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Full Discussion: URL Validation Help in C
Top Forums Programming URL Validation Help in C Post 302642425 by Corona688 on Thursday 17th of May 2012 11:37:15 AM
Old 05-17-2012
Your complete and total lack of comments makes it difficult to even begin to figure out where your code is going wrong. You haven't posted what's in your dictionary file either, making it very difficult to guess your intent. breaking the string apart on "." won't get you the http:// at the beginning, either. I've corrected your indenting as best I can.

I think your code needs a rewrite. A lot of things which could've been done with loops or function calls you've done by simple brute force.

Your for-loop while reading the file probably doesn't do what you want. It will loop through every line, meaning, you only get the value you checked for the very last line -- every other value is overwritten by the one after.

Whenever you've decided a URL is invalid, you can just return(0) right then and there, instead of checking f_valid every time thereafter.

You do realize that strtok() modifies its input string, yes?

Also, it'd be better to check for allowable characters than disallowed ones:

Code:
int url_specialchars(const char *url)
{
        // The compiler will stack "multiple" "strings" "end" "to" "end"
        // into "multiplestringsendtoend", so we don't need one giant line.
        static const char *nospecial="0123456789"
                "abcdefghijklmnopqrstuvwxyz"
                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                ".";

        while(*url) // Loop until (*url) == 0.  (*url) is about equivalent to url[0].
        {
                // Can we find the character at *url in the string 'nospecial'?
                // If not, it's a special character and we should return 0.
                if(strchr(nospecial, *url) == NULL) return(0);
                url++; // Jump to the next character.  Adding one to a pointer moves it ahead one element.
        }

        return(1); // Return 1 for success.
}

 

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LEARN ABOUT SUSE

uri::url

URI::URL(3)						User Contributed Perl Documentation					       URI::URL(3)

NAME

       URI::URL - Uniform Resource Locators

SYNOPSIS

	$u1 = URI::URL->new($str, $base);
	$u2 = $u1->abs;

DESCRIPTION

       This module is provided for backwards compatibility with modules that depend on the interface provided by the "URI::URL" class that used to
       be distributed with the libwww-perl library.

       The following differences exist compared to the "URI" class interface:

       o  The URI::URL module exports the url() function as an alternate constructor interface.

       o  The constructor takes an optional $base argument.  The "URI::URL" class is a subclass of "URI::WithBase".

       o  The URI::URL->newlocal class method is the same as URI::file->new_abs.

       o  URI::URL::strict(1)

       o  $url->print_on method

       o  $url->crack method

       o  $url->full_path: same as ($uri->abs_path || "/")

       o  $url->netloc: same as $uri->authority

       o  $url->epath, $url->equery: same as $uri->path, $uri->query

       o  $url->path and $url->query pass unescaped strings.

       o  $url->path_components: same as $uri->path_segments (if you don't consider path segment parameters)

       o  $url->params and $url->eparams methods

       o  $url->base method.  See URI::WithBase.

       o  $url->abs and $url->rel have an optional $base argument.  See URI::WithBase.

       o  $url->frag: same as $uri->fragment

       o  $url->keywords: same as $uri->query_keywords

       o  $url->localpath and friends map to $uri->file.

       o  $url->address and $url->encoded822addr: same as $uri->to for mailto URI

       o  $url->groupart method for news URI

       o  $url->article: same as $uri->message

SEE ALSO

       URI, URI::WithBase

COPYRIGHT

       Copyright 1998-2000 Gisle Aas.

perl v5.12.1							    2008-04-04							       URI::URL(3)
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