From 662179e36e70c501fa20229450aca384f727feaa Mon Sep 17 00:00:00 2001
From: Lajos Szoke <63732287+laliconfigcat@users.noreply.github.com>
Date: Wed, 27 Dec 2023 11:26:49 +0100
Subject: [PATCH] Send etag as query param (#91)

* sendetagasqueryparam

* comments

* v9.2.0
---
 package-lock.json    | 4 ++--
 package.json         | 2 +-
 src/ConfigFetcher.ts | 8 +++++++-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index deb4253..cebad0e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "configcat-js",
-  "version": "9.1.0",
+  "version": "9.2.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "configcat-js",
-      "version": "9.1.0",
+      "version": "9.2.0",
       "license": "MIT",
       "dependencies": {
         "configcat-common": "^9.0.0",
diff --git a/package.json b/package.json
index 311db1e..4a89a32 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "configcat-js",
-  "version": "9.1.0",
+  "version": "9.2.0",
   "description": "ConfigCat is a configuration as a service that lets you manage your features and configurations without actually deploying new code.",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",
diff --git a/src/ConfigFetcher.ts b/src/ConfigFetcher.ts
index e4a1d3e..31e286a 100644
--- a/src/ConfigFetcher.ts
+++ b/src/ConfigFetcher.ts
@@ -35,10 +35,16 @@ export class HttpConfigFetcher implements IConfigFetcher {
         httpRequest.onabort = () => reject(new FetchError("abort"));
         httpRequest.onerror = () => reject(new FetchError("failure"));
 
-        httpRequest.open("GET", options.getUrl(), true);
+        let url = options.getUrl();
+        if (lastEtag) {
+          // We are sending the etag as a query parameter so if the browser doesn't automatically adds the If-None-Match header, we can transorm this query param to the header in our CDN provider.
+          url += '&ccetag=' + lastEtag;
+        }
+        httpRequest.open("GET", url, true);
         httpRequest.timeout = options.requestTimeoutMs;
         // NOTE: It's intentional that we don't specify the If-None-Match header.
         // The browser automatically handles it, adding it manually would cause an unnecessary CORS OPTIONS request.
+        // In case the browser doesn't handle it, we are transforming the ccetag query parameter to the If-None-Match header in our CDN provider.
         httpRequest.send(null);
       }
       catch (err) {