How to configure create-react-pwa with nested homepage (localhost/app) - service-worker

Question

I create an app by create-react-pwa(CRP) tool and I deploy the app to a local IIS root path. Then I open Chrome at localhost. Everything works great, even Service worker makes its job, fetches and caches app bundle and other resources. In dev tool, I click on Add to homescreen button in Application tab and a shortcut is added.
There is a problem when I change the root path to a subfolder (localhost/myapp). Of course, I change CRP settings and edit homepage in the package.json and manifest.json
//package.json
"homepage" : "/myapp"
//manifest.json
"start_url": "/myapp/",
Then I build the app and edit a path to service-worker in index.html
<script>
"serviceWorker" in navigator && window.addEventListener("load", function () {
navigator.serviceWorker.register("/myapp/service-worker.js")
})
</script>
I deploy this build to IIS subfolder named "/myapp" and try to inspect result in Chrome. Everything works well, service-worker works. But when I try to Add to homescreen it fails. Chrome display the error bellow:
Site cannot be installed: no matching service worker detected. You may need to reload the page, or check that the service worker for the current page also controls the start URL from the manifest
Please, has someone idea what is wrong?
Build structure:
/wwwroot
/myapp
/static
/index.html
/manifest.json
/service-worker.js
/ etc...

Answer 1

You seem to have done everything correctly except one thing - not defining the scope of the service worker while registering. So there are two things you can try out:
1.Try explicitly adding the scope of the service worker while registration. Before making bigger efforts as described in option 2, check if this works for you. CODE:
<script>
"serviceWorker" in navigator && window.addEventListener("load", function () {
navigator.serviceWorker.register('/myapp/service-worker.js', { scope : '/myapp/' })
})
</script>
2.A full proof way would be this one. Since you are using IIS, you can make changes to your web.config file to add the Service-Worker-Allowed Http header to the response of your service worker file. CODE:
<location path="/myapp/service-worker.js">
<system.webServer>
<httpProtocol>
<customHeaders>
<add name="Service-Worker-Allowed" value="/" />
</customHeaders>
</httpProtocol>
</system.webServer>
</location>
and then just define the scope as {scope : '/'} while registering your service worker. This way irrespective of your project structure or placement of your service worker, it should work. Basically what you are doing now is that you are adding "Service-Worker-Allowed" header in HTTP response to the service worker's script resource request. This answer is inspired from the example 10 in the service worker's spec link above.

Answer 2

We were able to get this running on a tomcat server. We had to ensure that
1) The manifest.json, service-worker.js and the index.html reside in WEB-INF directory.
2) Set up a request mapping like to ensure that the manifest and service-worker are returned from the proper location
#RequestMapping(value = "/manifest.json", method = RequestMethod.GET)
public #ResponseBody InternalResourceView manifest() throws IOException {
return new InternalResourceView("/WEB-INF/manifest.json");
}
#RequestMapping(value = "/service-worker.js", method = RequestMethod.GET)
public #ResponseBody InternalResourceView serviceWorker() throws IOException {
return new InternalResourceView("/WEB-INF/service-worker.js");
}
3) We placed the assets from the build script inside resources/static/ directory and made sure that the resources to cache were supplied with proper names, like so, in the service-worker.js
const BASE_STATIC_URLS = [
'.',
'index.html',
'offline.html',
'/myapp/static/js/0.16823424.chunk.js'
];