Ytukyg

I'm weak in network technologies and maybe you can help me. I have a simple code

HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())

            .getRequest();

    UriComponents uriComponents = UriComponentsBuilder.fromHttpUrl(request.getRequestURL().toString()).build();

    UriComponents newUriComponents = UriComponentsBuilder.newInstance().scheme(uriComponents.getScheme())

            .host(uriComponents.getHost()).port(uriComponents.getPort()).build();



    return newUriComponents.toUriString() + request.getContextPath();

This code should return link to my server with specific path. The problem is - on product server uriComponents.getHost() returns IP instead of domain name. Domain works when I go via browser to server. I can go to
http://exmaple.com/some/one/path and want to get in answer (in JSON, there are no redirections. just get request and json answer) - http://exmaple.com/some/another/path but code which I have showed returns - http://78.54.128.98.com/some/another/path (IP address just example). So I don't know why my code returns IP but not domain name. Only what I can to say more - in my local machine I don't have any problems with it. Code returns localhost, or if i add 127.0.0.1 exmaple.com to hosts file, my code will return correct exmaple.com, no any ip

This is not a problem of the URIComponents, it parses what it gets in input. More specifically looking at the source of UriComponentsBuilder.fromHttpUrl you see:

public static UriComponentsBuilder fromHttpUrl(String httpUrl) {

    Assert.notNull(httpUrl, "HTTP URL must not be null");

    Matcher matcher = HTTP_URL_PATTERN.matcher(httpUrl);

    if (matcher.matches()) {

        UriComponentsBuilder builder = new UriComponentsBuilder();

        String scheme = matcher.group(1);

        builder.scheme(scheme != null ? scheme.toLowerCase() : null);

        builder.userInfo(matcher.group(4));

        String host = matcher.group(5);

        if (StringUtils.hasLength(scheme) && !StringUtils.hasLength(host)) {

            throw new IllegalArgumentException("[" + httpUrl + "] is not a valid HTTP URL");

        }

        builder.host(host);

        String port = matcher.group(7);

        if (StringUtils.hasLength(port)) {

            builder.port(port);

        }

        builder.path(matcher.group(8));

        builder.query(matcher.group(10));

        return builder;

    }

    else {

        throw new IllegalArgumentException("[" + httpUrl + "] is not a valid HTTP URL");

    }

}

where you can notice that a pattern matcher is defined on an expected structure of the url and parts are parsed according to the matcher. If you see IP it means that the url specified in input (request.getRequestURL().toString()) contained the IP address as a host.

This means that you should be looking for the guilty one above in the chain, starting by whoever calls this piece of code and following the links until you find the cause.