HTTPD

HTTPD is a multi-threaded HTTP/1.1 server for IBM MVS 3.8j, running on Hercules-emulated mainframe systems.

Originally created by Michael Dean Rayborn (versions 1.x–3.3.x), the project has been taken over and substantially reworked by Mike Großmann starting with version 4.0.0. The original author is no longer involved in development or support. A maintenance branch (v3.3.x) preserves the legacy codebase for reference; all active development happens on main.

Version 4.0.0 is a major release with two primary goals:

• HTTP/1.1 compliance — persistent connections (Keep-Alive), chunked transfer encoding, strict request parsing (h1spec 33/33 tests passing)
• Leaner footprint — removal of the embedded FTP daemon, MQTT telemetry, Lua scripting engine, and the 4-tier in-memory statistics system

What's New in 4.0.0

Added:

• Full HTTP/1.1 support with Keep-Alive and Chunked Transfer Encoding
• Parmlib-based configuration (replaces Lua scripting)
• SMF recording with configurable levels (NONE / ERROR / AUTH / ALL)
• Server module system with URL prefix and file extension routing
• Automatic chunked fallback for server modules that don't set Content-Length
• Hardened HTTP request parsing — invalid headers, methods, URIs rejected per RFC 7230

Changed:

• Static file serving is now UFS-only, provided by UFSD
• The old in-memory statistics system has been replaced by SMF Type 243 records

Removed:

• Embedded FTP daemon — replaced by the standalone FTPD project
• MQTT telemetry
• Lua configuration engine (replaced by Parmlib)
• DD-based document root (UFS-only now)

Outlook:

• JES2 browser and dataset browser will be re-implemented as part of mvsMF in a future release
• Lua and REXX scripting modules are being reworked in their own repositories and will be available as optional add-ons in a future release

Installation

Note: Installation instructions will be finalized once the packaging system is complete. The following is a preliminary guide.

Prerequisites

Install in this order on a Hercules-emulated MVS 3.8j system (TK4-, TK5, or MVS/CE):

1. UFSD — UFS filesystem daemon (provides the filesystem HTTPD serves from)
2. FTPD — FTP daemon (needed to transfer files to the UFS filesystem)
3. HTTPD — this project (includes mvsMF)

JCL Procedure

Copy the STC procedure from samplib/httpd to SYS2.PROCLIB(HTTPD):

//HTTPD    EXEC PGM=HTTPD,REGION=8M,TIME=1440
//STEPLIB  DD  DISP=SHR,DSN=HTTPD.LINKLIB
//HTTPPRM  DD  DSN=SYS2.PARMLIB(HTTPPRM0),DISP=SHR,FREE=CLOSE

Parmlib

Copy samplib/httpprm0 to SYS2.PARMLIB(HTTPPRM0) and adjust as needed. A minimal configuration:

PORT=8080
DOCROOT=/www
MOD=MVSMF /zosmf/*

Starting and Stopping

/S HTTPD                         Start with default config
/S HTTPD,M=HTTPPRM1              Start with alternate config member
/F HTTPD,DISPLAY CONFIG          Show current configuration
/F HTTPD,DISPLAY STATS           Show request counters
/F HTTPD,HELP                    List available commands
/P HTTPD                         Stop the server

For upgrading from HTTPD 3.x, see docs/migration.md.

Configuration

The server is configured through a Parmlib member referenced by the HTTPPRM DD card. Key settings:

Keyword	Default	Description
PORT	8080	Listening port
DOCROOT	/www	UFS document root
MINTASK	3	Minimum worker threads
MAXTASK	9	Maximum worker threads
KEEPALIVE_TIMEOUT	5	Keep-alive idle timeout (seconds)
KEEPALIVE_MAX	100	Max requests per connection
LOGIN	NONE	Authentication mode (NONE / RACF)
SMF	NONE	SMF recording level
MOD	—	Server module registration

For the complete reference, see docs/configuration.md.

Server Modules

HTTPD uses a server module system for extending the server with custom functionality. Unlike traditional CGI (which forks a new process per request and communicates via stdin/stdout), HTTPD modules are load modules that run inside the server's address space and are called directly through a function vector — similar to Apache's mod_php or mod_rewrite.

In version 4.0.0, the primary module is mvsMF, which provides a z/OSMF-compatible REST API for datasets, jobs, and USS files.

MOD=MVSMF /zosmf/*

Module routing supports URL prefix matching and automatic extension matching:

MOD=MVSMF /zosmf/*      URL prefix — all requests under /zosmf/
MOD=LUA                  Extension — *.lua files served from DOCROOT
MOD=REXX                 Extension — *.rexx files served from DOCROOT

Scripting modules like LUA and REXX don't need an explicit pattern — HTTPD derives the file extension from the module name automatically.

Debug modules (HTTPDSRV, HTTPDMTT) are included in the server binary but not enabled by default. They are intended for development and troubleshooting only. See docs/development.md for details on writing your own modules.

Ecosystem

HTTPD is part of the mvslovers open-source ecosystem for MVS 3.8j. For an overview of all projects and how they fit together, see the mvsMF Ecosystem documentation.

Project	Description
crent370	C runtime library for MVS 3.8j
ufsd	Cross-address-space UFS filesystem daemon
mvsmf	z/OSMF-compatible REST API
ftpd	Standalone FTP daemon (replaces embedded FTPD from 3.x)

For Developers

Build instructions, architecture overview, the ASCII/EBCDIC translation system, and how to write your own server modules are documented in docs/development.md.

Credits

• Michael Dean Rayborn — original author (HTTPD 1.x through 3.3.x)
• Mike Großmann — maintainer and developer of version 4.0.0+

License

See LICENSE for details.