= nng_url_parse(3)
:doctype: manpage
:manmanual: nng
:mansource: nng
:manvolnum: 3
:copyright: Copyright 2018 Staysail Systems, Inc. <info@staysail.tech> \
            Copyright 2018 Capitar IT Group BV <info@capitar.com> \
            This software is supplied under the terms of the MIT License, a \
            copy of which should be located in the distribution where this \
            file was obtained (LICENSE.txt).  A copy of the license may also \
            be found online at https://opensource.org/licenses/MIT.

== NAME

nng_url_parse - create URL structure from a string

== SYNOPSIS

[source, c]
-----------
#include <nng/nng.h>

int nng_url_parse(nng_url **urlp, const char *str);
-----------


== DESCRIPTION

The `nng_url_parse()` function parses the string _str_ containing an
https://tools.ietf.org/html/rfc3986[RFC 3986] compliant URL, and creates
a structure containing the results.  A pointer to the resulting structure
is stored in _urlp_.

The `nng_url` structure has at least the following members:

`char *u_scheme`::   The scheme, such as `http`.  Always lower case.

`char *u_rawurl`::   An unparsed form of the raw URL, with only minimal
                     canonicalization performed.

`char *u_userinfo`:: The userinfo component if one was present,
                     `NULL` otherwise.

`char *u_host`:: The full host, including hostname, and colon and port
                 if present, otehrwise the empty string.

`char *u_hostname`:: The hostname if present, otherwise the empty string.
                     Always lower case.

`char *u_port`:: The port if present.  If not present, a default port
                 will be stored here.  If no default is available, then
                 the empty string.

`char *u_path`:: The path component if present, or the empty string
                 otherwise.

`char *u_query`:: The query component if present, NULL otherwise.

`char *u_fragment`:: The fragment if present, NULL otherwise.

=== URL Canonicalization

The `nng_url_parse()` function also canonicalizes the results, as
follows:

  1. The URL is parsed into the various components.
  2. The `u_scheme`, `u_hostname`, `u_host`, and `u_port` members are
     converted to lower case.
  3. Percent-encoded values for
     https://tools.ietf.org/html/rfc3986#section-2.3[unreserved characters]
     converted to their unencoded forms.
  4. Additionally URL percent-encoded values for characters in the path
     and with numeric values larger than 127 (i.e. not ASCII) are decoded.
  5. The resulting `u_path` is checked for invalid UTF-8 sequences, consisting
     of surrogate pairs, illegal byte sequences, or overlong encodings.
     If this check fails, then the entire URL is considered invalid, and
     the function returns `NNG_EINVAL`.
  6. Path segments consisting of `.` and `..` are resolved as per
     https://tools.ietf.org/html/rfc3986#section-6.2.2.3[RFC 3986 6.2.2.3].
  7. Further, empty path segments are removed, meaning that duplicate
     slash (`/`) separators are removed from the path.
  8. If a port was not specified, but the scheme defines a default
     port, then `u_port` will be filled in with the value of the default port.


== RETURN VALUES

This function returns 0 on success, and non-zero otherwise.


== ERRORS

`NNG_ENOMEM`:: Insufficient free memory exists to allocate a message.
`NNG_EINVAL`:: An invalid URL was supplied.


== SEE ALSO

<<nng_url_clone#,nng_url_clone(3)>>,
<<nng_url_free#,nng_url_free(3)>>,
<<nng_strerror#,nng_strerror(3)>>,
<<nng#,nng(7)>>


== COPYRIGHT

Copyright 2018 mailto:info@staysail.tech[Staysail Systems, Inc.] +
Copyright 2018 mailto:info@capitar.com[Capitar IT Group BV]

This document is supplied under the terms of the
https://opensource.org/licenses/MIT[MIT License].