2

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。确认有效性后，我需要检查它是视频网址还是照片网址。我有两个所有可能的视频（MP4、MOV 等）和照片（JPG、PNG）文件格式的数组，如果 url 包含这两个数组中的任何元素，我会收到一条适当的消息。

这是一个示例 instagram 视频链接。例如：https ://www.instagram.com/p/B-PilcbFy2w/

以下链接是有效的视频链接，但不包含任何视频文件格式，如（MOV、MP4 等）。如何验证此类链接？

我知道正则表达式的概念来验证这些事情，但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示例。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。帮助重新评分将不胜感激。

这是我的示例代码..

@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))")
        }


}
4

2 回答 2

1

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

长答案：URL 中的“扩展名”根本没有意义。将 if 视为对客户端的提示，但 Web 服务器可能会做它想做的事。举个https://www.acme.com例子：根本没有文件扩展名，并且根据它的配置，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”之类的。更重要的是，https://www.acme.com/index.php有一个php扩展，但 Web 服务器通常会返回一个HTML文档，而不是PHP脚本。

获取信息的唯一方法是检查mimeType.URLResponse

如果您只对标头数据感兴趣（在下载所有内容之前），您应该检查这个答案：Get HTTP header fields only on iPhone

于 2020-04-08T10:18:37.790 回答
0

Instagram 不包含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代表视频还是照片。这就是您提供的 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，我们将得到如下内容：

{"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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 2020. Image may contain: text",
"is_video":false,
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您可以轻松搜索元素“is_video”，如果为 false，则帖子为图片，否则为视频。如果有帮助，请标记已回答。

于 2020-04-09T03:47:51.147 回答