From 397488df021e88380da24b68bb6b495fc098b637 Mon Sep 17 00:00:00 2001
From: alaa <kaddour-alaa@topvoce.com>
Date: Sat, 2 May 2026 18:50:35 +0100
Subject: [PATCH] feat(web): support GITNEXUS_BACKEND_URL env var for Docker
 deployments

---
 docker-compose.yaml                           |  7 ++
 docker-server.mjs                             | 65 +++++++++++++++----
 docker-server.test.mjs                        | 58 +++++++++++++++++
 gitnexus-web/src/config/ui-constants.ts       |  4 +-
 gitnexus-web/src/vite-env.d.ts                |  6 ++
 .../test/unit/server-connection.test.ts       | 25 +++++++
 6 files changed, 152 insertions(+), 13 deletions(-)

diff --git a/docker-compose.yaml b/docker-compose.yaml
index 297eab85e..7491ccdd3 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -30,6 +30,13 @@ services:
     container_name: ${WEB_CONTAINER_NAME:-gitnexus-web}
     ports:
       - '${WEB_HOST_PORT:-4173}:4173'
+    # Optional: override the backend URL served to the browser.
+    # Required when the gitnexus-server is not reachable at http://localhost:4747
+    # from the user's browser (e.g. remote server deployments).
+    # Use http://host.docker.internal:4747 on Docker Desktop (Mac/Windows),
+    # or the server's LAN IP for Linux hosts.
+    # environment:
+    #   - GITNEXUS_BACKEND_URL=http://host.docker.internal:4747
     depends_on:
       gitnexus-server:
         condition: service_healthy
diff --git a/docker-server.mjs b/docker-server.mjs
index adf84a07b..6ba3ddfe5 100644
--- a/docker-server.mjs
+++ b/docker-server.mjs
@@ -1,5 +1,5 @@
 import { createReadStream } from 'node:fs';
-import { stat } from 'node:fs/promises';
+import { readFile, stat } from 'node:fs/promises';
 import { createServer } from 'node:http';
 import { extname, join, normalize, sep } from 'node:path';
 
@@ -7,6 +7,26 @@ const host = '0.0.0.0';
 const port = Number(process.env.PORT || '4173');
 const root = join(process.cwd(), 'dist');
 
+function isValidUrl(value) {
+  try {
+    const u = new URL(value);
+    return u.protocol === 'http:' || u.protocol === 'https:';
+  } catch {
+    return false;
+  }
+}
+
+const rawBackendUrl = process.env.GITNEXUS_BACKEND_URL ?? null;
+if (rawBackendUrl && !isValidUrl(rawBackendUrl)) {
+  console.warn(
+    `[gitnexus-web] GITNEXUS_BACKEND_URL "${rawBackendUrl}" is not a valid http/https URL — ignoring.`,
+  );
+}
+const backendUrl = rawBackendUrl && isValidUrl(rawBackendUrl) ? rawBackendUrl : null;
+const configScript = backendUrl
+  ? `<script>window.__GITNEXUS_CONFIG__=${JSON.stringify({ backendUrl })};</script>`
+  : '';
+
 const contentTypes = {
   '.css': 'text/css; charset=utf-8',
   '.html': 'text/html; charset=utf-8',
@@ -59,17 +79,38 @@ const server = createServer(async (req, res) => {
       return;
     }
 
-    res.writeHead(200, {
-      'Cache-Control': filePath.includes('/assets/')
-        ? 'public, max-age=31536000, immutable'
-        : 'no-cache',
-      'Content-Type': contentTypes[extname(filePath)] || 'application/octet-stream',
-      'Cross-Origin-Opener-Policy': 'same-origin',
-      'Cross-Origin-Embedder-Policy': 'require-corp',
-    });
-    const stream = createReadStream(filePath);
-    stream.on('error', () => res.destroy());
-    stream.pipe(res);
+    const isHtml = extname(filePath) === '.html' || !extname(filePath);
+    const cacheControl = filePath.includes('/assets/')
+      ? 'public, max-age=31536000, immutable'
+      : 'no-cache';
+    const contentType = contentTypes[extname(filePath)] || 'application/octet-stream';
+
+    if (isHtml && configScript) {
+      const raw = await readFile(filePath, 'utf8');
+      if (!raw.includes('</head>')) {
+        console.warn('[gitnexus-web] Could not inject config: no </head> tag found in HTML');
+      }
+      const html = raw.includes('</head>') ? raw.replace('</head>', `${configScript}</head>`) : raw;
+      const buf = Buffer.from(html, 'utf8');
+      res.writeHead(200, {
+        'Cache-Control': cacheControl,
+        'Content-Type': 'text/html; charset=utf-8',
+        'Content-Length': buf.length,
+        'Cross-Origin-Opener-Policy': 'same-origin',
+        'Cross-Origin-Embedder-Policy': 'require-corp',
+      });
+      res.end(buf);
+    } else {
+      res.writeHead(200, {
+        'Cache-Control': cacheControl,
+        'Content-Type': contentType,
+        'Cross-Origin-Opener-Policy': 'same-origin',
+        'Cross-Origin-Embedder-Policy': 'require-corp',
+      });
+      const stream = createReadStream(filePath);
+      stream.on('error', () => res.destroy());
+      stream.pipe(res);
+    }
   } catch (error) {
     res.writeHead(500);
     res.end(error instanceof Error ? error.message : 'Internal server error');
diff --git a/docker-server.test.mjs b/docker-server.test.mjs
index a1005b0e4..f1118d5c3 100644
--- a/docker-server.test.mjs
+++ b/docker-server.test.mjs
@@ -105,3 +105,61 @@ it('returns 404 when dist/index.html is missing', async () => {
   const res = await rawGet(serverPort, '/nonexistent-page');
   assert.equal(res.status, 404);
 });
+
+// ── Config injection logic tests (inline, independent of server process) ─────
+
+import { readFileSync, mkdirSync, writeFileSync } from 'node:fs';
+
+function isValidUrl(value) {
+  try {
+    const u = new URL(value);
+    return u.protocol === 'http:' || u.protocol === 'https:';
+  } catch {
+    return false;
+  }
+}
+
+function makeInjectedHtml(envBackendUrl) {
+  const rawHtml = '<!doctype html><html><head></head><body></body></html>';
+  const backendUrl = envBackendUrl && isValidUrl(envBackendUrl) ? envBackendUrl : null;
+  const configScript = backendUrl
+    ? `<script>window.__GITNEXUS_CONFIG__=${JSON.stringify({ backendUrl })};</script>`
+    : '';
+  return configScript ? rawHtml.replace('</head>', `${configScript}</head>`) : rawHtml;
+}
+
+it('injects __GITNEXUS_CONFIG__ when GITNEXUS_BACKEND_URL is a valid URL', () => {
+  const html = makeInjectedHtml('http://10.0.0.1:4747');
+  assert.ok(
+    html.includes(
+      '<script>window.__GITNEXUS_CONFIG__={"backendUrl":"http://10.0.0.1:4747"};</script>',
+    ),
+    'Expected config script to be injected into index.html',
+  );
+});
+
+it('does not inject when GITNEXUS_BACKEND_URL is not set', () => {
+  const raw = '<!doctype html><html><head></head><body></body></html>';
+  const html = makeInjectedHtml(null);
+  assert.equal(html, raw, 'Expected index.html to be unchanged when no env var is set');
+});
+
+it('injects config script before </head>', () => {
+  const html = makeInjectedHtml('http://10.0.0.1:4747');
+  const headCloseIdx = html.indexOf('</head>');
+  const scriptIdx = html.indexOf('<script>window.__GITNEXUS_CONFIG__');
+  assert.ok(scriptIdx !== -1, 'Script tag must be present');
+  assert.ok(scriptIdx < headCloseIdx, 'Script must appear before </head>');
+});
+
+it('does not inject when GITNEXUS_BACKEND_URL is not a valid URL', () => {
+  const raw = '<!doctype html><html><head></head><body></body></html>';
+  const html = makeInjectedHtml('not-a-url');
+  assert.equal(html, raw, 'Expected index.html to be unchanged for an invalid URL');
+});
+
+it('does not inject when GITNEXUS_BACKEND_URL uses a non-http protocol', () => {
+  const raw = '<!doctype html><html><head></head><body></body></html>';
+  const html = makeInjectedHtml('ftp://somehost:21');
+  assert.equal(html, raw, 'Expected index.html to be unchanged for non-http protocol');
+});
diff --git a/gitnexus-web/src/config/ui-constants.ts b/gitnexus-web/src/config/ui-constants.ts
index c0a2b488c..1bdb9bae1 100644
--- a/gitnexus-web/src/config/ui-constants.ts
+++ b/gitnexus-web/src/config/ui-constants.ts
@@ -2,7 +2,9 @@
 export const ERROR_RESET_DELAY_MS = 3000;
 export const BACKEND_URL_DEBOUNCE_MS = 500;
 
-export const DEFAULT_BACKEND_URL = 'http://localhost:4747';
+export const DEFAULT_BACKEND_URL =
+  (typeof window !== 'undefined' && window.__GITNEXUS_CONFIG__?.backendUrl) ||
+  'http://localhost:4747';
 export const DEFAULT_OLLAMA_BASE_URL = 'http://localhost:11434';
 export const DEFAULT_OPENROUTER_BASE_URL = 'https://openrouter.ai/api/v1';
 
diff --git a/gitnexus-web/src/vite-env.d.ts b/gitnexus-web/src/vite-env.d.ts
index 11f02fe2a..4a8d41b00 100644
--- a/gitnexus-web/src/vite-env.d.ts
+++ b/gitnexus-web/src/vite-env.d.ts
@@ -1 +1,7 @@
 /// <reference types="vite/client" />
+
+interface Window {
+  __GITNEXUS_CONFIG__?: {
+    backendUrl?: string;
+  };
+}
diff --git a/gitnexus-web/test/unit/server-connection.test.ts b/gitnexus-web/test/unit/server-connection.test.ts
index f5ee43c53..6d51dbe17 100644
--- a/gitnexus-web/test/unit/server-connection.test.ts
+++ b/gitnexus-web/test/unit/server-connection.test.ts
@@ -165,3 +165,28 @@ describe('fetchGraph', () => {
     });
   });
 });
+
+describe('DEFAULT_BACKEND_URL resolution', () => {
+  afterEach(() => {
+    delete window.__GITNEXUS_CONFIG__;
+    vi.resetModules();
+  });
+
+  it('falls back to localhost:4747 when no config is injected', async () => {
+    delete window.__GITNEXUS_CONFIG__;
+    const { DEFAULT_BACKEND_URL } = await import('../../src/config/ui-constants');
+    expect(DEFAULT_BACKEND_URL).toBe('http://localhost:4747');
+  });
+
+  it('uses window.__GITNEXUS_CONFIG__.backendUrl when set', async () => {
+    window.__GITNEXUS_CONFIG__ = { backendUrl: 'http://10.0.0.1:4747' };
+    const { DEFAULT_BACKEND_URL } = await import('../../src/config/ui-constants');
+    expect(DEFAULT_BACKEND_URL).toBe('http://10.0.0.1:4747');
+  });
+
+  it('falls back to localhost:4747 when config object has no backendUrl', async () => {
+    window.__GITNEXUS_CONFIG__ = {};
+    const { DEFAULT_BACKEND_URL } = await import('../../src/config/ui-constants');
+    expect(DEFAULT_BACKEND_URL).toBe('http://localhost:4747');
+  });
+});