Rails duplicate GET requests - ruby-on-rails

Question

I have a Rails application sending double GET requests. I have found that the issue doesn't exist with POST requests.
The log shows I'm testing the website locally, but the issue persists on production(Heroku).
I found several reports of the same issue related to turbolinks, after that I proceeded to remove everything turbolinks related from my code. Issue still persisted. I also found some people with similar issues related to empty img tags, or url(). I haven't found anything like that either. I also tried deleting all html being rendered on certain pages to try and see if the error was there, including the partial renders, still no success. Now I am completely clueless.
Here's the log showing the double request:
Started GET "/" for 127.0.0.1 at 2019-07-04 18:38:30 -0300
Processing by HomeController#index as HTML
Cart Load (0.5ms) SELECT "carts".* FROM "carts" WHERE "carts"."id" IS NULL LIMIT $1 [["LIMIT", 1]]
Setting Load (0.5ms) SELECT "settings".* FROM "settings" WHERE "settings"."key" = $1 LIMIT $2 [["key", "featured_artist_slug"], ["LIMIT", 1]]
Artist Load (33.8ms) SELECT "users".* FROM "users" left outer join (select user_id from arts group by user_id) as arts on users.id = arts.user_id WHERE (arts.user_id is not null) AND "users"."slug" = $1 LIMIT $2 [["slug", "herisson-artes"], ["LIMIT", 1]]
Rendering home/index.html.erb within layouts/application
(0.5ms) SELECT COUNT(*) AS "size", MAX("banners"."updated_at") AS timestamp FROM "banners" WHERE "banners"."active" = $1 [["active", true]]
Admin::Banner Load (0.5ms) SELECT "banners".* FROM "banners" WHERE "banners"."active" = $1 ORDER BY "banners"."position" ASC [["active", true]]
Rendered home/index.html.erb within layouts/application (18.4ms)
Rendered shared/_google_tag_manager_head.html.erb (0.8ms)
User Load (0.6ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 56592], ["LIMIT", 1]]
Rendered shared/_google_analytics.html.erb (4.7ms)
Rendered layouts/application/_favicons.html.erb (2.6ms)
Rendered shared/_seo.html.erb (4.1ms)
Rendered layouts/application/_head.html.erb (20.4ms)
Rendered shared/_google_tag_manager_body.html.erb (1.1ms)
Rendered shared/_facebook_js_sdk.html (0.4ms)
(0.9ms) SELECT COUNT(*) AS "size", MAX("coupons"."updated_at") AS timestamp FROM "coupons"
Coupon Load (4.6ms) SELECT "coupons".* FROM "coupons"
Rendered shared/_smartbar.html.erb (219.3ms) [cache hit]
Rendered layouts/application/_navbar.html.erb (7.6ms) [cache hit]
Rendered shared/_alert.html.erb (0.9ms)
Rendered layouts/application/_footer.html.erb (3.4ms) [cache hit]
Art Load (0.6ms) SELECT "arts".* FROM "arts" WHERE "arts"."active" = $1 AND "arts"."user_id" = $2 LIMIT $3 [["active", true], ["user_id", 56592], ["LIMIT", 1]]
(1.2ms) SELECT COUNT(*) FROM "arts" WHERE "arts"."active" = $1 AND "arts"."user_id" = $2 [["active", true], ["user_id", 56592]]
Order Exists (0.5ms) SELECT 1 AS one FROM "orders" WHERE "orders"."deleted_at" IS NULL AND "orders"."user_id" = $1 LIMIT $2 [["user_id", 56592], ["LIMIT", 1]]
Rendered shared/_crisp.html.erb (12.2ms)
Completed 200 OK in 349ms (Views: 291.6ms | ActiveRecord: 44.3ms)
Started GET "/" for 127.0.0.1 at 2019-07-04 18:38:30 -0300
Processing by HomeController#index as HTML
Cart Load (0.5ms) SELECT "carts".* FROM "carts" WHERE "carts"."id" IS NULL LIMIT $1 [["LIMIT", 1]]
Setting Load (0.7ms) SELECT "settings".* FROM "settings" WHERE "settings"."key" = $1 LIMIT $2 [["key", "featured_artist_slug"], ["LIMIT", 1]]
Artist Load (140.1ms) SELECT "users".* FROM "users" left outer join (select user_id from arts group by user_id) as arts on users.id = arts.user_id WHERE (arts.user_id is not null) AND "users"."slug" = $1 LIMIT $2 [["slug", "herisson-artes"], ["LIMIT", 1]]
Rendering home/index.html.erb within layouts/application
(0.6ms) SELECT COUNT(*) AS "size", MAX("banners"."updated_at") AS timestamp FROM "banners" WHERE "banners"."active" = $1 [["active", true]]
Admin::Banner Load (1.2ms) SELECT "banners".* FROM "banners" WHERE "banners"."active" = $1 ORDER BY "banners"."position" ASC [["active", true]]
Rendered home/index.html.erb within layouts/application (26.7ms)
Rendered shared/_google_tag_manager_head.html.erb (0.7ms)
User Load (1.1ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 56592], ["LIMIT", 1]]
Rendered shared/_google_analytics.html.erb (6.8ms)
Rendered layouts/application/_favicons.html.erb (2.8ms)
Rendered shared/_seo.html.erb (5.6ms)
Rendered layouts/application/_head.html.erb (27.5ms)
Rendered shared/_google_tag_manager_body.html.erb (3.1ms)
Rendered shared/_facebook_js_sdk.html (0.7ms)
(1.8ms) SELECT COUNT(*) AS "size", MAX("coupons"."updated_at") AS timestamp FROM "coupons"
Coupon Load (20.7ms) SELECT "coupons".* FROM "coupons"
Rendered shared/_smartbar.html.erb (812.0ms) [cache hit]
Rendered layouts/application/_navbar.html.erb (13.8ms) [cache hit]
Rendered shared/_alert.html.erb (2.1ms)
Rendered layouts/application/_footer.html.erb (7.5ms) [cache hit]
Art Load (1.0ms) SELECT "arts".* FROM "arts" WHERE "arts"."active" = $1 AND "arts"."user_id" = $2 LIMIT $3 [["active", true], ["user_id", 56592], ["LIMIT", 1]]
(1.5ms) SELECT COUNT(*) FROM "arts" WHERE "arts"."active" = $1 AND "arts"."user_id" = $2 [["active", true], ["user_id", 56592]]
Order Exists (1.3ms) SELECT 1 AS one FROM "orders" WHERE "orders"."deleted_at" IS NULL AND "orders"."user_id" = $1 LIMIT $2 [["user_id", 56592], ["LIMIT", 1]]
Rendered shared/_crisp.html.erb (23.1ms)
Completed 200 OK in 1137ms (Views: 948.5ms | ActiveRecord: 170.5ms)
Started GET "/assets/favicons/favicon-359aff8efc45853aea627316f2ab1c7eb0242d855d0e5049152a699ac872092d.ico" for 127.0.0.1 at 2019-07-04 18:38:32 -0300
Started GET "/manifest.json" for 127.0.0.1 at 2019-07-04 18:38:32 -0300
Started GET "/assets/favicons/favicon-359aff8efc45853aea627316f2ab1c7eb0242d855d0e5049152a699ac872092d.ico" for 127.0.0.1 at 2019-07-04 18:38:32 -0300
Started GET "/manifest.json" for 127.0.0.1 at 2019-07-04 18:38:32 -0300
Started GET "/serviceworker.js" for 127.0.0.1 at 2019-07-04 18:38:34 -0300
Any tips are welcome. Thanks in advance.

Answer 1

So, by inspecting the Networking tab in my Browser's dev tools as suggested in the comments, I found out the problem was the Service Worker. It was duplicating the requests when the fetch event was fired. For anyone interested, here's the code that was duplicating the requests:
self.addEventListener('fetch', function(event) {
if (event.request.cache === 'only-if-cached' && event.request.mode !== 'same-origin') {
return;
}
event.respondWith(
checkResponse(event.request).catch(function() {
return returnFromCache(event.request)}
));
event.waitUntil(addToCache(event.request));
});
var checkResponse = function(request){
return new Promise(function(fulfill, reject) {
fetch(request).then(function(response){
if(response.status !== 404) {
fulfill(response)
} else {
reject()
}
}, reject)
});
};
var addToCache = function(request){
return caches.open('touts-offline').then(function (cache) {
return fetch(request).then(function (response) {
return cache.put(request, response);
});
});
};
var returnFromCache = function(request){
return caches.open('touts-offline').then(function (cache) {
return cache.match(request).then(function (matching) {
if(!matching || matching.status == 404) {
return cache.match('offline.html')
} else {
return matching
}
});
});
};
And here's the proper way of doing it.