Embedded Server Pages (ESP) is a collection of technologies
developed by Mbedthis and a community of developers to
provide an embeddable, standards-based, dynamic web page creation
environment. Similar in its ultimate goal to PHP, Active Server
Pages (ASP) and Java Server Pages (JSP), Embedded Server Pages
enables the easy creation of dynamic web pages for embedded
systems by embedding a powerful, standard scripting language into
HTML pages.
The ESP documentation includes sections on:
Essentail
Glue
ESP is a powerful and compact environment. It has a very small
memory footprint ~50K (about 20 time smaller than PHP) and
requires minimal CPU resources to execute. It is not intended to
be a complete programming language like PHP, but rather to
effectively provide the glue between the web and your
application. Embedded applications need to be able to create
powerful web applications using the minimum system resources
possible. They do not need another complete programming
environment, but rather an interface between HTML web pages and
the core logic and data of an embedded application or system. ESP
was designed to fill this role.
Embedded
JavaScript
Embedded Server Pages provides a simple and convenient way to
access dynamic data and script the generation of HTML. It
utilizes the standard JavaScript language for server-side
scripting inside ESP web pages. Best know as the de-facto
scripting language in most browsers, JavaScript is ideal for
server-side scripting in embedded systems due to its small memory
footprint and well understood and proven language.
ESP uses JavaScript to provide a close binding between your
application logic and the web page to be displayed. You can
"publish" C functions as JavaScript functions with a single line
of code so that your C code will be seamlessly invoked whenever
the JavaScript function is called in the Web
Page.
Web Form
Post-Back
ESP also allows the use of Post-Back where a single ESP page
can operate as both the displayed HTML form that prompts for user
input and also as the script that processes and accepts the user
input. Post-Back is a very natural methodology that facilitates
the placement of your application logic in one place (one web
page).
Embedded
Server Pages 2.0
Embedded Server Pages 2.0 represents a large enhancement over
ESP 1.0. The foundation JavaScript language has been enhanced and
the ESP parser has been rewritten.
Embedded JavaScript now has new features such as objects,
arrays, functions and floating point. See Using Embedded JavaScript for further
details. ESP leverages this to provide scriptable access to
request details, sessions, cookies and uploaded files.
Extending Embedded Server Pages
You can
easily create new ESP functions that you can invoke from the
JavaScript in your ESP page. See the Extending ESP section of the
Programmer's Guide for more details.
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