stats lambda: better caching (or lack thereof) & error handling

functions/send_view.js

@@ -1,12 +1,14 @@
 const axios = require("axios");
 
 exports.handler = function (event, context, callback) {
+  try {
     // if triggered as an image without JS (i.e. from AMP pages) set `?noscript=true`
     const noScript = event.queryStringParameters["noscript"] === "true";
 
     // https://docs.simpleanalytics.com/without-javascript
+    const endpointHost = "queue.simpleanalyticscdn.com";
     const endpointPath = noScript ? "noscript.gif" : "simple.gif";
-  const endpointUrl = "https://queue.simpleanalyticscdn.com/" + endpointPath;
+    const endpointUrl = "https://" + endpointHost + "/" + endpointPath;
 
     // pass these headers along to SA
     const reqHeaders = {
@@ -24,7 +26,7 @@ exports.handler = function (event, context, callback) {
       headers: reqHeaders,
       params: reqQuery,
       responseType: "arraybuffer",
-    timeout: 3000,
+      timeout: 2000,
     };
 
     console.info(`Proxying ${reqQuery["type"]} to ${endpointPath} ...`);
@@ -32,16 +34,24 @@ exports.handler = function (event, context, callback) {
     axios
       .request(reqConfig)
       .then(function (response) {
-      console.info(response.status, response.headers["simple-analytics-feedback"]);
+        // parse the feedback message from SA
+        const apiFeedback = response.headers["simple-analytics-feedback"] || "No feedback from Simple Analytics.";
+        const shortFeedback = apiFeedback.toLowerCase().includes("thanks for sending") ? "OK" : `ERROR: ${apiFeedback}`;
+
+        console.info(response.status, apiFeedback);
 
         // imitate the headers that would normally be sent back from SA's pixel
         const resHeaders = {
-        "cache-control": "no-cache, no-store, must-revalidate",
+          "Content-Type": "image/gif",
-        "content-type": response.headers["content-type"],
+          "Cache-Control": "private, no-cache, no-store, must-revalidate",
-        "x-api-feedback": response.headers["simple-analytics-feedback"],
+          Expires: "0",
-        "x-api-destination": response.headers["simple-analytics-location"],
+          Pragma: "no-cache",
+          "X-API-Response": shortFeedback,
+          "X-API-Endpoint": endpointHost,
         };
 
+        // reasoning for base64 encoding:
+        // https://community.netlify.com/t/debugging-a-function-returns-502/429/12
         callback(null, {
           statusCode: response.status,
           headers: resHeaders,
@@ -51,10 +61,20 @@ exports.handler = function (event, context, callback) {
       })
       .catch(function (error) {
         // this indicates a function error, NOT an error returned from SA
-      console.log(error);
+        throw error;
+      });
+  } catch (error) {
+    // something went VERY wrong...
+    console.log(error.message);
 
     callback(null, {
       statusCode: 500,
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        error: error.message,
+      }),
     });
-    });
+  }
 };

yarn.lock

@@ -1808,14 +1808,14 @@ camelcase@^5.0.0, camelcase@^5.3.1:
   integrity sha512-L28STB170nwWS63UjtlEOE3dldQApaJXZkOI1uMFfzf3rRuPegHaHesyee+YxQ+W6SvRDQV6UrdOdRiR153wJg==
 
 caniuse-db@^1.0.30001090:
-  version "1.0.30001115"
+  version "1.0.30001116"
-  resolved "https://registry.yarnpkg.com/caniuse-db/-/caniuse-db-1.0.30001115.tgz#fe52adf78535b8956b3df8b36870593b12cba7a1"
+  resolved "https://registry.yarnpkg.com/caniuse-db/-/caniuse-db-1.0.30001116.tgz#77635640080024292f9f239042e7d1acd5cb88a7"
-  integrity sha512-g1ZFLCOzTIk6QKTqqxRYV3GlW9SfeSAh2J1HYmeuj6YVnOBe7uCHybWJyWVlhCwjtQtq9B84WN1hIQMa3D5ghg==
+  integrity sha512-v7zj0MenYwLid3ENDLNlTMBOoIQdWYcShqnXbZZuuaq11xnn2y9DfL5VtZhiIb9PInT3sWpP11GVjmC8hPFBcA==
 
 caniuse-lite@^1.0.30000887, caniuse-lite@^1.0.30001109, caniuse-lite@^1.0.30001111:
-  version "1.0.30001115"
+  version "1.0.30001116"
-  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001115.tgz#c04cd828883ba47f6f776312e0817bcc9040cfa4"
+  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001116.tgz#f3a3dea347f9294a3bdc4292309039cc84117fb8"
-  integrity sha512-NZrG0439ePYna44lJX8evHX2L7Z3/z3qjVLnHgbBb/duNEnGo348u+BQS5o4HTWcrb++100dHFrU36IesIrC1Q==
+  integrity sha512-f2lcYnmAI5Mst9+g0nkMIznFGsArRmZ0qU+dnq8l91hymdc2J3SFbiPhOJEeDqC1vtE8nc1qNQyklzB8veJefQ==
 
 caw@^2.0.0, caw@^2.0.1:
   version "2.0.1"
@@ -2753,9 +2753,9 @@ ee-first@1.1.1:
   integrity sha1-WQxhFWsK4vTwJVcyoViyZrxWsh0=
 
 electron-to-chromium@^1.3.523:
-  version "1.3.534"
+  version "1.3.539"
-  resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.3.534.tgz#fc7af8518dd00a5b22a24aed3f116b5d097e2330"
+  resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.3.539.tgz#9952fb0bf3fb4295282e7df35f6e7a2a8b89d3fd"
-  integrity sha512-7x2S3yUrspNHQOoPk+Eo+iHViSiJiEGPI6BpmLy1eT2KRNGCkBt/NUYqjfXLd1DpDCQp7n3+LfA1RkbG+LqTZQ==
+  integrity sha512-rM0LWDIstdqfaRUADZetNrL6+zd/0NBmavbMEhBXgc2u/CC1d1GaDyN5hho29fFvBiOVFwrSWZkzmNcZnCEDog==
 
 elliptic@^6.5.3:
   version "6.5.3"