A SoupURI represents a (parsed) URI. SoupURI supports RFC 3986 (URI Generic Syntax), and can parse any valid URI. However, libsoup only uses "http" and "https" URIs internally; You can use SOUP_URI_VALID_FOR_HTTP() to test if a SoupURI is a valid HTTP URI. is always all lowercase. (If you parse a URI with a non-lowercase scheme, it will be converted to lowercase.) The macros SOUP_URI_SCHEME_HTTP and SOUP_URI_SCHEME_HTTPS provide the interned values for "http" and "https" and can be compared against URI scheme values. (ie, separated by a colon; RFC 3986 only talks about a single "userinfo" field). Note that password is not included in the output of soup_uri_to_string(). libsoup does not normally use these fields; authentication is handled via SoupSession signals. URI. If the URI doesn't contain a hostname, host will be NULL, and if it doesn't specify a port, port may be 0. However, for "http" and "https" URIs, host is guaranteed to be non-NULL (trying to parse an http URI with no host will return NULL), and to use when it is not specified in the URI). an empty string either; if the input URI has no path, the parsed SoupURI will have a path of "/". soup_form_decode_urlencoded() may be useful for parsing query. Note that path, query, and fragment may contain %-encoded characters. soup_uri_new() calls soup_uri_normalize() on them, but not soup_uri_decode(). This is necessary to ensure that soup_uri_to_string() will generate a URI that has exactly the same meaning as the original. (In theory, SoupURI should leave user, password, and host partially-encoded as well, but this would be more annoying than useful.)