uri.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct uri_param {
	char *key;
	char *value;
};

struct uri {
	char *proto;
	char *hostname;
	char *path;
	struct uri_param **get_params;
	size_t get_params_s;
};

struct uri *uri_new()
{
	struct uri *p = malloc(sizeof(struct uri));

	if (NULL == p)
		return NULL;

	p->proto = NULL;
	p->hostname = NULL;
	p->path = NULL;
	p->get_params = NULL;
	p->get_params_s = 0;
	return p;
}

int uri_free(struct uri *uri)
{
	if (uri->get_params != NULL) {
		int i;
		for(i = 0; i < uri->get_params_s; i++) {
			struct uri_param *p = uri->get_params[i];
			free(p->key);
			free(p->value);
			free(p);
		}
		free(uri->get_params);
	}

	free(uri);

	return 0;
}

int uri_add_get_param(struct uri *uri, const char *key, const char *value)
{
	if (NULL == uri)
		return -1;

	if (NULL == key)
		return -2;

	if (NULL == uri->get_params)
		uri->get_params = malloc(sizeof(struct uri_param*));
	else
		uri->get_params = realloc(uri->get_params, uri->get_params_s + 1);

	if (NULL == uri->get_params)
		return -3;

	struct uri_param *p = malloc(sizeof(struct uri_param));
	if (NULL == p)
		return -4;

	p->key = strdup(key);

	p->value = strdup(value);
	uri->get_params[uri->get_params_s++] = p;
	return 0;
}

char *uri_build(struct uri *uri)
{

#define ADD_TO_URI(s) \
	if (s != NULL) { \
		if (bufsize < (strlen(buf) + strlen(s))) { \
			bufsize = strlen(buf) + strlen(s) + 1 + 1; \
			buf = realloc(buf, bufsize); \
		} \
		strcat(buf, s); \
	}

	size_t bufsize = 64;
	char *buf = malloc(bufsize * sizeof(char));


	ADD_TO_URI(uri->proto);
	ADD_TO_URI("://");
	ADD_TO_URI(uri->hostname);
	ADD_TO_URI("/");
	ADD_TO_URI(uri->path);
	if (NULL != uri->get_params) {
		ADD_TO_URI("?");
		int i;
		for (i = 0; i < uri->get_params_s; i++) {
			struct uri_param *p = uri->get_params[i];
			ADD_TO_URI(p->key);
			ADD_TO_URI("=\"");
			ADD_TO_URI(p->value);
			ADD_TO_URI("\"");
			if (i < uri->get_params_s-1)
				ADD_TO_URI("&");
		}
	}

#undef ADD_TO_URI
	return buf;
}

int main() {
	struct uri *myuri = uri_new();
	myuri->proto = "http";
	myuri->hostname = "lukrop.is.best";
	myuri->path = "/this/is/some/path/";
	uri_add_get_param(myuri, "key1", "value1");
	uri_add_get_param(myuri, "key2", "value 2 with spaces");
	uri_add_get_param(myuri, "key3", "value 3 with !§$ special chars äöü");

	char *url = uri_build(myuri);
	printf("url: %s\n", url);
	free(url);
	uri_free(myuri);

	return 0;
}