Lesson 15 · Split path from query string

Split path from query string

A request target bundles the path and an optional query string behind a question mark. Today you separate the two, since routing cares about the path while handlers care about the query.

The goal

Split a request target at the first "?" into a path and a raw query string.

Start here - the target

TO DO

Scenario: Separating path and query

Giventhe target "/search?q=cats&n=2"

Whenit is split

Thenpath = "/search" and rawQuery = "q=cats&n=2"

Andthe target "/about" gives path = "/about" and rawQuery = ""

Background

The request target is really two things glued together: the path that names a resource and an optional query string carrying parameters. They are separated by the first ?. Routing decisions look only at the path, so pulling the query off keeps /search?q=cats from being treated as a different route than /search.

Split at the first ? and keep everything after it as the raw query — you will decode it into key/value pairs in a later lesson. A target with no ? has an empty query, and the path is the whole target. Store both on the Request so handlers can reach them.

Make it work

if i := strings.IndexByte(target, '?'); i >= 0 {
    path, rawQuery = target[:i], target[i+1:]
} else {
    path, rawQuery = target, ""
}

CheckpointDONE

The target splits into a path and a raw query string. Commit.