Problem when loading php file into variable (Load result of php code instead of the code as a string)

I have a site architechure where I assign content to variables and then print them in a master page. My problem is that php code in the sub pages is imported into the variables as strings. Is there anyway to make sure that the code is actually executed and the results is imported in the variables instead?

Failed to append data in .json file using node

I want to append my data which is array of object format to the existing .json file so I have written code for it, but on stackoverflow I noticed so many developers suggesting before appending to existing json file first read file and then push new data to existing json file. So I followed this and made changes according to this but getting error :