Error Handling Code Asp
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Try Catch Asp
Join them; it only takes a minute: Sign up Is try-catch like error handling possible in ASP Classic? up vote 26 down vote favorite 9 What options are there in ASP Classic for error handling? For example: I'm using the Mail.SendMail function but when switching on the testing server it doesn't work, which is normal. I want to test classic asp on error resume next if mailing is possible, if not then continue and/or show a message. Any ideas? error-handling asp-classic share|improve this question edited Nov 19 '11 at 2:52 casperOne 58k10126202 asked Jan 23 '09 at 11:08 Sander Versluys 23k186785 add a comment| 8 Answers 8 active oldest votes up vote 37 down vote accepted There are two approaches, you can code in JScript or VBScript which do have the construct or you can fudge it in your code. Using JScript you'd use the following type of construct: In your ASP code you fudge it by using on error resume next at the point you'd have a try and checking err.Number at the point of a catch like: <% Dim i ' Turn on error Handling On Error Resume Next 'Code here that you want to catch errors from ' Error Handler If Err.Number <> 0 Then ' Error Occurred / Trap it On Error Goto 0 ' But don't let other errors hide! ' Code
Forums Links DISCUSSIONARCHIVES DISCUSSIONARCHIVES2 DISCUSSIONARCHIVES3 BLOG We didn't realize the site was so popular. Other Stuff How To Use On Error Resume Next Often asp on error goto when using ASP or Active Server Pages with VBScript you will find it necessary
Asp On Error Goto 0
to check for errors when you do certain things that may fail and then handle it accordingly. Things like opening a database
Asp Error Number
connection or writing to a text file come to mind. Generally if an error is encountered in your .asp file, the processing of your script stops and an error message is returned to the browser. http://stackoverflow.com/questions/472558/is-try-catch-like-error-handling-possible-in-asp-classic If you want to continue processing your page even if an error is encountered, include the following line at the beginning of your .asp file: <% On Error Resume Next %> That being said just ignoring errors in your code is not a very good idea. What you really want to do is handle the error in some way. The example below opens a database connection and shows you how to http://www.powerasp.net/content/new/on-error-resume-next.asp trap a potential error and do whatever you want because of it. In this case we are simply displaying the error. <% ConnectionString = "DBQ=c:\inetpub\wwwroot\mysite\data\mydatabase.mdb;Driver={Microsoft Access Driver (*.mdb)};" '*** This code checks the ConnectionString info you entered and reports back the error code if it is not ok Err.Clear On Error Resume Next Set ConnPasswords = Server.CreateObject("ADODB.Connection") ConnPasswords.Open ConnectionString If Err.Number <> 0 Then Response.Write (Err.Description& "
") Response.Write("This means there is most likely a problem with the" & vbCrLf) Response.Write("""ConnectionString"" info that you specified.
" & vbCrLf) Response.End End If On Error GoTo 0 %> We put the "On Error GoTo 0 at the end because that will essentially end the "on error resume next" That is something you want to do so any later errors in your application do not get ignored without you knowing about it. Below is another example. In this example our application logs user info in a text file when they sign in to a site. We add "On Error Resume Next" here simply so no nasty error message come up if by chance write permissions to the text file do not exist. <% Set ObjMyFile = CreateObject("Scripting.FileSystemObject") Err.Clear On Error Resume Next LogFileName = "aspprotect.log" LogFileDirectory = "c
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.NET 4 Error handling can be done in three ways in .NET 4.1 Classic ASP 5 Vulnerable Patterns for Error Handling 5.1 Page_Error 5.2 Global.asax 5.3 Web.config 6 Best Practices for Error Handling 6.1 Try & Catch (Java/ .NET) 6.2 Releasing resources and good housekeeping 6.3 Centralised exception handling (Struts Example) Error, Exception Handling & Logging An important aspect of secure application development is to prevent information leakage. Error messages give an attacker great insight into the inner workings of an application. The purpose of reviewing the Error Handling code is to assure the application fails safely under all possible error conditions, expected and unexpected. No sensitive information is presented to the user when an error occurs. For example SQL injection is much tougher to successfully pull off without some healthy error messages. It lessens the attack footprint and our attacker would have to resort to use “blind SQL injection” which is more difficult and time consuming. A well-planned error/exception handling strategy is important for three reasons: Good error handling does not give an attacker any information which is a means to an end, attacking the application A proper centralised error strategy is easier to maintain and reduces the chance of any uncaught errors “Bubbling up” to the front end of an application. Information leakage can lead to social engineering exploits. Some development languages provide checked exceptions which mean that the compiler shall complain if an exception for a particular API call is not caught Java and C# are good examples of this. Languages like C++ and C do not provide this safety net. Languages with checked exception handling still are prone to information leakage as not all types of error are checked for. When an exception or error is thrown we also need to log this occurrence. Sometimes this is due to bad development, but it can be the result of an attack or some other service your application relies on failing. All code paths that can cause an exception to be thrown should check for success in order for the exception not to be thrown. To avoid a NullPointerException we should check is the object being accessed is not null. Generic error messages We should use a