nano/issues/36

    Streamable multipart attachments are not supported

    Consider a scenario when you want to upload a document and several attachments to a CouchDB in a single request - a typical example would be uploading a "Couchapp": a design doc with multiple HTML/JS/CSS attachments. This scenario is [supported by CouchDB API](http://docs.couchdb.org/en/1.6.1/api/document/common.html?highlight=multipart/related#creating-multiple-attachments) using `Content-Type: multipart/related` request. Furthermore, you could expect to leverage Node `Stream`s in order to avoid the necessity of buffering a bunch of files in memory. Unfortunately, the combination of issues in CouchDB and `request` prevents this.
    
    1) CouchDB has [a nasty bug](https://issues.apache.org/jira/browse/COUCHDB-2295) which prevents from using `Transfer-Encoding: chunked` along with `Content-Type: multipart/related`. It won't be fixed until `1.7`, and its status in `2.x` branch is unknown.
    2) `request` uses exactly the `Transfer-Encoding: chunked` to upload data from `Stream`s. Uh-oh.
    3) `request` could be told explicitly not to use `chunked` encoding - but then you can't give it any `Stream`s! See [docs for a `multipart` option in request(options, callback)](https://github.com/request/request#requestoptions-callback). Bummer.
    
    Technically, it should be possible to stream a bunch of attachments, in case where one knows the length of the stream beforehand (which is not a problem when you upload files from a disk). I attempted to add the support for this case in dscape/nano#300, but failed miserably because `request` rightfully thinks it's smarter than me.

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> Connection hangs on document update for multipart/related and transfer encoding chunked request
> -----------------------------------------------------------------------------------------------
>
>                 Key: COUCHDB-2295
>                 URL: https://issues.apache.org/jira/browse/COUCHDB-2295
>             Project: CouchDB
>          Issue Type: Bug
>          Components: HTTP Interface
>            Reporter: Alexander Shorin
>             Fix For: 1.7.0
>
>
> Script to reproduce:
> {code}
> import pprint
> import requests
> body = [
>     b'--996713c691ec4fd5b717ef2740893b78\r\n',
>     b'Content-Type: application/json\r\n',
>     b'\r\n',
>     b'{"_id": "test","_attachments": {"foo": {"follows": true, "content_type": "text/plain", "length": 12}}}\r\n',
>     b'--996713c691ec4fd5b717ef2740893b78\r\n',
>     b'Content-Type: text/plain\r\n'
>     b'Content-Disposition: attachment;filename="foo"\r\n'
>     b'Content-Length: 12\r\n'
>     b'\r\n',
>     b'Time to Relax!',
>     b'--996713c691ec4fd5b717ef2740893b78--\r\n'
> ]
> url = 'http://localhost:5984/db/test'
> headers = {
>     'Content-Type': 'multipart/related; boundary="996713c691ec4fd5b717ef2740893b78"'
> }
> resp = requests.put(url, headers=headers, data=iter(body))
> pprint.pprint(resp.json())
> {code}
> This runs a request:
> {code}
> PUT /db/test HTTP/1.1
> Host: localhost:5984
> Accept-Encoding: gzip, deflate
> Transfer-Encoding: chunked
> User-Agent: python-requests/2.3.0 CPython/3.4.1 Linux/3.15.5-gentoo
> Accept: */*
> Content-Type: multipart/related; boundary="996713c691ec4fd5b717ef2740893b78"
> 24
> --996713c691ec4fd5b717ef2740893b78
> 20
> Content-Type: application/json
> 2
> 68
> {"_id": "test","_attachments": {"foo": {"follows": true, "content_type": "text/plain", "length": 14}}}
> 24
> --996713c691ec4fd5b717ef2740893b78
> 60
> Content-Type: text/plain
> Content-Disposition: attachment;filename="foo"
> Content-Length: 12
> e
> Time to Relax!
> 26
> --996713c691ec4fd5b717ef2740893b78--
> 0
> {code}
> But connection hangs: CouchDB thinks that there have to more data while zero length chunk had been send and doesn't reply with anything back to client which had finished the request and awaits for the response.
> The problem could be "fixed" by specifying full Content-Length of multipart body in request, which kills all the idea of chunked transfer.



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