Sippet.Message.fetch_header_back
You're seeing just the function
fetch_header_back
, go back to Sippet.Message module for more information.
Specs
fetch_header_back(t(), header()) :: {:ok, multiple_value()} | :error
Fetches the last value of a specific header
and returns it in a tuple.
If the header
does not exist, or the value is not a list, returns :error
.
If the header
exists but it is an empty list, returns {:ok, nil}
.
Examples:
iex> request =
...> Sippet.Message.build_request(:invite, "sip:foo@bar.com")
...> |> Sippet.Message.put_header(:content_language, ["en-US", "de-DE"])
...> |> Sippet.Message.put_header(:max_forwards, 70)
iex> request |> Sippet.Message.fetch_header_back(:content_language)
{:ok, "de-DE"}
iex> request |> Sippet.Message.fetch_header_back(:max_forwards)
:error
iex> request |> Sippet.Message.fetch_header_back(:cseq)
:error