Why is all my check50 server2 red?

Question

Below are my parse() and lookup() functions for server.c pset6. I have gone over and over but maybe I didn't understand what lookup does. Any help is highly welcome and appreciated. My check50 for server2 is all red while that for server1 is red only at the request for non existant file. Hope I am clear enough for good help. Thank you.

const char* lookup(const char* path) { // TODO if(path == NULL) { error(404); }

else
{
    {
        for( int i = 0, n  = strlen(path); i <= n; i++)
        {
            char * ext = 0;
            char c = '.';

            ext = strchr (path, c);
            int k = atoi(ext);

            if(strcmp(".css",ext) == 0)
            k = 0;

            if(strcmp(".html",ext) == 0)
            k = 1;

            if(strcmp(".gif",ext) == 0)
            k = 2;

            if(strcmp(".ico",ext) == 0)
            k = 3;

            if(strcmp(".jpg",ext) == 0)
            k = 4;

            if(strcmp(".jv",ext) == 0)
            k = 5;

            if(strcmp(".png",ext) == 0)
            k = 6;

            switch(k)
            {
            case 0: return "text/css";
            case 1: return "text/html";
            case 2: return "image/gif";
            case 3: return "image/x-icon";
            case 4: return "image/jpeg";
            case 5: return "text/javascript";
            case 6: return "image/png";
            default:  return NULL;
            }

        }
    }
}
return NULL;

}

and here is parse

bool parse(const char* line, char* abs_path, char* query) { // TODO

if(line[0] == 0)
{
    error(404);
}
// declaring delimiters for future call to strtok().
const char * space = " ";
const char * marker = "?";

// generates modifiable string from const char* line.
int l = strlen(line);
char string[l + 1];
for(int i = 0; i <= l; i++)
{
    string[i] = line[i];
    string[l] = '\0';
}

// creating tokens from string for method, target and version.
char * method = strtok(string, space);
char * target = strtok(NULL, space);
char * version = strtok(NULL, space);

// creating copy of target, storing it in duplicate.
int n = strlen(target);

char duplicate[n + 1];
for (int a = 0; a <= n; a++)
{
    duplicate[a] = target[a];
    duplicate[n] = '\0';

    if(duplicate[0] == 0)
{
    error(404);
}

}


// generating abs_path and query from target.

abs_path = strtok(duplicate, marker);
query = strtok(NULL, marker);

// ensure method is "GET"
        if(strcmp(method, "GET") != 0)
        {
            error(405);
        }
// ensures request-target starts with '/' and has no '"'.

        for(int j = 0; j <= n; j++)
        {
            if(target[0] != '/')
            {
            error(501);
            }

            if(target[j] == '"')
            {
                error(400);
            }
            if(!target)
            {
                error(400);
            }
        }

// ensures abs_path has a '.'
            if(strchr(abs_path, '.') == NULL)
            {
            error(501);
            }

// ensures version is "HTTP/1.1".
            if(strncmp(version, "HTTP/1.1", 8) != 0)
            {
                error(505);
            }


error(501);
return false;

}

Answer 1

Scope. Pointers. At least one problem with check50/server1 lies here
abs_path = strtok(duplicate, marker);. duplicate is local to the parse function. The strtok returns a pointer (to the local duplicate). Which will be "destroyed" when control returns to main. (query too!)

Consider using debug50 or gdb (the ADDENDUM) to troubleshoot. You may want to set a break in main when it returns from parse and inspect abs_path in main.

Remember this hint from the spec:

Odds are you’ll find functions like strchr, strcpy, strncpy, and/or strstr of help!

There's a bug in lookup. From the man page atoi() does not detect errors. This line int k = atoi(ext); is wrong. ext is going to be string data, that would be an error. So k could be anything. If it is 0 what will happen in the case statment? Use gdb or printfs to help you troubleshoot. And remember this from the spec:

(or any capitalization thereof),

check50/server2 will not pass if load and indexes are not completed (and correct!).