GoSteamAuth

A small set of utility functions to quickly process Steam OpenID 2.0 logins. Cousin to the Python library designed to do the same thing: pySteamSignIn

Similar to why the Python edition was wrote there's no straightforwards Steam authentication flow for Go, so this exists to fulfil the same purpose. Another language, same idea!

Installing

GoSteamAuth assumes that you're using module aware-mode so any importing errors found related to GO111MODULE=off should not be reported.

To install: go install github.com/TeddiO/GoSteamAuth/src

Authentication

Assuming you're using the typical net/http package, then the entire process is effectively a one-liner:

func ExamplePage(response http.ResponseWriter, request *http.Request) {
    gosteamauth.RedirectClient(response, request, gosteamauth.BuildQueryString("http://localhost:8080/process"))
    return
}

(Replace http://localhost:8080/process with whatever your landing point for the user would be)

This redirects the user to https://steamcommunity.com/openid/login with all the required parameters and takes them through the auth flow on Steam's end. If they successfully log in then they'll be returned to http://localhost:8080/process.

Verifying the request

When the user returns, they bring with them a response from Steam that tacks on a sizeable query string which is used by us to validate what the client is bringing with them is valid.

// Some function signature that conforms to response / request args
queryString, _ := url.ParseQuery(request.URL.RawQuery)
queryMap := gosteamauth.ValuesToMap(queryString)

steamID64, isValid, err := gosteamauth.ValidateResponse(queryMap)
if err != nil {
    fmt.Fprintf(response, "Failed to log in\nError: %s", err)
    return
}
    
if isValid {
    fmt.Fprintf(response, "Successfully logged in!\nSteamID: %s", steamID64)
} else {
    io.WriteString(response, "Failed to log in.")
}

And that's it! A full example is available here