"Hello world" HTTP server

***************************

.. todo::

Now that we've seen how we can deal with request and response objects from the

client side, we'll see how we can then use the same abstractions on the server

side. In this example we're going to create a simple HTTP Server in C++ using

:mod:`cpp-netlib`.

The text needs to show that we're building on knowledge gained

from the HTTP client (hello world) example. Make sure there's

more description than code.

The Code

========

The :mod:`cpp-netlib` provides the framework to develop embedded HTTP

servers. For this example, the server is configured to return a

This is about a straightforward as server programming will get in C++.

Building the Server

===================

Just like with the HTTP client, we can build this example by doing the following

on the shell::

$ cd ~/cpp-netlib

$ g++ -o hello_world_server \

> libs/network/example/http/hello_world_server.cpp \

> -I$BOOST_ROOT \

> -I. \

> -L$BOOST_ROOT/stage/lib \

> -lboost_system \

> -pthread

The first two arguments to the ``server`` constructor are the host and

the port on which the server will listen. The third argument is the

the handler object defined previously. This example can be run from

a command line as follows:

::

shell$ ./hello_world_server 0.0.0.0 80

.. note:: If you're going to run the server on port 80, you may have to run it

as an administrator.

Diving into the Code

====================

Let's take a look at the code listing above in greater detail.

.. code-block:: c++

#include <boost/network/protocol/http/server.hpp>

This header contains all the code needed to develop an HTTP server.

This header contains all the code needed to develop an HTTP server with

:mod:`cpp-netlib`.

.. code-block:: c++

``hello_world`` is a functor class which handles HTTP requests. All

the operator does here is return an HTTP response with HTTP code 200

and the body ``"Hello, World!"``.

and the body ``"Hello, World!"``. There are a number of pre-defined stock

replies differentiated by status code with configurable bodies.

All the supported enumeration values for the response status codes can be found

in ``boost/network/protocol/http/impl/response.ipp``.

.. code-block:: c++

The first two arguments to the ``server`` constructor are the host and

the port on which the server will listen. The third argument is the

the handler object defined previously. This example can be run from

a command line as follows:

::

shell$ ./hello_world_server 0.0.0.0 80

the handler object defined previously.

.. note:: In this example, the server is specifically made to be single-threaded.

In a multi-threaded server, you would invoke the ``hello_world::run`` member

method in a set of threads. In a multi-threaded environment you would also

make sure that the handler does all the necessary synchronization for shared

resources across threads. The handler is passed by reference to the server

constructor and you should ensure that any calls to the ``operator()`` overload

are thread-safe.

using namespace boost::network;

http::client client;

http::request request("http://www.boost.org/");

http::response response = client.get(request);

http::client::request request("http://www.boost.org/");

http::client::response response = client.get(request);

Accessing data from ``http::response`` is also done using directives.

To get the response headers, we use the ``headers`` directive which

HTTP URI

````````

Firstly,cpp-netlib provides a specialization and ``typedef`` for an

:mod:`cpp-netlib` provides a specialization and ``typedef`` for an

HTTP URI:

.. code-block:: c++

.. :Authors: Glyn Matthews <glyn.matthews@gmail.com>

.. Dean Michael Berris <mikhailberis@gmail.com>

.. :Date:Sep 19, 2010

.. :Date:Oct 9, 2010

.. :Version: 0.7

.. :Description: Complete user documentation, with examples, for the :mod:`cpp-netlib`.

.. :Copyright: Copyright Glyn Matthews, Dean Michael Berris 2008-2010.

presentation about :mod:`cpp-netlib` was given at `BoostCon 2010`_,

for which the `slides`_ and the `paper`_ can be found on-line.

Sneak Peak

==========

The :mod:`cpp-netlib` allows you to write semantically consistent code for

making different kinds of higher level network applications.

The library allows for writing simple code like:

.. code-block:: c++

using namespace boost::network;

using namespace boost::network::http;

client::request request_("http://www.boost.org/");

request_ << header("Connection", "close");

client client_;

client::response response_ = client_.get(request);

std::string body = body(response_);

For simple C++ HTTP client applications.

The :mod:`cpp-netlib` is being developed for eventual submission to Boost_.

Download

========

You can download the latest releases of the library at:

http://github.com/mikhailberis/cpp-netlib/downloads

You can also get the latest developments from the Git_ repository at:

git://github.com/mikhailberis/cpp-netlib.git

You can find more information about the progress of the development by checking

the GitHub_ project page at:

http://github.com/mikhailberis/cpp-netlib

Support

=======

You can ask questions, join the discussion, and report issues to the developers

mailing list by joining via:

https://lists.sourceforge.net/lists/listinfo/cpp-netlib-devel

You may also file issues on the Github_ issue tracker at:

http://github.com/mikhailberis/cpp-netlib/issues

Contents

========

.. toctree::

:maxdepth:1

:maxdepth:2

whats_new.rst

getting_started.rst

.. _`BoostCon 2010`: http://www.boostcon.com/

.. _`slides`: http://www.filetolink.com/b0e89d06

.. _`paper`: http://github.com/downloads/mikhailberis/cpp-netlib-boostcon-paper/cpp-netlib.pdf

.. _Git: http://git-scm.com/

.. _GitHub: http://github.com/

This division is purely logical -- in the underlying implementation,

the message type can choose to have different means of storing the

data,dependinn on the type used to tag the message. This section

data,depending on the type used to tag the message. This section

covers the `Message Concept`_ as well as the `basic_message`_

implementation.

**Legend**

:M: The message type.

:H: A headers container type.

:m,n: An instance of **M**.

:S: A string type.

:s,k,v: An instance of **S**.

+----------------------------+----------------------+-----------------------------------------+

| ``destination(m);`` | unspecified | Retrieve the destination of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``headers(m);`` | ``Range<Pair<S,S>>`` | Get the range of headers of ``m``. |

| ``headers(m);`` | unspecified | Get the range of headers of ``m``. The |

| | | result should be convertible to ``H`` |

+----------------------------+----------------------+-----------------------------------------+

| ``body(m);`` | unspecified | Retrieve the body of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``m << source(s);`` | ``M &`` | Set the source of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``source(m,s);`` | ``M &`` | Set the source of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``m << destination(s);`` | ``M &`` | Set the destination of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``destination(m,s);`` | ``M &`` | Set the destination of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``m << header(k, v);`` | ``M &`` | Add a header to ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``add_header(m, k, v);`` | ``M &`` | Add a header to ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``m << remove_header(k);`` | ``M &`` | Remove a header from ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``remove_header(m, k);`` | ``M &`` | Remove a header from ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``m << body(s);`` | ``M &`` | Set the body of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

| ``body(m,s);`` | ``M &`` | Set the body of ``m``. |

+----------------------------+----------------------+-----------------------------------------+

Types that model the Message Concept are meant to encapsulate data

that has a source, a destination, one or more named headers, and a

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