Request

Requests handling library. More...

Classes
class	Request::KeyParserBase
	Base class for key parsers. More...
class	Request::Key< T >
	Scalar key parser. More...
class	Request::Key< std::vector< T > >
	Vector key parser. More...
class	Request::CommandParser
	Base class for command parsers. More...
class	Request::Parser
	Request parser. More...

Functions
template<typename T >
Key< T > *	Request::key (std::string name, T &destination)
	Helper function to create key parsers.

Detailed Description

Requests handling library.

This module handles requests composed of:

• a command, and
• a set of named and typed arguments (refered to as keys in the following)

In the following, we will take "repeat" to be a command taking two keys:

• "times" of integer type, and
• "input" of string type.

Commands can be formatted in one of two ways:

• plain text, e.g:

    repeat
    times 5
    input foo

• JSON value, e.g:

    {
      "command": "repeat",
      "times":   5,
      "input":   "foo"
    }

This module helps parsing such requests and define appropriate C++ functors to handle commands. For example in this case, handling this request would output 5 times the string "foo".

Additionally, a request parser understands (only in plain-text form) an "help" command displaying help messages :

• general help, listing available commands:

    help

• help on a specific command, listing available keys:

    help COMMAND

See test_request.cxx for an example showing how to use this module. Here is a example interactive session for an application defining the "repeat" command as above:

Command> help
Example application
Commands:
  help                 Display this help
  help COMMAND         Display help about COMMAND
  repeat               Repeat provided input

Command> help repeat
Repeat provided input

Arguments:
  input STRING
      message to repeat
      required

  times N
      number of times to repeat
      default: 2

Command> repeat
Repeat> times 5
Repeat> input foo
Repeat>
foo
foo
foo
foo
foo
Command> ^D

Function Documentation

template<typename T >

Key<T>* Request::key	(	std::string	name,
		T &	destination
	)

Helper function to create key parsers.

Create a vector key parser when the provided destination is of type std::vector<T>. Create a scalar key parser otherwise.

Template Parameters

T	type of key value

Parameters

name	name of the key parameter
destination	reference to a variable where key values will be stored

Returns

pointer to a newly allocated key parser