chore: Configure proxy from env-vars

feat: Add support for configuring proxy settings through conventional environment variables HTTP_PROXY, HTTPS_PROXY, ALL_PROXY & NO_PROXY (used if proxy is not explicitly configured through 'fcli config proxy' commands)

fcli-core/fcli-common/src/main/java/com/fortify/cli/common/http/proxy/helper/ProxyHelper.java

@@ -12,27 +12,100 @@
  *******************************************************************************/
 package com.fortify.cli.common.http.proxy.helper;
 
+import java.net.MalformedURLException;
+import java.net.URL;
 import java.nio.file.Path;
 import java.util.Comparator;
 import java.util.stream.Stream;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.fortify.cli.common.util.FcliDataHelper;
+import com.fortify.cli.common.util.StringUtils;
 
 import kong.unirest.UnirestInstance;
 
 public final class ProxyHelper {
+    private static final Logger LOG = LoggerFactory.getLogger(ProxyHelper.class);
     private ProxyHelper() {}
 
-    public static final void configureProxy(UnirestInstance unirest, String module, String url) {
+    public static final void configureProxy(UnirestInstance unirest, String module, String targetUrl) {
         getProxiesStream()
             .sorted(Comparator.comparingInt(ProxyDescriptor::getPriority).reversed())
-            .filter(d->d.matches(module, url))
+            .filter(d->d.matches(module, targetUrl))
             .findFirst()
-            .ifPresent(d->
+            .ifPresentOrElse(d->
                 unirest.config().proxy(d.getProxyHost(), d.getProxyPort(), d.getProxyUser(), d.getProxyPasswordAsString())
+                , ()->configureProxyFromEnvVars(unirest, targetUrl)
             );
     }
 
+    private static final void configureProxyFromEnvVars(UnirestInstance unirest, String targetUrlString) {
+        try {
+            var targetUrl = new URL(targetUrlString);
+            if ( !matchesNoProxyEnv(targetUrl) ) {
+                Stream.of("http_proxy", "HTTP_PROXY", "https_proxy", "HTTPS_PROXY", "all_proxy", "ALL_PROXY")
+                   .filter(e->StringUtils.isNotBlank(System.getenv(e))).findFirst()
+                   .ifPresent(envVar->configureProxyFromEnvVar(unirest, envVar));
+            }
+        } catch (Exception e) {
+            // We don't want to interfere with potential progress messages, so we
+            // just log a debug message.
+            LOG.debug("WARN: Unable to configure proxy settings from environment variables", e);
+        }
+    }
+
+    private static final void configureProxyFromEnvVar(UnirestInstance unirest, String envVarName) {
+        var proxyString = System.getenv(envVarName);
+        try {
+            configureProxyFromUrlEnvVar(unirest, envVarName, new URL(proxyString));
+        } catch ( MalformedURLException e ) {
+            configureProxyFromNonUrlVar(unirest, envVarName, proxyString);
+        }
+    }
+
+    private static void configureProxyFromUrlEnvVar(UnirestInstance unirest, String envVarName, URL proxyUrl) throws MalformedURLException {
+        var host = proxyUrl.getHost();
+        var port = proxyUrl.getPort();
+        if ( port==-1 ) { port = proxyUrl.getDefaultPort(); }
+        var userInfo = proxyUrl.getUserInfo();
+        var userInfoElts = StringUtils.isBlank(userInfo) ? null : userInfo.split(":", 2);
+        var user = userInfoElts==null || userInfoElts.length==0 ? null : userInfoElts[0];
+        var pwd = userInfoElts==null || userInfoElts.length<2 ? null : userInfoElts[1];
+        unirest.config().proxy(host, port, user, pwd);
+    }
+
+    private static void configureProxyFromNonUrlVar(UnirestInstance unirest, String envVarName, String proxyString) {
+        var proxyElts = proxyString.split(":");
+        if ( proxyElts.length>2 ) {
+            throw new IllegalStateException(String.format("Unexpected format for environment variable %s: %s", envVarName, proxyString));
+        }
+        var host = proxyElts[0];
+        var port = proxyElts.length<2 ? -1 : Integer.parseInt(proxyElts[1]);
+        if ( port==-1 ) {
+            var lowerEnvVarName = envVarName.toLowerCase(); 
+            if ( lowerEnvVarName.startsWith("http_") ) { port = 80; }
+            else if ( lowerEnvVarName.startsWith("https_") ) { port = 443; }
+            else { throw new IllegalStateException(String.format("Unable to determine proxy port from environment variable %s: %s", envVarName, proxyString)); }
+        }
+        unirest.config().proxy(host, port);
+    }
+
+    private static final boolean matchesNoProxyEnv(URL url) {
+        var targetHost = url.getHost();
+        var env = System.getenv();
+        var noProxyEnv = env.getOrDefault("no_proxy", env.get("NO_PROXY"));
+        var noProxyHosts = noProxyEnv==null ? null : noProxyEnv.split(",");
+        return noProxyHosts==null 
+                ? false 
+                : Stream.of(noProxyHosts).anyMatch(noProxyEntry->matchesNoProxy(targetHost, noProxyEntry));
+    }
+
+    private static final boolean matchesNoProxy(String targetHost, String noProxyEntry) {
+        return noProxyEntry.equals("*") || targetHost.endsWith(noProxyEntry);
+    }
+
     public static final ProxyDescriptor getProxy(String name) {
         Path proxyConfigPath = getProxyConfigPath(name);
         if ( !FcliDataHelper.exists(proxyConfigPath) ) {