VB.NET使用WebRequest检查URI是否有效 [英] VB.NET Use WebRequest to check if URI is valid

问题描述

寻找一种无需下载实际内容即可确定VB.NET中是否存在URI的最佳方法.可以在本地使用System.IO.FileExists/My.Computer.FileSystem.FileExists来确定文件是否存在，Web是否有等效文件?

Looking for the best way to determine if a URI exists in VB.NET without downloading the actual content. System.IO.FileExists/My.Computer.FileSystem.FileExists can be used locally to determine if a file exists, is there an equivalent for the Web?

当前，我正在使用HttpWebRequest来使用ResponseStream检查URI是否存在.如果目标确实存在，则将填充流，如果目标不存在，则将引发异常.该功能已被扩展为还可以检查PDF文件(通常为5MB以上)，图像等，将内容实际填充到流中会浪费时间/带宽.

Currently I am using a HttpWebRequest to check URI existance using the ResponseStream. This populates the stream if the target does exist and throws an exception if it doesn't. The function is being expanded to also check for PDF files (typically 5MB +), images, etc and it will be a waste of time/bandwidth to actually populate the content into a stream.

对于成功"(目标确实存在)的情况，我不希望下载文件或页面，只是希望以布尔值结尾，该布尔值指示在此URI的末尾是否存在某些内容.

In the case of "Success" (the target does exist) I do not wish to download the file or page, simply to end up with a Boolean which indicates the whether something exists at the end of this URI.

推荐答案

此处在VB.NET中.确保您的地址以 http://或 https://开头.

Here it is in VB.NET. Make sure that your addresses start with http:// or https://.

Public Function CheckAddress(ByVal URL As String) As Boolean
    Try
        Dim request As WebRequest = WebRequest.Create(URL)
        Dim response As WebResponse = request.GetResponse()
    Catch ex As Exception
        Return False
    End Try
    Return True
End Function

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