Resolve a URL reference against this base URL

Synopsis

Declared in header <boost/url/url_base.hpp>

system::result<void>
resolve(url_view_base const& ref);

Description

This function attempts to resolve a URL reference ref against this base URL in a manner similar to that of a web browser resolving an anchor tag.

This URL must satisfy the URI grammar. In other words, it must contain a scheme.

Relative references are only usable when in the context of a base absolute URI. This process of resolving a relative reference within the context of a base URI is defined in detail in rfc3986 (see below).

The resolution process works as if the relative reference is appended to the base URI and the result is normalized.

Given the input base URL, this function resolves the relative reference as if performing the following steps:

  • Ensure the base URI has at least a scheme

  • Normalizing the reference path

  • Merge base and reference paths

  • Normalize the merged path

This function places the result of the resolution into this URL in place.

If an error occurs, the contents of this URL are unspecified and a result with an system::error_code is returned.

Note
 Abnormal hrefs where the number of ".." segments exceeds the number of segments in the base path are handled by including the unmatched ".." segments in the result, as described in Errata 4547 .

Example

url base1( "/one/two/three" );
base1.resolve("four");
assert( base1.buffer() == "/one/two/four" );

url base2( "http://example.com/" )
base2.resolve("/one");
assert( base2.buffer() == "http://example.com/one" );

url base3( "http://example.com/one" );
base3.resolve("/two");
assert( base3.buffer() == "http://example.com/two" );

url base4( "http://a/b/c/d;p?q" );
base4.resolve("g#s");
assert( base4.buffer() == "http://a/b/c/g#s" );

BNF

absolute-URI  = scheme ":" hier-part [ "?" query ]

Exception Safety

Basic guarantee. Calls to allocate may throw.

Specification

5. Reference Resolution (rfc3986)

Return Value

An empty result upon success, otherwise an error code if !base.has_scheme().

Parameters

Name Description

ref

The URL reference to resolve.

See Also

url , url_view .