[GitHub] couchdb-nano issue #36: Streamable multipart attachments are not supported

[stevebest <gi...@git.apache.org>]

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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