陷阱对象要求:MSXML2.ServerXMLHTTP.6.0中的"[object]" [英] Trapping Object required: '[object]' with MSXML2.ServerXMLHTTP.6.0

问题描述

我正在使用Flickr API和MSXML2.ServerXMLHTTP.6.0来读取XML响应.

I am using the Flickr API and MSXML2.ServerXMLHTTP.6.0 to read the XML response.

例如:

返回:

<rsp stat="ok">
    <photos page="1" pages="847622" perpage="1" total="847622">
        <photo id="8658999887" owner="46248160@N04" secret="13e2615193" server="8123" farm="9" title="cheeses" ispublic="1" isfriend="0" isfamily="0"/>
    </photos>
</rsp>

我做了一些简单的ASP来设置变量值:

I do some simple ASP to set variable values:

vurl = https://www.flickr.com/services/rest/?method=flickr.photos.search&api_key=[mykey]&text=cheese&per_page=1&sort=relevance&min_upload_date=2010-05-25
Set http = Server.CreateObject("MSXML2.ServerXMLHTTP.6.0")
http.Open "GET", vurl, False
http.Send

Set dom = http.responseXML

Set items = dom.getElementsByTagName("photos")

If NOT (items IS Nothing) Then

    For Each item In items

        Set tags = item.getElementsByTagName("photo")
        If NOT (tags IS Nothing) Then 
            var_id = tags(0).getAttribute("id")
            var_owner = tags(0).getAttribute("owner")
            var_server = tags(0).getAttribute("server")
            var_farm = tags(0).getAttribute("farm")
            var_title = tags(0).getAttribute("title")
            var_public = tags(0).getAttribute("public")
            var_secret = tags(0).getAttribute("secret")
            var_img_url2 = "https://farm"&var_farm&".staticflickr.com/"&var_server&"/"&var_id&"_"&var_secret&"_b.jpg"
            var_id = ""
            %>
            <%
        End If

    Next

end if

我的问题是，如果API没有针对搜索字词返回任何图片，例如"aplogranite"的XML响应是:

My problem is that if there is no image returned by the API for a search term - e.g. "aplogranite" the XML response is:

<rsp stat="ok">
    <photos page="1" pages="0" perpage="1" total="0"/>
</rsp>

我上面的代码返回此错误:

My code above returns this error:

Microsoft VBScript runtime error '800a01a8'

Object required: '[object]' 

我尝试通过以下方式捕获它:

I tried trapping it via:

Set items = dom.getElementsByTagName("photos")

If NOT (items IS Nothing) Then...

但是它仍然是错误的.

我想知道如何捕获该错误，以便处理XML在照片"标签内不包含任何数据的情况?

I wondered how I could trap the error so that I can handle the scenario where the XML does not contain any data within the "photo" tag?

推荐答案

在没有元素匹配的情况下， getElementsByTagName()似乎返回了空集合，而不是 Nothing .标签名称参数.因此，请尝试检查返回值的 Length :

Seems that instead of Nothing, getElementsByTagName() returns empty collection in the case when no element match tag name parameter. So try to check Length of the return value instead :

If tags.Length > 0 Then
    ....
End If

或者测试第一个元素是否为 Nothing :

Or maybe test the first element for Nothing :

If Not (tags(0) Is Nothing) Then
    ....
End If

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