Use of the flexible __Body__ concept customization point enables authors to preserve the self-contained nature of the __message__ object while allowing domain specific behaviors. Common operations for HTTP servers include sending responses which deliver file contents, and allowing for file uploads. In this example we build the [link beast.ref.boost__beast__http__basic_file_body `basic_file_body`] type which supports both reading and writing to a file on the file system. The interface is a class templated on the type of file used to access the file system, which must meet the requirements of __File__.
Use of the flexible __Body__ concept customization point enables authors to preserve the self-contained nature of the __message__ object while allowing domain specific behaviors. Common operations for HTTP servers include sending responses which deliver file contents, and allowing for file uploads. In this example we build the [link beast.ref.boost__beast__http__basic_file_body `basic_file_body`] type which supports both reading and writing to a file on the file system. The interface is a class templated on the type of file used to access the file system, which must meet the requirements of __File__.