Function llmProxyPlugin

apps/webuiapps/vite.config.ts:256–320

LLM API proxy plugin — resolves browser CORS restrictions

()

/** LLM API proxy plugin — resolves browser CORS restrictions */
function llmProxyPlugin(): Plugin {
  return {
    name: 'llm-proxy',
    configureServer(server) {
      server.middlewares.use('/api/llm-proxy', async (req, res) => {
        const targetUrl = req.headers['x-llm-target-url'] as string;
        if (!targetUrl) {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: 'Missing X-LLM-Target-URL header' }));
          return;
        }
        const chunks: Buffer[] = [];
        req.on('data', (chunk: Buffer) => chunks.push(chunk));
        req.on('end', async () => {
          try {
            const body = Buffer.concat(chunks).toString();
            const headers: Record<string, string> = {};
            // Forward all headers except host/connection/internal ones
            const skipKeys = new Set(['host', 'connection', 'content-length', 'x-llm-target-url']);
            for (const [key, val] of Object.entries(req.headers)) {
              if (typeof val !== 'string') continue;
              if (skipKeys.has(key)) continue;
              if (key.startsWith('x-custom-')) {
                headers[key.replace('x-custom-', '')] = val;
              } else {
                headers[key] = val;
              }
            }

            const fetchRes = await fetch(targetUrl, {
              method: req.method || 'POST',
              headers,
              body,
            });

            res.writeHead(fetchRes.status, {
              'Content-Type': fetchRes.headers.get('Content-Type') || 'application/json',
              'Transfer-Encoding': 'chunked',
            });

            if (fetchRes.body) {
              const reader = (fetchRes.body as ReadableStream<Uint8Array>).getReader();
              const pump = async () => {
                let done = false;
                while (!done) {
                  const result = await reader.read();
                  done = result.done;
                  if (!done) res.write(result.value);
                }
                res.end();
              };
              pump().catch(() => res.end());
            } else {
              const text = await fetchRes.text();
              res.end(text);
            }
          } catch (err: unknown) {
            res.writeHead(502, { 'Content-Type': 'application/json' });