request.getRequestURL() 獲取服務器地址， nginx反向代理 host配置，與spring boot中內嵌的tomcat的配合使用

tomcat使用了nginx反向代理，獲取的服務器路徑變成了nginx中配置的內網地址，若是在同一臺服務器上，就變成了127.0.0.1或是localhost，而咱們須要的是外網地址，這時候咱們須要啓用轉發的請求頭配置

 

如何啓用？下面經過查看源碼找一下如何解決

不少人都會強調看源碼，若是在沒有目的的狀況下直接看源碼比較枯燥，很難堅持（大神略過），不會有太大的收穫。若是咱們遇到問題，不少時候都是網上一百度，配置項或是代碼複製粘貼，而後測試一下沒有問題就過了，可是若是網上的信息不多，或者幾乎找不到解決辦法，這時候，咱們查看一下源碼，找到對應實現，有時候直接就能發現問題在哪，我認爲這種時候就是讀源碼的最好時機，利用好eclipse或是intellij IDEA的搜索功能，通常均可以找到對應的源碼

 

先來看一下spring boot tomcat源碼  TomcatWebServerFactoryCustomizer類

private void  customizeRemoteIpValve(ConfigurableTomcatWebServerFactory  factory) {
          Tomcat tomcatProperties =  this.serverProperties.getTomcat();
          String protocolHeader =  tomcatProperties.getProtocolHeader();
          String remoteIpHeader =  tomcatProperties.getRemoteIpHeader();
          // For back compatibility the valve is also  enabled if protocol-header is set
          if (StringUtils.hasText(protocolHeader) ||  StringUtils.hasText(remoteIpHeader)
                   || getOrDeduceUseForwardHeaders()) {
              RemoteIpValve valve = new RemoteIpValve();
              valve.setProtocolHeader(StringUtils.hasLength(protocolHeader) ? protocolHeader
                        : "X-Forwarded-Proto");
              if (StringUtils.hasLength(remoteIpHeader))  {
                   valve.setRemoteIpHeader(remoteIpHeader);
              }
              // The internal proxies default to a white  list of "safe" internal IP
              // addresses
              valve.setInternalProxies(tomcatProperties.getInternalProxies());
              valve.setPortHeader(tomcatProperties.getPortHeader());
              valve.setProtocolHeaderHttpsValue(
                        tomcatProperties.getProtocolHeaderHttpsValue());
              // ... so it's safe to add this valve by  default.
              factory.addEngineValves(valve);
          }
     }

 

 

能夠看出，只要protocolHeader和remoteIpHeader任意一項有值就啓用了RemoteIpValve

 

spring boot 對應配置項在Tomcat類裏面：

server.use-forward-headers=true
server.tomcat.remote-ip-header=x-forwarded-for
server.tomcat.protocol-header=X-Forwarded-Proto

 

 

獲取服務器地址的實如今RemoteIpValve類的invoke方法裏面

 

實如今大體過程是若是啓用RemoteIpValve，會去獲取指定的請求頭，更新RemoteAddr和Scheme的值，以及https轉的http服務，secure表示是不是https服務

 

那麼就須要在nginx中配置好咱們服務的請求地址，也就是host請求頭

 

對應nginx配置項：   

proxy_set_header   Host             $host:$server_port;
            
proxy_set_header   X-Real-IP        $remote_addr;
proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
proxy_set_header   X-Forwarded-Port  $server_port;
proxy_set_header   X-Forwarded-Proto  $scheme;

 

這樣咱們在後端服務中直接使用request.getRequestURL()方法就能夠獲取到咱們在nginx中指定的服務器地址了，若是沒有使用nginx，就不存在該問題，因此後端服務不須要考慮服務是否使用了反向代理

 

  public void invoke(Request request, Response response)  throws IOException, ServletException {
        final String originalRemoteAddr =  request.getRemoteAddr();
        final String originalRemoteHost =  request.getRemoteHost();
        final String originalScheme = request.getScheme();
        final boolean originalSecure = request.isSecure();
        final int originalServerPort =  request.getServerPort();
        final String originalProxiesHeader =  request.getHeader(proxiesHeader);
        final String originalRemoteIpHeader =  request.getHeader(remoteIpHeader);
        boolean isInternal = internalProxies != null &&
                 internalProxies.matcher(originalRemoteAddr).matches();
        if (isInternal || (trustedProxies != null &&
                 trustedProxies.matcher(originalRemoteAddr).matches())) {
            String remoteIp = null;
            // In java 6, proxiesHeaderValue should be  declared as a java.util.Deque
            LinkedList<String> proxiesHeaderValue = new  LinkedList<>();
            StringBuilder concatRemoteIpHeaderValue = new  StringBuilder();
            for (Enumeration<String> e =  request.getHeaders(remoteIpHeader); e.hasMoreElements();)  {
                if (concatRemoteIpHeaderValue.length() > 0)  {
                    concatRemoteIpHeaderValue.append(", ");
                }
                 concatRemoteIpHeaderValue.append(e.nextElement());
            }
            String[] remoteIpHeaderValue =  commaDelimitedListToStringArray(concatRemoteIpHeaderValue.toString());
            int idx;
            if (!isInternal) {
                 proxiesHeaderValue.addFirst(originalRemoteAddr);
            }
            // loop on remoteIpHeaderValue to find the  first trusted remote ip and to build the proxies chain
            for (idx = remoteIpHeaderValue.length - 1; idx  >= 0; idx--) {
                String currentRemoteIp =  remoteIpHeaderValue[idx];
                remoteIp = currentRemoteIp;
                if (internalProxies !=null &&  internalProxies.matcher(currentRemoteIp).matches()) {
                    // do nothing, internalProxies IPs are  not appended to the
                } else if (trustedProxies != null &&
                         trustedProxies.matcher(currentRemoteIp).matches()) {
                     proxiesHeaderValue.addFirst(currentRemoteIp);
                } else {
                    idx--; // decrement idx because break  statement doesn't do it
                    break;
                }
            }
            // continue to loop on remoteIpHeaderValue to  build the new value of the remoteIpHeader
            LinkedList<String> newRemoteIpHeaderValue =  new LinkedList<>();
            for (; idx >= 0; idx--) {
                String currentRemoteIp =  remoteIpHeaderValue[idx];
                 newRemoteIpHeaderValue.addFirst(currentRemoteIp);
            }
            if (remoteIp != null) {
                request.setRemoteAddr(remoteIp);
                request.setRemoteHost(remoteIp);
                if (proxiesHeaderValue.size() == 0) {
                     request.getCoyoteRequest().getMimeHeaders().removeHeader(proxiesHeader);
                } else {
                    String commaDelimitedListOfProxies =  listToCommaDelimitedString(proxiesHeaderValue);
                     request.getCoyoteRequest().getMimeHeaders().setValue(proxiesHeader).setString(commaDelimitedListOfProxies);
                }
                if (newRemoteIpHeaderValue.size() == 0) {
                     request.getCoyoteRequest().getMimeHeaders().removeHeader(remoteIpHeader);
                } else {
                    String  commaDelimitedRemoteIpHeaderValue =  listToCommaDelimitedString(newRemoteIpHeaderValue);
                     request.getCoyoteRequest().getMimeHeaders().setValue(remoteIpHeader).setString(commaDelimitedRemoteIpHeaderValue);
                }
            }
            if (protocolHeader != null) {
                String protocolHeaderValue =  request.getHeader(protocolHeader);
                if (protocolHeaderValue == null) {
                    // Don't modify the secure, scheme and  serverPort attributes
                    // of the request
                } else if  (isForwardedProtoHeaderValueSecure(protocolHeaderValue))  {
                    request.setSecure(true);
                     request.getCoyoteRequest().scheme().setString("https");
                    setPorts(request, httpsServerPort);
                } else {
                    request.setSecure(false);
                     request.getCoyoteRequest().scheme().setString("http");
                    setPorts(request, httpServerPort);
                }
            }
            if (log.isDebugEnabled()) {
                log.debug("Incoming request " +  request.getRequestURI() + " with originalRemoteAddr '" +  originalRemoteAddr
                          + "', originalRemoteHost='" +  originalRemoteHost + "', originalSecure='" +  originalSecure + "', originalScheme='"
                          + originalScheme + "' will be seen  as newRemoteAddr='" + request.getRemoteAddr() + "',  newRemoteHost='"
                          + request.getRemoteHost() + "',  newScheme='" + request.getScheme() + "', newSecure='" +  request.isSecure() + "'");
            }
        } else {
            if (log.isDebugEnabled()) {
                log.debug("Skip RemoteIpValve for request "  + request.getRequestURI() + " with originalRemoteAddr '"
                        + request.getRemoteAddr() + "'");
            }
        }
        if (requestAttributesEnabled) {
             request.setAttribute(AccessLog.REMOTE_ADDR_ATTRIBUTE,
                    request.getRemoteAddr());
             request.setAttribute(Globals.REMOTE_ADDR_ATTRIBUTE,
                    request.getRemoteAddr());
             request.setAttribute(AccessLog.REMOTE_HOST_ATTRIBUTE,
                    request.getRemoteHost());
             request.setAttribute(AccessLog.PROTOCOL_ATTRIBUTE,
                    request.getProtocol());
             request.setAttribute(AccessLog.SERVER_PORT_ATTRIBUTE,
                     Integer.valueOf(request.getServerPort()));
        }
        try {
            getNext().invoke(request, response);
        } finally {
            request.setRemoteAddr(originalRemoteAddr);
            request.setRemoteHost(originalRemoteHost);
            request.setSecure(originalSecure);
             request.getCoyoteRequest().scheme().setString(originalScheme);
            request.setServerPort(originalServerPort);
            MimeHeaders headers =  request.getCoyoteRequest().getMimeHeaders();
            if (originalProxiesHeader == null ||  originalProxiesHeader.length() == 0) {
                headers.removeHeader(proxiesHeader);
            } else {
                 headers.setValue(proxiesHeader).setString(originalProxiesHeader);
            }
            if (originalRemoteIpHeader == null ||  originalRemoteIpHeader.length() == 0) {
                headers.removeHeader(remoteIpHeader);
            } else {
                 headers.setValue(remoteIpHeader).setString(originalRemoteIpHeader);
            }
        }
    }