Fix Transmission proxy error with URL and CSRF caching

src/widgets/transmission/proxy.js

@@ -1,21 +1,39 @@
+import cache from "memory-cache";
+
 import { httpProxy } from "utils/proxy/http";
 import { formatApiCall } from "utils/proxy/api-helpers";
 import getServiceWidget from "utils/config/service-helpers";
+import createLogger from "utils/logger";
+import widgets from "widgets/widgets";
+
+const proxyName = "transmissionProxyHandler";
+const headerCacheKey = `${proxyName}__headers`;
+const logger = createLogger(proxyName);
 
 export default async function transmissionProxyHandler(req, res) {
   const { group, service, endpoint } = req.query;
 
   if (!group || !service) {
+    logger.debug("Invalid or missing service '%s' or group '%s'", service, group);
     return res.status(400).json({ error: "Invalid proxy service type" });
   }
 
   const widget = await getServiceWidget(group, service);
 
   if (!widget) {
+    logger.debug("Invalid or missing widget for service '%s' in group '%s'", service, group);
     return res.status(400).json({ error: "Invalid proxy service type" });
   }
 
-  const url = new URL(formatApiCall(widget.type, { endpoint, ...widget }));
+  let headers = cache.get(headerCacheKey);
+  if (!headers) {
+    headers = {
+      "content-type": "application/json",
+    }
+    cache.put(headerCacheKey, headers);
+  }
+
+  const url = new URL(formatApiCall(widgets[widget.type].api, { endpoint, ...widget }));
   const csrfHeaderName = "x-transmission-session-id";
 
   const method = "POST";
@@ -27,10 +45,6 @@ export default async function transmissionProxyHandler(req, res) {
     },
   });
 
-  const headers = {
-    "content-type": "application/json",
-  };
-
   let [status, contentType, data, responseHeaders] = await httpProxy(url, {
     method,
     auth,
@@ -39,8 +53,9 @@ export default async function transmissionProxyHandler(req, res) {
   });
 
   if (status === 409) {
-    // Transmission is rejecting the request, but returning a CSRF token
+    logger.debug("Transmission is rejecting the request, but returning a CSRF token");
     headers[csrfHeaderName] = responseHeaders[csrfHeaderName];
+    cache.put(headerCacheKey, headers);
 
     // retry the request, now with the CSRF token
     [status, contentType, data, responseHeaders] = await httpProxy(url, {
@@ -51,6 +66,10 @@ export default async function transmissionProxyHandler(req, res) {
     });
   }
 
+  if (status !== 200) {
+    logger.error("Error getting data from Transmission: %d.  Data: %s", status, data);
+  }
+
   if (contentType) res.setHeader("Content-Type", contentType);
   return res.status(status).send(data);
 }