PlantUML Viewer

A web application that introduces a new algorithm for displaying UML diagrams using PlantUML. This application allows users to input PlantUML code via a web interface, render it as a PNG image using a Node.js backend, and display the resulting diagram.

Requires

• Node.js (v18 or higher recommended)
  • Verify: node -v and npm -v
• Java 17 JRE or JDK for running PlantUML
  • Verify: java -version (should show version 17 or higher, e.g., java version "17.0.9")

Installation

1. Move Project to a Path Without Spaces

   • Ensure the project is in a directory without spaces in the path to avoid issues with PlantUML. For example:
     • Correct: C:\Users\Zord\plantuml-viewer
     • Incorrect: C:\Users\Zord\Downloads\New folder (103)\plantuml-viewer-main
   • Move the project if needed:

     cd C:\Users\Zord\plantuml-viewer

2. Install Dependencies

   npm install

3. Start the Server

   • Run the server:

     node server.js

   • The server will run at http://localhost:3000.

4. Access the Application

   • Open a browser and navigate to http://localhost:3000.
   • Enter PlantUML code (e.g., the sample below) in the text area and click "Render Diagram":

     @startuml
     Alice -> Bob: Hello
     Bob --> Alice: Hi back!
     @enduml

If an error occurs

• Error: ENOENT: no such file or directory, open 'temp.png'

  • Cause: PlantUML failed to generate temp.png, likely due to:
    • Missing or incorrect plantuml-gplv2-1.2025.3.jar.
    • Java not installed or not in PATH.
    • Spaces in the project path (e.g., New folder (103)).
  • Fix:
    1. Move the project to a path without spaces (e.g., C:\Users\Zord\plantuml-viewer).
    2. Verify Java: java -version. Install Java 17 if missing.
    3. Verify JAR: Ensure plantuml-gplv2-1.2025.3.jar is in the project directory.
    4. Test PlantUML manually:

       echo "@startuml\nAlice -> Bob: Hello\nBob --> Alice: Hi back!\n@enduml" > test.puml
       java -jar plantuml-gplv2-1.2025.3.jar -tpng test.puml -o .

       Check if test.png is created.
    5. Check server logs for errors (e.g., PlantUML execution error).
    6. Ensure the project directory has write permissions:
       • Right-click the folder > Properties > Security > Confirm your user has "Full control".

• Other Issues

  • Java not recognized: Add Java to PATH (e.g., C:\Program Files\Java\jdk-17\bin).
  • Antivirus interference: Temporarily disable antivirus to test file creation.
  • Logs: Check server logs in the terminal for detailed errors (e.g., PlantUML execution error).
  • X : m4ua If an error occurs, contact me.

Notes

• The application requires plantuml-gplv2-1.2025.3.jar to match server.js. If using a different version, update the JAR name in server.js.
• Avoid spaces and special characters in the project path to ensure PlantUML compatibility.