How can I call opentopodata from javascript?

[evgakis]

I try to call the api with

`function onGet(url) {

var headers = {}

fetch(url, {
    method: "GET",
    mode: 'no-cors',
    headers: headers
})
    .then((response) => {
        if (!response.ok) {
            throw new Error(response.error)
        }
        return response.json();
    })
    .then(data => {
        dat = data.messages;
    })
    .catch(function (error) {
        err = error.toString();
        var test = 1;
        ee = test;
    });

}`

but I receive an error. Is it possible to call https://api.opentopodata.org/v1/eudem25m?locations= from javascript?

[ajnisbet]

Hi, thanks for opening an issue!

If you host opentopodata yourself you can call it from the browser just fine, the software supports it.

But for the public api that I host at api.opentopodata.org, CORS requests are unfortunately disabled as the bypass the IP-based ratelimiting I use to ensure the server is stable for everyone.

There's more information here: https://github.com/ajnisbet/opentopodata/issues/9

The open software in this repo has full support for browser-based fetch requests and CORS policy. However, the free instance I'm hosting at api.opentopodata.org is configured to block cross-origin requests. These requests effectively bypass the per-IP rate limit, and I want to make sure the server has enough capacity for everyone!

So there are a couple of options to get this working:

• Host ajnisbet/opentopodata on your own server with CORS enabled
• Proxy requests from api.opentopodata.org through your own server, adding the appropriate CORS header
• If you're working on academic research or a small non-commercial project, send me an email and I can add you to a whitelist on the public api.
• Use the GPXZ elevation api