Follow proxy no proxy host configuration (#745)

src/main/java/jenkins/plugins/slack/HttpClient.java

@@ -1,6 +1,7 @@
 package jenkins.plugins.slack;
 
 import hudson.ProxyConfiguration;
+import jenkins.plugins.slack.NoProxyHostCheckerRoutePlanner;
 import org.apache.http.HttpHost;
 import org.apache.http.auth.AuthScope;
 import org.apache.http.auth.Credentials;
@@ -13,7 +14,6 @@
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.client.HttpClients;
-import org.apache.http.impl.conn.DefaultProxyRoutePlanner;
 import org.kohsuke.accmod.Restricted;
 import org.kohsuke.accmod.restrictions.NoExternalUse;
 
@@ -37,7 +37,7 @@ public static CloseableHttpClient getCloseableHttpClient(ProxyConfiguration prox
 
         if (proxy != null) {
             final HttpHost proxyHost = new HttpHost(proxy.name, proxy.port);
-            final HttpRoutePlanner routePlanner = new DefaultProxyRoutePlanner(proxyHost);
+            final HttpRoutePlanner routePlanner = new NoProxyHostCheckerRoutePlanner(proxy.getNoProxyHost(), proxyHost);
             clientBuilder.setRoutePlanner(routePlanner);
 
             String username = proxy.getUserName();
@@ -60,5 +60,4 @@ private static Credentials createCredentials(String userName, String password) {
             return new UsernamePasswordCredentials(userName, password);
         }
     }
-
 }

src/main/java/jenkins/plugins/slack/NoProxyHostCheckerRoutePlanner.java

@@ -0,0 +1,47 @@
+package jenkins.plugins.slack;
+
+import hudson.ProxyConfiguration;
+import java.util.regex.Pattern;
+import org.apache.http.HttpHost;
+import org.apache.http.HttpRequest;
+import org.apache.http.conn.routing.HttpRoute;
+import org.apache.http.conn.routing.HttpRoutePlanner;
+import org.apache.http.impl.conn.DefaultProxyRoutePlanner;
+import org.apache.http.impl.conn.DefaultRoutePlanner;
+import org.apache.http.impl.conn.DefaultSchemePortResolver;
+import org.apache.http.protocol.HttpContext;
+
+public class NoProxyHostCheckerRoutePlanner implements HttpRoutePlanner {
+
+    private DefaultProxyRoutePlanner defaultProxyRoutePlanner = null;
+    private DefaultRoutePlanner defaultRoutePlanner = null;
+    private String noProxyHost = null;
+
+    public NoProxyHostCheckerRoutePlanner(String noProxyHost, HttpHost host){
+        defaultProxyRoutePlanner = new DefaultProxyRoutePlanner(host);
+        defaultRoutePlanner = new DefaultRoutePlanner(new DefaultSchemePortResolver());
+        this.noProxyHost = noProxyHost;
+    }
+
+    public void setProxy(HttpHost host){
+        defaultProxyRoutePlanner = new DefaultProxyRoutePlanner(host);
+    }
+
+    public HttpRoute determineRoute(HttpHost target, HttpRequest request, HttpContext context) throws org.apache.http.HttpException {
+        final String targetHostUri = target.toURI();
+        if(isNoProxyHost(targetHostUri))
+            return defaultRoutePlanner.determineRoute(target,request,context);
+        return defaultProxyRoutePlanner.determineRoute(target,request,context);
+    }
+
+    private boolean isNoProxyHost(String host) {
+        if (host!=null && noProxyHost!=null) {
+            for (Pattern p : ProxyConfiguration.getNoProxyHostPatterns(noProxyHost)) {
+                if (p.matcher(host).matches()) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}