Feature / Web server redirect (#297)

* Add redirects to web server config proto

* Add redirect handling to web server content server

* Update rewrite rules in content server to the same pattern as redirects

tracdap-api/tracdap-config/src/main/proto/tracdap/config/platform.proto

@@ -80,6 +80,7 @@ message WebServerConfig {
 
   PluginConfig contentRoot = 3;
   repeated WebServerRewriteRule rewriteRules = 4;
+  repeated WebServerRedirect redirects = 5;
 }
 
 message WebServerRewriteRule {
@@ -88,6 +89,13 @@ message WebServerRewriteRule {
   string target = 2;
 }
 
+message WebServerRedirect {
+
+  string source = 1;
+  string target = 2;
+  int32 status = 3;
+}
+
 
 message InstantMap {
 

tracdap-services/tracdap-webserver/src/main/java/org/finos/tracdap/webserver/ContentServer.java

@@ -26,6 +26,8 @@
 import org.finos.tracdap.common.storage.FileType;
 import org.finos.tracdap.common.storage.IFileStorage;
 import org.finos.tracdap.config.WebServerConfig;
+import org.finos.tracdap.config.WebServerRedirect;
+import org.finos.tracdap.config.WebServerRewriteRule;
 
 import java.net.URI;
 import java.net.URISyntaxException;
@@ -51,25 +53,36 @@ public class ContentServer {
     private final IFileStorage storage;
 
     private final Map<String, String> mimeTypes;
-    private final List<Map.Entry<Pattern, String>> rewriteRules;
+    private final List<Map.Entry<Pattern, WebServerRedirect>> redirects;
+    private final List<Map.Entry<Pattern, WebServerRewriteRule>> rewriteRules;
 
     public ContentServer(WebServerConfig config, IFileStorage storage) {
 
         this.storage = storage;
 
         this.mimeTypes = MimeTypes.loadMimeTypeMap();
 
+        this.redirects = new ArrayList<>();
         this.rewriteRules = new ArrayList<>();
 
+        for (var redirect : config.getRedirectsList()) {
+            var source = Pattern.compile(redirect.getSource());
+            redirects.add(Map.entry(source, redirect));
+        }
+
         for (var rule : config.getRewriteRulesList()) {
             var source = Pattern.compile(rule.getSource());
-            var target = rule.getTarget();
-            rewriteRules.add(Map.entry(source, target));
+            rewriteRules.add(Map.entry(source, rule));
         }
     }
 
     public CompletionStage<ContentResponse> headRequest(String requestUri, IExecutionContext execCtx) {
 
+        var redirect = processRedirects(requestUri);
+
+        if (redirect != null)
+            return CompletableFuture.completedFuture(redirect);
+
         var storagePath = translateStoragePath(requestUri);
 
         return headRequestForPath(storagePath, execCtx);
@@ -86,6 +99,11 @@ private CompletionStage<ContentResponse> headRequestForPath(String storagePath,
 
     public CompletionStage<ContentResponse> getRequest(String requestUri, IDataContext dataCtx) {
 
+        var redirect = processRedirects(requestUri);
+
+        if (redirect != null)
+            return CompletableFuture.completedFuture(redirect);
+
         var storagePath = translateStoragePath(requestUri);
 
         return storage.stat(storagePath, dataCtx)
@@ -95,6 +113,28 @@ public CompletionStage<ContentResponse> getRequest(String requestUri, IDataConte
                 .thenApplyAsync(Function.identity(), dataCtx.eventLoopExecutor());
     }
 
+    private ContentResponse processRedirects(String requestUri) {
+
+        try {
+            var uri = new URI(requestUri);
+            var path = uri.getPath();
+
+            for (var redirect : redirects) {
+
+                var pattern = redirect.getKey();
+                var match = pattern.matcher(path);
+
+                if (match.matches())
+                    return buildRedirectResponse(redirect.getValue());
+            }
+
+            return null;
+        }
+        catch (URISyntaxException e) {
+            throw new ENetworkHttp(HttpResponseStatus.BAD_REQUEST.code(), "Invalid URL: " + e.getMessage(), e);
+        }
+    }
+
     private String translateStoragePath(String requestUri) {
 
         try {
@@ -105,10 +145,10 @@ private String translateStoragePath(String requestUri) {
 
                 var pattern = rule.getKey();
                 var match = pattern.matcher(path);
-                var replacement = rule.getValue();
+                var rewrite = rule.getValue();
 
                 if (match.matches())
-                    path = match.replaceFirst(replacement);
+                    path = match.replaceFirst(rewrite.getTarget());
             }
 
             if (path.equals("/"))
@@ -195,6 +235,15 @@ private ContentResponse buildErrorResponse(Throwable e) {
         return response;
     }
 
+    private ContentResponse buildRedirectResponse(WebServerRedirect redirect) {
+
+        var response = new ContentResponse();
+        response.statusCode = HttpResponseStatus.valueOf(redirect.getStatus());
+        response.headers.set(HttpHeaderNames.LOCATION, redirect.getTarget());
+
+        return response;
+    }
+
     private void addStandardHeaders(HttpHeaders headers) {
 
         var date = DateTimeFormatter.RFC_1123_DATE_TIME.format(ZonedDateTime.now());