ruby/lib/open-uri.rb

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11 KiB
Ruby

#= open-uri.rb
#
#open-uri.rb is easy-to-use wrapper for net/http and net/ftp.
#
#== Example
#
#It is possible to open http/ftp URL as usual a file:
#
# open("http://www.ruby-lang.org/") {|f|
# f.each_line {|line| p line}
# }
#
#The opened file has several methods for meta information as follows since
#it is extended by OpenURI::Meta.
#
# open("http://www.ruby-lang.org/en") {|f|
# f.each_line {|line| p line}
# p f.base_uri # <URI::HTTP:0x40e6ef2 URL:http://www.ruby-lang.org/en/>
# p f.content_type # "text/html"
# p f.charset # "iso-8859-1"
# p f.content_encoding # []
# p f.last_modified # Thu Dec 05 02:45:02 UTC 2002
# }
#
#Additional header fields can be specified by an optional hash argument.
#
# open("http://www.ruby-lang.org/en/",
# "User-Agent" => "Ruby/#{RUBY_VERSION}",
# "From" => "foo@bar.invalid",
# "Referer" => "http://www.ruby-lang.org/") {|f|
# ...
# }
#
#The environment variables such as http_proxy and ftp_proxy are in effect by
#default. :proxy => nil disables proxy.
#
# open("http://www.ruby-lang.org/en/raa.html",
# :proxy => nil) {|f|
# ...
# }
#
#URI objects can be opened in similar way.
#
# uri = URI.parse("http://www.ruby-lang.org/en/")
# uri.open {|f|
# ...
# }
#
#URI objects can be read directly.
#The returned string is also extended by OpenURI::Meta.
#
# str = uri.read
# p str.base_uri
#
#Author:: Tanaka Akira <akr@m17n.org>
require 'uri'
require 'stringio'
require 'time'
module Kernel
private
alias open_uri_original_open open # :nodoc:
# makes possible to open URIs.
# If the first argument is URI::HTTP, URI::FTP or
# String beginning with http:// or ftp://,
# the URI is opened.
# The opened file object is extended by OpenURI::Meta.
def open(name, *rest, &block)
if name.respond_to?("open")
name.open(*rest, &block)
elsif name.respond_to?("to_str") && %r{\A(http|ftp)://} =~ name
OpenURI.open_uri(name, *rest, &block)
else
open_uri_original_open(name, *rest, &block)
end
end
module_function :open
end
module OpenURI
def OpenURI.scan_open_optional_arguments(*rest) # :nodoc:
if !rest.empty? && (String === rest.first || Integer === rest.first)
mode = rest.shift
if !rest.empty? && Integer === rest.first
perm = rest.shift
end
end
return mode, perm, rest
end
def OpenURI.open_uri(name, *rest) # :nodoc:
uri = URI::Generic === name ? name : URI.parse(name)
mode, perm, rest = OpenURI.scan_open_optional_arguments(*rest)
options = rest.shift if !rest.empty? && Hash === rest.first
raise ArgumentError.new("extra arguments") if !rest.empty?
unless mode == nil ||
mode == 'r' || mode == 'rb' ||
mode == O_RDONLY
raise ArgumentError.new("invalid access mode #{mode} (#{uri.class} resource is read only.)")
end
io = open_loop(uri, options || {})
if block_given?
begin
yield io
ensure
io.close
end
else
io
end
end
def OpenURI.open_loop(uri, options) # :nodoc:
header = {}
options.each {|k, v|
if String === k
header[k] = v
end
}
case opt_proxy = options.fetch(:proxy, true)
when true
find_proxy = lambda {|u| u.find_proxy}
when nil, false
find_proxy = lambda {|u| nil}
when String
opt_proxy = URI.parse(opt_proxy)
find_proxy = lambda {|u| opt_proxy}
when URI::Generic
find_proxy = lambda {|u| opt_proxy}
else
raise ArgumentError.new("Invalid proxy option: #{opt_proxy}")
end
uri_set = {}
begin
buf = Buffer.new
if proxy_uri = find_proxy.call(uri)
proxy_uri.proxy_open(buf, uri, header)
else
uri.direct_open(buf, header)
end
rescue Redirect
loc = $!.uri
if loc.relative?
# Although it violates RFC 2616, Location: field may have relative URI.
# It is converted to absolute URI using uri.
loc = uri + loc
end
uri = loc
raise "HTTP redirection loop: #{uri}" if uri_set.include? uri.to_s
uri_set[uri.to_s] = true
retry
end
io = buf.io
io.base_uri = uri
io
end
class Redirect < StandardError # :nodoc:
def initialize(uri)
super("redirection to #{uri.to_s}")
@uri = uri
end
attr_reader :uri
end
class HTTPError < StandardError
def initialize(message, io)
super(message)
@io = io
end
attr_reader :io
end
class Buffer # :nodoc:
def initialize
@io = StringIO.new
end
StringMax = 10240
def <<(str)
@io << str
if StringIO === @io && StringMax < @io.size
require 'tempfile'
io = Tempfile.new('open-uri')
Meta.init io, @io if Meta === @io
io << @io.string
@io = io
end
end
def io
Meta.init @io unless Meta === @io
@io
end
end
# Mixin for holding meta-information.
module Meta
def Meta.init(obj, src=nil) # :nodoc:
obj.extend Meta
obj.instance_eval {
@base_uri = nil
@meta = {}
}
if src
obj.status = src.status
obj.base_uri = src.base_uri
src.meta.each {|name, value|
obj.meta_add_field(name, value)
}
end
end
# returns an Array which consits status code and message.
attr_accessor :status
# returns a URI which is base of relative URIs in the data.
# It may differ from the URI supplied by a user because redirection.
attr_accessor :base_uri
# returns a Hash which represents header fields.
# The Hash keys are downcased for canonicalization.
attr_reader :meta
def meta_add_field(name, value) # :nodoc:
@meta[name.downcase] = value
end
# returns a Time which represents Last-Modified field.
def last_modified
if v = @meta['last-modified']
Time.httpdate(v)
else
nil
end
end
RE_LWS = /[\r\n\t ]+/n
RE_TOKEN = %r{[^\x00- ()<>@,;:\\"/\[\]?={}\x7f]+}n
RE_QUOTED_STRING = %r{"(?:[\r\n\t !#-\[\]-~\x80-\xff]|\\[\x00-\x7f])"}n
RE_PARAMETERS = %r{(?:;#{RE_LWS}?#{RE_TOKEN}#{RE_LWS}?=#{RE_LWS}?(?:#{RE_TOKEN}|#{RE_QUOTED_STRING})#{RE_LWS}?)*}n
def content_type_parse # :nodoc:
v = @meta['content-type']
if v && %r{\A#{RE_LWS}?(#{RE_TOKEN})#{RE_LWS}?/(#{RE_TOKEN})#{RE_LWS}?(#{RE_PARAMETERS})\z}o =~ v
type = $1.downcase
subtype = $2.downcase
parameters = []
$3.scan(/;#{RE_LWS}?(#{RE_TOKEN})#{RE_LWS}?=#{RE_LWS}?(?:(#{RE_TOKEN})|(#{RE_QUOTED_STRING}))/o) {|att, val, qval|
val = qval.gsub(/[\r\n\t !#-\[\]-~\x80-\xff]+|(\\[\x00-\x7f])/) { $1 ? $1[1,1] : $& } if qval
parameters << [att.downcase, val]
}
["#{type}/#{subtype}", *parameters]
else
nil
end
end
# returns "type/subtype" which is MIME Content-Type.
# It is downcased for canonicalization.
# Content-Type parameters are stripped.
def content_type
type, *parameters = content_type_parse
type || 'application/octet-stream'
end
# returns a charset parameter in Content-Type field.
# It is downcased for canonicalization.
#
# If charset parameter is not given but a block is given,
# the block is called and its result is returned.
# It can be used to guess charset.
#
# If charset parameter and block is not given,
# nil is returned except text type in HTTP.
# In that case, "iso-8859-1" is returned as defined by RFC2616 3.7.1.
def charset
type, *parameters = content_type_parse
if pair = parameters.assoc('charset')
pair.last.downcase
elsif block_given?
yield
elsif type && %r{\Atext/} =~ type &&
@base_uri && @base_uri.scheme == 'http'
"iso-8859-1" # RFC2616 3.7.1
else
nil
end
end
# returns a list of encodings in Content-Encoding field
# as an Array of String.
# The encodings are downcased for canonicalization.
def content_encoding
v = @meta['content-encoding']
if v && %r{\A#{RE_LWS}?#{RE_TOKEN}#{RE_LWS}?(?:,#{RE_LWS}?#{RE_TOKEN}#{RE_LWS}?)*}o =~ v
v.scan(RE_TOKEN).map {|content_coding| content_coding.downcase}
else
[]
end
end
end
# Mixin for URIs.
module OpenRead
# opens the URI.
def open(*rest, &block)
OpenURI.open_uri(self, *rest, &block)
end
# reads a content of the URI.
def read(options={})
self.open(options) {|f|
str = f.read
Meta.init str, f
str
}
end
end
end
module URI
class Generic
# returns a proxy URI.
# The proxy URI is obtained from environment variables such as http_proxy,
# ftp_proxy, no_proxy, etc.
# If there is no proper proxy, nil is returned.
def find_proxy
name = self.scheme + '_proxy'
if proxy_uri = ENV[name] || ENV[name.upcase]
proxy_uri = URI.parse(proxy_uri)
name = 'no_proxy'
if no_proxy = ENV[name] || ENV[name.upcase]
no_proxy.scan(/([^:,]*)(?::(\d+))?/) {|host, port|
if /(\A|\.)#{Regexp.quote host}\z/i =~ proxy_uri.host &&
(!port || self.port == port.to_i)
proxy_uri = nil
break
end
}
end
proxy_uri
else
nil
end
end
end
class HTTP
def direct_open(buf, header) # :nodoc:
proxy_open(buf, request_uri, header)
end
def proxy_open(buf, uri, header) # :nodoc:
require 'net/http'
resp = Net::HTTP.start(self.host, self.port) {|http|
http.get(uri.to_s, header) {|str| buf << str}
}
io = buf.io
io.rewind
io.status = [resp.code, resp.message]
resp.each {|name,value| buf.io.meta_add_field name, value }
case resp
when Net::HTTPSuccess
when Net::HTTPMovedPermanently, # 301
Net::HTTPFound, # 302
Net::HTTPSeeOther, # 303
Net::HTTPTemporaryRedirect # 307
raise OpenURI::Redirect.new(URI.parse(resp['location']))
else
raise OpenURI::HTTPError.new(io.status.join(' '), io)
end
end
include OpenURI::OpenRead
end
class FTP
def direct_open(buf, header) # :nodoc:
require 'net/ftp'
# xxx: header is discarded.
# todo: extract user/passwd from .netrc.
user = 'anonymous'
passwd = nil
user, passwd = self.userinfo.split(/:/) if self.userinfo
ftp = Net::FTP.open(self.host)
ftp.login(user, passwd)
ftp.getbinaryfile(self.path, '/dev/null', Net::FTP::DEFAULT_BLOCKSIZE) {|str| buf << str}
ftp.close
buf.io.rewind
end
include OpenURI::OpenRead
end
end