express.static根路径的规则是什么？

Question

I ran

node src/app.js

in the mean-to directory

express.static('public') 

would work,why?

don't need to specify the path?

what's the rule?

and I know

__dirname+'/../public'` 

works just fine.

---

Just want to make sure the the logic here

I look up the doc http://expressjs.com/en/starter/static-files.html

it says

"Pass the name of the directory that contains the static assets to the express.static middleware function to start serving the files directly. "

"the path that you provide to the express.static function is relative to the directory from where you launch your node process "

Does that mean

1. if I run node src/app.js in mean-to folder --> use express.static('public')
2. if I run node app.js in src folder => use express.static('../public')

and for safety, better use __dirname to get the absolute path of the directory

Answer 1

Express static uses resolve function from module path

Example using path :

var p = require('path');
p.resolve('public'); // will return your absolute path for `public` directory

So rules for express static the same as for path#resolve function

You can see more example in the docs for path module

---

What's the difference between p.resolve and __dirname ?

path#resolve

p.resolve() resolves to an absolute path

path.resolve('public');

Will return your absolute path for public ' directory(eg " C:\\projects\\myapp\\public ")

path.resolve('src'); // => "C:\projects\myapp\src")

__dirname

__dirname - name of the directory(absolute path) from which you're currently running your app

file app.js

console.log(__dirname);

Running node app.js will print your absolute path for your app, eg " C:\\projects\\myapp "

Answer 2

You mixed 2 lines in one... And both are necessary:

//This line is to say that the statics files are in public
app.use(express.static(__dirname + "/public")); 

//This another line is to say that when call the route "/" render a page
app.get("/", function (req, res) {
  res.send('Hello World!'); 
}

Answer 3

Probably, the reason is in running it from directory highter one level than dir with code? Try run it from src:

cd src
node app.js