3270Web

Web-based 3270 terminal interface in Go with session recording to a 3270Connect-compatible workflow.

Features

• Web UI for 3270 sessions
• Embedded s3270 binary support (Windows)
• Record sessions to workflow.json, compatible with 3270Connect (Connect/FillString/Press keys/Disconnect)
• Load workflow.json and play it back
• Chaos mode for automated exploration, run persistence, and workflow JSON export
• Docker image and GHCR workflow
• Windows build script

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Screenshots

Requirements

• Go 1.22+
• Access to a 3270 host

Run locally

go run ./cmd/3270Web

Then open http://localhost:8080

Build Windows EXE

.\scripts\build-windows.ps1

This produces 3270Web.exe in the repo root.

Docker

docker build -t 3270web .
docker run -p 8080:8080 3270web

The Docker image installs the s3270 package so it is available at /usr/bin/s3270.

Recording workflow.json

1. Connect to a host.
2. Click Start Recording.
3. Interact with the screen (edits + Enter/PF keys).
4. Click Stop Recording.
5. Download workflow.json.

To replay a workflow, use Load workflow and Play on the session screen.

The output matches the 3270Connect workflow format. See Workflow Configuration for file format details.

Chaos mode

Chaos mode explores screens by writing generated values into input fields and submitting AID keys (Enter, Tab, PF*, and others). It is useful for discovering navigation paths and generating reusable workflow JSON.

Toolbar flow

1. Connect to a host.
2. Click Start chaos exploration.
3. Monitor progress from:
   • the toolbar indicators/stats, and
   • the Workflow Status widget (attempt details, transitions, errors).
4. Stop with Stop chaos exploration or let limits/time budget finish the run.
5. Export with Download chaos workflow JSON.

Saved runs

• Completed runs are persisted and can be loaded from Load previous chaos run.
• You can seed chaos from the currently loaded recording with Load recording into chaos.
• You can continue a loaded run with Resume chaos exploration from loaded run.
• You can clear completed/loaded run state from the toolbar with Remove chaos run.
• Run artifacts are stored under the local chaos-runs/ directory.
• Chaos output files are isolated from loaded recording filenames to avoid overwrite collisions.

Chaos hints

• Open Edit chaos hints from the chaos toolbar.
• Add one or more hints with:
  • a known transaction code, and/or
  • known working data values (comma or newline separated), and/or
  • key assignment mappings (Screen Label = Key, for example Return = PF3, Confirm = Enter).
• Use Load from recording in the hints modal to import hint candidates from a previous recording JSON.
• Click Save hints to persist hints, or Load saved to reload the current saved set.
• Saved hints are stored in chaos-hints.json and are automatically used by chaos start/resume when request-level hints are not provided.

Chaos settings

Chaos behavior can be tuned in Settings -> Chaos or via environment values:

• CHAOS_MAX_STEPS
• CHAOS_TIME_BUDGET_SEC
• CHAOS_STEP_DELAY_SEC
• CHAOS_SEED
• CHAOS_MAX_FIELD_LENGTH
• CHAOS_OUTPUT_FILE
• CHAOS_EXCLUDE_NO_PROGRESS_EVENTS

See Chaos Mode for full details.

Sample applications

Sample apps now spin up local Go-based 3270 servers (from the 3270Connect examples) and connect via s3270, instead of loading dump files. Use the Start Example App button to launch one on the selected port.

Configuration

The application loads webapp/WEB-INF/3270Web-config.xml if present. If missing, defaults are used.

See the Configuration Reference for details on available options, including:

• Customizing the s3270 execution path and model
• Setting a default target host and auto-connect behavior
• Defining custom color schemes and fonts

An optional .env file (created with defaults on first run) lets you override the full set of s3270 command-line options using S3270_* environment variables.

Documentation Site

Project documentation is built with MkDocs and published from gh-pages at:

https://3270Web.3270.io

Local docs commands:

pip install -r requirements-docs.txt
mkdocs serve