Express中的app.set和app.engine [英] app.set and app.engine in Express

问题描述

我正在关注 Node.js教程.

我不确定的两行是:

app.set('view engine', 'html');
app.engine('html', hbs.__express);

我检查了文档中的app.set，它只告诉我:

I checked the documentation for app.set and it only tells me:

将设置名称分配为值.

Assigns setting name to value.

但是我的问题是使用这个有什么意义.我用Google搜索了它，并在以前使用app.set的任何地方都被调用过.

But my question is what's the relevance of using this. I googled it and wherever app.engine is used app.set is called before.

让我知道在app.engine之前使用app.set的重要性.

Let me know the significance of using app.set before the app.engine.

编辑

我找到了以下行，但是我还是不清楚，因为我是第一次使用模板引擎:

I found the following line, but I am still unclear as I am using template engine very first time:

但是我们可以告诉Express，通过使用view engine指令将HTML文件视为动态文件，如上所示.

But we can tell Express to treat HTML files as dynamic by using the view engine directive, you see above.

推荐答案

第一行app.set告诉Express使用哪个模板引擎:在这种情况下，为html.这就要求安装一个带有该名称的模板引擎，并且该模板引擎对带有.html扩展名的文件负责.

The first line, app.set tells Express which template engine to use: In this case, html. This requires that there is a template engine installed with that name, and that this template engine feels responsible for files with the .html extension.

例如，如果您使用的是ejs，则单行就足够了(尽管您通常还会再次调用app.set来定义用于查找视图文件的目录):

If you are using ejs, e.g., this single line is enough (although you usually also have a second call to app.set that defines the directory where to look for view files):

app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

现在，假设您想为另一个文件扩展名使用模板引擎，例如您希望ejs引擎不仅要处理.ejs文件，而且还要处理.html文件.

Now, supposed you would like to use a template engine for another file extension, e.g. you would like the ejs engine not only to take care of .ejs files, but also of .html files.

在这种情况下，您可以使用第二行，它告诉Express对于扩展名为html的文件，您想调用hbs.__express函数来呈现它们(因为实际上没有名为html的模板引擎) .从本质上讲，这意味着您希望hbs引擎呈现.html文件.

In this case you can use the second line, which tells Express that for files with extension html you would like to call the hbs.__express function to render them (as there actually is no template engine called html). This essentially means that you want the hbs engine to render .html files.

__express函数是Node.js下与Express兼容的模板引擎的事实上的标准:这就是它们的呈现函数的名称，以便Express可以轻松找到它(如果它具有不同的名称，则可以也可以配置它，但这是另外一回事了.

The __express function is a de-facto standard for template engines under Node.js to be Express compatible: That's what their rendering function should be called so that Express can find it easily (if it has a different name, you can configure this as well, but that's a different story).

希望这会有所帮助.

这篇关于Express中的app.set和app.engine的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！