Solved

User entered URL validation

Posted on 2003-12-11
13
430 Views
Last Modified: 2013-11-20
Could anyone help me out with some validation code to remove all invalid characters from a string? I was hoping to find a way of using CString.Remove by specifying a range of ASCII numbers to remove. For instance, remove all ASCII chars with code less than 48. Obviously I could go through and say

strURL.Remove(‘ ‘);
strURL.Remove(‘£‘);
strURL.Remove(‘$‘);

and so on but that’s not very efficient and a lot more work! Any help much appreciated!

Cheers,
Will
0
Comment
Question by:wjdashwood
  • 6
  • 5
  • 2
13 Comments
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
Comment Utility
Why don't you use 'InternetCanonicalizeUrl()' and check the result for 'ERROR_INTERNET_INVALID_URL'?
0
 

Author Comment

by:wjdashwood
Comment Utility
Never even heard of that before. Excellent! I'll investigate further.

Cheers,
Will
0
 
LVL 23

Expert Comment

by:Roshan Davis
Comment Utility
Thatz a nice one!

You can try this also..

IsValidURL()


Syntax
=====

HRESULT IsValidURL(
    LPBC pBC,
    LPCWSTR szURL,
    DWORD dwReserved
);


Parameters
========

pBC
        It should be set to NULL.
szURL
        Address of a string value that contains the full URL to be checked.

dwReserved
        Reserved. Must be set to zero.


Return Value
=========

Returns one of the following values:

S_OK The szURL parameter contains a valid URL.
S_FALSE The szURL parameter does not contain a valid URL.
E_INVALIDARG One of the parameters is invalid.

Function Information
===============

Header Urlmon.h
Import library Urlmon.lib
Minimum availability Internet Explorer 3.0
Minimum operating systems Windows NT 4.0, Windows 95


Rosh :)
0
 
LVL 23

Expert Comment

by:Roshan Davis
Comment Utility
Ooops, the above function is only for validating the URL
0
 

Author Comment

by:wjdashwood
Comment Utility
I'm trying to get InternetCanonicalizeUrl() to work but GetLastError simply returns ERROR_INVALID_PARAMETER. Can someone help me with the useage?

Thanks,
Will
0
 
LVL 86

Expert Comment

by:jkr
Comment Utility
>>ERROR_INVALID_PARAMETER. Can someone help me with the useage?

How *are* you using it?
0
How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

 

Author Comment

by:wjdashwood
Comment Utility
LPDWORD lpdwBufferLength = NULL;
LPTSTR lpszBuffer = NULL;
LPCTSTR lpszUrl = _T("http://www.experts-exchange.com/");

InternetCanonicalizeUrl(lpszUrl,lpszBuffer,lpdwBufferLength,NULL));

DWORD dwLastError = GetLastError();
if (dwLastError == ERROR_INVALID_PARAMETER)
      AfxMessageBox("ERROR_INVALID_PARAMETER");
if (dwLastError == ERROR_INTERNET_INVALID_URL)
      AfxMessageBox("ERROR_INTERNET_INVALID_URL");


I guess I'm not delcaring or passing lpszBuffer and lpdwBufferLength correctly.
0
 
LVL 86

Expert Comment

by:jkr
Comment Utility
>>LPDWORD lpdwBufferLength = NULL;
>>LPTSTR lpszBuffer = NULL;

That actually is the problem - the API expects a buffer to receive the output, not a NULL pointer. And, what's worese, the buffer size parameter is a null pointer also.

Make it read

LPCTSTR lpszUrl = _T("http://www.experts-exchange.com/");
DWORD dwBufferLength = 2 * _tcslen ( lpszUrl); // worst case
TCHAR szBuffer [ dwBufferLength];

InternetCanonicalizeUrl(lpszUrl,szBuffer,&dwBufferLength,NULL));


0
 

Author Comment

by:wjdashwood
Comment Utility
Many thanks. I'll give that a try.
0
 

Author Comment

by:wjdashwood
Comment Utility
I've got it working (I had to declare a size of the szBuffer) but the function doesn't seem to remove invalid characters. Is there a flag I need to set or something?
0
 
LVL 86

Expert Comment

by:jkr
Comment Utility
>>but the function doesn't seem to remove invalid characters

Hm, it should *test* for them (at least this was my intention) - removing chars is a bit dangerous, as in approx. 90% of all cases you won't end up with an existing URL
0
 

Author Comment

by:wjdashwood
Comment Utility
Well your algorithm in the other question does exactly what I want and probably much faster :)
0
 
LVL 86

Expert Comment

by:jkr
Comment Utility
Well, we have a proverb here about 'catching two flies with a single slap' :o)
0

Featured Post

Highfive + Dolby Voice = No More Audio Complaints!

Poor audio quality is one of the top reasons people don’t use video conferencing. Get the crispest, clearest audio powered by Dolby Voice in every meeting. Highfive and Dolby Voice deliver the best video conferencing and audio experience for every meeting and every room.

Join & Write a Comment

Suggested Solutions

Introduction: Database storage, where is the exe actually on the disc? Playing a game selected randomly (how to generate random numbers).  Error trapping with try..catch to help the code run even if something goes wrong. Continuing from the seve…
Introduction: The undo support, implementing a stack. Continuing from the eigth article about sudoku.   We need a mechanism to keep track of the digits entered so as to implement an undo mechanism.  This should be a ‘Last In First Out’ collec…
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.

772 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now