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Kong Gateway
2.6.x
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kong.request

kong.request

Client request module A set of functions to retrieve information about the incoming requests made by clients.

kong.request.get_scheme()

Returns the scheme component of the request’s URL. The returned value is normalized to lower-case form.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string a string like "http" or "https"

Usage

-- Given a request to https://example.com:1234/v1/movies

kong.request.get_scheme() -- "https"

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kong.request.get_host()

Returns the host component of the request’s URL, or the value of the “Host” header. The returned value is normalized to lower-case form.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the host

Usage

-- Given a request to https://example.com:1234/v1/movies

kong.request.get_host() -- "example.com"

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kong.request.get_port()

Returns the port component of the request’s URL. The value is returned as a Lua number.

Phases

  • certificate, rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • number the port

Usage

-- Given a request to https://example.com:1234/v1/movies

kong.request.get_port() -- 1234

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kong.request.get_forwarded_scheme()

Returns the scheme component of the request’s URL, but also considers X-Forwarded-Proto if it comes from a trusted source. The returned value is normalized to lower-case.

Whether this function considers X-Forwarded-Proto or not depends on several Kong configuration parameters:

Note: support for the Forwarded HTTP Extension (RFC 7239) is not offered yet since it is not supported by ngx_http_realip_module.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the forwarded scheme

Usage

kong.request.get_forwarded_scheme() -- "https"

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kong.request.get_forwarded_host()

Returns the host component of the request’s URL or the value of the “host” header. Unlike kong.request.get_host(), this function will also consider X-Forwarded-Host if it comes from a trusted source. The returned value is normalized to lower-case.

Whether this function considers X-Forwarded-Host or not depends on several Kong configuration parameters:

Note: we do not currently offer support for Forwarded HTTP Extension (RFC 7239) since it is not supported by ngx_http_realip_module.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the forwarded host

Usage

kong.request.get_forwarded_host() -- "example.com"

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kong.request.get_forwarded_port()

Returns the port component of the request’s URL, but also considers X-Forwarded-Host if it comes from a trusted source. The value is returned as a Lua number.

Whether this function considers X-Forwarded-Proto or not depends on several Kong configuration parameters:

Note: we do not currently offer support for Forwarded HTTP Extension (RFC 7239) since it is not supported by ngx_http_realip_module.

When running Kong behind the L4 port mapping (or forwarding) you can also configure:

port_maps configuration parameter enables this function to return the port to which the port Kong is listening to is mapped to (in case they differ).

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • number the forwarded port

Usage

kong.request.get_forwarded_port() -- 1234

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kong.request.get_forwarded_path()

Returns the path component of the request’s URL, but also considers X-Forwarded-Path if it comes from a trusted source. The value is returned as a Lua string.

Whether this function considers X-Forwarded-Path or not depends on several Kong configuration parameters:

Note: we do not currently do any normalization on the request path.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the forwarded path

Usage

kong.request.get_forwarded_path() -- /path

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kong.request.get_forwarded_prefix()

Returns the prefix path component of the request’s URL that Kong stripped before proxying to upstream. It also checks if X-Forwarded-Prefix comes from a trusted source, and uses it as is when given. The value is returned as a Lua string.

If a trusted X-Forwarded-Prefix is not passed, this function must be called after Kong has ran its router (access phase), as the Kong router may strip the prefix of the request path. That stripped path will become the return value of this function, unless there was already a trusted X-Forwarded-Prefix header in the request.

Whether this function considers X-Forwarded-Prefix or not depends on several Kong configuration parameters:

Note: we do not currently do any normalization on the request path prefix.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string|nil the forwarded path prefix or nil if prefix was not stripped

Usage

kong.request.get_forwarded_prefix() -- /prefix

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kong.request.get_http_version()

Returns the HTTP version used by the client in the request as a Lua number, returning values such as 1, 1.1, 2.0, or nil for unrecognized values.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • number|nil the HTTP version as a Lua number

Usage

kong.request.get_http_version() -- 1.1

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kong.request.get_method()

Returns the HTTP method of the request. The value is normalized to upper-case.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the request method

Usage

kong.request.get_method() -- "GET"

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kong.request.get_path()

Returns the path component of the request’s URL. It is not normalized in any way and does not include the querystring.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the path

Usage

-- Given a request to https://example.com:1234/v1/movies?movie=foo

kong.request.get_path() -- "/v1/movies"

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kong.request.get_path_with_query()

Returns the path, including the querystring if any. No transformations/normalizations are done.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the path with the querystring

Usage

-- Given a request to https://example.com:1234/v1/movies?movie=foo

kong.request.get_path_with_query() -- "/v1/movies?movie=foo"

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kong.request.get_raw_query()

Returns the query component of the request’s URL. It is not normalized in any way (not even URL-decoding of special characters) and does not include the leading ? character.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string the query component of the request’s URL

Usage

-- Given a request to https://example.com/foo?msg=hello%20world&bla=&bar

kong.request.get_raw_query() -- "msg=hello%20world&bla=&bar"

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kong.request.get_query_arg()

Returns the value of the specified argument, obtained from the query arguments of the current request.

The returned value is either a string, a boolean true if an argument was not given a value, or nil if no argument with name was found.

If an argument with the same name is present multiple times in the querystring, this function will return the value of the first occurrence.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Returns

  • string|boolean|nil the value of the argument

Usage

-- Given a request GET /test?foo=hello%20world&bar=baz&zzz&blo=&bar=bla&bar

kong.request.get_query_arg("foo") -- "hello world"
kong.request.get_query_arg("bar") -- "baz"
kong.request.get_query_arg("zzz") -- true
kong.request.get_query_arg("blo") -- ""

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kong.request.get_query([max_args])

Returns the table of query arguments obtained from the querystring. Keys are query argument names. Values are either a string with the argument value, a boolean true if an argument was not given a value, or an array if an argument was given in the query string multiple times. Keys and values are unescaped according to URL-encoded escaping rules.

Note that a query string ?foo&bar translates to two boolean true arguments, and ?foo=&bar= translates to two string arguments containing empty strings.

By default, this function returns up to 100 arguments. The optional max_args argument can be specified to customize this limit, but must be greater than 1 and not greater than 1000.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Parameters

  • max_args (number, optional): set a limit on the maximum number of parsed arguments

Returns

  • table A table representation of the query string

Usage

-- Given a request GET /test?foo=hello%20world&bar=baz&zzz&blo=&bar=bla&bar

for k, v in pairs(kong.request.get_query()) do
  kong.log.inspect(k, v)
end

-- Will print
-- "foo" "hello world"
-- "bar" {"baz", "bla", true}
-- "zzz" true
-- "blo" ""

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kong.request.get_header(name)

Returns the value of the specified request header.

The returned value is either a string, or can be nil if a header with name was not found in the request. If a header with the same name is present multiple times in the request, this function will return the value of the first occurrence of this header.

Header names in are case-insensitive and are normalized to lowercase, and dashes (-) can be written as underscores (_); that is, the header X-Custom-Header can also be retrieved as x_custom_header.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Parameters

  • name (string): the name of the header to be returned

Returns

  • string|nil the value of the header or nil if not present

Usage

-- Given a request with the following headers:

-- Host: foo.com
-- X-Custom-Header: bla
-- X-Another: foo bar
-- X-Another: baz

kong.request.get_header("Host")            -- "foo.com"
kong.request.get_header("x-custom-header") -- "bla"
kong.request.get_header("X-Another")       -- "foo bar"

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kong.request.get_headers([max_headers])

Returns a Lua table holding the request headers. Keys are header names. Values are either a string with the header value, or an array of strings if a header was sent multiple times. Header names in this table are case-insensitive and are normalized to lowercase, and dashes (-) can be written as underscores (_); that is, the header X-Custom-Header can also be retrieved as x_custom_header.

By default, this function returns up to 100 headers. The optional max_headers argument can be specified to customize this limit, but must be greater than 1 and not greater than 1000.

Phases

  • rewrite, access, header_filter, response, body_filter, log, admin_api

Parameters

  • max_headers (number, optional): set a limit on the maximum number of parsed headers

Returns

  • table the request headers in table form

Usage

-- Given a request with the following headers:

-- Host: foo.com
-- X-Custom-Header: bla
-- X-Another: foo bar
-- X-Another: baz
local headers = kong.request.get_headers()

headers.host            -- "foo.com"
headers.x_custom_header -- "bla"
headers.x_another[1]    -- "foo bar"
headers["X-Another"][2] -- "baz"

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kong.request.get_raw_body()

Returns the plain request body.

If the body has no size (empty), this function returns an empty string.

If the size of the body is greater than the Nginx buffer size (set by client_body_buffer_size), this function will fail and return an error message explaining this limitation.

Phases

  • rewrite, access, response, admin_api

Returns

  • string the plain request body

Usage

-- Given a body with payload "Hello, Earth!":

kong.request.get_raw_body():gsub("Earth", "Mars") -- "Hello, Mars!"

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kong.request.get_body([mimetype[, max_args]])

Returns the request data as a key/value table. A high-level convenience function. The body is parsed with the most appropriate format:

  • If mimetype is specified:
    • Decodes the body with the requested content type (if supported).
  • If the request content type is application/x-www-form-urlencoded:
    • Returns the body as form-encoded.
  • If the request content type is multipart/form-data:
    • Decodes the body as multipart form data (same as multipart(kong.request.get_raw_body(), kong.request.get_header("Content-Type")):get_all() ).
  • If the request content type is application/json:
    • Decodes the body as JSON (same as json.decode(kong.request.get_raw_body())).
    • JSON types are converted to matching Lua types.
  • If none of the above, returns nil and an error message indicating the body could not be parsed.

The optional argument mimetype can be one of the following strings:

  • application/x-www-form-urlencoded
  • application/json
  • multipart/form-data

The optional argument max_args can be used to set a limit on the number of form arguments parsed for application/x-www-form-urlencoded payloads.

The third return value is string containing the mimetype used to parsed the body (as per the mimetype argument), allowing the caller to identify what MIME type the body was parsed as.

Phases

  • rewrite, access, response, admin_api

Parameters

  • mimetype (string, optional): the MIME type
  • max_args (number, optional): set a limit on the maximum number of parsed arguments

Returns

  1. table|nil a table representation of the body

  2. string|nil an error message

  3. string|nil mimetype the MIME type used

Usage

local body, err, mimetype = kong.request.get_body()
body.name -- "John Doe"
body.age  -- "42"

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