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#
# cgi.rb - cgi support library
#
# Copyright (C) 2000 Network Applied Communication Laboratory, Inc.
#
# Copyright (C) 2000 Information-technology Promotion Agency, Japan
#
# Author: Wakou Aoyama <wakou@ruby-lang.org>
#
# Documentation: Wakou Aoyama (RDoc'd and embellished by William Webber)
#
# == Overview
#
# The Common Gateway Interface (CGI) is a simple protocol
# for passing an HTTP request from a web server to a
# standalone program, and returning the output to the web
# browser. Basically, a CGI program is called with the
# parameters of the request passed in either in the
# environment (GET) or via $stdin (POST), and everything
# it prints to $stdout is returned to the client.
#
# This file holds the +CGI+ class. This class provides
# functionality for retrieving HTTP request parameters,
# managing cookies, and generating HTML output. See the
# class documentation for more details and examples of use.
#
# The file cgi/session.rb provides session management
# functionality; see that file for more details.
#
# See http://www.w3.org/CGI/ for more information on the CGI
# protocol.
raise "Please, use ruby 1.9.0 or later." if RUBY_VERSION < "1.9.0"
# CGI class. See documentation for the file cgi.rb for an overview
# of the CGI protocol.
#
# == Introduction
#
# CGI is a large class, providing several categories of methods, many of which
# are mixed in from other modules. Some of the documentation is in this class,
# some in the modules CGI::QueryExtension and CGI::HtmlExtension. See
# CGI::Cookie for specific information on handling cookies, and cgi/session.rb
# (CGI::Session) for information on sessions.
#
# For queries, CGI provides methods to get at environmental variables,
# parameters, cookies, and multipart request data. For responses, CGI provides
# methods for writing output and generating HTML.
#
# Read on for more details. Examples are provided at the bottom.
#
# == Queries
#
# The CGI class dynamically mixes in parameter and cookie-parsing
# functionality, environmental variable access, and support for
# parsing multipart requests (including uploaded files) from the
# CGI::QueryExtension module.
#
# === Environmental Variables
#
# The standard CGI environmental variables are available as read-only
# attributes of a CGI object. The following is a list of these variables:
#
#
# AUTH_TYPE HTTP_HOST REMOTE_IDENT
# CONTENT_LENGTH HTTP_NEGOTIATE REMOTE_USER
# CONTENT_TYPE HTTP_PRAGMA REQUEST_METHOD
# GATEWAY_INTERFACE HTTP_REFERER SCRIPT_NAME
# HTTP_ACCEPT HTTP_USER_AGENT SERVER_NAME
# HTTP_ACCEPT_CHARSET PATH_INFO SERVER_PORT
# HTTP_ACCEPT_ENCODING PATH_TRANSLATED SERVER_PROTOCOL
# HTTP_ACCEPT_LANGUAGE QUERY_STRING SERVER_SOFTWARE
# HTTP_CACHE_CONTROL REMOTE_ADDR
# HTTP_FROM REMOTE_HOST
#
#
# For each of these variables, there is a corresponding attribute with the
# same name, except all lower case and without a preceding HTTP_.
# +content_length+ and +server_port+ are integers; the rest are strings.
#
# === Parameters
#
# The method #params() returns a hash of all parameters in the request as
# name/value-list pairs, where the value-list is an Array of one or more
# values. The CGI object itself also behaves as a hash of parameter names
# to values, but only returns a single value (as a String) for each
# parameter name.
#
# For instance, suppose the request contains the parameter
# "favourite_colours" with the multiple values "blue" and "green". The
# following behaviour would occur:
#
# cgi.params["favourite_colours"] # => ["blue", "green"]
# cgi["favourite_colours"] # => "blue"
#
# If a parameter does not exist, the former method will return an empty
# array, the latter an empty string. The simplest way to test for existence
# of a parameter is by the #has_key? method.
#
# === Cookies
#
# HTTP Cookies are automatically parsed from the request. They are available
# from the #cookies() accessor, which returns a hash from cookie name to
# CGI::Cookie object.
#
# === Multipart requests
#
# If a request's method is POST and its content type is multipart/form-data,
# then it may contain uploaded files. These are stored by the QueryExtension
# module in the parameters of the request. The parameter name is the name
# attribute of the file input field, as usual. However, the value is not
# a string, but an IO object, either an IOString for small files, or a
# Tempfile for larger ones. This object also has the additional singleton
# methods:
#
# #local_path():: the path of the uploaded file on the local filesystem
# #original_filename():: the name of the file on the client computer
# #content_type():: the content type of the file
#
# == Responses
#
# The CGI class provides methods for sending header and content output to
# the HTTP client, and mixes in methods for programmatic HTML generation
# from CGI::HtmlExtension and CGI::TagMaker modules. The precise version of HTML
# to use for HTML generation is specified at object creation time.
#
# === Writing output
#
# The simplest way to send output to the HTTP client is using the #out() method.
# This takes the HTTP headers as a hash parameter, and the body content
# via a block. The headers can be generated as a string using the #header()
# method. The output stream can be written directly to using the #print()
# method.
#
# === Generating HTML
#
# Each HTML element has a corresponding method for generating that
# element as a String. The name of this method is the same as that
# of the element, all lowercase. The attributes of the element are
# passed in as a hash, and the body as a no-argument block that evaluates
# to a String. The HTML generation module knows which elements are
# always empty, and silently drops any passed-in body. It also knows
# which elements require matching closing tags and which don't. However,
# it does not know what attributes are legal for which elements.
#
# There are also some additional HTML generation methods mixed in from
# the CGI::HtmlExtension module. These include individual methods for the
# different types of form inputs, and methods for elements that commonly
# take particular attributes where the attributes can be directly specified
# as arguments, rather than via a hash.
#
# == Examples of use
#
# === Get form values
#
# require "cgi"
# cgi = CGI.new
# value = cgi['field_name'] # <== value string for 'field_name'
# # if not 'field_name' included, then return "".
# fields = cgi.keys # <== array of field names
#
# # returns true if form has 'field_name'
# cgi.has_key?('field_name')
# cgi.has_key?('field_name')
# cgi.include?('field_name')
#
# CAUTION! cgi['field_name'] returned an Array with the old
# cgi.rb(included in ruby 1.6)
#
# === Get form values as hash
#
# require "cgi"
# cgi = CGI.new
# params = cgi.params
#
# cgi.params is a hash.
#
# cgi.params['new_field_name'] = ["value"] # add new param
# cgi.params['field_name'] = ["new_value"] # change value
# cgi.params.delete('field_name') # delete param
# cgi.params.clear # delete all params
#
#
# === Save form values to file
#
# require "pstore"
# db = PStore.new("query.db")
# db.transaction do
# db["params"] = cgi.params
# end
#
#
# === Restore form values from file
#
# require "pstore"
# db = PStore.new("query.db")
# db.transaction do
# cgi.params = db["params"]
# end
#
#
# === Get multipart form values
#
# require "cgi"
# cgi = CGI.new
# value = cgi['field_name'] # <== value string for 'field_name'
# value.read # <== body of value
# value.local_path # <== path to local file of value
# value.original_filename # <== original filename of value
# value.content_type # <== content_type of value
#
# and value has StringIO or Tempfile class methods.
#
# === Get cookie values
#
# require "cgi"
# cgi = CGI.new
# values = cgi.cookies['name'] # <== array of 'name'
# # if not 'name' included, then return [].
# names = cgi.cookies.keys # <== array of cookie names
#
# and cgi.cookies is a hash.
#
# === Get cookie objects
#
# require "cgi"
# cgi = CGI.new
# for name, cookie in cgi.cookies
# cookie.expires = Time.now + 30
# end
# cgi.out("cookie" => cgi.cookies) {"string"}
#
# cgi.cookies # { "name1" => cookie1, "name2" => cookie2, ... }
#
# require "cgi"
# cgi = CGI.new
# cgi.cookies['name'].expires = Time.now + 30
# cgi.out("cookie" => cgi.cookies['name']) {"string"}
#
# === Print http header and html string to $DEFAULT_OUTPUT ($>)
#
# require "cgi"
# cgi = CGI.new("html3") # add HTML generation methods
# cgi.out() do
# cgi.html() do
# cgi.head{ cgi.title{"TITLE"} } +
# cgi.body() do
# cgi.form() do
# cgi.textarea("get_text") +
# cgi.br +
# cgi.submit
# end +
# cgi.pre() do
# CGI::escapeHTML(
# "params: " + cgi.params.inspect + "\n" +
# "cookies: " + cgi.cookies.inspect + "\n" +
# ENV.collect() do |key, value|
# key + " --> " + value + "\n"
# end.join("")
# )
# end
# end
# end
# end
#
# # add HTML generation methods
# CGI.new("html3") # html3.2
# CGI.new("html4") # html4.01 (Strict)
# CGI.new("html4Tr") # html4.01 Transitional
# CGI.new("html4Fr") # html4.01 Frameset
#
require 'cgi/core'
require 'cgi/cookie'
require 'cgi/util'
CGI.autoload(:HtmlExtension, 'cgi/html')
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