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rest-client--rest-client/lib/restclient/request.rb
Andy Brody 4ba9f7ee63 Skip netrc with Authorization header, up/downcase.
The fix for the Netrc user/password overriding a user-set Authorization
header that was committed in #374 was case-sensitive and does not cover
users who pass `:authorization` or `"authorization"` as the header name.

Add @processed_headers_lowercase so that case-insensitive tests like
this are easier in the future. It would be better if
`Request#stringify_headers` normalized both Symbols and Strings.
https://github.com/rest-client/rest-client/issues/599

Also add a test for the case-insensitive behavior.

Fixes: #524, #550
2017-05-04 01:20:00 -04:00

875 lines
28 KiB
Ruby

require 'tempfile'
require 'cgi'
require 'netrc'
require 'set'
begin
# Use mime/types/columnar if available, for reduced memory usage
require 'mime/types/columnar'
rescue LoadError
require 'mime/types'
end
module RestClient
# This class is used internally by RestClient to send the request, but you can also
# call it directly if you'd like to use a method not supported by the
# main API. For example:
#
# RestClient::Request.execute(:method => :head, :url => 'http://example.com')
#
# Mandatory parameters:
# * :method
# * :url
# Optional parameters (have a look at ssl and/or uri for some explanations):
# * :headers a hash containing the request headers
# * :cookies may be a Hash{String/Symbol => String} of cookie values, an
# Array<HTTP::Cookie>, or an HTTP::CookieJar containing cookies. These
# will be added to a cookie jar before the request is sent.
# * :user and :password for basic auth, will be replaced by a user/password available in the :url
# * :block_response call the provided block with the HTTPResponse as parameter
# * :raw_response return a low-level RawResponse instead of a Response
# * :max_redirects maximum number of redirections (default to 10)
# * :proxy An HTTP proxy URI to use for this request. Any value here
# (including nil) will override RestClient.proxy.
# * :verify_ssl enable ssl verification, possible values are constants from
# OpenSSL::SSL::VERIFY_*, defaults to OpenSSL::SSL::VERIFY_PEER
# * :read_timeout and :open_timeout are how long to wait for a response and
# to open a connection, in seconds. Pass nil to disable the timeout.
# * :timeout can be used to set both timeouts
# * :ssl_client_cert, :ssl_client_key, :ssl_ca_file, :ssl_ca_path,
# :ssl_cert_store, :ssl_verify_callback, :ssl_verify_callback_warnings
# * :ssl_version specifies the SSL version for the underlying Net::HTTP connection
# * :ssl_ciphers sets SSL ciphers for the connection. See
# OpenSSL::SSL::SSLContext#ciphers=
# * :before_execution_proc a Proc to call before executing the request. This
# proc, like procs from RestClient.before_execution_procs, will be
# called with the HTTP request and request params.
class Request
attr_reader :method, :uri, :url, :headers, :payload, :proxy,
:user, :password, :read_timeout, :max_redirects,
:open_timeout, :raw_response, :processed_headers, :args,
:ssl_opts
# An array of previous redirection responses
attr_accessor :redirection_history
def self.execute(args, & block)
new(args).execute(& block)
end
SSLOptionList = %w{client_cert client_key ca_file ca_path cert_store
version ciphers verify_callback verify_callback_warnings}
def inspect
"<RestClient::Request @method=#{@method.inspect}, @url=#{@url.inspect}>"
end
def initialize args
@method = normalize_method(args[:method])
@headers = (args[:headers] || {}).dup
if args[:url]
@url = process_url_params(normalize_url(args[:url]), headers)
else
raise ArgumentError, "must pass :url"
end
@user = @password = nil
parse_url_with_auth!(url)
# process cookie arguments found in headers or args
@cookie_jar = process_cookie_args!(@uri, @headers, args)
@payload = Payload.generate(args[:payload])
@user = args[:user] if args.include?(:user)
@password = args[:password] if args.include?(:password)
if args.include?(:timeout)
@read_timeout = args[:timeout]
@open_timeout = args[:timeout]
end
if args.include?(:read_timeout)
@read_timeout = args[:read_timeout]
end
if args.include?(:open_timeout)
@open_timeout = args[:open_timeout]
end
@block_response = args[:block_response]
@raw_response = args[:raw_response] || false
@stream_log_percent = args[:stream_log_percent] || 10
if @stream_log_percent <= 0 || @stream_log_percent > 100
raise ArgumentError.new(
"Invalid :stream_log_percent #{@stream_log_percent.inspect}")
end
@proxy = args.fetch(:proxy) if args.include?(:proxy)
@ssl_opts = {}
if args.include?(:verify_ssl)
v_ssl = args.fetch(:verify_ssl)
if v_ssl
if v_ssl == true
# interpret :verify_ssl => true as VERIFY_PEER
@ssl_opts[:verify_ssl] = OpenSSL::SSL::VERIFY_PEER
else
# otherwise pass through any truthy values
@ssl_opts[:verify_ssl] = v_ssl
end
else
# interpret all falsy :verify_ssl values as VERIFY_NONE
@ssl_opts[:verify_ssl] = OpenSSL::SSL::VERIFY_NONE
end
else
# if :verify_ssl was not passed, default to VERIFY_PEER
@ssl_opts[:verify_ssl] = OpenSSL::SSL::VERIFY_PEER
end
SSLOptionList.each do |key|
source_key = ('ssl_' + key).to_sym
if args.has_key?(source_key)
@ssl_opts[key.to_sym] = args.fetch(source_key)
end
end
# Set some other default SSL options, but only if we have an HTTPS URI.
if use_ssl?
# If there's no CA file, CA path, or cert store provided, use default
if !ssl_ca_file && !ssl_ca_path && !@ssl_opts.include?(:cert_store)
@ssl_opts[:cert_store] = self.class.default_ssl_cert_store
end
end
@log = args[:log]
@max_redirects = args[:max_redirects] || 10
@processed_headers = make_headers headers
@processed_headers_lowercase = Hash[@processed_headers.map {|k, v| [k.downcase, v]}]
@args = args
@before_execution_proc = args[:before_execution_proc]
end
def execute & block
# With 2.0.0+, net/http accepts URI objects in requests and handles wrapping
# IPv6 addresses in [] for use in the Host request header.
transmit uri, net_http_request_class(method).new(uri, processed_headers), payload, & block
ensure
payload.close if payload
end
# SSL-related options
def verify_ssl
@ssl_opts.fetch(:verify_ssl)
end
SSLOptionList.each do |key|
define_method('ssl_' + key) do
@ssl_opts[key.to_sym]
end
end
# Return true if the request URI will use HTTPS.
#
# @return [Boolean]
#
def use_ssl?
uri.is_a?(URI::HTTPS)
end
# Extract the query parameters and append them to the url
#
# Look through the headers hash for a :params option (case-insensitive,
# may be string or symbol). If present and the value is a Hash or
# RestClient::ParamsArray, *delete* the key/value pair from the headers
# hash and encode the value into a query string. Append this query string
# to the URL and return the resulting URL.
#
# @param [String] url
# @param [Hash] headers An options/headers hash to process. Mutation
# warning: the params key may be removed if present!
#
# @return [String] resulting url with query string
#
def process_url_params(url, headers)
url_params = nil
# find and extract/remove "params" key if the value is a Hash/ParamsArray
headers.delete_if do |key, value|
if key.to_s.downcase == 'params' &&
(value.is_a?(Hash) || value.is_a?(RestClient::ParamsArray))
if url_params
raise ArgumentError.new("Multiple 'params' options passed")
end
url_params = value
true
else
false
end
end
# build resulting URL with query string
if url_params && !url_params.empty?
query_string = RestClient::Utils.encode_query_string(url_params)
if url.include?('?')
url + '&' + query_string
else
url + '?' + query_string
end
else
url
end
end
# Render a hash of key => value pairs for cookies in the Request#cookie_jar
# that are valid for the Request#uri. This will not necessarily include all
# cookies if there are duplicate keys. It's safer to use the cookie_jar
# directly if that's a concern.
#
# @see Request#cookie_jar
#
# @return [Hash]
#
def cookies
hash = {}
@cookie_jar.cookies(uri).each do |c|
hash[c.name] = c.value
end
hash
end
# @return [HTTP::CookieJar]
def cookie_jar
@cookie_jar
end
# Render a Cookie HTTP request header from the contents of the @cookie_jar,
# or nil if the jar is empty.
#
# @see Request#cookie_jar
#
# @return [String, nil]
#
def make_cookie_header
return nil if cookie_jar.nil?
arr = cookie_jar.cookies(url)
return nil if arr.empty?
return HTTP::Cookie.cookie_value(arr)
end
# Process cookies passed as hash or as HTTP::CookieJar. For backwards
# compatibility, these may be passed as a :cookies option masquerading
# inside the headers hash. To avoid confusion, if :cookies is passed in
# both headers and Request#initialize, raise an error.
#
# :cookies may be a:
# - Hash{String/Symbol => String}
# - Array<HTTP::Cookie>
# - HTTP::CookieJar
#
# Passing as a hash:
# Keys may be symbols or strings. Values must be strings.
# Infer the domain name from the request URI and allow subdomains (as
# though '.example.com' had been set in a Set-Cookie header). Assume a
# path of '/'.
#
# RestClient::Request.new(url: 'http://example.com', method: :get,
# :cookies => {:foo => 'Value', 'bar' => '123'}
# )
#
# results in cookies as though set from the server by:
# Set-Cookie: foo=Value; Domain=.example.com; Path=/
# Set-Cookie: bar=123; Domain=.example.com; Path=/
#
# which yields a client cookie header of:
# Cookie: foo=Value; bar=123
#
# Passing as HTTP::CookieJar, which will be passed through directly:
#
# jar = HTTP::CookieJar.new
# jar.add(HTTP::Cookie.new('foo', 'Value', domain: 'example.com',
# path: '/', for_domain: false))
#
# RestClient::Request.new(..., :cookies => jar)
#
# @param [URI::HTTP] uri The URI for the request. This will be used to
# infer the domain name for cookies passed as strings in a hash. To avoid
# this implicit behavior, pass a full cookie jar or use HTTP::Cookie hash
# values.
# @param [Hash] headers The headers hash from which to pull the :cookies
# option. MUTATION NOTE: This key will be deleted from the hash if
# present.
# @param [Hash] args The options passed to Request#initialize. This hash
# will be used as another potential source for the :cookies key.
# These args will not be mutated.
#
# @return [HTTP::CookieJar] A cookie jar containing the parsed cookies.
#
def process_cookie_args!(uri, headers, args)
# Avoid ambiguity in whether options from headers or options from
# Request#initialize should take precedence by raising ArgumentError when
# both are present. Prior versions of rest-client claimed to give
# precedence to init options, but actually gave precedence to headers.
# Avoid that mess by erroring out instead.
if headers[:cookies] && args[:cookies]
raise ArgumentError.new(
"Cannot pass :cookies in Request.new() and in headers hash")
end
cookies_data = headers.delete(:cookies) || args[:cookies]
# return copy of cookie jar as is
if cookies_data.is_a?(HTTP::CookieJar)
return cookies_data.dup
end
# convert cookies hash into a CookieJar
jar = HTTP::CookieJar.new
(cookies_data || []).each do |key, val|
# Support for Array<HTTP::Cookie> mode:
# If key is a cookie object, add it to the jar directly and assert that
# there is no separate val.
if key.is_a?(HTTP::Cookie)
if val
raise ArgumentError.new("extra cookie val: #{val.inspect}")
end
jar.add(key)
next
end
if key.is_a?(Symbol)
key = key.to_s
end
# assume implicit domain from the request URI, and set for_domain to
# permit subdomains
jar.add(HTTP::Cookie.new(key, val, domain: uri.hostname.downcase,
path: '/', for_domain: true))
end
jar
end
# Generate headers for use by a request. Header keys will be stringified
# using `#stringify_headers` to normalize them as capitalized strings.
#
# The final headers consist of:
# - default headers from #default_headers
# - user_headers provided here
# - headers from the payload object (e.g. Content-Type, Content-Lenth)
# - cookie headers from #make_cookie_header
#
# BUG: stringify_headers does not alter the capitalization of headers that
# are passed as strings, it only normalizes those passed as symbols. This
# behavior will probably remain for a while for compatibility, but it means
# that the warnings that attempt to detect accidental header overrides may
# not always work.
# https://github.com/rest-client/rest-client/issues/599
#
# @param [Hash] user_headers User-provided headers to include
#
# @return [Hash<String, String>] A hash of HTTP headers => values
#
def make_headers(user_headers)
headers = stringify_headers(default_headers).merge(stringify_headers(user_headers))
# override headers from the payload (e.g. Content-Type, Content-Length)
if @payload
payload_headers = @payload.headers
# Warn the user if we override any headers that were previously
# present. This usually indicates that rest-client was passed
# conflicting information, e.g. if it was asked to render a payload as
# x-www-form-urlencoded but a Content-Type application/json was
# also supplied by the user.
payload_headers.each_pair do |key, val|
if headers.include?(key) && headers[key] != val
warn("warning: Overriding #{key.inspect} header " +
"#{headers.fetch(key).inspect} with #{val.inspect} " +
"due to payload")
end
end
headers.merge!(payload_headers)
end
# merge in cookies
cookies = make_cookie_header
if cookies && !cookies.empty?
if headers['Cookie']
warn('warning: overriding "Cookie" header with :cookies option')
end
headers['Cookie'] = cookies
end
headers
end
# The proxy URI for this request. If `:proxy` was provided on this request,
# use it over `RestClient.proxy`.
#
# Return false if a proxy was explicitly set and is falsy.
#
# @return [URI, false, nil]
#
def proxy_uri
if defined?(@proxy)
if @proxy
URI.parse(@proxy)
else
false
end
elsif RestClient.proxy_set?
if RestClient.proxy
URI.parse(RestClient.proxy)
else
false
end
else
nil
end
end
def net_http_object(hostname, port)
p_uri = proxy_uri
if p_uri.nil?
# no proxy set
Net::HTTP.new(hostname, port)
elsif !p_uri
# proxy explicitly set to none
Net::HTTP.new(hostname, port, nil, nil, nil, nil)
else
Net::HTTP.new(hostname, port,
p_uri.hostname, p_uri.port, p_uri.user, p_uri.password)
end
end
def net_http_request_class(method)
Net::HTTP.const_get(method.capitalize, false)
end
def net_http_do_request(http, req, body=nil, &block)
if body && body.respond_to?(:read)
req.body_stream = body
return http.request(req, nil, &block)
else
return http.request(req, body, &block)
end
end
# Normalize a URL by adding a protocol if none is present.
#
# If the string has no HTTP-like scheme (i.e. scheme followed by '//'), a
# scheme of 'http' will be added. This mimics the behavior of browsers and
# user agents like cURL.
#
# @param [String] url A URL string.
#
# @return [String]
#
def normalize_url(url)
url = 'http://' + url unless url.match(%r{\A[a-z][a-z0-9+.-]*://}i)
url
end
# Return a certificate store that can be used to validate certificates with
# the system certificate authorities. This will probably not do anything on
# OS X, which monkey patches OpenSSL in terrible ways to insert its own
# validation. On most *nix platforms, this will add the system certifcates
# using OpenSSL::X509::Store#set_default_paths. On Windows, this will use
# RestClient::Windows::RootCerts to look up the CAs trusted by the system.
#
# @return [OpenSSL::X509::Store]
#
def self.default_ssl_cert_store
cert_store = OpenSSL::X509::Store.new
cert_store.set_default_paths
# set_default_paths() doesn't do anything on Windows, so look up
# certificates using the win32 API.
if RestClient::Platform.windows?
RestClient::Windows::RootCerts.instance.to_a.uniq.each do |cert|
begin
cert_store.add_cert(cert)
rescue OpenSSL::X509::StoreError => err
# ignore duplicate certs
raise unless err.message == 'cert already in hash table'
end
end
end
cert_store
end
def redacted_uri
if uri.password
sanitized_uri = uri.dup
sanitized_uri.password = 'REDACTED'
sanitized_uri
else
uri
end
end
def redacted_url
redacted_uri.to_s
end
# Default to the global logger if there's not a request-specific one
def log
@log || RestClient.log
end
def log_request
return unless log
out = []
out << "RestClient.#{method} #{redacted_url.inspect}"
out << payload.short_inspect if payload
out << processed_headers.to_a.sort.map { |(k, v)| [k.inspect, v.inspect].join("=>") }.join(", ")
log << out.join(', ') + "\n"
end
# Return a hash of headers whose keys are capitalized strings
#
# BUG: stringify_headers does not fix the capitalization of headers that
# are already Strings. Leaving this behavior as is for now for
# backwards compatibility.
# https://github.com/rest-client/rest-client/issues/599
#
def stringify_headers headers
headers.inject({}) do |result, (key, value)|
if key.is_a? Symbol
key = key.to_s.split(/_/).map(&:capitalize).join('-')
end
if 'CONTENT-TYPE' == key.upcase
result[key] = maybe_convert_extension(value.to_s)
elsif 'ACCEPT' == key.upcase
# Accept can be composed of several comma-separated values
if value.is_a? Array
target_values = value
else
target_values = value.to_s.split ','
end
result[key] = target_values.map { |ext|
maybe_convert_extension(ext.to_s.strip)
}.join(', ')
else
result[key] = value.to_s
end
result
end
end
# Default headers set by RestClient. In addition to these headers, servers
# will receive headers set by Net::HTTP, such as Accept-Encoding and Host.
#
# @return [Hash<Symbol, String>]
def default_headers
{
:accept => '*/*',
:user_agent => RestClient::Platform.default_user_agent,
}
end
private
# Parse the `@url` string into a URI object and save it as
# `@uri`. Also save any basic auth user or password as @user and @password.
# If no auth info was passed, check for credentials in a Netrc file.
#
# @param [String] url A URL string.
#
# @return [URI]
#
# @raise URI::InvalidURIError on invalid URIs
#
def parse_url_with_auth!(url)
uri = URI.parse(url)
if uri.hostname.nil?
raise URI::InvalidURIError.new("bad URI(no host provided): #{url}")
end
@user = CGI.unescape(uri.user) if uri.user
@password = CGI.unescape(uri.password) if uri.password
if !@user && !@password
@user, @password = Netrc.read[uri.hostname]
end
@uri = uri
end
def print_verify_callback_warnings
warned = false
if RestClient::Platform.mac_mri?
warn('warning: ssl_verify_callback return code is ignored on OS X')
warned = true
end
if RestClient::Platform.jruby?
warn('warning: SSL verify_callback may not work correctly in jruby')
warn('see https://github.com/jruby/jruby/issues/597')
warned = true
end
warned
end
# Parse a method and return a normalized string version.
#
# Raise ArgumentError if the method is falsy, but otherwise do no
# validation.
#
# @param method [String, Symbol]
#
# @return [String]
#
# @see net_http_request_class
#
def normalize_method(method)
raise ArgumentError.new('must pass :method') unless method
method.to_s.downcase
end
def transmit uri, req, payload, & block
# We set this to true in the net/http block so that we can distinguish
# read_timeout from open_timeout. Now that we only support Ruby 2.0+,
# this is only needed for Timeout exceptions thrown outside of Net::HTTP.
established_connection = false
setup_credentials req
net = net_http_object(uri.hostname, uri.port)
net.use_ssl = uri.is_a?(URI::HTTPS)
net.ssl_version = ssl_version if ssl_version
net.ciphers = ssl_ciphers if ssl_ciphers
net.verify_mode = verify_ssl
net.cert = ssl_client_cert if ssl_client_cert
net.key = ssl_client_key if ssl_client_key
net.ca_file = ssl_ca_file if ssl_ca_file
net.ca_path = ssl_ca_path if ssl_ca_path
net.cert_store = ssl_cert_store if ssl_cert_store
# We no longer rely on net.verify_callback for the main SSL verification
# because it's not well supported on all platforms (see comments below).
# But do allow users to set one if they want.
if ssl_verify_callback
net.verify_callback = ssl_verify_callback
# Hilariously, jruby only calls the callback when cert_store is set to
# something, so make sure to set one.
# https://github.com/jruby/jruby/issues/597
if RestClient::Platform.jruby?
net.cert_store ||= OpenSSL::X509::Store.new
end
if ssl_verify_callback_warnings != false
if print_verify_callback_warnings
warn('pass :ssl_verify_callback_warnings => false to silence this')
end
end
end
if OpenSSL::SSL::VERIFY_PEER == OpenSSL::SSL::VERIFY_NONE
warn('WARNING: OpenSSL::SSL::VERIFY_PEER == OpenSSL::SSL::VERIFY_NONE')
warn('This dangerous monkey patch leaves you open to MITM attacks!')
warn('Try passing :verify_ssl => false instead.')
end
if defined? @read_timeout
if @read_timeout == -1
warn 'Deprecated: to disable timeouts, please use nil instead of -1'
@read_timeout = nil
end
net.read_timeout = @read_timeout
end
if defined? @open_timeout
if @open_timeout == -1
warn 'Deprecated: to disable timeouts, please use nil instead of -1'
@open_timeout = nil
end
net.open_timeout = @open_timeout
end
RestClient.before_execution_procs.each do |before_proc|
before_proc.call(req, args)
end
if @before_execution_proc
@before_execution_proc.call(req, args)
end
log_request
start_time = Time.now
tempfile = nil
net.start do |http|
established_connection = true
if @block_response
net_http_do_request(http, req, payload, &@block_response)
else
res = net_http_do_request(http, req, payload) { |http_response|
if @raw_response
# fetch body into tempfile
tempfile = fetch_body_to_tempfile(http_response)
else
# fetch body
http_response.read_body
end
http_response
}
process_result(res, start_time, tempfile, &block)
end
end
rescue EOFError
raise RestClient::ServerBrokeConnection
rescue Net::OpenTimeout => err
raise RestClient::Exceptions::OpenTimeout.new(nil, err)
rescue Net::ReadTimeout => err
raise RestClient::Exceptions::ReadTimeout.new(nil, err)
rescue Timeout::Error, Errno::ETIMEDOUT => err
# handling for non-Net::HTTP timeouts
if established_connection
raise RestClient::Exceptions::ReadTimeout.new(nil, err)
else
raise RestClient::Exceptions::OpenTimeout.new(nil, err)
end
rescue OpenSSL::SSL::SSLError => error
# TODO: deprecate and remove RestClient::SSLCertificateNotVerified and just
# pass through OpenSSL::SSL::SSLError directly.
#
# Exceptions in verify_callback are ignored [1], and jruby doesn't support
# it at all [2]. RestClient has to catch OpenSSL::SSL::SSLError and either
# re-throw it as is, or throw SSLCertificateNotVerified based on the
# contents of the message field of the original exception.
#
# The client has to handle OpenSSL::SSL::SSLError exceptions anyway, so
# we shouldn't make them handle both OpenSSL and RestClient exceptions.
#
# [1] https://github.com/ruby/ruby/blob/89e70fe8e7/ext/openssl/ossl.c#L238
# [2] https://github.com/jruby/jruby/issues/597
if error.message.include?("certificate verify failed")
raise SSLCertificateNotVerified.new(error.message)
else
raise error
end
end
def setup_credentials(req)
if user && !@processed_headers_lowercase.include?('authorization')
req.basic_auth(user, password)
end
end
def fetch_body_to_tempfile(http_response)
# Taken from Chef, which as in turn...
# Stolen from http://www.ruby-forum.com/topic/166423
# Kudos to _why!
tf = Tempfile.new('rest-client.')
tf.binmode
size = 0
total = http_response['Content-Length'].to_i
stream_log_bucket = nil
http_response.read_body do |chunk|
tf.write chunk
size += chunk.size
if log
if total == 0
log << "streaming %s %s (%d of unknown) [0 Content-Length]\n" % [@method.upcase, @url, size]
else
percent = (size * 100) / total
current_log_bucket, _ = percent.divmod(@stream_log_percent)
if current_log_bucket != stream_log_bucket
stream_log_bucket = current_log_bucket
log << "streaming %s %s %d%% done (%d of %d)\n" % [@method.upcase, @url, (size * 100) / total, size, total]
end
end
end
end
tf.close
tf
end
# @param res The Net::HTTP response object
# @param start_time [Time] Time of request start
def process_result(res, start_time, tempfile=nil, &block)
if @raw_response
unless tempfile
raise ArgumentError.new('tempfile is required')
end
response = RawResponse.new(tempfile, res, self, start_time)
else
response = Response.create(res.body, res, self, start_time)
end
response.log_response
if block_given?
block.call(response, self, res, & block)
else
response.return!(&block)
end
end
def parser
URI.const_defined?(:Parser) ? URI::Parser.new : URI
end
# Given a MIME type or file extension, return either a MIME type or, if
# none is found, the input unchanged.
#
# >> maybe_convert_extension('json')
# => 'application/json'
#
# >> maybe_convert_extension('unknown')
# => 'unknown'
#
# >> maybe_convert_extension('application/xml')
# => 'application/xml'
#
# @param ext [String]
#
# @return [String]
#
def maybe_convert_extension(ext)
unless ext =~ /\A[a-zA-Z0-9_@-]+\z/
# Don't look up strings unless they look like they could be a file
# extension known to mime-types.
#
# There currently isn't any API public way to look up extensions
# directly out of MIME::Types, but the type_for() method only strips
# off after a period anyway.
return ext
end
types = MIME::Types.type_for(ext)
if types.empty?
ext
else
types.first.content_type
end
end
end
end