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| 1 | +defmodule ComponentsGuide.Fetch.Get do |
| 2 | + alias ComponentsGuide.Fetch.{Request, Response} |
| 3 | + |
| 4 | + @timeout 5000 |
| 5 | + |
| 6 | + defmodule Timings do |
| 7 | + defstruct [:duration, :start] |
| 8 | + |
| 9 | + def start() do |
| 10 | + %__MODULE__{ |
| 11 | + start: System.monotonic_time() |
| 12 | + } |
| 13 | + end |
| 14 | + |
| 15 | + def finish(timings = %__MODULE__{start: start}) do |
| 16 | + duration = System.monotonic_time() - start |
| 17 | + put_in(timings.duration, duration) |
| 18 | + end |
| 19 | + |
| 20 | + def start_with_telemetry(event_name, metadata \\ %{}) do |
| 21 | + t = start() |
| 22 | + |
| 23 | + :telemetry.execute( |
| 24 | + event_name, |
| 25 | + %{start: t.start}, |
| 26 | + metadata |
| 27 | + ) |
| 28 | + |
| 29 | + t |
| 30 | + end |
| 31 | + |
| 32 | + def finish_with_telemetry(t = %__MODULE__{}, event_name, metadata \\ %{}) do |
| 33 | + t = finish(t) |
| 34 | + |
| 35 | + :telemetry.execute( |
| 36 | + event_name, |
| 37 | + %{duration: t.duration}, |
| 38 | + metadata |
| 39 | + ) |
| 40 | + |
| 41 | + t |
| 42 | + end |
| 43 | + end |
| 44 | + |
| 45 | + def get_following_redirects!(url_string) when is_binary(url_string) do |
| 46 | + request = Request.new!(url_string) |
| 47 | + |
| 48 | + case load!(request) do |
| 49 | + %Response{status: status, headers: headers} = resp when status >= 300 and status < 400 -> |
| 50 | + case Enum.find(headers, fn {key, _} -> key == "location" end) do |
| 51 | + # No redirect! |
| 52 | + nil -> |
| 53 | + resp |
| 54 | + |
| 55 | + {_, location} -> |
| 56 | + IO.puts("Following #{status} redirect to #{location}") |
| 57 | + |
| 58 | + case Request.new(location) do |
| 59 | + {:ok, request} -> |
| 60 | + # TODO: use existing conn if host is the same. |
| 61 | + load!(request) |
| 62 | + |
| 63 | + _ -> |
| 64 | + {:error, {:invalid_url, location}} |
| 65 | + end |
| 66 | + end |
| 67 | + |
| 68 | + other -> |
| 69 | + other |
| 70 | + end |
| 71 | + end |
| 72 | + |
| 73 | + def load!(req = %Request{uri: %URI{host: host, port: 443}}) do |
| 74 | + t = Timings.start_with_telemetry([:fetch, :load!, :start], %{req: req}) |
| 75 | + |
| 76 | + {:ok, conn} = Mint.HTTP.connect(:https, host, 443, mode: :passive, protocols: [:http1]) |
| 77 | + {conn, response} = do_request(conn, req) |
| 78 | + Mint.HTTP.close(conn) |
| 79 | + |
| 80 | + t = |
| 81 | + Timings.finish_with_telemetry(t, [:fetch, :load!, :done], %{ |
| 82 | + req: req |
| 83 | + }) |
| 84 | + |
| 85 | + response = Response.add_timings(response, t) |
| 86 | + |
| 87 | + IO.puts( |
| 88 | + "Loaded #{req.url_string} in #{System.convert_time_unit(t.duration, :native, :millisecond)}ms. #{inspect(response.done?)}" |
| 89 | + ) |
| 90 | + |
| 91 | + response |
| 92 | + end |
| 93 | + |
| 94 | + def load_many_example(n \\ 2) do |
| 95 | + load_many!( |
| 96 | + "components.guide", |
| 97 | + Enum.map(0..n, fn _ -> Request.new!("https://components.guide/") end) |
| 98 | + ) |
| 99 | + end |
| 100 | + |
| 101 | + def load_many!(host, reqs) when is_binary(host) and is_list(reqs) do |
| 102 | + t = Timings.start_with_telemetry([:fetch, :load_many!, :start], %{host: host}) |
| 103 | + |
| 104 | + {:ok, conn} = Mint.HTTP.connect(:https, host, 443, mode: :passive, protocols: [:http1]) |
| 105 | + |
| 106 | + {conn, results} = |
| 107 | + Enum.reduce(reqs, {conn, []}, fn |
| 108 | + %Request{uri: %URI{host: ^host, port: 443}} = req, {conn, results} -> |
| 109 | + t = Timings.start_with_telemetry([:fetch, :load_many!, :request, :start], %{req: req}) |
| 110 | + |
| 111 | + {conn, response} = do_request(conn, req) |
| 112 | + |
| 113 | + t = |
| 114 | + Timings.finish_with_telemetry(t, [:fetch, :load_many!, :request, :done], %{ |
| 115 | + req: req |
| 116 | + }) |
| 117 | + |
| 118 | + response = Response.add_timings(response, t) |
| 119 | + |
| 120 | + {conn, [response | results]} |
| 121 | + end) |
| 122 | + |
| 123 | + Mint.HTTP.close(conn) |
| 124 | + results = Enum.reverse(results) |
| 125 | + |
| 126 | + Timings.finish_with_telemetry(t, [:fetch, :load_many!, :done], %{host: host}) |
| 127 | + results |
| 128 | + end |
| 129 | + |
| 130 | + defp recv_all(result = %Response{done?: true}, conn, _request_ref), do: {conn, result} |
| 131 | + |
| 132 | + defp recv_all(result, conn, request_ref) do |
| 133 | + case Mint.HTTP.recv(conn, 0, @timeout) do |
| 134 | + {:ok, conn, responses} -> |
| 135 | + Response.add_responses(result, responses, request_ref) |
| 136 | + |> recv_all(conn, request_ref) |
| 137 | + |
| 138 | + {:error, conn, error, _responses} -> |
| 139 | + {conn, Response.add_error(result, error)} |
| 140 | + end |
| 141 | + end |
| 142 | + |
| 143 | + defp do_request( |
| 144 | + conn, |
| 145 | + %Request{ |
| 146 | + method: method, |
| 147 | + uri: %URI{path: path}, |
| 148 | + headers: headers, |
| 149 | + body: body, |
| 150 | + url_string: url_string |
| 151 | + } |
| 152 | + ) do |
| 153 | + result = Response.new(url_string) |
| 154 | + |
| 155 | + case Mint.HTTP.request(conn, method, path || "/", headers, body) do |
| 156 | + {:error, conn, reason} -> |
| 157 | + {conn, Response.add_error(result, reason)} |
| 158 | + |
| 159 | + {:ok, conn, request_ref} -> |
| 160 | + recv_all(result, conn, request_ref) |
| 161 | + end |
| 162 | + end |
| 163 | +end |
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