How to implement date filters with operators like = in a JSON query string?
OK, below is what appears to be the solution for it ... We need to pass the query string as follows (all string, sorry for the formatting ...):


  http://web.com/drupal/api[endpoint name]/chart(view service pathname).json?field_invoice_date_value[min][year]=2013&amp;field_invoice_date_value[min][month]=12&amp;field_invoice_date_value[min][day]=1&amp;field_invoice_date_value[max][year]=2014&amp;field_invoice_date_value[max][month]=1&amp;field_invoice_date_value[max][day]=1


Things to notice in what is shown above:


No (more) &lt;= or &gt;= (can't use that in such JSON string).
Use notations like [min][month], [max][day], etc. instead (rather self explaining ... if you know about this syntax of course).


Done, works as designed ...