Two calls on demand: from http 204 and 200
I have implemented the Cors policy in core with network core: In Startup.cs
the section ConfigureServices
I added the following cors policy
services.AddCors(options =>{
options.AddPolicy("CorsPolicy",
builder => builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials());
});
I got a weird problem after adding a CORS policy, each time a POST is called from the UI, two calls are made: the first calls return with 204, and the other call returns data with a 200 status code.
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The first is a pre-check request . The main goal is to determine if it is safe to send a real request. Cross-site requests are prepended because they can have implications for user data.
A CORS preflight request is a CORS request that checks if the CORS protocol is understood.
This is a request
OPTIONS
using two HTTP request headers: Access-Control-Request-Method and Access-Control-Request-Headers and an Origin header.A pre-check request is automatically issued by the browser when needed.
This HTTP Access Control (CORS) describes the conditions that, if true, the request is requested.
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