Enable export support for already opened files

[jeanferri]

No description provided.

[turicas]

The StringIO module is gone on Python 3. We do not support it yet but using io.BytesIO or io.StringIO now will make the migration easier. Could you please change it?

[turicas]

Hello, @jeanferri. Thanks for your contribution. :-)

I made two comments, can you please address them?
It would be good to include tests for these cases also. Could you please add one for each format? If you're not used to it or need any help just ask and I'll help you!

And a curiosity: what is your use case to need binary XLS data (instead of writing to the filesystem)? Are you going to use it to stream data over the Web?

Thanks again.

[jeanferri]

Ok, I'll try to make compatible also with python3, because we are still using python 2.7 with Plone 4.3, and yes, I'm using it into an web application and it's because I dont need to write it to filesystem.

This last commit fix an error on older versions of urllib, for example, the original python-urllib3 package in the last Ubuntu LTS.

[jeanferri]

May it #125 (comment) be like this last commit?

[turicas]

@jeanferri, you can just use:

from io import BytesIO

And it will work on Python 2.7 and 3.x. ;-)
(there is no need to support Python < 2.7 in my opinion)

[jeanferri]

Ok, you win! ;-)

[jeanferri]

This last commit closes #80

[turicas]

@jeanferri, I'm working on your branch but on my fork (feature/support-already-opened-files) and already rebased it with develop (I made some changes to develop since you created this PR).
There are some things I need to fix:

• Do not read the whole CSV file to guess its Dialect (the first KiB may be enough)
• Use the whole Dialect object instead of delimiter only
• Add tests for automatic Dialect detection
• Refactor export code in order to create a function in rows.plugins.utils
• Add tests for already opened files (JSON, CSV, TXT and XLS plugins)
• Add support for other plugins and its respective tests (HTML) -- SQLite is not needed

I'll work on this list on the next days.

[turicas]

@jeanferri, I updated my branch. There are some tests missing and I'll work on this tomorrow.

[turicas]

@jeanferri, I merged my branch into develop (05b0e39), but GitHub didn't detected the change on this PR because I made a git rebase and the commits created were different from this PR, but your code was improved and merged anyway. :) So, I'm closing this PR manually.

Thanks!

[jeanferri]

Ok, thank you! I'll test it and send you another pull request with more things I'm doing... ;-)