first stab at file content API endpoint

- no line number support

fixes oracle#3048

Author: Vladimir Kotal

apiary.apib

@@ -67,6 +67,18 @@ Besides `/suggester` and `/search` endpoints, everything is accessible from `loc
 
 + Response 204
 
+## File content [/filecontent{?path}]
+
+### get history entries [GET]
+
++ Parameters
+  + path (string) - path of file/directory to get history for, relative to source root
+
++ Response 200 (application/json)
+  + Body
+
+        XXX
+
 ## History [/history{?path,withFiles,start,max}]
 
 ### get history entries [GET]

opengrok-web/src/main/java/org/opengrok/web/api/v1/controller/FileContentController.java

@@ -0,0 +1,102 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * See LICENSE.txt included in this distribution for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at LICENSE.txt.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2020 Oracle and/or its affiliates. All rights reserved.
+ */
+
+package org.opengrok.web.api.v1.controller;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import org.opengrok.indexer.configuration.RuntimeEnvironment;
+import org.opengrok.web.api.v1.filter.CorsEnable;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+
+import static org.opengrok.web.util.AuthPathUtil.isPathAuthorized;
+
+@Path(FileContentController.PATH)
+public class FileContentController {
+
+    public static final String PATH = "/filecontent";
+
+    private static final RuntimeEnvironment env = RuntimeEnvironment.getInstance();
+
+    class FileContentDTO {
+        @JsonProperty
+        ArrayList<String> lines;
+
+        FileContentDTO() {
+            lines = new ArrayList<>();
+        }
+
+        public ArrayList<String> getLines() {
+            return lines;
+        }
+
+        public void add(String line) {
+            lines.add(line);
+        }
+    }
+
+    @GET
+    @CorsEnable
+    @Produces(MediaType.APPLICATION_JSON)
+    public Object get(@Context HttpServletRequest request,
+                      @Context HttpServletResponse response,
+                      @QueryParam("path") final String path) throws IOException {
+
+        if (!isPathAuthorized(path, request)) {
+            response.sendError(Response.status(Response.Status.FORBIDDEN).build().getStatus(),
+                    "not authorized");
+            return null;
+        }
+
+        // TODO: identify the file type and return only for text files
+
+        File file = new File(env.getSourceRootFile(), path);
+        if (!file.isFile()) {
+            // TODO: set error
+            return null;
+        }
+        FileContentDTO fileContent = new FileContentDTO();
+        try (BufferedReader br = new BufferedReader(new FileReader(file))) {
+            String line;
+            while ((line = br.readLine()) != null) {
+               fileContent.add(line);
+            }
+        }
+
+        // TODO: array of lines with line number
+        return fileContent.getLines();
+    }
+}

opengrok-web/src/main/java/org/opengrok/web/api/v1/filter/LocalhostFilter.java

@@ -23,6 +23,7 @@
 package org.opengrok.web.api.v1.filter;
 
 import org.opengrok.indexer.logger.LoggerFactory;
+import org.opengrok.web.api.v1.controller.FileContentController;
 import org.opengrok.web.api.v1.controller.HistoryController;
 import org.opengrok.web.api.v1.controller.SearchController;
 import org.opengrok.web.api.v1.controller.SuggesterController;
@@ -58,7 +59,7 @@ public class LocalhostFilter implements ContainerRequestFilter {
      */
     private static final Set<String> allowedPaths = new HashSet<>(Arrays.asList(
             SearchController.PATH, SuggesterController.PATH, SuggesterController.PATH + "/config",
-            HistoryController.PATH));
+            HistoryController.PATH, FileContentController.PATH));
 
     @Context
     private HttpServletRequest request;