Failed to fecth with companion to localhost in https with self-sign certificate

[Seksit]

Hi,

TypeError: failed to fetch from Fitbit Ionic over port 443 (but works with port 80), which I setting up API server with nginx and self-signed certificate and I works fine when testing from others with postman to GET/POST over port 80 and 443

How can i fix fetch with self-sign? may i guess it cause of certification verify during fetch.

Mobile OS: iOS

Permission Grant: "access_internet",

Error message: TypeError: Failed to fetch

Example Code:

fetch(`https://192.168.1.100/api/v1/test`, {
      method: "POST",
      body: `data=test-sent-over-https`,
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
        "Authorization": "asdlkfjapoifhsld'alsjdk;fasakfd"
      }
    })
    .then((res) => {
      return res.json()
      .then((res) => {
        console.log(`response: ${JSON.stringify(res)}`);
      });
    })
    .catch((err)=>{
      console.log(err);
    });

[Seksit]

I just found below topic but i not sure my problem is the same thing:-

https://community.fitbit.com/t5/SDK-Development/Fetch-API-stops-working-with-latest-Fitbit-PlayStore...

[Seksit]

Any ideas?

[Gondwana]

I've spent many hours trying to get companion fetch() to accept a self-signed certificate, but have failed. The certificate works fine via a browser, but that's probably because the browser can set a security exception.

[Seksit]

Hi,

Today i just go back to read Fetch API documents of Fitbit again, I not sure when below description added to the page, but it think it related with my problem:-

fetch()
This API is used to GET and POST across a network.

Please note: fetch() can only be used to access https endpoints and resources, except when accessing resources on a local network by IP address.

 So, that my problem cause of Fitbit fetch cannot accessing to local network by IP address.

[Gondwana]

You're right. But I can't get fetch to work with http on a LAN server accessed via IP. I wonder if it may be limited to specific IPs and/or ports (which may have the side-effect of limiting it to localhost).

[Gondwana]

Further to the theory about specific IPs, see this.

I think I've reached the conclusion that fetch over LAN requires https with a not-self-signed certificate.