How to Query URLs in Go without Following Redirects?

Querying URLs without Redirection in Go

In benchmark testing for a redirect script, it is necessary to query a URL without initiating an automatic redirect. This requires preventing the program from downloading the redirected content while still logging the redirect URL or any associated errors.

Solution 1: Using http.DefaultTransport.RoundTrip

One approach is to leverage the http.DefaultTransport.RoundTrip() function within your http.Request. Unlike http.Client, Transport does not automatically follow redirects:

req, err := http.NewRequest("GET", "http://example.com/redirectToAppStore", nil)
// ...
resp, err := http.DefaultTransport.RoundTrip(req)

However, this solution may encounter performance issues and errors under high-load scenarios.

Solution 2: Setting CheckRedirect to False

Alternatively, you can modify the CheckRedirect field of the http.Client to disable automatic redirects:

client := &http.Client{
    CheckRedirect: func(req *http.Request, via []*http.Request) error {
        return http.ErrUseLastResponse
    },
}
// ...
resp, err := client.Get("http://example.com/redirectToAppStore")

This method ensures consistent performance, but it does not guarantee the closure of connections after each query.

Ensuring Connection Closure

To enforce connection closure, you can create a new HTTP client for each request:

for i := 0; i < n; i++ {
    client := &http.Client{
        CheckRedirect: func(req *http.Request, via []*http.Request) error {
            return http.ErrUseLastResponse
        },
    }
    resp, err := client.Get("http://example.com/redirectToAppStore")
    // ...
}

This approach ensures that each query uses a fresh connection, preventing performance issues due to connection reuse.

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