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# frozen_string_literal: true # # 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. # # The file CGI::Session provides session management functionality; see that # class for more details. # # See http://www.w3.org/CGI/ for more information on 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 behavior 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 #http_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. # # === Utility HTML escape and other methods like a function. # # There are some utility tools defined in cgi/util.rb and cgi/escape.rb. # Escape and unescape methods are defined in cgi/escape.rb. # And when include, you can use utility methods like a function. # # == 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! <code>cgi['field_name']</code> 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("html4") # add HTML generation methods # cgi.out do # cgi.html do # cgi.head do # cgi.title { "TITLE" } # end + # cgi.body do # cgi.form("ACTION" => "uri") do # cgi.p do # cgi.textarea("get_text") + # cgi.br + # cgi.submit # end # 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 # CGI.new("html5") # html5 # # === Some utility methods # # require 'cgi/escape' # CGI.escapeHTML('Usage: foo "bar" <baz>') # # # === Some utility methods like a function # # require 'cgi/escape' # include CGI::Escape # escapeHTML('Usage: foo "bar" <baz>') # h('Usage: foo "bar" <baz>') # alias # # class CGI VERSION = "0.5.0" end require 'cgi/util' require 'cgi/escape' unless defined?(CGI::EscapeExt) require 'cgi/core' require 'cgi/cookie' CGI.autoload(:HtmlExtension, 'cgi/html')