GCP Python 3 caching

[kitsook]

The GCP Python 3 environment has removed support for memcache. Commented out the caching part.

newsSum/main.py

Lines 49 to 54 in a91908c

	if thePath in allSources:
	# try to retrieve from cache
	# encodedArticles = memcache.get(thePath)
	encodedArticles = None
	if (encodedArticles == None):
	articles.extend(allSources[thePath].get_articles())

Need to switch to external redis or Google Cloud Memorystore.

[kitsook]

As an interim solution, set http headers and let browsers cache the result:

newsSum/main.py

Lines 63 to 67 in 9540662

	# since we don't have memcache in GCP py3, tell browsers to cache everything to minimize our traffic
	@app.after_request
	def add_header(response):
	response.cache_control.max_age = 300
	return response

[kitsook]

Set cache-control header to public with max-age to have browsers and any cache-capable servers along the path to cache the result.