Google Commerce Search Deployment Guide - Manual (Page 22)

XML:
&fields=openSearch:*,s:facets,entry(title,s:product/
s:attributes,s:product/s:providedId,s:product/s:link)
Use the attributeFilter parameter to specify which of an item’s attributes you need:
&attributeFilter=name(text),thumbnail(text),product+review+average(flo
at),condition(text),price(float),brand(text)
Best Practice: Limit the number of results returned for your default searches. You can provide
the option for users to retrieve 50,100 or even 1000 results--but these requests can take longer
to return. Google is optimized to return small result sets very quickly--stick to returning 10 to 30
results per page by default.
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