Class: Relaxo::QueryServer::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/relaxo/query_server/context.rb

Overview

A query server context includes all state required for implementing the query server protocol.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(shell, options = {}) ⇒ Context

Returns a new instance of Context.



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# File 'lib/relaxo/query_server/context.rb', line 46

def initialize(shell, options = {})
  @shell = shell
  @options = options
  
  @mapper = Mapper.new(self)
  @reducer = Reducer.new(self)
  @designer = Designer.new(self)
  
  @config = {}
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/relaxo/query_server/context.rb', line 57

def config
  @config
end

#shell ⇒ Object (readonly)

Returns the value of attribute shell.



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# File 'lib/relaxo/query_server/context.rb', line 58

def shell
  @shell
end

Instance Method Details

#error_for_exception(exception) ⇒ Object

Return an error structure from the given exception.



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# File 'lib/relaxo/query_server/context.rb', line 61

def error_for_exception(exception)
  ["error", exception.class.to_s, exception.message, exception.backtrace]
end

#log(message) ⇒ Object

Write a log message back to the shell.



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# File 'lib/relaxo/query_server/context.rb', line 99

def log(message)
  @shell.write_object ['log', message]
end

#parse_function(text, scope, filename = 'query-server') ⇒ Object

Given a function as text, and an execution scope, return a callable object.



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# File 'lib/relaxo/query_server/context.rb', line 34

def parse_function(text, scope, filename = 'query-server')
  safe_level = @options[:safe] || 0

  function = lambda { $SAFE = safe_level; eval(text, scope, filename) }.call

  unless function.respond_to? :call
    raise CompilationError.new('Expression does not evaluate to procedure!')
  end
  
  return function
end

#run(command) ⇒ Object

Process a single command as per the query server protocol.



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# File 'lib/relaxo/query_server/context.rb', line 66

def run(command)
  case command[0]
  # ** Map functionality
  when 'add_fun'
    @mapper.add_function command[1]; true
  when 'add_lib'
    @mapper.add_libraries command[1]
    @reducer.add_libraries command[1]; true
  when 'map_doc'
    @mapper.map command[1]
  when 'reset'
    @config = command[1] || {}
    @mapper = Mapper.new(self); true
  
  # ** Reduce functionality
  when 'reduce'
    @reducer.reduce command[1], command[2]
  when 'rereduce'
    @reducer.rereduce command[1], command[2]
  
  # ** Design document functionality
  when 'ddoc'
    if command[1] == 'new'
      @designer.create(command[2], command[3]); true
    else
      @designer.run(command[1], command[2], command[3])
    end
  end
rescue Exception => exception
  error_for_exception(exception)
end