How to obtain numeric HTTP status codes in PowerSh

问题:

I know of a few good ways to build web clients in PowerShell: the .NET classes System.Net.WebClient and System.Net.HttpWebRequest, or the COM object Msxml2.XMLHTTP. From what I can tell, the only one which gives you access to the numeric status code (e.g. 200, 404), is the last, the COM object. The problem I have is that I don't like the way it works and I don't like relying on the COM object being there. I also know that from time to time Microsoft will decide to kill COM objects (ActiveX kill bits) due to security vulnerabilities and so on.

Is there another .NET method I'm missing? Is the status code in one of these other two objects and I just don't know how to get at it?

回答1:

Using both x0n and joshua ewer's answers to come full circle with a code example, I hope that's not too bad form:

$url = 'http://google.com'
$req = [system.Net.WebRequest]::Create($url)

try {
    $res = $req.GetResponse()
} 
catch [System.Net.WebException] {
    $res = $_.Exception.Response
}

$res.StatusCode
#OK

[int]$res.StatusCode
#200

回答2:

Use the [system.net.httpstatuscode] enumerated type.

ps> [enum]::getnames([system.net.httpstatuscode])
Continue
SwitchingProtocols
OK
Created
Accepted
NonAuthoritativeInformation
NoContent
ResetContent
...

To get the numeric code, cast to [int]:

ps> [int][system.net.httpstatuscode]::ok
200

Hope this helps,

-Oisin

回答3:

I realize the question's title is about powershell, but not really what the question is asking? Either way...

The WebClient is a very dumbed down wrapper for HttpWebRequest. WebClient is great if you just doing very simple consumption of services or posting a bit of Xml, but the tradeoff is that it's not as flexible as you might want it to be. You won't be able to get the information you are looking for from WebClient.

If you need the status code, get it from the HttpWebResponse. If you were doing something like this (just posting a string to a Url) w/ WebClient:

var bytes = 
    System.Text.Encoding.ASCII.GetBytes("my xml"); 

var response = 
    new WebClient().UploadData("http://webservice.com", "POST", bytes);

then you'd do this with HttpWebRequest to get status code. Same idea, just more options (and therefore more code).

//create a stream from whatever you want to post here
var bytes = 
  System.Text.Encoding.ASCII.GetBytes("my xml"); 
var request = 
  (HttpWebRequest)WebRequest.Create("http://webservice.com");

//set up your request options here (method, mime-type, length)

//write something to the request stream
var requestStream = request.GetRequestStream();
requestStream.Write(bytes, 0, bytes.Length);        
requestStream.Close();

var response = (HttpWebResponse)request.GetResponse();

//returns back the HttpStatusCode enumeration
var httpStatusCode = response.StatusCode;

回答4:

It looks very easy

$wc = New-Object NET.WebClient
$wc.DownloadString($url)
$wc.ResponseHeaders.Item("status")

You can find the other available Response Headers in the ResponseHeaders property (like content-type, content-length, x-powered-by and such), and retrieve any of them via the Item() method.

... but as rob mentions below, sadly, the status property is not available here