Packages
ecto_raw_sql_helpers
0.1.2
EctoRawSQLHelpers aims to improve raw SQL support in Ecto by providing helper functions, such as: - Named parameters support - Response parsing (getting query results as lists of maps, number of rows affected on statements, etc) - Stream support for dealing with big result sets
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lib/internals/stream_server.ex
defmodule EctoRawSQLHelpers.StreamServer do
defmodule StreamRequest do
defstruct [
:client_pid,
:instruction,
]
end
defmodule StreamResponse do
defstruct [
:server_pid,
:state,
:data,
]
end
def initialize_stream_server_and_wait_for_demand(repo_or_pid, sql, params, options) do
spawn_link(
fn ->
repo_or_pid.transaction(
fn ->
Ecto.Adapters.SQL.stream(repo_or_pid, sql, params, options)
|> Enum.each(&wait_for_demand_and_send_response/1)
end
)
wait_for_demand_and_send_finished_state()
end
)
end
defp wait_for_demand_and_send_response(chunk) do
receive do
%StreamRequest{
client_pid: pid,
instruction: :next_page
} -> send(pid, %StreamResponse{server_pid: self(), state: :ok, data: chunk})
end
end
defp wait_for_demand_and_send_finished_state() do
receive do
%StreamRequest{
client_pid: pid,
instruction: :next_page
} -> send(pid, %StreamResponse{server_pid: self(), state: :finished})
end
end
end