hook.md

Hook

DBX provides a macro to hook all queries (exec or query).

This can be done with around_query_or_exec(&block) macro.

This macro allows injecting code to be run before and after the execution of the request. It should return the yielded value. It must be called with 1 block argument that will be used to pass the args : Enumerable. This macro should be called at the top level, not from a method.

DBX.around_query_or_exec do |args|
  puts "before"
  res = yield
  puts "after"

  puts res.class
  puts "exec" if res.is_a?(DB::ExecResult)
  puts "query" if res.is_a?(DB::ResultSet)

  puts "with args:"
  pp args

  res
end

Be careful of the performance penalty that each hook may cause, be aware that your code will be executed at each query and exec.

around_query_or_exec(&block) is useful for debugging and profiling all queries.

Example to measure query execution time:

DBX.around_query_or_exec do |args|
  start = Time.monotonic
  res = yield
  elapsed_time = Time.monotonic - start

  puts "Query execution time: #{elapsed_time}"
  res
end