<URL:http://www.webthing.com/cgiplusplus/>

CGI++: A C++ Library for CGI programming

The current version is 2000-11-10, which is basically an update to remove the dependence on the no-longer-supported GNU libg++ and the C librx, which appears to be system-dependent. This is the second update concerned with GNU libraries++: the update of 2000-08-02 got rid of dependence on libg++ but left a remaining dependancy on librx.

An additional Smart Text class is also provided.

Introduction

Since the CGI protocol was first defined in 1993, Perl has been the majority language for CGI programming. A major reason for this is the superb libraries available, including CGI.pm for elementary tasks and the LWP for more advanced applications.

C and C++ are less well-served. Libraries including Jemtek's and Boutell's exist for C, but do not provide the notational convenience of CGI.pm. In this author's uninformed view - having read the documentation but not the source - they are closer to the obsolete Perl "cgi-lib.pl". To the best of my knowledge (based on - among other things - regular participation in the CGI newsgroup and a reading of Nikki Locke's C++ Libraries list), no libraries whatsoever exist for C++.

CGI++ not only fills that gap, but is I believe the first library in any language written for CGI programming with HTTP/1.1.

CGI++ provides programmers with direct access to CGI/1.1 and HTTP/1.1. It resists the temptation to offer incompatible proprietary 'enhancements', adopted by many "No CGI required" programming packages. So you are not stuck with a nightmare hack as soon as you need to do something the Author didn't foresee.

Features

CGI++ combines an easy and intuitive 'look and feel' (inspired in some measure by CGI.pm) with a powerful and rich object-oriented implementation. Features include:

• Full support for CGI/1.1 and HTTP/1.0 (the current standards)
• Support for Netscape's Cookie and File Upload features.
• Provisional support for new HTTP/1.1 methods PUT, GET, OPTIONS and TRACE, in addition to GET, HEAD and POST.
• Intelligent parsing of HTTP/1.0 and HTTP/1.1 Headers.
• Clean and elegant methods for reading and rendering form elements, and for preserving state, based on a deep object-oriented hierarchy.
• Powerful interactive debugging mode (going well beyond that of CGI.pm).
• Highly-automated and safe memory management.

Related Projects

CGI++ is not under active development, and future developments remain a wish-list. Some areas of prospective future work include:

• Web Server integration to run CGI programs as shared libraries without forking.
• Integrated management of "tainted" (unsafe) data.
• Enhanced support for Basic and Digest Authentication (NOT including the actual authentication - which is explicitly forbidden to CGI).
• Support for HTTP/1.2 Protocol Extension Protocol (PEP).
• HTTP class hierarchy: (Base/Request/Response/Entity; 0.9/1.0/1.1/1.2/PEP)
• Intelligent output streaming, with enhanced error management and debugging tools (including intelligent exit handler to avoid server-generated Error 500).
• Production-quality internal error handling and documentation.
• Integrated MIME facilities for output
• An SGML class library to define output methods. The use of type CDATA for rendered form elements is currently merely a typedef.
• DBM and SQL handling

Implementation

1. FEP (Form Element Pointer) is a deep object-orietented class hierarchy of the Form Elements.
2. FORM defines (and manages) HTML Forms as collections of FEPs.
3. CGI extends FORM, with CGI and HTTP environment variables and form data, and interactive emulation (debug mode). Parts of CGI properly belong in the HTTP classes.

In addition, some accessory functions are provided.

19970222: The new Manual/Programmers Guide is a lot more complete than the old Technical Overview, but I'm keeping both for the time being. See also the sample programs source code.

Availability

CGI++ is free software subject to the terms of the GNU Library General Public License (LGPL).

Platform

CGI++ is now believed to be fully POSIX and ANSI compliant. If you find anything that fails either of these standards, please let me know!

Further Information

• Technical Overview (more-or-less obsoleted by the Manual/Programmers Guide).
• Manual/Programmers Guide (new 970222).
• General Demo program with source code. Illustrates persistence, dump (debugging) feature, and use of Request Headers.
• File Upload Demo program with source code. Simpler than the other demo, but requires browser supporting file upload.
• Downloading CGI++