Elegant parsing of query string in C

Question

I'm trying to parse a URL query string in C and I don't see how to do it elegantly. Any hints or suggestions would be greatly appreciated:

static void readParams(char * string, char * param, char * value) {
    char arg[100] = {0};  // Not elegant, brittle
    char value2[1024] = {0};

    sscanf(string, "%[^=]=%s", arg, value2);
    strcpy(param, arg);
    strcpy(value, value2);
}
char * contents = "username=ted&age=25";
char * splitted = strtok (contents,"&");
char * username;
char * age;

while (splitted != NULL)
{
    char param[100]; // Not elegant, brittle
    char value[100];
    char * t_str = strdup(splitted);
    readParams(t_str, param, value);
    if (strcmp(param, "username") == 0) {
        username = strdup(value);
    }
    if (strcmp(param, "age") == 0) {
        age = strdup(value); // This is a string, can do atoi
    }
   splitted = strtok (NULL, "&");
 }

The problem I kept on having is that because of the strtok function anything that was seemed more intelligent to do before the last strtok function seemed to break the while loop.

Answer 1

You either need to tailor complex and effective parser or settle with libraries that will do it for you.

uriparser should provide all you need (plus it supports unicode).