Update Dockerfile for API + frontend architecture with nginx reverse proxy

Rewrote Dockerfile as multi-stage build: Stage 1 builds Next.js frontend,
Stage 2 runs R plumber API + Next.js + nginx behind supervisord on port 7860.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Dockerfile

@@ -1,20 +1,28 @@
-# MCAT Shiny App Dockerfile
-# For deployment to Hugging Face Spaces, AWS, or any Docker-compatible platform
+# MCAT - Adaptive Mental Health Assessment
+# Runs R plumber API + Next.js frontend behind nginx
+# For Hugging Face Spaces (exposes port 7860)
 
-# Use Ubuntu with R (stable, supports ARM64/Apple Silicon)
+# ---- Stage 1: Build Next.js frontend ----
+FROM node:18-alpine AS frontend-build
+
+WORKDIR /frontend
+COPY frontend/package.json frontend/package-lock.json ./
+RUN npm ci
+COPY frontend/ ./
+
+# API calls go to /api/* which nginx proxies to the R backend
+ENV NEXT_PUBLIC_API_URL=/api
+RUN npm run build
+
+# ---- Stage 2: Runtime ----
 FROM ubuntu:22.04
 
-# Prevent interactive prompts during installation
 ENV DEBIAN_FRONTEND=noninteractive
-
-# Set UTF-8 locale
 ENV LANG=C.UTF-8
 ENV LC_ALL=C.UTF-8
-
-# Prevent browser launch attempts
 ENV BROWSER=""
 
-# Install R and system dependencies
+# Install R, Node.js, nginx, supervisor
 RUN apt-get update && apt-get install -y \
     locales \
     r-base \
@@ -29,26 +37,37 @@ RUN apt-get update && apt-get install -y \
     libjpeg-dev \
     libharfbuzz-dev \
     libfribidi-dev \
+    nginx \
+    curl \
+    supervisor \
+    && curl -fsSL https://deb.nodesource.com/setup_18.x | bash - \
+    && apt-get install -y nodejs \
     && rm -rf /var/lib/apt/lists/*
 
-# Install R packages (this may take several minutes)
-RUN R -e "install.packages('shiny', repos='https://cloud.r-project.org/', dependencies=TRUE)"
-RUN R -e "install.packages(c('dplyr', 'ggplot2'), repos='https://cloud.r-project.org/', dependencies=TRUE)"
+# Install R packages
+RUN R -e "install.packages(c('plumber', 'jsonlite'), repos='https://cloud.r-project.org/', dependencies=TRUE)"
 RUN R -e "install.packages('mirt', repos='https://cloud.r-project.org/', dependencies=TRUE)"
 RUN R -e "install.packages('mirtCAT', repos='https://cloud.r-project.org/', dependencies=TRUE)"
 
 # Create app directory
-RUN mkdir -p /app
+RUN mkdir -p /app/frontend
 
-# Copy application files
-COPY app.R /app/app.R
+# Copy R backend files
+COPY api.R /app/api.R
+COPY run_api.R /app/run_api.R
+COPY mirtcat_helper.R /app/mirtcat_helper.R
 COPY Fullmodel.rds /app/Fullmodel.rds
 
-# Set working directory
+# Copy built Next.js standalone server + static assets
+COPY --from=frontend-build /frontend/.next/standalone /app/frontend/
+COPY --from=frontend-build /frontend/.next/static /app/frontend/.next/static
+
+# Copy config files
+COPY nginx.conf /etc/nginx/nginx.conf
+COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf
+
 WORKDIR /app
 
-# Expose port
 EXPOSE 7860
 
-# Run the app.R script directly (mirtCAT handles its own Shiny server)
-CMD ["Rscript", "/app/app.R"]
+CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]

nginx.conf

@@ -0,0 +1,44 @@
+worker_processes 1;
+pid /tmp/nginx.pid;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    include /etc/nginx/mime.types;
+    default_type application/octet-stream;
+
+    # Use /tmp for temp files (no root needed)
+    client_body_temp_path /tmp/nginx_body;
+    proxy_temp_path /tmp/nginx_proxy;
+    fastcgi_temp_path /tmp/nginx_fastcgi;
+    uwsgi_temp_path /tmp/nginx_uwsgi;
+    scgi_temp_path /tmp/nginx_scgi;
+
+    access_log /dev/stdout;
+    error_log /dev/stderr;
+
+    server {
+        listen 7860;
+
+        # API requests -> R plumber backend
+        location /api/ {
+            rewrite ^/api/(.*) /$1 break;
+            proxy_pass http://127.0.0.1:8000;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+            proxy_read_timeout 120s;
+        }
+
+        # Everything else -> Next.js frontend
+        location / {
+            proxy_pass http://127.0.0.1:3000;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+            proxy_http_version 1.1;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection "upgrade";
+        }
+    }
+}

supervisord.conf

@@ -0,0 +1,35 @@
+[supervisord]
+nodaemon=true
+logfile=/dev/null
+logfile_maxbytes=0
+pidfile=/tmp/supervisord.pid
+
+[program:r-api]
+command=Rscript /app/run_api.R
+directory=/app
+autostart=true
+autorestart=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+
+[program:nextjs]
+command=node /app/frontend/server.js
+directory=/app/frontend
+environment=PORT=3000,HOSTNAME="0.0.0.0"
+autostart=true
+autorestart=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+
+[program:nginx]
+command=nginx -g "daemon off;"
+autostart=true
+autorestart=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0