Enable CORS?
Closed this issue · 10 comments
I am using the javascritp fetch api to call your basic server test code. Works perfectly with the vanilla GET. I am having the trouble when I move to a more complicated POST setup that is seems similar to this discussion. Do you have advice on how to resolve this? Thank you.
My error:
Access to fetch at 'http://35.238.222.54/bin' from origin 'http://localhost:3000' has been blocked by CORS
policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin'
header is present on the requested resource. If an opaque response serves your needs, set the request's
mode to 'no-cors' to fetch the resource with CORS disabled.
My code:
callpost(){
postData('http://xx.xxx.xxx.xx/bin', {"n": 4, "k": 3})
.then(data => console.log(JSON.stringify(data))) // JSON-string from `response.json()` call
.catch(error => console.error(error));
}
export function postData(url = ``, data = {}) {
// Default options are marked with *
return fetch(url, {
method: "POST", // *GET, POST, PUT, DELETE, etc.
//mode: "no-cors", // no-cors, cors, *same-origin
cache: "no-cache", // *default, no-cache, reload, force-cache, only-if-cached
headers: {
"Content-Type": "application/json; charset=utf-8",
},
body: JSON.stringify(data), // body data type must match "Content-Type" header
})
.then(response => response.json()); // parses response to JSON
}
I think you might need to add an endpoint which accepts OPTIONS requests -- before sending POST requests browsers make pre-flight OPTIONS requests to see if it's OK to make POST requests and maybe that's also happening automatically here? There may also be a header you need to set on the client side -- I'll check one of my projects where I've done this on Monday.
Hi @amellnik . Have you had time to look at this yet? This is my first exposure to these ideas and I appreciate your experience.
When you state above, I think you might need to add an endpoint which accepts OPTIONS requests, do you mean in Kubernetes or in the Julia Docker code?
This discussion encountered the CORS problem using Kubernetes by configuring their nginx server. Is there a similar approach we can take with our Julia server?
Here, the author suggests a general solution by rerouting through Heroku. That seems a little hacky, but I don't know. What do you think?
On the server I am using the default middleware item Joseki.add_cors! and I have an endpoint that looks like (req -> req.response, "OPTIONS", "*"). I don't think you should need to do anything beyond this. On the client the only header that I set is Content-Type.
So, if I understand correctly, the only change I need to make is to change the endpoints like below? Because the Joseki.jl server I am using has the middleware item Joseki.add_cors! already set up by default and my above header is already ok.
I don’t think I asked this correctly- do I have to change anything to enable Joseki.add_cors!
endpoints = [
(pow, "GET", "/pow"),
(bin, "POST", "/bin"),
(req -> req.response, "OPTIONS", "*")
]
That should work as written. Under the hood Joseki uses JSON.json to serialize objects and it should work happily on matrices, (which are represented as arrays of arrays in json).