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kong.request

Client request module.

This module provides 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 lowercase form.

Phases

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

Returns

  • string: A string like "http" or "https".

Usage

  1. -- Given a request to https://example.com:1234/v1/movies
  3. kong.request.get_scheme() -- "https"

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 lowercase form.

Phases

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

Returns

  • string: The hostname.

Usage

  1. -- Given a request to https://example.com:1234/v1/movies
  3. kong.request.get_host() -- "example.com"

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

  1. -- Given a request to https://example.com:1234/v1/movies
  3. kong.request.get_port() -- 1234

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 lowercase.

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

Note: Kong does not offer support for the 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 scheme.

Usage

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

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 also considers X-Forwarded-Host if it comes from a trusted source. The returned value is normalized to lowercase.

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

Note: Kong does not offer support for the 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

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

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: Kong does not offer support for the 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:

The 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

  1. kong.request.get_forwarded_port() -- 1234

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: Kong does not do any normalization on the request path.

Phases

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

Returns

  • string: The forwarded path.

Usage

  1. kong.request.get_forwarded_path() -- /path

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 run its router (access phase), as the Kong router may strip the prefix of the request path. That stripped path becomes the return value of this function, unless there is 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: Kong does not 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 the prefix was not stripped.

Usage

  1. kong.request.get_forwarded_prefix() -- /prefix

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

  1. kong.request.get_http_version() -- 1.1

kong.request.get_method()

Returns the HTTP method of the request. The value is normalized to uppercase.

Phases

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

Returns

  • string: The request method.

Usage

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

kong.request.get_path()

Returns the normalized path component of the request’s URL. The return value is the same as kong.request.get_raw_path() but normalized according to RFC 3986 section 6:

  • Percent-encoded values of unreserved characters are decoded (%20 becomes ` `).
  • Percent-encoded values of reserved characters have their hexidecimal value uppercased (%2f becomes %2F).
  • Relative path elements (/. and /..) are dereferenced.
  • Duplicate slashes are consolidated (// becomes /).

Phases

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

Returns

  • string: the path

Usage

  1. -- Given a request to https://example.com/t/Abc%20123%C3%B8%2f/parent/..//test/./
  3. kong.request.get_path() -- "/t/Abc 123ø%2F/test/"

kong.request.get_raw_path()

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

NOTE: Using the raw path to perform string comparison during request handling (such as in routing, ACL/authorization checks, setting rate-limit keys, etc) is widely regarded as insecure, as it can leave plugin code vulnerable to path traversal attacks. Prefer kong.request.get_path() for such use cases.

Phases

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

Returns

  • string: The path.

Usage

  1. -- Given a request to https://example.com/t/Abc%20123%C3%B8%2f/parent/..//test/./?movie=foo
  3. kong.request.get_raw_path() -- "/t/Abc%20123%C3%B8%2f/parent/..//test/./"

kong.request.get_path_with_query()

Returns the path, including the query string if any. No transformations or normalizations are done.

Phases

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

Returns

  • string: The path with the query string.

Usage

  1. -- Given a request to https://example.com:1234/v1/movies?movie=foo
  3. kong.request.get_path_with_query() -- "/v1/movies?movie=foo"

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

  1. -- Given a request to https://example.com/foo?msg=hello%20world&bla=&bar
  3. kong.request.get_raw_query() -- "msg=hello%20world&bla=&bar"

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 query string, this function returns 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

  1. -- Given a request GET /test?foo=hello%20world&bar=baz&zzz&blo=&bar=bla&bar
  3. kong.request.get_query_arg("foo") -- "hello world"
  4. kong.request.get_query_arg("bar") -- "baz"
  5. kong.request.get_query_arg("zzz") -- true
  6. kong.request.get_query_arg("blo") -- ""

kong.request.get_query([max_args])

Returns the table of query arguments obtained from the query string. 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 (or what has been configured using lua_max_uri_args). 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): Sets a limit on the maximum number of parsed arguments.

Returns

  • table: A table representation of the query string.

Usage

  1. -- Given a request GET /test?foo=hello%20world&bar=baz&zzz&blo=&bar=bla&bar
  3. for k, v in pairs(kong.request.get_query()) do
  4.   kong.log.inspect(k, v)
  5. end
  7. -- Will print
  8. -- "foo" "hello world"
  9. -- "bar" {"baz", "bla", true}
  10. -- "zzz" true
  11. -- "blo" ""

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 returns 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

  1. -- Given a request with the following headers:
  3. -- Host: foo.com
  4. -- X-Custom-Header: bla
  5. -- X-Another: foo bar
  6. -- X-Another: baz
  8. kong.request.get_header("Host")            -- "foo.com"
  9. kong.request.get_header("x-custom-header") -- "bla"
  10. kong.request.get_header("X-Another")       -- "foo bar"

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.

By default, this function returns up to 100 headers (or what has been configured using lua_max_req_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): Sets a limit on the maximum number of parsed headers.

Returns

  • table: The request headers in table form.

Usage

  1. -- Given a request with the following headers:
  3. -- Host: foo.com
  4. -- X-Custom-Header: bla
  5. -- X-Another: foo bar
  6. -- X-Another: baz
  7. local headers = kong.request.get_headers()
  9. headers.host            -- "foo.com"
  10. headers.x_custom_header -- "bla"
  11. headers.x_another[1]    -- "foo bar"
  12. headers["X-Another"][2] -- "baz"

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 fails and returns an error message explaining this limitation.

Phases

  • rewrite, access, response, admin_api

Returns

  1. string|nil: The plain request body or nil if it does not fit into the NGINX temporary buffer.
  2. nil|string: An error message.

Usage

  1. -- Given a body with payload "Hello, Earth!":
  3. kong.request.get_raw_body():gsub("Earth", "Mars") -- "Hello, Mars!"

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, it decodes the body with the requested content type (if supported). This takes precedence over any content type present in the request.

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

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

Whether mimetype is specified or a request content type is otherwise present in the request, each content type behaves as follows:

  • 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 the request contains none of the above and the mimetype argument is not set, returns nil and an error message indicating the body could not be parsed.

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, which is by default 100 (or what has been configured using lua_max_post_args).

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): Sets 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

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

kong.request.get_start_time()

Returns the request start time, in Unix epoch milliseconds.

Phases

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

Returns

  • number: The timestamp

Usage

  1. kong.request.get_start_time() -- 1649960273000

kong.request.get_uri_captures()

Returns the URI captures matched by the router.

Phases

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

Returns

  • table: tables containing unnamed and named captures.

Usage

  1. local captures = kong.request.get_uri_captures()
  2. for idx, value in ipairs(captures.unnamed) do
  3.   -- do what you want to captures
  4. end
  5. for name, value in pairs(captures.named) do
  6.   -- do what you want to captures
  7. end