# `Tesla.SecretString`
[🔗](https://github.com/elixir-tesla/tesla/blob/v1.22.0/lib/tesla/secret_string.ex#L1)

A string that is redacted when inspected.

Middleware options live in the client for as long as it exists, and every
`%Tesla.Env{}` embeds its client, so a token given to a middleware would
otherwise print wherever a client or env is inspected, including a
`Logger.error("request failed: #{inspect(env)}")`. Wrapping the value keeps
the redaction with the value itself, however the surrounding structure is
inspected:

    iex> secret = Tesla.SecretString.new("Bearer s3cret")
    iex> inspect(secret)
    "#Tesla.SecretString<redacted>"
    iex> inspect([{"authorization", secret}])
    ~s([{"authorization", #Tesla.SecretString<redacted>}])
    iex> to_string(secret)
    "Bearer s3cret"

`String.Chars` returns the value, so middleware that builds a header by
interpolation works with a wrapped value unchanged. The flip side is that
`"#{secret}"` prints it: interpolate a secret where it goes on the request,
never into a log message.

## Examples

```elixir
Tesla.client([
  {Tesla.Middleware.Headers, [{"authorization", Tesla.SecretString.new("Bearer #{token}")}]}
])

Tesla.client([
  {Tesla.Middleware.BearerAuth, token: Tesla.SecretString.new(token)}
])

Tesla.client([
  {Tesla.Middleware.BasicAuth, %{username: username, password: Tesla.SecretString.new(password)}}
])
```

# `t`

```elixir
@opaque t()
```

# `new`

```elixir
@spec new(String.t()) :: t()
```

Wraps `value`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*