URL前缀的不同操作 [英] Different action by prefix of URL

问题描述

以下是我的情况：我正在我的ios应用程序本地调用文件（在Swift中运行）。

Here is my situation: i'm calling file locally on my ios application ( Running in Swift).

如果文件是jpg，则会发生一个动作，如果文件是mp4，则会发生另一个动作。

If the file is a jpg, one action happen, if the file is a mp4, another action happen.

对于这个我正在使用此代码：

For this i'musing this code:

    let urlString = "\(posts[selectedIndexPath].link)"

    let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]

    let fileName = urlString as NSString;
    let filePath="\(documentsPath)/\(fileName.lastPathComponent)";
    let fileURL = NSURL.init(fileURLWithPath: filePath)
    let request = NSURLRequest.init(url: fileURL as URL)


    /* END DOWNLOAD + READ LOCALY */

    if (fileURL.pathExtension?.hasPrefix("jpg"))! {
        Swift.print("THIS IS A JPG")


    }
    else if (fileURL.pathExtension == "mp4") {

        Swift.print("THIS IS A MP4")

    }

这非常有效。

我现在需要做的不是在本地调用eifle，而是通过URL调用它。

What i need to do now is instead of calling th eifle locally, to calling it form an URL.

我通过以下网址从网址读取我的文件：

I read my file from an url by:

videoVRView.load(from: URL(string: "\(posts[selectedIndexPath].link)")

哪项工作。

但是，由此，行动无效，我尝试以下方法：

But from that, the action is not working, i've try the following:

 if ((from: URL(string: "\(posts[selectedIndexPath].link)").hasPrefix("jpg"))! {
    Swift.print("THIS IS A JPG")


}
else if ((from: URL(string: "\(posts[selectedIndexPath].link)") == "mp4") {

    Swift.print("THIS IS A MP4")

}

没有任何成功!!

有人知道这是如何实现的吗？

Does anybody know how is this achievable ?

非常感谢=）

- 编辑 -

我想要做的是继续恢复：

What im trying to do is th efollowing to resume:

at th emoment我通过以下方式在本地调用图像：

at th emoment i call image locally via:

       imageVRView.load(UIImage(named: "\(documentsPath)/\(fileName.lastPathComponent)" ),
   of: GVRPanoramaImageType.stereoOverUnder)

我尝试使用：

imageVRView.load(UIImage(named: "\(posts[selectedIndexPath].link)" ),
   of: GVRPanoramaImageType.stereoOverUnder)

没有成功。 。 。 。我需要通过这种方法调用图像...任何想法？
非常感谢！

Without success . . . . I need to call the image via this method ... any idea ? Thanks a lot !

推荐答案

您可以使用httpMethod HEAD来检查您的网址请求url mime类型，无需先下载数据：

You can make a URL request for the url header using the httpMethod HEAD to check your url mime type without the need to download the data first:

let link = "https://www.dropbox.com/s/sk46eyglvijlrec/horse.jpg?dl=1"
let url = URL(string: link)!

var request = URLRequest(url: url)
request.httpMethod = "HEAD"
URLSession.shared.dataTask(with: request) { _ , response , _ in
    guard let response = response, (response as? HTTPURLResponse)?.statusCode == 200 else { return }
    DispatchQueue.main.async() {
        print("mimeType", response.mimeType ?? "nil")            // image/jpeg
        print("suggestedFilename:", response.suggestedFilename ?? "no suggestedFilename")   // horse.jpg
        print("expectedContentLength:", response.expectedContentLength ?? "nil")   // 352614
        print("textEncodingName:", response.textEncodingName ?? "nil")
        print("url:", response.url ?? "nil")                 // "https://dl.dropboxusercontent.com/content_link/RNrhGtvroTLU1Gww7eQo1N1ePRiix68zsqZJ1xWPjKm3pmOUNQwNVntbPuFG4jZ8/file?dl=1"
    }
}.resume()

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