捕捉全部异常消息 [英] Catching FULL Exception Message
问题描述
Invoke-WebRequest $sumoApiURL -Headers @{"Content-Type"= "application/json"} -Credential $cred -WebSession $webRequestSession -Method post -Body $sumojson -ErrorAction Stop
这会抛出以下异常：
如何完全抓住它，或至少过滤掉具有相同名称的资源已经存在。 ？
How can I catch it entirely or at least filter out the "A resource with the same name already exist."?
使用 $ _。Exception.GetType（）。FullName yield
System.Net.WebException
System.Net.WebException
和 $ _ .Exception.Message 给出
远程服务器返回错误：（400）错误请求。
The remote server returned an error: (400) Bad Request.
推荐答案
PowerShell中的错误和异常是结构化对象。您在控制台上看到的错误消息实际上是一个带有来自错误/异常对象的多个元素的信息的格式化消息。你可以（重新）自己的构造：
Errors and exceptions in PowerShell are structured objects. The error message you see printed on the console is actually a formatted message with information from several elements of the error/exception object. You can (re-)construct it yourself like this:
$formatstring = "{0} : {1}`n{2}`n" +
" + CategoryInfo : {3}`n"
" + FullyQualifiedErrorId : {4}`n"
$fields = $_.InvocationInfo.MyCommand.Name,
$_.ErrorDetails.Message,
$_.InvocationInfo.PositionMessage,
$_.CategoryInfo.ToString(),
$_.FullyQualifiedErrorId
$formatstring -f $fields
如果您只想要在<$ c $中显示错误消息c> catch 阻止你可以简单地回显当前的对象变量（它在那时保存错误）：
If you just want the error message displayed in your catch block you can simply echo the current object variable (which holds the error at that point):
try {
...
} catch {
$_
}
如果您需要彩色输出，请使用如上所述的格式化字符串写入主机
If you need colored output use Write-Host with a formatted string as described above:
try {
...
} catch {
...
Write-Host -Foreground Red -Background Black ($formatstring -f $fields)
}
不想在异常处理程序中显示错误消息（否则 -ErrorAction Stop 将是无意义的）。结构化错误/异常对象为您提供可用于更好的错误控制的其他信息。例如，您有 $ _。Exception.HResult 与实际的错误号。 $ _。ScriptStackTrace 和 $ _。Exception.StackTrace ，因此您可以在调试时显示堆栈跟踪。 $ _。Exception.InnerException 允许您访问通常包含有关错误的附加信息的嵌套异常（顶级PowerShell错误可能有些通用）。您可以使用以下方式展开这些嵌套的异常：
With that said, usually you don't want to just display the error message as-is in an exception handler (otherwise the -ErrorAction Stop would be pointless). The structured error/exception objects provide you with additional information that you can use for better error control. For instance you have $_.Exception.HResult with the actual error number. $_.ScriptStackTrace and $_.Exception.StackTrace, so you can display stacktraces when debugging. $_.Exception.InnerException gives you access to nested exceptions that often contain additional information about the error (top level PowerShell errors can be somewhat generic). You can unroll these nested exceptions with something like this:
$e = $_.Exception
$msg = $e.Message
while ($e.InnerException) {
$e = $e.InnerException
$msg += "`n" + $e.Message
}
$msg
在您的情况下，您要提取的信息似乎位于 $ _。ErrorDetails.Message 。如果您有一个对象或JSON字符串，那么我不太清楚，但您应该可以获取有关 $ _的成员的类型和值的信息。ErrorDetails 通过运行
In your case the information you want to extract seems to be in $_.ErrorDetails.Message. It's not quite clear to me if you have an object or a JSON string there, but you should be able to get information about the types and values of the members of $_.ErrorDetails by running
$_.ErrorDetails | Get-Member
$_.ErrorDetails | Format-List *
如果 $ _。ErrorDetails.Message 是一个对象，你应该可以得到这样的消息字符串：
If $_.ErrorDetails.Message is an object you should be able to obtain the message string like this:
$_.ErrorDetails.Message.message
否则您需要先将JSON字符串转换为对象：
otherwise you need to convert the JSON string to an object first:
$_.ErrorDetails.Message | ConvertFrom-Json | Select-Object -Expand message
根据您处理的是什么类型的错误，特定类型的异常可能会还包括有关手头问题的更多具体信息。在你的情况下，你有一个 WebException 除了错误消息（ $ _。Exception.Message ）包含服务器的实际响应：
Depending what kind of error you're handling, exceptions of particular types might also include more specific information about the problem at hand. In your case for instance you have a WebException which in addition to the error message ($_.Exception.Message) contains the actual response from the server:
PS C:\> $e.Exception | Get-Member
TypeName: System.Net.WebException
Name MemberType Definition
---- ---------- ----------
Equals Method bool Equals(System.Object obj), bool _Exception.E...
GetBaseException Method System.Exception GetBaseException(), System.Excep...
GetHashCode Method int GetHashCode(), int _Exception.GetHashCode()
GetObjectData Method void GetObjectData(System.Runtime.Serialization.S...
GetType Method type GetType(), type _Exception.GetType()
ToString Method string ToString(), string _Exception.ToString()
Data Property System.Collections.IDictionary Data {get;}
HelpLink Property string HelpLink {get;set;}
HResult Property int HResult {get;}
InnerException Property System.Exception InnerException {get;}
Message Property string Message {get;}
Response Property System.Net.WebResponse Response {get;}
Source Property string Source {get;set;}
StackTrace Property string StackTrace {get;}
Status Property System.Net.WebExceptionStatus Status {get;}
TargetSite Property System.Reflection.MethodBase TargetSite {get;}它为您提供信息像这样：
which provides you with information like this:
PS C:\> $e.Exception.Response
IsMutuallyAuthenticated : False
Cookies : {}
Headers : {Keep-Alive, Connection, Content-Length, Content-T...}
SupportsHeaders : True
ContentLength : 198
ContentEncoding :
ContentType : text/html; charset=iso-8859-1
CharacterSet : iso-8859-1
Server : Apache/2.4.10
LastModified : 17.07.2016 14:39:29
StatusCode : NotFound
StatusDescription : Not Found
ProtocolVersion : 1.1
ResponseUri : http://www.example.com/
Method : POST
IsFromCache : False由于并非所有异常都具有完全相同的属性集，您可能希望为特定异常使用特定的处理程序：
Since not all exceptions have the exact same set of properties you may want to use specific handlers for particular exceptions:
try {
...
} catch [System.ArgumentException] {
# handle argument exceptions
} catch [System.Net.WebException] {
# handle web exceptions
} catch {
# handle all other exceptions
}
如果您有操作需要完成，无论是否发生错误（清除任务，如关闭套接字或数据库连接），您可以pu在处理异常处理之后，他们在终止块中：
If you have operations that need to be done regardless of whether an error occured or not (cleanup tasks like closing a socket or a database connection) you can put them in a finally block after the exception handling:
try {
...
} catch {
...
} finally {
# cleanup operations go here
}
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