检查URL是视频URL还是照片URL

Question

我有一个文本视图，用户应该在其中输入一个url。首先，我正在检查URL的有效性。一旦有效性被确认，我需要检查它是一个视频网址或照片网址。我有两个数组的所有可能的视频(MP4，MOV等)和照片(JPG，PNG)文件格式，我得到一个适当的消息，如果url包含来自这两个数组的任何元素。

以下是instagram视频链接的示例。例如：https://www.instagram.com/p/B-PilcbFy2w/

下面的链接是一个有效的视频链接，但它不包含任何视频文件格式，如(MOV，MP4等)。如何验证这些链接？

我知道正则表达式的概念来验证这些东西，但是为此，我必须实现一堆IF语句，这不是一种有效的方法。示例视频链接只是一个例子。我需要验证所有类型的视频链接，无论它们来自社交媒体平台还是其他什么。帮助重新评级，这将是真正的赞赏。

这是我的代码样本。

@IBOutlet weak var textVW: UITextView!

@IBAction func validateButton(_ sender: UIButton) {


    let userInputURL = URL(string: textVW.text)

    if userInputURL != nil && userInputURL?.scheme != nil && userInputURL?.host != nil {
        //  - a scheme (like http://)
        //  - a host (like stackoverflow.com)

        print("Valid URL..")

        // Now checking url type, if its a video or image url..
        checkURLType(inputURL: userInputURL!)

    }

    else {
        print("Invalid URL..")
    }
}

func checkURLType(inputURL : URL) {

    // Most commom image types..
    let imageExtensions = ["png", "jpg", "gif", "tif"]

    // Most cmmon video types..
    let videoExtensions = ["WEBM", "MPG", "MPEG", "MPE", "MP4", "M4P", "M4V", "AVI", "WMV", "MOV"]

    let url: URL? = NSURL(fileURLWithPath: inputURL.path) as URL
    let pathExtention = url?.pathExtension

    if imageExtensions.contains(pathExtention!)
        {
            print("Image URL: \(String(describing: url))")

        }

    else if videoExtensions.contains(pathExtention!)
        {
             print("Video URL: \(String(describing: url))")
        }

        else
        {
             print("Does Not Exist: \(String(describing: url))")
        }


}

Answer 1

Instagram不包括您正在寻找的文件格式。相反，您可以使用一个简单的技巧来确认链接是表示视频还是照片。这是您提供的Instagram链接：https://www.instagram.com/p/B-PilcbFy2w/

当我们在Instagram帖子的链接末尾添加?__a=1时，我们会得到如下内容：

{"graphql":{"shortcode_media":{"__typename":"GraphImage",
"id":"2275681914071665931",
"shortcode":"B-U2KTOBc0L",
"dimensions":{"height":1080,
"width":1080},
"gating_info":null,
"fact_check_overall_rating":null,
"fact_check_information":null,
"sensitivity_friction_info":null,
"media_preview":"ACoq2XcL+PbvQ24KW6kDIHr7VDbKW/eN15C+w9fx/lUm/PIb/wAdNIb0GfaApxtYj1Cn/CnQzGXqrLgZ5GPwpd5/vf8AjpoLn+9/46aYiaimIc98/gR/On0ARxD92o6fKP5U3Jx/H+lMtX3QqRyQMEdORxT9vsf++v8A69A2Lk/7f5Cjn/b/ACH6UbT6H/vr/wCvRtPof++qBDkyeTu/4Fj+lPqNF29AR9Tnp0qSgDMg/djcw+R+cdSD/eq4EDjICFT0PNSOMg1nQsVn2g4BA4HT8qnbQrfUv7D3C/r/AIUeX/srn8f8KmoqiSJUA6gA9sVJS0UAf//Z",
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"accessibility_caption":"Photo by \ud83c\udde7\ud83c\udded Dallaspresso on March 29,
 2020. Image may contain: text",
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您可以很容易地搜索元素"is_video"，如果它是假的，那么文章是一张图片，否则它是一个视频。如果帮助的话，请标记回答。

Answer 2

简短的回答，正如您已经发现的，您不能以可靠的方式使用URL来确定返回的重新源。

长答案: URL中的“扩展名”根本没有任何意义。考虑一下，如果是对客户端的提示，但是web服务器可能会做它想做的事情。以https://www.acme.com为例:根本没有文件扩展名，取决于它的配置，web服务器决定返回什么资源。通常，这将是一个HTML文档，例如"index.html“或其他什么。更重要的是，https://www.acme.com/index.php有一个php扩展，但是web服务器通常会返回一个HTML，而不是php脚本。

获取信息的唯一方法是检查mimeType属性的URLResponse。

如果您只对头数据感兴趣(在不加载所有内容之前)，您应该检查以下答案：Get HTTP header fields only on iPhone