@spec banner(:error | :exit | :throw, term()) :: String.t()

Formats an exception, throw or exit as a bounded one line banner. Exception.format_banner/2 inspects throw and exit reasons without limits.

iex> PhoenixDevToolbar.Truncate.banner(:error, %RuntimeError{message: "bad"})
"** (RuntimeError) bad"

iex> PhoenixDevToolbar.Truncate.banner(:throw, :oops)
"** (throw) :oops"

@spec inspect_value(term(), keyword()) :: String.t()

Inspects a value with the toolbar limits.

iex> PhoenixDevToolbar.Truncate.inspect_value(Enum.to_list(1..60)) |> String.ends_with?("...]")
true

@spec preview(term(), pos_integer(), [String.t()]) :: String.t()

Redacted, bounded inspect of any value, at most bytes long.

Unlike redact/2, the cost does not depend on the value: at most 200 nodes and 20 items per container are walked, and whatever is not walked is replaced by "…", so a sensitive key deep in a large value is cut, never shown.

iex> PhoenixDevToolbar.Truncate.preview(%{user: %{password: "hunter2"}})
~s(%{user: %{password: "[REDACTED]"}})

iex> PhoenixDevToolbar.Truncate.preview(Enum.to_list(1..30))
"[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, ...]"

@spec redact(term(), [String.t() | atom()]) :: term()

Replaces the value of sensitive keys with "[REDACTED]".

A key is sensitive when its name (atom or string, case insensitive, the first 256 bytes of it) contains one of keys. Walks maps, structs, keyword lists, lists and tuples, at most 50 entries per container and 1000 nodes in total, so the cost does not depend on the value.

Contract: a sensitive key's value is "[REDACTED]"; anything the walk does not reach is replaced by "…", never returned as is. The rest of a list or tuple becomes a final "…" element (so does the tail of an improper list), the rest of a map becomes a "…" => "…" entry, and a struct with more than 50 fields becomes a plain map with that entry. Scalars, including large binaries, are returned as they are (they are cheap; inspect_value/2 bounds their size). Key matching only sees map, struct and keyword keys: a bare {"password", "x"} tuple outside a list, a charlist key and a secret inside a string value are not recognised.

iex> PhoenixDevToolbar.Truncate.redact(%{"user" => %{"password" => "hunter2", "name" => "Ada"}})
%{"user" => %{"password" => "[REDACTED]", "name" => "Ada"}}

iex> PhoenixDevToolbar.Truncate.redact([api_token: "abc", page: 1])
[api_token: "[REDACTED]", page: 1]

iex> PhoenixDevToolbar.Truncate.redact({:login, %{password: "hunter2"}})
{:login, %{password: "[REDACTED]"}}

iex> PhoenixDevToolbar.Truncate.redact([%{password: "hunter2"} | :tail])
[%{password: "[REDACTED]"}, "…"]

@spec sql(String.t() | nil) :: String.t() | nil

Caps a SQL string at 8192 bytes.

iex> PhoenixDevToolbar.Truncate.sql("SELECT 1")
"SELECT 1"

iex> PhoenixDevToolbar.Truncate.sql(nil)
nil

@spec stacktrace(Exception.stacktrace() | nil, [module()]) :: [String.t()]

Formats the first 10 stacktrace frames that do not belong to the toolbar, to :telemetry or to the extra skip modules and namespaces (an Elixir module skips itself and every module nested under it).

iex> PhoenixDevToolbar.Truncate.stacktrace([{MyApp.Users, :list, 0, [file: ~c"lib/users.ex", line: 3]}])
["lib/users.ex:3: MyApp.Users.list/0"]

iex> PhoenixDevToolbar.Truncate.stacktrace([{Ecto.Repo.Queryable, :all, 3, []}], [Ecto])
[]

iex> PhoenixDevToolbar.Truncate.stacktrace(nil)
[]

@spec string(String.t(), pos_integer()) :: String.t()

Caps any text (exception messages, banners) at limit bytes, 2048 by default.

iex> PhoenixDevToolbar.Truncate.string("boom")
"boom"

iex> "x" |> String.duplicate(3000) |> PhoenixDevToolbar.Truncate.string() |> byte_size()
2060