Class: Exocora::Sheet

Inherits:
Object
  • Object
show all
Defined in:
lib/exocora/sheet.rb

Overview

A single CGI script. Requests are processed through a chain of actions

validate - extract and sanitize data from the CGI request process - do stuff render - render to the specified template.

Constant Summary collapse

@@validations =

Parameters with validations

Hash.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Sheet

Returns a new instance of Sheet.



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# File 'lib/exocora/sheet.rb', line 13

def initialize
  @cgi = CGI.new
  @headers = {
  }
  
  @params = {}
  @errors = {}
  
  @template = self.class.to_s.module_path
  @log_file = self.class.to_s.underscore + '.log'
end

Instance Attribute Details

#errors ⇒ Object (readonly)

Returns the value of attribute errors.



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# File 'lib/exocora/sheet.rb', line 11

def errors
  @errors
end

#params ⇒ Object (readonly)

Returns the value of attribute params.



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# File 'lib/exocora/sheet.rb', line 11

def params
  @params
end

Class Method Details

.run ⇒ Object

Creates an instance of this sheet, and runs it.



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# File 'lib/exocora/sheet.rb', line 41

def self.run
  new.run
end

.validate(param, message = 'must be valid', &block) ⇒ Object

Adds a validation condition for a parameter. validate :query { |q| q.size > 0 } validate :query, “is invalid” { |q|



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# File 'lib/exocora/sheet.rb', line 28

def self.validate(param, message='must be valid', &block)
  validation = Validation.new(nil, message)
  if block_given?
    validation.when block
  end

  @@validations[param.to_s] ||= []
  @@validations[param.to_s] << validation
  
  validation
end

Instance Method Details

#cast_params(params) ⇒ Object

Casts incoming CGI parameters to nil, numerics, collapses single-element arrays, and so forth.



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# File 'lib/exocora/sheet.rb', line 47

def cast_params(params)
  cast = {}
  params.each do |key, values|
    cast_values = values.map do |value|
      if value =~ /^\d+$/
        value.to_i
      elsif value =~ /^[\d.]+$/
        value.to_f
      else
        value
      end
    end

    if values.empty?
      cast[key] = nil
    elsif values.size == 1
      cast[key] = cast_values.first
    else
      cast[key] = cast_values
    end
  end

  cast
end

#log(message) ⇒ Object

Logs a message to a file.



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# File 'lib/exocora/sheet.rb', line 73

def log(message)
  File.open(@log_file, 'a') do |file|
    file.puts message
  end
end

#log_to(file) ⇒ Object

Chooses the file for logging.



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# File 'lib/exocora/sheet.rb', line 80

def log_to(file)
  @log_file = file
end

#output(string) ⇒ Object

Sends output to the client. The first time output is called, it sends an HTTP header first.



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# File 'lib/exocora/sheet.rb', line 86

def output(string)
  unless @headers_sent
    puts @cgi.header(@headers)
    @headers_sent = true
  end

  puts string
end

#process ⇒ Object

Process is the meat of the script. It returns a hash like => 2, which become instance variables @a = 2 in the template.



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# File 'lib/exocora/sheet.rb', line 98

def process
end

#redirect_to(uri_fragment) ⇒ Object

Breaks the normal rendering flow, and outputs an HTTP redirect header.



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# File 'lib/exocora/sheet.rb', line 102

def redirect_to(uri_fragment)
  @headers['Status'] = '302 Moved'
  @headers['Location'] = @cgi.full_uri_for uri_fragment
  output
end

#render(context = Erubis::Context.new) ⇒ Object

Renders the erubis template for this action. Takes a hash of variables to render. The default template is determined by underscoring this sheet’s class name, but another template can be specified using #template.



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# File 'lib/exocora/sheet.rb', line 111

def render(context = Erubis::Context.new)
  # Read template data
  template_filename = "#{@template}.rhtml"
  begin
    template = File.read(template_filename)
  rescue Errno::ENOENT
    raise ScriptError.new("Template #{template_filename} does not exist!")
  end

  # Prepare template and variables
  eruby = Erubis::Eruby.new template
  
  # Perform templating
  begin
    result = eruby.evaluate context
  rescue
    raise TemplateError.new("Encountered error processing template #{template_filename}.", $!)
  end

  # Output result
  output result 
end

#request ⇒ Object

Accessor for the CGI object



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# File 'lib/exocora/sheet.rb', line 135

def request
  @cgi
end

#run ⇒ Object

This is the action which initiates processing of the script.



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# File 'lib/exocora/sheet.rb', line 140

def run
  begin
    # Cast parameters
    @params = cast_params @cgi.params

    # Check parameters
    validate

    # Run process
    context = process

    # Render output
    render context
  rescue
    # Handle errors
    output "<html><head><title>Exocora Error</title></head><body>"
    output "<h1>#{$!.class}</h1>"

    output $!.to_html

    output "</body></html>"
  end
end

#use_template(template) ⇒ Object

Sets the name of the template to render.



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# File 'lib/exocora/sheet.rb', line 165

def use_template(template)
  @template = template
end

#valid?(param = nil) ⇒ Boolean

Returns true if the specified (or all) parameters have no errors.

Returns:

  • (Boolean) 


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# File 'lib/exocora/sheet.rb', line 170

def valid?(param = nil)
  if param.nil?
    @errors.empty?
  else
    @errors[param].nil? or @errors[param].empty?
  end
end

#validate(params = @params) ⇒ Object

Validates CGI parameters according to @@validations.

Parameters which fail validation have entries recorderd in @errors.



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# File 'lib/exocora/sheet.rb', line 181

def validate(params = @params)
  @@validations.each do |param, validations|
    validations.each do |validation|
      values = params[param]

      # If there are multiple values, check each one.
      unless values.kind_of? Array
        values = [values]
      end
 
      values.each do |value| 
        begin
          validation.validate(value)
        rescue ValidationError => e
          @errors[param] ||= []
          @errors[param] << e
        end
      end
    end
  end

  params
end