1+ // Copyright (c) .NET Foundation. All rights reserved.
2+ // Licensed under the MIT License. See License.txt in the project root for license information.
3+
4+ using System ;
5+ using System . Collections . Generic ;
6+ using System . Diagnostics ;
7+ using System . Net ;
8+ using System . Net . Http ;
9+ using System . Security . Cryptography ;
10+ using System . Web . Http ;
11+ using System . Web . Http . ExceptionHandling ;
12+ using System . Web . Http . Results ;
13+ using Microsoft . Azure . WebJobs . Host ;
14+ using Microsoft . Azure . WebJobs . Host . Diagnostics ;
15+ using Microsoft . Azure . WebJobs . Script . WebHost . Models ;
16+ using Newtonsoft . Json ;
17+ using ExceptionProcessor = System . Action < System . Web . Http . ExceptionHandling . ExceptionContext ,
18+ Microsoft . Azure . WebJobs . Script . AuthorizationLevel , Microsoft . Azure . WebJobs . Script . WebHost . Models . ApiErrorModel > ;
19+
20+ namespace Microsoft . Azure . WebJobs . Script . WebHost . Controllers
21+ {
22+ public class ExceptionProcessingHandler : ExceptionHandler
23+ {
24+ private readonly IDictionary < Type , ExceptionProcessor > _handlers ;
25+ private readonly HttpConfiguration _config ;
26+ private readonly Lazy < TraceWriter > _traceWriterLoader ;
27+
28+ public ExceptionProcessingHandler ( HttpConfiguration config )
29+ {
30+ if ( config == null )
31+ {
32+ throw new ArgumentNullException ( "config" ) ;
33+ }
34+
35+ _config = config ;
36+ _traceWriterLoader = new Lazy < TraceWriter > ( ( ) => _config . DependencyResolver . GetService < TraceWriter > ( ) ) ;
37+ _handlers = InitializeExceptionHandlers ( ) ;
38+ }
39+
40+ private static IDictionary < Type , ExceptionProcessor > InitializeExceptionHandlers ( )
41+ {
42+ var handlers = new Dictionary < Type , ExceptionProcessor >
43+ {
44+ { typeof ( CryptographicException ) , CryptographicExceptionHandler }
45+ } ;
46+
47+ return handlers ;
48+ }
49+
50+ public override void Handle ( ExceptionHandlerContext context )
51+ {
52+ var error = new ApiErrorModel ( HttpStatusCode . InternalServerError ) ;
53+
54+ AuthorizationLevel currentLevel = context . Request . GetAuthorizationLevel ( ) ;
55+ foreach ( var handler in GetExceptionHandlers ( context . Exception ) )
56+ {
57+ handler ( context . ExceptionContext , currentLevel , error ) ;
58+ }
59+
60+ TraceErrorEvent ( context . ExceptionContext , error ) ;
61+
62+ context . Result = new ResponseMessageResult ( context . Request . CreateResponse ( error . StatusCode , error ) ) ;
63+ }
64+
65+ private IEnumerable < ExceptionProcessor > GetExceptionHandlers ( Exception exc )
66+ {
67+ if ( exc == null )
68+ {
69+ yield break ;
70+ }
71+
72+ // We return our default handler first.
73+ // Subsequent handlers can override everything done by it.
74+ yield return DefaultExceptionHandler ;
75+
76+ Type exceptionType = exc . GetType ( ) ;
77+ ExceptionProcessor exceptionHandler = null ;
78+ if ( exceptionType != null && _handlers . TryGetValue ( exceptionType , out exceptionHandler ) )
79+ {
80+ yield return exceptionHandler ;
81+ }
82+ }
83+
84+ private static void DefaultExceptionHandler ( ExceptionContext exceptionContext , AuthorizationLevel currentLevel , ApiErrorModel error )
85+ {
86+ if ( currentLevel == AuthorizationLevel . Admin || exceptionContext . RequestContext . IsLocal )
87+ {
88+ error . Message = GetExceptionMessage ( exceptionContext . Exception ) ;
89+
90+ if ( exceptionContext . RequestContext . IncludeErrorDetail )
91+ {
92+ error . ErrorDetails = ExceptionFormatter . GetFormattedException ( exceptionContext . Exception ) ;
93+ }
94+ }
95+ else
96+ {
97+ error . Message = $ "An error has occurred. For more information, please check the logs for error ID { error . Id } ";
98+ }
99+ }
100+
101+ private void TraceErrorEvent ( ExceptionContext exceptionContext , ApiErrorModel error )
102+ {
103+ string controllerName = exceptionContext . ControllerContext ? . ControllerDescriptor . ControllerName ?? "<unknown>" ;
104+ string actionName = exceptionContext . ActionContext ? . ActionDescriptor . ActionName ?? "<unknown>" ;
105+
106+ string message = JsonConvert . SerializeObject ( error ) ;
107+ var traceEvent = new TraceEvent ( TraceLevel . Error , message , $ "ApiError.{ controllerName } .{ actionName } ", exceptionContext . Exception ) ;
108+ _traceWriterLoader . Value . Trace ( traceEvent ) ;
109+ }
110+
111+ private static void CryptographicExceptionHandler ( ExceptionContext exceptionContext , AuthorizationLevel currentLevel , ApiErrorModel error )
112+ {
113+ if ( currentLevel == AuthorizationLevel . Admin )
114+ {
115+ error . ErrorCode = ErrorCodes . KeyCryptographicError ;
116+ error . Message = "Cryptographic error. Unable to encrypt or decrypt keys." ;
117+ }
118+ }
119+
120+ private static string GetExceptionMessage ( Exception exception )
121+ {
122+ if ( exception == null )
123+ {
124+ return string . Empty ;
125+ }
126+
127+ var aggregateException = exception as AggregateException ;
128+ if ( aggregateException != null )
129+ {
130+ exception = aggregateException . Flatten ( ) . InnerException ;
131+ }
132+
133+ var messages = new List < string > ( ) ;
134+ while ( exception != null )
135+ {
136+ messages . Add ( exception . Message ) ;
137+ exception = exception . InnerException ;
138+ }
139+
140+ return string . Join ( " -> " , messages ) ;
141+ }
142+ }
143+ }
0 commit comments