PandaJS 使用说明(1.6)：日志与 proxy 对象
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2022-03-02 11:11:06
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PandaJS 使用说明(1.6)：日志与 proxy 对象
这篇文章里我们将继续探讨日志处理(panda.log)和 proxy 对象(panda.proxy)。结合使用 panda.log 和 panda.proxy 可以实现灵活的日志处理，有效地分离业务逻辑和日志记录的代码。panda.log 是在 slf4j 和 log4j 的基础上完成的；panda.proxy 是利用 Rhinio JS 的 __noSuchMethod__ 实现的。
添加日志 proxy
在 HelloPanda 项目的 scripts/app/proxy 文件夹中创建文件 log.js，内容如下：
(function() {
// 分别用不同的名称注册两个 log 对象
var timeLog = panda.log("panda.log.time");
var aroundLog = panda.log("panda.log.around");
// 表示日志输出格式的字符串
var timeString = "{}.{}() completed in {} seconds.";
var inputString = "Excuting {}.{}(), with param: {}.";
var outputString = "{}.{}() completed, with result: {}.";
// proxy.log 对象，用于记录日志，优先级 100
proxy.log = { priority: 100 };
// proxy.log.time 对象，记录执行时间
proxy.log.time = {
// 优先级 80，将在内层执行
priority: 80,
// 截获以 "api."、"page."、"dbo." 开头的表达式
expr: /^(api|page|dbo)\./,
// 代理函数，name: 对象名称，method:函数名称，args：函数调用参数
func: function(name, method, args) {
// 在执行函数的前后，插入计执行时间的代码
var start = new Date().getTime();
var ret = this[method].apply(this, args);
var seconds = (new Date().getTime() - start) / 1000;
// 输出日志并返回
timeLog.info(timeString, [ name, method, seconds ]);
return ret;
}
}
// proxy.log.around 对象，记录函数的输入和输出
proxy.log.around = {
// 优先级 100，将在外层执行
priority: 100,
// 截获以 "api."、"page."、"dbo." 开头的表达式
expr: /^(api|page|dbo)\./,
// 代理函数，name: 对象名称，method:函数名称，args：函数调用参数
func: function(name, method, args) {
// 执行函数前，将第一个参数序列化后输出到日志
var toLog = JSON.stringify(args[0]);
aroundLog.info(inputString, [name, method, toLog]);
// 执行函数
var ret = this[method].apply(this, args);
// 缩短函数执行结果并序列化，输出到日志
toLog = JSON.stringify(shorten());
aroundLog.info(outputString, [name, method, toLog]);
// 返回结果
return ret;
// 缩短 ret 以便显示，实现略。
function shorten() { ... }
}
}
}());
要使得 proxy 生效，还需要通过 panda.proxy(name) 创建对象，比如在scripts/app/api/users.js 中创建 dbo.users 的 proxy：
api.users = {
add: function(params, req, res) {
return panda.proxy("dbo.users").add(params);
},
update: function(params, req, res) {
return panda.proxy("dbo.users").update(params);
},
remove: function(params, req, res) {
return panda.proxy("dbo.users").remove(params);
}
};
以及 scripts/app/page/index.js:
page.index = function(params, req, res) {
return panda.render("index", function($){
views.index($, panda.proxy("dbo.users").list());
});
};
执行顺序
proxy.log 中的函数与被截获的核心代码的执行顺序如下图所示（priority 较大的在较外层）：
实际运行结果
启动应用并通过 http://localhost访问，可以看到如下日志：
引用
2011-08-27 12:54:16 INFO server - Loading Scripts ...
2011-08-27 12:54:18 INFO server - Starting Monit ...
2011-08-27 12:54:18 INFO server - Starting Server ...
2011-08-27 12:54:19 INFO org.eclipse.jetty.util.log - jetty-7.4.1.v20110513
2011-08-27 12:54:19 INFO org.eclipse.jetty.util.log - started o.e.j.s.ServletContextHandler{/,file:/C:/Users/dev/Downloads/HelloPanda/HelloPanda/webapp/}
2011-08-27 12:54:19 INFO org.eclipse.jetty.util.log - Started SelectChannelConnector@0.0.0.0:80 STARTING
2011-08-27 12:54:25 INFO proxy.log.around - Excuting page.index(), with param: undefined.
2011-08-27 12:54:26 INFO proxy.log.around - Excuting dbo.users.list(), with param: undefined.
2011-08-27 12:54:26 INFO proxy.log.time - dbo.users.list() completed in 0.272 seconds.
2011-08-27 12:54:26 INFO proxy.log.around - dbo.users.list() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},"..."].
2011-08-27 12:54:26 INFO proxy.log.time - page.index() completed in 1.722 seconds.
2011-08-27 12:54:26 INFO proxy.log.around - page.index() completed, with result: "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-str...".
2011-08-27 12:54:18 INFO server - Starting Monit ...
2011-08-27 12:54:18 INFO server - Starting Server ...
2011-08-27 12:54:19 INFO org.eclipse.jetty.util.log - jetty-7.4.1.v20110513
2011-08-27 12:54:19 INFO org.eclipse.jetty.util.log - started o.e.j.s.ServletContextHandler{/,file:/C:/Users/dev/Downloads/HelloPanda/HelloPanda/webapp/}
2011-08-27 12:54:19 INFO org.eclipse.jetty.util.log - Started SelectChannelConnector@0.0.0.0:80 STARTING
2011-08-27 12:54:25 INFO proxy.log.around - Excuting page.index(), with param: undefined.
2011-08-27 12:54:26 INFO proxy.log.around - Excuting dbo.users.list(), with param: undefined.
2011-08-27 12:54:26 INFO proxy.log.time - dbo.users.list() completed in 0.272 seconds.
2011-08-27 12:54:26 INFO proxy.log.around - dbo.users.list() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},"..."].
2011-08-27 12:54:26 INFO proxy.log.time - page.index() completed in 1.722 seconds.
2011-08-27 12:54:26 INFO proxy.log.around - page.index() completed, with result: "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-str...".
在界面的输入框中输入 user 的 name 和 desc，并点击save，可以看到如下日志：
引用
2011-08-27 12:55:01 INFO proxy.log.around - Excuting api.users.add(), with param: {"name":"aaa","desc":"bbb"}.
2011-08-27 12:55:01 INFO proxy.log.around - Excuting dbo.users.add(), with param: {"name":"aaa","desc":"bbb"}.
2011-08-27 12:55:01 INFO proxy.log.around - Excuting dbo.users.list(), with param: undefined.
2011-08-27 12:55:01 INFO proxy.log.time - dbo.users.list() completed in 0.002 seconds.
2011-08-27 12:55:01 INFO proxy.log.around - dbo.users.list() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},{"name":"user2","desc":"desc2"},"..."].
2011-08-27 12:55:01 INFO proxy.log.time - dbo.users.add() completed in 0.007 seconds.
2011-08-27 12:55:01 INFO proxy.log.around - dbo.users.add() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},{"name":"user2","desc":"desc2"},"..."].
2011-08-27 12:55:01 INFO proxy.log.time - api.users.add() completed in 0.009 seconds.
2011-08-27 12:55:01 INFO proxy.log.around - api.users.add() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},{"name":"user2","desc":"desc2"},"..."].
2011-08-27 12:55:01 INFO proxy.log.around - Excuting dbo.users.add(), with param: {"name":"aaa","desc":"bbb"}.
2011-08-27 12:55:01 INFO proxy.log.around - Excuting dbo.users.list(), with param: undefined.
2011-08-27 12:55:01 INFO proxy.log.time - dbo.users.list() completed in 0.002 seconds.
2011-08-27 12:55:01 INFO proxy.log.around - dbo.users.list() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},{"name":"user2","desc":"desc2"},"..."].
2011-08-27 12:55:01 INFO proxy.log.time - dbo.users.add() completed in 0.007 seconds.
2011-08-27 12:55:01 INFO proxy.log.around - dbo.users.add() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},{"name":"user2","desc":"desc2"},"..."].
2011-08-27 12:55:01 INFO proxy.log.time - api.users.add() completed in 0.009 seconds.
2011-08-27 12:55:01 INFO proxy.log.around - api.users.add() completed, with result: [{"name":"aaa","desc":"bbb"},{"name":"user1","desc":"desc1"},{"name":"user2","desc":"desc2"},"..."].