swift - URLComponents queryItems 在突变时丢失百分比编码

Question

当使用 URLComponents 的 queryItems 时，我发现如果您有一个查询项，其值包含一些百分比编码字符，在我的例子中是 / 被编码为 %2F，那么如果您从包含此类查询项的 String URL 构造一个 URLComponents 对象，则改变 URLComponents 对象的查询项列表，然后如果您尝试通过调用 URLComponents 上的 .url 来获取 URL 对象，则查询项将丢失其百分比编码。

这是我在 Playground 上测试过的代码:

import UIKit

// --- Part 1 ---
print("--- Part 1 ---\n")

let startURL = "https://test.com/test.jpg?X-Test-Token=FQdzEPH%2F%2F%2F"
var components = URLComponents(string: startURL)!

if let compURL = components.url {
    print(URL(string: startURL)! == compURL) // True
    print(startURL)
    print(compURL)
}

// --- Part 2 ---
print("\n--- Part 2 ---\n")

let startURLTwo = "https://test.com/test.jpg?X-Test-Token=FQdzEPH%2F%2F%2F"
let finalURL = "https://test.com/test.jpg?X-Test-Token=FQdzEPH%2F%2F%2F&foo=bar"
var componentsTwo = URLComponents(string: startURLTwo)!

let extraQueryItem = URLQueryItem(name: "foo", value: "bar")
componentsTwo.queryItems!.append(extraQueryItem)

if let compURLTwo = componentsTwo.url {
    print(URL(string: finalURL)! == compURLTwo) // False
    print(finalURL)
    print(compURLTwo)
}

如果可以更容易地理解正在发生的事情，这里有一张图片:

Answer 1

如果你有一个已经被百分比编码的查询，你应该使用 percentEncodedQuery:

let startURL = "https://test.com/test.jpg"
var components = URLComponents(string: startURL)!
components.percentEncodedQuery = "X-Test-Token=FQdzEPH%2F%2F%2F"

if let compURL = components.url {
    print(compURL)
}

---

或者您可以将其指定为未转义(并且它保持未转义，因为不必在查询中转义 / 字符):

let startURL = "https://test.com/test.jpg"
var components = URLComponents(string: startURL)!
components.queryItems = [URLQueryItem(name: "X-Test-Token", value: "FQdzEPH///")]

if let compURL = components.url {
    print(compURL)
}

---

如果您必须更新 queryItems，只需确保在最后设置 percentEncodedQuery:

let startURL = "https://test.com/test.jpg"
let encodedQuery = "X-Test-Token=FQdzEPH%2F%2F%2F"
var components = URLComponents(string: startURL)!
components.queryItems = [URLQueryItem(name: "foo", value: "bar, baz, & qux")]
if let query = components.percentEncodedQuery {
    components.percentEncodedQuery = query + "&" + encodedQuery
} else {
    components.percentEncodedQuery = encodedQuery
}

if let compURL = components.url {
    print(compURL)
}