Shulou(Shulou.com)06/02 Report--

Today, I will talk to you about what is the filter header of zuul in Springcloud. Many people may not know much about it. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

The version of Springcloud is Greenwich.SR2,Springboot and the version is 2.1.6.release.

When using zuul, I have two requirements: one is not to let zuul filter the Cookie of the header, and the other is to set requestId-- to the header of request in the zuul gateway to facilitate link tracking.

After searching the Internet, I found that sensitiveHeaders and ignoredHeaders describe more, but most of them are not described in more detail, and I also want to know how to do it at the bottom, so I read the source code and record it. In the following List-1, set sensitiveHeaders and ignoredHeaders of zuul in application.yml. First of all, it is concluded that x1 of servletRequest header will not be transmitted downstream when sensitiveHeaders is set to x1, and x2 of servletRequest header will not be transmitted downstream when ignoredHeaders is set to x2.

List-1

Zuul: sensitiveHeaders: x1 ignoredHeaders: x2

As shown in the following List-2, the configuration in List-1 will be parsed by Spring to ZuulProperties,sensitiveHeaders. There are default values, that is, Cookie, Set-Cookie, Authorization.

List-2

@ ConfigurationProperties ("zuul") public class ZuulProperties {... Private Set ignoredHeaders = new LinkedHashSet ();... Private Set sensitiveHeaders = new LinkedHashSet (Arrays.asList ("Cookie", "Set-Cookie", "Authorization");

Let's take a look at the run method implementation of PreDecorationFilter. At List-3,1 and 2 below, the value of sensitiveHeaders in ZuulProperties is added to the field to be filtered. Let's take a look at the addIgnoredHeaders method of ProxyRequestHelper. As shown in the following List-4, RequestContext is a ConcurrentHashMap.

List-3

Public class PreDecorationFilter extends ZuulFilter {... @ Override public Object run () {RequestContext ctx = RequestContext.getCurrentContext (); final String requestURI = this.urlPathHelper .getPathWithinApplication (ctx.getRequest ()); Route route = this.routeLocator.getMatchingRoute (requestURI) If (route! = null) {String location = route.getLocation (); if (location! = null) {ctx.put (REQUEST_URI_KEY, route.getPath ()); ctx.put (PROXY_KEY, route.getId ()) If (! route.isCustomSensitiveHeaders ()) {this.proxyRequestHelper.addIgnoredHeaders (/ / 1 this.properties.getSensitiveHeaders () .toArray (new String [0])) } else {this.proxyRequestHelper.addIgnoredHeaders (/ / 2 route.getSensitiveHeaders () .toArray (new String [0])) }...}

List-4

Public void addIgnoredHeaders (String... Names) {RequestContext ctx = RequestContext.getCurrentContext (); if (! ctx.containsKey (IGNORED_HEADERS)) {ctx.set (IGNORED_HEADERS, new HashSet ());} @ SuppressWarnings ("unchecked") Set set = (Set) ctx.get (IGNORED_HEADERS); for (String name: this.ignoredHeaders) {set.add (name.toLowerCase ()) / / 1} for (String name: names) {set.add (name.toLowerCase ()) / / 2}}

In List-4, 1 this.ignoredHeaders () gets the ignoredHeaders in the ZuulProperties and then adds it to the HashSet.

Add all the parameter values on the method to the HashSet.

In this way, all the sensitiveHeaders and ignoredHeaders we set are added to the HashSet, and it is important to note that the toLowerCase () method is called at 1 and 2, so the field key in the downstream received header is lowercase.

Looking at the run method of RibbonRoutingFilter, the following List-5,run () calls buildCommandContext to construct the buildZuulRequestHeaders method that calls ProxyRequestHelper in the RibbonCommand,buildCommandContext method, as shown in List-6.

List-5

@ Overridepublic Object run () {RequestContext context = RequestContext.getCurrentContext (); this.helper.addIgnoredHeaders (); try {RibbonCommandContext commandContext = buildCommandContext (context); ClientHttpResponse response = forward (commandContext); setResponse (response); return response;...} protected RibbonCommandContext buildCommandContext (RequestContext context) {HttpServletRequest request = context.getRequest (); MultiValueMap headers = this.helper .buildZuulRequestHeaders (request);...}

List-6

Public MultiValueMap buildZuulRequestHeaders (HttpServletRequest request) {RequestContext context = RequestContext.getCurrentContext (); MultiValueMap headers = new HttpHeaders (); Enumeration headerNames = request.getHeaderNames (); if (headerNames! = null) {while (headerNames.hasMoreElements ()) {String name = headerNames.nextElement (); if (isIncludedHeader (name)) {/ / 1 Enumeration values = request.getHeaders (name) While (values.hasMoreElements ()) {String value = values.nextElement (); headers.add (name, value);}} Map zuulRequestHeaders = context.getZuulRequestHeaders () For (String header: zuulRequestHeaders.keySet ()) {if (isIncludedHeader (header)) {/ / 2 headers.set (header, zuulRequestHeaders.get (header);}} if (! headers.containsKey (HttpHeaders.ACCEPT_ENCODING)) {headers.set (HttpHeaders.ACCEPT_ENCODING, "gzip");} return headers;} public boolean isIncludedHeader (String headerName) {String name = headerName.toLowerCase () RequestContext ctx = RequestContext.getCurrentContext (); if (ctx.containsKey (IGNORED_HEADERS)) {Object object = ctx.get (IGNORED_HEADERS); if (object instanceof Collection & & ((Collection) object) .requests (name)) {return false;}} switch (name) {case "host": if (addHostHeader) {return true } case "connection": case "content-length": case "server": case "transfer-encoding": case "x-application-context": return false; default: return true;}}

Get the header of HttpServletRequest, then iterate through it, call the isIncludedHeader method, and get the RequestContext in isIncludedHeader to determine whether the current header key is set in the IGNORED_HEADERS collection-- List-4. If it is in it, false is returned, and the header field is not passed down.

2, context.getZuulRequestHeaders () gets the header we set manually (call the addZuulResponseHeader method setting), and then iterates through it one by one. If it is in the collection of IGNORED_HEADERS-List-4, it will not be added to the headers, that is, it will not be uploaded down.

Note: why the link goes from PreDecorationFilter to RibbonRoutingFilter is related to the internal ZuulFilter mechanism of Zuul.

Note that if the header to be uploaded downstream contains uppercase, then the downstream header is lowercase, and the reason can be seen in the List-4.

After reading the above, do you have any further understanding of what is the filter header of zuul in Springcloud? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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