新增downloadFile接口，支持下载限定目录下任意文件 (#3073)

conf/config.ini

@@ -15,6 +15,8 @@ secret=035c73f7-bb6b-4889-a715-d9eb2d1925cc
 snapRoot=./www/snap/
 #默认截图图片，在启动FFmpeg截图后但是截图还未生成时，可以返回默认的预设图片
 defaultSnap=./www/logo.png
+#downloadFile http接口可访问文件的根目录，支持多个目录，不同目录通过分号(;)分隔
+downloadRoot=./www
 
 [ffmpeg]
 #FFmpeg可执行程序路径,支持相对路径/绝对路径

postman/ZLMediaKit.postman_collection.json

@@ -2184,6 +2184,38 @@
 				}
 			},
 			"response": []
+		},
+		{
+			"name": "下载文件(downloadFile)",
+			"request": {
+				"method": "GET",
+				"header": [],
+				"url": {
+					"raw": "{{ZLMediaKit_URL}}/index/api/downloadFile?file_path=/path/to/file.ext",
+					"host": [
+						"{{ZLMediaKit_URL}}"
+					],
+					"path": [
+						"index",
+						"api",
+						"downloadFile"
+					],
+					"query": [
+						{
+							"key": "file_path",
+							"value": "/path/to/file.ext",
+							"description": "文件绝对路径，根据文件名生成Content-Type；该接口将触发on_http_access hook"
+						},
+						{
+							"key": "save_name",
+							"value": "test",
+							"description": "浏览器下载文件后保存文件名；可选参数",
+							"disabled": true
+						}
+					]
+				}
+			},
+			"response": []
 		}
 	],
 	"event": [

server/WebApi.cpp

@@ -72,12 +72,14 @@ const string kApiDebug = API_FIELD"apiDebug";
 const string kSecret = API_FIELD"secret";
 const string kSnapRoot = API_FIELD"snapRoot";
 const string kDefaultSnap = API_FIELD"defaultSnap";
+const string kDownloadRoot = API_FIELD"downloadRoot";
 
 static onceToken token([]() {
     mINI::Instance()[kApiDebug] = "1";
     mINI::Instance()[kSecret] = "035c73f7-bb6b-4889-a715-d9eb2d1925cc";
     mINI::Instance()[kSnapRoot] = "./www/snap/";
     mINI::Instance()[kDefaultSnap] = "./www/logo.png";
+    mINI::Instance()[kDownloadRoot] = "./www";
 });
 }//namespace API
 
@@ -1824,6 +1826,57 @@ void installWebApi() {
         // sample_ms设置为0，从配置文件加载；file_repeat可以指定，如果配置文件也指定循环解复用，那么强制开启
         reader->startReadMP4(0, true, allArgs["file_repeat"]);
     });
+
+    GET_CONFIG_FUNC(std::set<std::string>, download_roots, API::kDownloadRoot, [](const string &str) -> std::set<std::string> {
+        std::set<std::string> ret;
+        auto vec = toolkit::split(str, ";");
+        for (auto &item : vec) {
+            auto root = File::absolutePath(item, "", true);
+            ret.emplace(std::move(root));
+        }
+        return ret;
+    });
+
+    api_regist("/index/api/downloadFile", [](API_ARGS_MAP_ASYNC) {
+        CHECK_ARGS("file_path");
+        auto file_path = allArgs["file_path"];
+
+        if (file_path.find("..") != std::string::npos) {
+            invoker(401, StrCaseMap{}, "You can not access parent directory");
+            return;
+        }
+        bool safe = false;
+        for (auto &root : download_roots) {
+            if (start_with(file_path, root)) {
+                safe = true;
+                break;
+            }
+        }
+        if (!safe) {
+            invoker(401, StrCaseMap{}, "You can not download files outside the root directory");
+            return;
+        }
+
+        // 通过on_http_access完成文件下载鉴权，请务必确认访问鉴权url参数以及访问文件路径是否合法
+        HttpSession::HttpAccessPathInvoker file_invoker = [allArgs, invoker](const string &err_msg, const string &cookie_path_in, int life_second) mutable {
+            if (!err_msg.empty()) {
+                invoker(401, StrCaseMap{}, err_msg);
+            } else {
+                StrCaseMap res_header;
+                auto save_name = allArgs["save_name"];
+                if (!save_name.empty()) {
+                    res_header.emplace("Content-Disposition", "attachment;filename=\"" + save_name + "\"");
+                }
+                invoker.responseFile(allArgs.getParser().getHeader(), res_header, allArgs["file_path"]);
+            }
+        };
+
+        bool flag = NOTICE_EMIT(BroadcastHttpAccessArgs, Broadcast::kBroadcastHttpAccess, allArgs.getParser(), file_path, false, file_invoker, sender);
+        if (!flag) {
+            // 文件下载鉴权事件无人监听，不允许下载
+            invoker(401, StrCaseMap {}, "None http access event listener");
+        }
+    });
 }
 
 void unInstallWebApi(){

src/Http/HttpFileManager.cpp

@@ -725,6 +725,9 @@ void HttpResponseInvokerImp::responseFile(const StrCaseMap &requestHeader,
         return;
     }
 
+    // 尝试添加Content-Type
+    httpHeader.emplace("Content-Type", HttpConst::getHttpContentType(file.data()));
+
     auto &strRange = const_cast<StrCaseMap &>(requestHeader)["Range"];
     int code = 200;
     if (!strRange.empty()) {