urldecode_query_parameters.swift

var query = [String: String]()

if let queryString = url.query {
    for q in queryString.componentsSeparatedByString("&") {
        let pair = q.componentsSeparatedByString("=")

        let value = pair[1]
            .stringByReplacingOccurrencesOfString("+", withString: " ")
            .stringByReplacingPercentEscapesUsingEncoding(NSUTF8StringEncoding)
        
        query[pair[0]] = value
    }
}