How to parse query strings in Iris

Question

Based on the Hi example for Iris I want to create an application that can parse a request like

wget -qO- "http://localhost:8080/hi?name=John" and respond with Hi John!.

Here's my handler code:

func hi(ctx *iris.Context) {
    name := ctx.ParamDecoded("name")
    ctx.Writef("Hi %s!", name)
}

This just answers Hi ! - how can I make it answer Hi John!

Answer 1

Important: There is controversy about whether to use Iris at all as the author apparently deleted the history multiple times, which makes it hard to use as a stable API. Please read Why you should not use Iris for your Go and form your own opinion

Just use ctx.FormValue(...) instead of ctx.ParamDecoded():

func hi(ctx *iris.Context) {
    name := ctx.FormValue("name")
    ctx.Writef("Hi %s!", name)
}

If there is no such form value (i.e. query parameter) present, this will just return an empty string.

If you want to test whether a form value is actually present, you can use ctx.FormValues() to obtain a map. This is a little bit more complex, however, because the map contains a list of string values for each key:

func hi(ctx *iris.Context) {
    form := ctx.FormValues()
    names, ok := form["name"]
    name := ""
    if !ok { // No name parameter
        name = "<unknown>"
    } else { // At least one name
        name = names[0]
    }
    ctx.Writef("Hi %s!", name)
}