Diesel-Engine Documentation |
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Introducing Diesel back to top -
Diesel-Engine, or simply Diesel, is an interpreted language, a scripting language, suited to run within web servers, custom applications, or as a stand-alone language interpreter. This allows scripting of a wide range of software aspects, ranging from dynamic web-pages to
data transport and manipulation, including application configuration, user-interaction, and much more.
The language was designed from the ground up to be as secure, simple, and easy to use as possible, while offering a very large base of high-level user functions.
The Diesel Scripting language has many similarities to Perl, HTML, PHP, and C, however,
the syntax is such that even non-professional programmers can quickly create interactive and functional web-pages or extend the functionality of a Diesel-enabled software
application. At the same time, the language is complete and has high level functions making it possible to quickly create complete and secure database driven eBusiness store fronts.
Use Cases back to top -
Dynamic Web-page ScriptingThe most common deployment of Diesel currently is in web applications. Specifically, Diesel script is embedded in HTML pages to create functional web-pages that can easily manage form input, database queries, e-mail, and complex e-commerce functions.
Diesel integrates logic and high-level functionality into the web-pages themselves, rendering CGI a thing of the past. Unlike CGI, which must execute and 'die' with each request, Diesel code runs
in resident memory, which means it does not have the same overhead as CGI and
is much faster. Furthermore, using the dsl2ops utility program, it is
possible to bundle up an entire directory tree, an entire website, into one fully optimized pre-parsed flat-file database. This allows rapid deployment of modified content, while providing a high degree of reliability and application version control. Software Application Extensibility While the most common use of Diesel is in web applications, a fast-growing
area of application for Diesel scripting is in non-web applications.
For instance, while building an application whose primary function is not
user-interaction or data-manipulation, adding these aspects is often done
in a hodge-podge and highly sub-optimal way. However, Diesel, through its
Application Programming Interface (API), allows a
programmer to add full scripting power to an application extremely quickly,
efficiently, and safely. The full power of diesel is made available to the
calling program via a few simple library calls. This simplifies scripting
user input, creation and maintenance of complex configuration files,
database interaction, and much more.
Command-line Script Interpretor One such program implementing Diesel script is the utility
dsltool, a program which functions as a stand-alone
interpreter for the Diesel language and which can be used to
test, debug, and develop new Diesel functionality.
Headline Features back to top -
Easy of UseThink of Diesel as a set of commonly used and reusable functions utilized
via an easy to understand "template" language. Particularly in dynamic website
development, the programming and design duties are assigned to different people,
if not different departments. The first design decision in any dynamic website project is determining how to separate design from functionality. This is exactly what Blueprint set out to do with Diesel - built by programmers for non-programmers. Extensibility Diesel can be incorporated into software applications and architectures
to instantly leverage all the power of Diesel's scripting language and functionality. Functionality is taken out of the core application source code
and is instead scripted in Diesel. The Diesel language itself is also extensible. Using Diesel's C API, software developers are able to create application specific Diesel script functions - essentially, low-level, application-specific functions can be exposed to the scripting language and easily used in script form.
Database Connectivity Using databases is an integral part of Diesel. Diesel supports
several database sources to allow for highly dynamic content. At an
abstract level, Diesel ties database sources (such as SQL tables or
flat-file databases) to hash-table primitives for queries, updates,
insertion & deletion to be possible. Diesel currently supports CDB, BerkeleyDB (SleepyCat), MySQL, MS-SQL and Oracle database sources. New
database formats can be added to Diesel fairly easily due to the
low-level design of Diesel and separation between abstraction layers.
User Sessions There is a special hash table, %session, that can be used to
store Client Persistent Data. Every browser that accesses a Diesel page is
assigned a unique, cryptographically-secure identifier as an HTTP
Cookie. This identifier makes it possible to recognize a visitor and
automatically associate stored data with that user. Having the %session hash makes it very easy to "carry"
information from page to page without having to worry about making hidden
form fields or putting the data in every link. This increases the
security of the site, since data isn't being passed back-and-forth to the
client, and it can't be altered en-route or by a malicious client. A userid
(set after authentication) is a natural field to set in
the %session hash. E-mail Handling Diesel can send e-mail (including attachments) using straightforward
function calls. This replaces the need for clunky, insecure
e-mail sending CGI scripts or form re-mailers that inevitably make the
output look terrible. Diesel allows the scripter to generates elegant, standards-conforming
e-mail messages, with all the formatting power of a complete programming
language, and the ease of use of a scripting language. Not only can Diesel send email, it can read it as well - even MIME encoded attachments! Diesel allowing scripts to easily manipulate messages, mailboxes, and folders.
Complete on-line e-mail systems have been built with Diesel - notably, a secure on-line e-mail messaging system which incorporated OpenPGP encryption &
authentication technologies. eBusiness Functions Diesel is integrated with support for CyberCash based on the premise that the
scripter should be able to use the service as painlessly as possible. As
an example, all it takes is one function call to get a credit card
authorization from CyberCash.
Spell Checking An example of the huge flexibility of diesel is its spell checking
facility. Using external data hooks, it is a simple matter to pass
static or dynamic text through a spell-checker on the server, either to
provide as a service to users or as a fail-safe for outgoing materials. Much, Much More! We tried to keep this overview as short as possible
while giving the reader a taste of what Diesel has to offer. If you
would like to learn more about Diesel (the language) or Diesel-Engine
(the interpreter), please contact us!
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Copyright © 2005 Blueprint Networks, Inc.
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