Add an option to return 'date' as 'string' for easy conversion to geojson.

[rados]

Hello,

Currently I am converting shape file to a geojson. In my shape file there are dates and I have to pay special attention to convert those dates to strings in order to json-ify them. So this could be a kind of common operation and then maybe the best thing is for the pyshp library to support this inherently somehow. Probably with a kind of flag or something better. I think this could be a simple change in the Reader.__record method, 'D' case.

I am ready to help with a PR.

Thanks,
Rado

[cipri-tom]

I am having the same problem.

@rados are you doing any manual conversion, or just using the .__geo_interface__ on the file reader ?

How do you find the dates after the conversion ?

Thank you !

---

An additional problem is if the date is empty, the except branch should probably encode the result as string

pyshp/shapefile.py

Lines 1207 to 1216 in 69c60f6

	elif typ == 'D':
	# date: 8 bytes - date stored as a string in the format YYYYMMDD.
	if value.count(b'0') == len(value): # QGIS NULL is all '0' chars
	value = None
	else:
	try:
	y, m, d = int(value[:4]), int(value[4:6]), int(value[6:8])
	value = date(y, m, d)
	except:
	value = value.strip()

[karimbahgat]

Just pushed new commits to address this, no custom args needed. Date fields are loaded into python date objects for convenience to the user as usual, but calls to geo_interface will automatically convert them back to the original date string, so that they are directly able to be json serialized. Added tests to ensure that all geo_interface calls can be dumped to json.

Based on your suggestion @cipri-tom I also ensured faulty date formats (those that end in the except clause) are converted to unicode/string.

Also added better handling of possible date field null values, although the dbf format doesn't officially support date null values.

Until I push a new release version, you can try it out from the latest Github version.