A simple HTTP static file server written using nodejs and Python

In the daily development process, we often need to modify some static files (such as JavaScript, CSS, HTML files, etc.) placed on the CDN. In this process, we hope to have a way to map the online CDN directory to local A directory on the hard disk, so that when we modify a file locally, there is no need to publish it, and the effect can be seen immediately after refreshing.

For example, our CDN domain name is: http://a.mycdn.com, and the corresponding local directory is: D:\workassets. We hope that all requests to http://a.mycdn.com/* Access is mapped to the local D:\workassets\*. For example, when accessing http://a.mycdn.com/s/atp.js, the local D:\workassetss\atp.js is actually read, without downloading online files from the Internet.

It is very simple to implement this function. The key points are as follows:

1. Open an HTTP service locally and listen to port 80;
2. Modify the system hosts file and add "127.0.0.1 a.mycdn.com", bind the CDN domain name to the local server address;
3. Configure the local HTTP service. After receiving a GET request, first check whether the corresponding file exists on the local hard disk. If it exists, return If the content of this file does not exist, the corresponding content online will be returned.

As you can see, the key part is to build a local HTTP service. There are many tutorials in this area, such as installing server software such as Apache or Ngnix locally, and then configuring corresponding forwarding rules. However, I personally feel that this method is still a bit complicated. What this article will introduce is another method that does not require the installation of server software.

Because we are developing and debugging locally, the requirements for performance and concurrency are not high, so we actually do not need a professional HTTP software like Apache/Ngnix, we only need a section that can provide HTTP Just use the service script. For example, use nodejs to implement it.

Copy code The code is as follows:

/**
 * author: oldj
 *
 **/

var http = require("http"),
url = require("url"),
path = require("path"),
fs = require("fs"),
local_folders,
base_url;

local_folders = [ // Local path, the agent will search for files in the directories in this list, and if not found, go to the online address
"D:/work/assets"
];
base_url = "http://10.232.133.214"; // Online path, if the file cannot be found, redirect to this address

function loadFile(pathname, response) {
var i, l = local_folders.length,
fn;

console.log("try to load " + pathname);

for (i = 0; i < l; i++ ) {

fn = local_folders[i] + pathname;
if (path.existsSync(fn) && fs.statSync(fn).isFile()) {
fs.readFile(fn, function (err, data) {
response.writeHead(200);
response.write(data);
response.end();
});

return;
}

}

response.writeHead(302, {
"Location":base_url + pathname
});
response.end();
}

http.createServer(
function (request, response) {

var req_url = request.url,
pathname;

// Processing Request similar to http://www.php.cn/,tbsp/tbsp.css?t=20110920172000.css
pathname = req_url.indexOf("??") == -1 ? url.parse(request. url).pathname : req_url;
console.log("Request for '" + pathname + "' received.");
loadFile(pathname, response);

}).listen( 80);

Please change the values ​​of the local_folders and base_url variables above to the values ​​you need. Save this file, for example, as local-cdn-proxy.js, and then execute "node local-cdn-proxy.js" on the command line. The local server will be running. Of course, don't forget to bind hosts.

When accessing a path through http, the above script will first search in the corresponding local directory. If found, it will return the contents of the corresponding file. If it is not found, it will directly 302 jump to the corresponding online address. For situations where it cannot be found, another solution is to have the local server download the corresponding content from online and return it, but for this requirement, a 302 jump is enough.

In addition to the nodejs version, I also wrote a Python version:

Copy code The code is as follows:

# -*- coding: utf-8 -*-

## author: oldj

#import os
import BaseHTTPServer

LOCAL_FOLDERS = [
"D:/work/assets"
]
BASE_URL = "http://10.232.133.214"

class WebRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):

def do_GET(self):
print "Request for '%s' received." % self.path
for folder in LOCAL_FOLDERS:
fn = os.path.join(folder, self. path.replace("/", os.sep)[1:])
If os.path.isfile(fn):
self.send_response(200)
self.wfile.write(open( fn, "rb").read())
                                                                                                                                       ’s (BASE_URL, self.path))

server = BaseHTTPServer.HTTPServer(("0.0.0.0", 80), WebRequestHandler)
server.serve_forever()

As you can see, the Python version of the code is much more streamlined than the nodejs version.

The functions of the above two pieces of code are relatively simple. For example, there is no output of MIME-Type, Content-Length and other header information of the content, and no possible blocking operations (such as file reading timeout, etc.) are done. Special handling. They are already working versions for local development environments, and you can continue to extend these two scripts to meet more needs.

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