HTTP
----

HTTP transaction details are exposes to Lua scripts with the
``suricata.http`` library, For example::

  local http = require("suricata.http")

Setup
^^^^^

If your purpose is to create a logging script, initialize the buffer as:

::

  function init (args)
     local needs = {}
     needs["protocol"] = "http"
     return needs
  end

If you are going to use the script for rule matching, choose one of
the available HTTP buffers listed in :ref:`lua-detection` and follow
the pattern:

::

  function init (args)
     local needs = {}
     needs["http.request_line"] = tostring(true)
     return needs
  end

Transaction
~~~~~~~~~~~

HTTP is transaction based, and the current transaction must be obtained before use::

  local tx, err = http.get_tx()
  if tx == err then
      print(err)
  end

All other functions are methods on the transaction table. Header functions cover the
header section; trailer fields have the functions at the end of this page.

Transaction Methods
~~~~~~~~~~~~~~~~~~~

``request_header()``
^^^^^^^^^^^^^^^^^^^^

Get the HTTP request header value by key.

Example::

  local tx = http.get_tx()
  local ua = tx:request_header("User-Agent")
  if ua ~= nil then
        print(ua)
  end

``response_header()``
^^^^^^^^^^^^^^^^^^^^^

Get the HTTP response header value by key.

Example::

  local tx = http.get_tx()
  local content_type = tx:response_header("Content-Type")
  if content_type ~= nil then
        print(content_type)
  end

``request_line``
^^^^^^^^^^^^^^^^

Get the HTTP request line as a string.

Example::

  local tx = http.get_tx()
  local http_request_line = tx:request_line();
  if #http_request_line > 0 then
      if http_request_line:find("^GET") then
          print(http_request_line)
      end
  end

``response_line``
^^^^^^^^^^^^^^^^^

Get the HTTP response line as a string.

Example::

  local tx = http.get_tx()
  local http_response_line = tx:response_line();
  if #http_response_line > 0 then
        print(http_response_line)
  end

``request_headers_raw()``
^^^^^^^^^^^^^^^^^^^^^^^^^

Get the raw HTTP request headers.

Example::

  http_request_headers_raw = tx:request_headers_raw()

  if #http_request_headers_raw > 0 then
      if http_request_headers_raw:find("User%-Agent: curl") then
          print(http_request_headers_raw)
      end
  end

``response_headers_raw()``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Get the raw HTTP response headers.

Example::

  http_response_headers_raw = tx:response_headers_raw()

  if #http_response_headers_raw > 0 then
        print(http_response_headers_raw)
  end

``request_uri_raw()``
^^^^^^^^^^^^^^^^^^^^^

Get the raw HTTP request URI.

Example::

  local tx = http.get_tx()
  http_request_uri_raw = tx:request_uri_raw()
  print(http_request_uri_raw)

``request_uri_normalized()``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Get the normalized HTTP request URI.

Example::

  local tx = http.get_tx()
  http_request_uri_normalized = tx:request_uri_normalized()
  print(http_request_uri_normalized)

``request_headers()``
^^^^^^^^^^^^^^^^^^^^^

Get the HTTP request headers.

Example::

  local tx = http.get_tx()
  http_request_headers = tx:request_headers()
  print(http_request_headers)

``response_headers()``
^^^^^^^^^^^^^^^^^^^^^^

Get the HTTP response headers.

Example::

  local tx = http.get_tx()
  http_response_headers = tx:response_headers()
  print(http_response_headers)

``request_trailer()``
^^^^^^^^^^^^^^^^^^^^^

Get the value of an HTTP request trailer field by name, or nil and an error if the
transaction has no field of that name. Names are matched case insensitively.

Example::

  local tx = http.get_tx()
  local value, err = tx:request_trailer("X-Trailed")

``response_trailer()``
^^^^^^^^^^^^^^^^^^^^^^

Get the value of an HTTP response trailer field by name.

``request_trailers()``
^^^^^^^^^^^^^^^^^^^^^^

Get all HTTP request trailer fields as a table.

Example::

  local tx = http.get_tx()
  for name, value in pairs(tx:request_trailers()) do
      print(name, value)
  end

``response_trailers()``
^^^^^^^^^^^^^^^^^^^^^^^

Get all HTTP response trailer fields as a table.

``request_trailers_raw()``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Get the raw HTTP request trailer block, as it appeared on the wire.

``response_trailers_raw()``
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Get the raw HTTP response trailer block, as it appeared on the wire.

``request_body()``
^^^^^^^^^^^^^^^^^^

Get the HTTP request body.

Example::

  local tx = http.get_tx()
  http_request_body = tx:request_body()
  print(http_request_body)

``response_body()``
^^^^^^^^^^^^^^^^^^^

Get the HTTP response body.

Example::

  local tx = http.get_tx()
  http_response_body = tx:response_body()
  print(http_response_body)

``request_host()``
^^^^^^^^^^^^^^^^^^

Get the HTTP request host.

Example::

  local tx = http.get_tx()
  http_host = tx:request_host()
  print(http_host)