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# frozen_string_literal: true
require 'forwardable'
require_relative 'constants'
require_relative 'utils'
module Rack
# Rack::Lint validates your application and the requests and
# responses according to the Rack spec.
class Lint
def initialize(app)
@app = app
end
# :stopdoc:
class LintError < RuntimeError; end
# AUTHORS: n.b. The trailing whitespace between paragraphs is important and
# should not be removed. The whitespace creates paragraphs in the RDoc
# output.
#
## This specification aims to formalize the Rack protocol. You
## can (and should) use Rack::Lint to enforce it.
##
## When you develop middleware, be sure to add a Lint before and
## after to catch all mistakes.
##
## = Rack applications
##
## A Rack application is a Ruby object (not a class) that
## responds to +call+.
def call(env = nil)
Wrapper.new(@app, env).response
end
class Wrapper
def initialize(app, env)
@app = app
@env = env
@response = nil
@head_request = false
@status = nil
@headers = nil
@body = nil
@invoked = nil
@content_length = nil
@closed = false
@size = 0
end
def response
## It takes exactly one argument, the *environment*
raise LintError, "No env given" unless @env
check_environment(@env)
@env[RACK_INPUT] = InputWrapper.new(@env[RACK_INPUT])
@env[RACK_ERRORS] = ErrorWrapper.new(@env[RACK_ERRORS])
## and returns a non-frozen Array of exactly three values:
@response = @app.call(@env)
raise LintError, "response is not an Array, but #{@response.class}" unless @response.kind_of? Array
raise LintError, "response is frozen" if @response.frozen?
raise LintError, "response array has #{@response.size} elements instead of 3" unless @response.size == 3
@status, @headers, @body = @response
## The *status*,
check_status(@status)
## the *headers*,
check_headers(@headers)
hijack_proc = check_hijack_response(@headers, @env)
if hijack_proc
@headers[RACK_HIJACK] = hijack_proc
end
## and the *body*.
check_content_type(@status, @headers)
check_content_length(@status, @headers)
@head_request = @env[REQUEST_METHOD] == HEAD
@lint = (@env['rack.lint'] ||= []) << self
if (@env['rack.lint.body_iteration'] ||= 0) > 0
raise LintError, "Middleware must not call #each directly"
end
return [@status, @headers, self]
end
##
## == The Environment
##
def check_environment(env)
## The environment must be an unfrozen instance of Hash that includes
## CGI-like headers. The Rack application is free to modify the
## environment.
raise LintError, "env #{env.inspect} is not a Hash, but #{env.class}" unless env.kind_of? Hash
raise LintError, "env should not be frozen, but is" if env.frozen?
##
## The environment is required to include these variables
## (adopted from {PEP 333}[https://peps.python.org/pep-0333/]), except when they'd be empty, but see
## below.
## <tt>REQUEST_METHOD</tt>:: The HTTP request method, such as
## "GET" or "POST". This cannot ever
## be an empty string, and so is
## always required.
## <tt>SCRIPT_NAME</tt>:: The initial portion of the request
## URL's "path" that corresponds to the
## application object, so that the
## application knows its virtual
## "location". This may be an empty
## string, if the application corresponds
## to the "root" of the server.
## <tt>PATH_INFO</tt>:: The remainder of the request URL's
## "path", designating the virtual
## "location" of the request's target
## within the application. This may be an
## empty string, if the request URL targets
## the application root and does not have a
## trailing slash. This value may be
## percent-encoded when originating from
## a URL.
## <tt>QUERY_STRING</tt>:: The portion of the request URL that
## follows the <tt>?</tt>, if any. May be
## empty, but is always required!
## <tt>SERVER_NAME</tt>:: When combined with <tt>SCRIPT_NAME</tt> and
## <tt>PATH_INFO</tt>, these variables can be
## used to complete the URL. Note, however,
## that <tt>HTTP_HOST</tt>, if present,
## should be used in preference to
## <tt>SERVER_NAME</tt> for reconstructing
## the request URL.
## <tt>SERVER_NAME</tt> can never be an empty
## string, and so is always required.
## <tt>SERVER_PORT</tt>:: An optional +Integer+ which is the port the
## server is running on. Should be specified if
## the server is running on a non-standard port.
## <tt>SERVER_PROTOCOL</tt>:: A string representing the HTTP version used
## for the request.
## <tt>HTTP_</tt> Variables:: Variables corresponding to the
## client-supplied HTTP request
## headers (i.e., variables whose
## names begin with <tt>HTTP_</tt>). The
## presence or absence of these
## variables should correspond with
## the presence or absence of the
## appropriate HTTP header in the
## request. See
## {RFC3875 section 4.1.18}[https://tools.ietf.org/html/rfc3875#section-4.1.18]
## for specific behavior.
## In addition to this, the Rack environment must include these
## Rack-specific variables:
## <tt>rack.url_scheme</tt>:: +http+ or +https+, depending on the
## request URL.
## <tt>rack.input</tt>:: See below, the input stream.
## <tt>rack.errors</tt>:: See below, the error stream.
## <tt>rack.hijack?</tt>:: See below, if present and true, indicates
## that the server supports partial hijacking.
## <tt>rack.hijack</tt>:: See below, if present, an object responding
## to +call+ that is used to perform a full
## hijack.
## Additional environment specifications have approved to
## standardized middleware APIs. None of these are required to
## be implemented by the server.
## <tt>rack.session</tt>:: A hash-like interface for storing
## request session data.
## The store must implement:
if session = env[RACK_SESSION]
## store(key, value) (aliased as []=);
unless session.respond_to?(:store) && session.respond_to?(:[]=)
raise LintError, "session #{session.inspect} must respond to store and []="
end
## fetch(key, default = nil) (aliased as []);
unless session.respond_to?(:fetch) && session.respond_to?(:[])
raise LintError, "session #{session.inspect} must respond to fetch and []"
end
## delete(key);
unless session.respond_to?(:delete)
raise LintError, "session #{session.inspect} must respond to delete"
end
## clear;
unless session.respond_to?(:clear)
raise LintError, "session #{session.inspect} must respond to clear"
end
## to_hash (returning unfrozen Hash instance);
unless session.respond_to?(:to_hash) && session.to_hash.kind_of?(Hash) && !session.to_hash.frozen?
raise LintError, "session #{session.inspect} must respond to to_hash and return unfrozen Hash instance"
end
end
## <tt>rack.logger</tt>:: A common object interface for logging messages.
## The object must implement:
if logger = env[RACK_LOGGER]
## info(message, &block)
unless logger.respond_to?(:info)
raise LintError, "logger #{logger.inspect} must respond to info"
end
## debug(message, &block)
unless logger.respond_to?(:debug)
raise LintError, "logger #{logger.inspect} must respond to debug"
end
## warn(message, &block)
unless logger.respond_to?(:warn)
raise LintError, "logger #{logger.inspect} must respond to warn"
end
## error(message, &block)
unless logger.respond_to?(:error)
raise LintError, "logger #{logger.inspect} must respond to error"
end
## fatal(message, &block)
unless logger.respond_to?(:fatal)
raise LintError, "logger #{logger.inspect} must respond to fatal"
end
end
## <tt>rack.multipart.buffer_size</tt>:: An Integer hint to the multipart parser as to what chunk size to use for reads and writes.
if bufsize = env[RACK_MULTIPART_BUFFER_SIZE]
unless bufsize.is_a?(Integer) && bufsize > 0
raise LintError, "rack.multipart.buffer_size must be an Integer > 0 if specified"
end
end
## <tt>rack.multipart.tempfile_factory</tt>:: An object responding to #call with two arguments, the filename and content_type given for the multipart form field, and returning an IO-like object that responds to #<< and optionally #rewind. This factory will be used to instantiate the tempfile for each multipart form file upload field, rather than the default class of Tempfile.
if tempfile_factory = env[RACK_MULTIPART_TEMPFILE_FACTORY]
raise LintError, "rack.multipart.tempfile_factory must respond to #call" unless tempfile_factory.respond_to?(:call)
env[RACK_MULTIPART_TEMPFILE_FACTORY] = lambda do |filename, content_type|
io = tempfile_factory.call(filename, content_type)
raise LintError, "rack.multipart.tempfile_factory return value must respond to #<<" unless io.respond_to?(:<<)
io
end
end
## The server or the application can store their own data in the
## environment, too. The keys must contain at least one dot,
## and should be prefixed uniquely. The prefix <tt>rack.</tt>
## is reserved for use with the Rack core distribution and other
## accepted specifications and must not be used otherwise.
##
%w[REQUEST_METHOD SERVER_NAME QUERY_STRING SERVER_PROTOCOL
rack.input rack.errors].each { |header|
raise LintError, "env missing required key #{header}" unless env.include? header
}
## The <tt>SERVER_PORT</tt> must be an Integer if set.
server_port = env["SERVER_PORT"]
unless server_port.nil? || (Integer(server_port) rescue false)
raise LintError, "env[SERVER_PORT] is not an Integer"
end
## The <tt>SERVER_NAME</tt> must be a valid authority as defined by RFC7540.
unless (URI.parse("http://#{env[SERVER_NAME]}/") rescue false)
raise LintError, "#{env[SERVER_NAME]} must be a valid authority"
end
## The <tt>HTTP_HOST</tt> must be a valid authority as defined by RFC7540.
unless (URI.parse("http://#{env[HTTP_HOST]}/") rescue false)
raise LintError, "#{env[HTTP_HOST]} must be a valid authority"
end
## The <tt>SERVER_PROTOCOL</tt> must match the regexp <tt>HTTP/\d(\.\d)?</tt>.
server_protocol = env['SERVER_PROTOCOL']
unless %r{HTTP/\d(\.\d)?}.match?(server_protocol)
raise LintError, "env[SERVER_PROTOCOL] does not match HTTP/\\d(\\.\\d)?"
end
## If the <tt>HTTP_VERSION</tt> is present, it must equal the <tt>SERVER_PROTOCOL</tt>.
if env['HTTP_VERSION'] && env['HTTP_VERSION'] != server_protocol
raise LintError, "env[HTTP_VERSION] does not equal env[SERVER_PROTOCOL]"
end
## The environment must not contain the keys
## <tt>HTTP_CONTENT_TYPE</tt> or <tt>HTTP_CONTENT_LENGTH</tt>
## (use the versions without <tt>HTTP_</tt>).
%w[HTTP_CONTENT_TYPE HTTP_CONTENT_LENGTH].each { |header|
if env.include? header
raise LintError, "env contains #{header}, must use #{header[5..-1]}"
end
}
## The CGI keys (named without a period) must have String values.
## If the string values for CGI keys contain non-ASCII characters,
## they should use ASCII-8BIT encoding.
env.each { |key, value|
next if key.include? "." # Skip extensions
unless value.kind_of? String
raise LintError, "env variable #{key} has non-string value #{value.inspect}"
end
next if value.encoding == Encoding::ASCII_8BIT
unless value.b !~ /[\x80-\xff]/n
raise LintError, "env variable #{key} has value containing non-ASCII characters and has non-ASCII-8BIT encoding #{value.inspect} encoding: #{value.encoding}"
end
}
## There are the following restrictions:
## * <tt>rack.url_scheme</tt> must either be +http+ or +https+.
unless %w[http https].include?(env[RACK_URL_SCHEME])
raise LintError, "rack.url_scheme unknown: #{env[RACK_URL_SCHEME].inspect}"
end
## * There must be a valid input stream in <tt>rack.input</tt>.
check_input env[RACK_INPUT]
## * There must be a valid error stream in <tt>rack.errors</tt>.
check_error env[RACK_ERRORS]
## * There may be a valid hijack callback in <tt>rack.hijack</tt>
check_hijack env
## * The <tt>REQUEST_METHOD</tt> must be a valid token.
unless env[REQUEST_METHOD] =~ /\A[0-9A-Za-z!\#$%&'*+.^_`|~-]+\z/
raise LintError, "REQUEST_METHOD unknown: #{env[REQUEST_METHOD].dump}"
end
## * The <tt>SCRIPT_NAME</tt>, if non-empty, must start with <tt>/</tt>
if env.include?(SCRIPT_NAME) && env[SCRIPT_NAME] != "" && env[SCRIPT_NAME] !~ /\A\//
raise LintError, "SCRIPT_NAME must start with /"
end
## * The <tt>PATH_INFO</tt>, if non-empty, must start with <tt>/</tt>
if env.include?(PATH_INFO) && env[PATH_INFO] != "" && env[PATH_INFO] !~ /\A\//
raise LintError, "PATH_INFO must start with /"
end
## * The <tt>CONTENT_LENGTH</tt>, if given, must consist of digits only.
if env.include?("CONTENT_LENGTH") && env["CONTENT_LENGTH"] !~ /\A\d+\z/
raise LintError, "Invalid CONTENT_LENGTH: #{env["CONTENT_LENGTH"]}"
end
## * One of <tt>SCRIPT_NAME</tt> or <tt>PATH_INFO</tt> must be
## set. <tt>PATH_INFO</tt> should be <tt>/</tt> if
## <tt>SCRIPT_NAME</tt> is empty.
unless env[SCRIPT_NAME] || env[PATH_INFO]
raise LintError, "One of SCRIPT_NAME or PATH_INFO must be set (make PATH_INFO '/' if SCRIPT_NAME is empty)"
end
## <tt>SCRIPT_NAME</tt> never should be <tt>/</tt>, but instead be empty.
unless env[SCRIPT_NAME] != "/"
raise LintError, "SCRIPT_NAME cannot be '/', make it '' and PATH_INFO '/'"
end
## <tt>rack.response_finished</tt>:: An array of callables run by the server after the response has been
## processed. This would typically be invoked after sending the response to the client, but it could also be
## invoked if an error occurs while generating the response or sending the response; in that case, the error
## argument will be a subclass of +Exception+.
## The callables are invoked with +env, status, headers, error+ arguments and should not raise any
## exceptions. They should be invoked in reverse order of registration.
if callables = env[RACK_RESPONSE_FINISHED]
raise LintError, "rack.response_finished must be an array of callable objects" unless callables.is_a?(Array)
callables.each do |callable|
raise LintError, "rack.response_finished values must respond to call(env, status, headers, error)" unless callable.respond_to?(:call)
end
end
end
##
## === The Input Stream
##
## The input stream is an IO-like object which contains the raw HTTP
## POST data.
def check_input(input)
## When applicable, its external encoding must be "ASCII-8BIT" and it
## must be opened in binary mode, for Ruby 1.9 compatibility.
if input.respond_to?(:external_encoding) && input.external_encoding != Encoding::ASCII_8BIT
raise LintError, "rack.input #{input} does not have ASCII-8BIT as its external encoding"
end
if input.respond_to?(:binmode?) && !input.binmode?
raise LintError, "rack.input #{input} is not opened in binary mode"
end
## The input stream must respond to +gets+, +each+, and +read+.
[:gets, :each, :read].each { |method|
unless input.respond_to? method
raise LintError, "rack.input #{input} does not respond to ##{method}"
end
}
end
class InputWrapper
def initialize(input)
@input = input
end
## * +gets+ must be called without arguments and return a string,
## or +nil+ on EOF.
def gets(*args)
raise LintError, "rack.input#gets called with arguments" unless args.size == 0
v = @input.gets
unless v.nil? or v.kind_of? String
raise LintError, "rack.input#gets didn't return a String"
end
v
end
## * +read+ behaves like IO#read.
## Its signature is <tt>read([length, [buffer]])</tt>.
##
## If given, +length+ must be a non-negative Integer (>= 0) or +nil+,
## and +buffer+ must be a String and may not be nil.
##
## If +length+ is given and not nil, then this method reads at most
## +length+ bytes from the input stream.
##
## If +length+ is not given or nil, then this method reads
## all data until EOF.
##
## When EOF is reached, this method returns nil if +length+ is given
## and not nil, or "" if +length+ is not given or is nil.
##
## If +buffer+ is given, then the read data will be placed
## into +buffer+ instead of a newly created String object.
def read(*args)
unless args.size <= 2
raise LintError, "rack.input#read called with too many arguments"
end
if args.size >= 1
unless args.first.kind_of?(Integer) || args.first.nil?
raise LintError, "rack.input#read called with non-integer and non-nil length"
end
unless args.first.nil? || args.first >= 0
raise LintError, "rack.input#read called with a negative length"
end
end
if args.size >= 2
unless args[1].kind_of?(String)
raise LintError, "rack.input#read called with non-String buffer"
end
end
v = @input.read(*args)
unless v.nil? or v.kind_of? String
raise LintError, "rack.input#read didn't return nil or a String"
end
if args[0].nil?
unless !v.nil?
raise LintError, "rack.input#read(nil) returned nil on EOF"
end
end
v
end
## * +each+ must be called without arguments and only yield Strings.
def each(*args)
raise LintError, "rack.input#each called with arguments" unless args.size == 0
@input.each { |line|
unless line.kind_of? String
raise LintError, "rack.input#each didn't yield a String"
end
yield line
}
end
## * +close+ can be called on the input stream to indicate that the
## any remaining input is not needed.
def close(*args)
@input.close(*args)
end
end
##
## === The Error Stream
##
def check_error(error)
## The error stream must respond to +puts+, +write+ and +flush+.
[:puts, :write, :flush].each { |method|
unless error.respond_to? method
raise LintError, "rack.error #{error} does not respond to ##{method}"
end
}
end
class ErrorWrapper
def initialize(error)
@error = error
end
## * +puts+ must be called with a single argument that responds to +to_s+.
def puts(str)
@error.puts str
end
## * +write+ must be called with a single argument that is a String.
def write(str)
raise LintError, "rack.errors#write not called with a String" unless str.kind_of? String
@error.write str
end
## * +flush+ must be called without arguments and must be called
## in order to make the error appear for sure.
def flush
@error.flush
end
## * +close+ must never be called on the error stream.
def close(*args)
raise LintError, "rack.errors#close must not be called"
end
end
##
## === Hijacking
##
## The hijacking interfaces provides a means for an application to take
## control of the HTTP connection. There are two distinct hijack
## interfaces: full hijacking where the application takes over the raw
## connection, and partial hijacking where the application takes over
## just the response body stream. In both cases, the application is
## responsible for closing the hijacked stream.
##
## Full hijacking only works with HTTP/1. Partial hijacking is functionally
## equivalent to streaming bodies, and is still optionally supported for
## backwards compatibility with older Rack versions.
##
## ==== Full Hijack
##
## Full hijack is used to completely take over an HTTP/1 connection. It
## occurs before any headers are written and causes the request to
## ignores any response generated by the application.
##
## It is intended to be used when applications need access to raw HTTP/1
## connection.
##
def check_hijack(env)
## If +rack.hijack+ is present in +env+, it must respond to +call+
if original_hijack = env[RACK_HIJACK]
raise LintError, "rack.hijack must respond to call" unless original_hijack.respond_to?(:call)
env[RACK_HIJACK] = proc do
io = original_hijack.call
## and return an +IO+ instance which can be used to read and write
## to the underlying connection using HTTP/1 semantics and
## formatting.
raise LintError, "rack.hijack must return an IO instance" unless io.is_a?(IO)
io
end
end
end
##
## ==== Partial Hijack
##
## Partial hijack is used for bi-directional streaming of the request and
## response body. It occurs after the status and headers are written by
## the server and causes the server to ignore the Body of the response.
##
## It is intended to be used when applications need bi-directional
## streaming.
##
def check_hijack_response(headers, env)
## If +rack.hijack?+ is present in +env+ and truthy,
if env[RACK_IS_HIJACK]
## an application may set the special response header +rack.hijack+
if original_hijack = headers[RACK_HIJACK]
## to an object that responds to +call+,
unless original_hijack.respond_to?(:call)
raise LintError, 'rack.hijack header must respond to #call'
end
## accepting a +stream+ argument.
return proc do |io|
original_hijack.call StreamWrapper.new(io)
end
end
##
## After the response status and headers have been sent, this hijack
## callback will be invoked with a +stream+ argument which follows the
## same interface as outlined in "Streaming Body". Servers must
## ignore the +body+ part of the response tuple when the
## +rack.hijack+ response header is present. Using an empty +Array+
## instance is recommended.
else
##
## The special response header +rack.hijack+ must only be set
## if the request +env+ has a truthy +rack.hijack?+.
if headers.key?(RACK_HIJACK)
raise LintError, 'rack.hijack header must not be present if server does not support hijacking'
end
end
nil
end
## == The Response
##
## === The Status
##
def check_status(status)
## This is an HTTP status. It must be an Integer greater than or equal to
## 100.
unless status.is_a?(Integer) && status >= 100
raise LintError, "Status must be an Integer >=100"
end
end
##
## === The Headers
##
def check_headers(headers)
## The headers must be a unfrozen Hash.
unless headers.kind_of?(Hash)
raise LintError, "headers object should be a hash, but isn't (got #{headers.class} as headers)"
end
if headers.frozen?
raise LintError, "headers object should not be frozen, but is"
end
headers.each do |key, value|
## The header keys must be Strings.
unless key.kind_of? String
raise LintError, "header key must be a string, was #{key.class}"
end
## Special headers starting "rack." are for communicating with the
## server, and must not be sent back to the client.
next if key.start_with?("rack.")
## The header must not contain a +Status+ key.
raise LintError, "header must not contain status" if key == "status"
## Header keys must conform to RFC7230 token specification, i.e. cannot
## contain non-printable ASCII, DQUOTE or "(),/:;<=>?@[\]{}".
raise LintError, "invalid header name: #{key}" if key =~ /[\(\),\/:;<=>\?@\[\\\]{}[:cntrl:]]/
## Header keys must not contain uppercase ASCII characters (A-Z).
raise LintError, "uppercase character in header name: #{key}" if key =~ /[A-Z]/
## Header values must be either a String instance,
if value.kind_of?(String)
check_header_value(key, value)
elsif value.kind_of?(Array)
## or an Array of String instances,
value.each{|value| check_header_value(key, value)}
else
raise LintError, "a header value must be a String or Array of Strings, but the value of '#{key}' is a #{value.class}"
end
end
end
def check_header_value(key, value)
## such that each String instance must not contain characters below 037.
if value =~ /[\000-\037]/
raise LintError, "invalid header value #{key}: #{value.inspect}"
end
end
##
## === The content-type
##
def check_content_type(status, headers)
headers.each { |key, value|
## There must not be a <tt>content-type</tt> header key when the +Status+ is 1xx,
## 204, or 304.
if key == "content-type"
if Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.key? status.to_i
raise LintError, "content-type header found in #{status} response, not allowed"
end
return
end
}
end
##
## === The content-length
##
def check_content_length(status, headers)
headers.each { |key, value|
if key == 'content-length'
## There must not be a <tt>content-length</tt> header key when the
## +Status+ is 1xx, 204, or 304.
if Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.key? status.to_i
raise LintError, "content-length header found in #{status} response, not allowed"
end
@content_length = value
end
}
end
def verify_content_length(size)
if @head_request
unless size == 0
raise LintError, "Response body was given for HEAD request, but should be empty"
end
elsif @content_length
unless @content_length == size.to_s
raise LintError, "content-length header was #{@content_length}, but should be #{size}"
end
end
end
##
## === The Body
##
## The Body is typically an +Array+ of +String+ instances, an enumerable
## that yields +String+ instances, a +Proc+ instance, or a File-like
## object.
##
## The Body must respond to +each+ or +call+. It may optionally respond
## to +to_path+ or +to_ary+. A Body that responds to +each+ is considered
## to be an Enumerable Body. A Body that responds to +call+ is considered
## to be a Streaming Body.
##
## A Body that responds to both +each+ and +call+ must be treated as an
## Enumerable Body, not a Streaming Body. If it responds to +each+, you
## must call +each+ and not +call+. If the Body doesn't respond to
## +each+, then you can assume it responds to +call+.
##
## The Body must either be consumed or returned. The Body is consumed by
## optionally calling either +each+ or +call+.
## Then, if the Body responds to +close+, it must be called to release
## any resources associated with the generation of the body.
## In other words, +close+ must always be called at least once; typically
## after the web server has sent the response to the client, but also in
## cases where the Rack application makes internal/virtual requests and
## discards the response.
##
def close
##
## After calling +close+, the Body is considered closed and should not
## be consumed again.
@closed = true
## If the original Body is replaced by a new Body, the new Body must
## also consume the original Body by calling +close+ if possible.
@body.close if @body.respond_to?(:close)
index = @lint.index(self)
unless @env['rack.lint'][0..index].all? {|lint| lint.instance_variable_get(:@closed)}
raise LintError, "Body has not been closed"
end
end
def verify_to_path
##
## If the Body responds to +to_path+, it must return a +String+
## path for the local file system whose contents are identical
## to that produced by calling +each+; this may be used by the
## server as an alternative, possibly more efficient way to
## transport the response. The +to_path+ method does not consume
## the body.
if @body.respond_to?(:to_path)
unless ::File.exist? @body.to_path
raise LintError, "The file identified by body.to_path does not exist"
end
end
end
##
## ==== Enumerable Body
##
def each
## The Enumerable Body must respond to +each+.
raise LintError, "Enumerable Body must respond to each" unless @body.respond_to?(:each)
## It must only be called once.
raise LintError, "Response body must only be invoked once (#{@invoked})" unless @invoked.nil?
## It must not be called after being closed.
raise LintError, "Response body is already closed" if @closed
@invoked = :each
@body.each do |chunk|
## and must only yield String values.
unless chunk.kind_of? String
raise LintError, "Body yielded non-string value #{chunk.inspect}"
end
##
## The Body itself should not be an instance of String, as this will
## break in Ruby 1.9.
##
## Middleware must not call +each+ directly on the Body.
## Instead, middleware can return a new Body that calls +each+ on the
## original Body, yielding at least once per iteration.
if @lint[0] == self
@env['rack.lint.body_iteration'] += 1
else
if (@env['rack.lint.body_iteration'] -= 1) > 0
raise LintError, "New body must yield at least once per iteration of old body"
end
end
@size += chunk.bytesize
yield chunk
end
verify_content_length(@size)
verify_to_path
end
BODY_METHODS = {to_ary: true, each: true, call: true, to_path: true}
def to_path
@body.to_path
end
def respond_to?(name, *)
if BODY_METHODS.key?(name)
@body.respond_to?(name)
else
super
end
end
##
## If the Body responds to +to_ary+, it must return an +Array+ whose
## contents are identical to that produced by calling +each+.
## Middleware may call +to_ary+ directly on the Body and return a new
## Body in its place. In other words, middleware can only process the
## Body directly if it responds to +to_ary+. If the Body responds to both
## +to_ary+ and +close+, its implementation of +to_ary+ must call
## +close+.
def to_ary
@body.to_ary.tap do |content|
unless content == @body.enum_for.to_a
raise LintError, "#to_ary not identical to contents produced by calling #each"
end
end
ensure
close
end
##
## ==== Streaming Body
##
def call(stream)
## The Streaming Body must respond to +call+.
raise LintError, "Streaming Body must respond to call" unless @body.respond_to?(:call)
## It must only be called once.
raise LintError, "Response body must only be invoked once (#{@invoked})" unless @invoked.nil?
## It must not be called after being closed.
raise LintError, "Response body is already closed" if @closed
@invoked = :call
## It takes a +stream+ argument.
##
## The +stream+ argument must implement:
## <tt>read, write, <<, flush, close, close_read, close_write, closed?</tt>
##
@body.call(StreamWrapper.new(stream))
end
class StreamWrapper
extend Forwardable
## The semantics of these IO methods must be a best effort match to
## those of a normal Ruby IO or Socket object, using standard arguments
## and raising standard exceptions. Servers are encouraged to simply
## pass on real IO objects, although it is recognized that this approach
## is not directly compatible with HTTP/2.
REQUIRED_METHODS = [
:read, :write, :<<, :flush, :close,
:close_read, :close_write, :closed?
]
def_delegators :@stream, *REQUIRED_METHODS
def initialize(stream)
@stream = stream
REQUIRED_METHODS.each do |method_name|
raise LintError, "Stream must respond to #{method_name}" unless stream.respond_to?(method_name)
end
end
end
# :startdoc:
end
end
end
##
## == Thanks
## Some parts of this specification are adopted from {PEP 333 – Python Web Server Gateway Interface v1.0}[https://peps.python.org/pep-0333/]
## I'd like to thank everyone involved in that effort.