如何实现在Python中一个最小的服务器AJAX？ [英] How to implement a minimal server for AJAX in Python?
问题描述
我想创建一个非常简单的HTML / AJAX基于GUI的Python程序。因此，前端是通过AJAX程序进行通信的HTML页面。你能不能给我一个最小的实现服务器端使用Python SimpleHTTPServer.SimpleHTT prequestHandler ？
I want to create a very simple HTML/AJAX based GUI for a Python program. So the frontend is a HTML page which communicates with the program via AJAX. Can you give me a minimal implementation for the server-side using the python SimpleHTTPServer.SimpleHTTPRequestHandler?
一个简单的例子是一个文本框和一个按钮。当按钮pressed字段的内容被发送到哪个然后发送回相应的答案的服务器。我知道有在Python如此多强大的解决方案，但我想保持这很简单。 我已经找到了这样一个服务器的一些很好的例子（如这里），但到目前为止，我能不来与真正的最小的之一。
A simple example would be a textfield and a button. When the button is pressed the content of the field is send to the server which then sends back a corresponding answer. I am aware that there are many powerful solutions for this in Python, but I would like to keep this very simple. I already found some nice examples for such a server (e.g. here), but so far I could not come up with a truly minimal one.
如果你想知道为什么我要实现的GUI以这样的方式：我的重点为这个应用程序是显示在一个不错的布局大量数据，只有最少的交互 - 因此，使用HTML + CSS似乎是最方便的（和我已经被使用它的非交互式数据显示）。
In case you wonder why I want to implement the GUI in such a way: My focus for this application is to display lots of data in a nice layout with only minimal interaction - so using HTML+CSS seems most convenient (and I have been already using it for non-interactive data display).
推荐答案
OK，我想我现在可以回答我的问题。这里是一个示例实现，用于计算一个数字的服务器上的平方。请让我知道，如果有任何改进或误解。
O.K., I think I can now answer my own question. Here is an example implementation for calculating the square of a number on the server. Please let me know if there are any improvements or misconceptions.
蟒蛇服务器文件：
import threading
import webbrowser
import BaseHTTPServer
import SimpleHTTPServer
FILE = 'frontend.html'
PORT = 8080
class TestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
"""The test example handler."""
def do_POST(self):
"""Handle a post request by returning the square of the number."""
length = int(self.headers.getheader('content-length'))
data_string = self.rfile.read(length)
try:
result = int(data_string) ** 2
except:
result = 'error'
self.wfile.write(result)
def open_browser():
"""Start a browser after waiting for half a second."""
def _open_browser():
webbrowser.open('http://localhost:%s/%s' % (PORT, FILE))
thread = threading.Timer(0.5, _open_browser)
thread.start()
def start_server():
"""Start the server."""
server_address = ("", PORT)
server = BaseHTTPServer.HTTPServer(server_address, TestHandler)
server.serve_forever()
if __name__ == "__main__":
open_browser()
start_server()
...和HTML文件（我称之为'frontend.html，遗憾的是这个名字已经出现在JavaScript的code和）：
...and the HTML file (I call it 'frontend.html', unfortunately the name has to appear in the JavaScript code as well):
<html>
<head>
<title>AJAX test</title>
</head>
<body>
<script type="text/javascript">
function xml_http_post(url, data, callback) {
var req = false;
try {
// Firefox, Opera 8.0+, Safari
req = new XMLHttpRequest();
}
catch (e) {
// Internet Explorer
try {
req = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e) {
try {
req = new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e) {
alert("Your browser does not support AJAX!");
return false;
}
}
}
req.open("POST", url, true);
req.onreadystatechange = function() {
if (req.readyState == 4) {
callback(req);
}
}
req.send(data);
}
function test_button() {
var data = document.test_form.test_text.value;
xml_http_post("frontend.html", data, test_handle)
}
function test_handle(req) {
var elem = document.getElementById('test_result')
elem.innerHTML = req.responseText
}
</script>
<form name=test_form>
sqr(
<input type="text" name="test_text" value="0" size="4">
) =
<span id="test_result">0</span>
<input type=button onClick="test_button();" value="start" title="start">
</form>
</body>
</html>
当然，这将是很大的使用 jQuery的，在XML请求更方便，但在简单的利益我会离开它这样的。
Of course it would be much more convenient to use jQuery for the XML request, but in the interest of simplicity I'll leave it like that.
最后使用WSGI（可惜我没有看到一个方法来依傍标准的文件服务处理程序，如果该请求不是POST）的另一种实现：
Finally an alternative implementation using WSGI (unfortunately I didn't see a way to fall back on the standard file-serving handler if the request is not a POST):
import threading
import webbrowser
from wsgiref.simple_server import make_server
FILE = 'frontend.html'
PORT = 8080
def test_app(environ, start_response):
if environ['REQUEST_METHOD'] == 'POST':
try:
request_body_size = int(environ['CONTENT_LENGTH'])
request_body = environ['wsgi.input'].read(request_body_size)
except (TypeError, ValueError):
request_body = "0"
try:
response_body = str(int(request_body) ** 2)
except:
response_body = "error"
status = '200 OK'
headers = [('Content-type', 'text/plain')]
start_response(status, headers)
return [response_body]
else:
response_body = open(FILE).read()
status = '200 OK'
headers = [('Content-type', 'text/html'),
('Content-Length', str(len(response_body)))]
start_response(status, headers)
return [response_body]
def open_browser():
"""Start a browser after waiting for half a second."""
def _open_browser():
webbrowser.open('http://localhost:%s/%s' % (PORT, FILE))
thread = threading.Timer(0.5, _open_browser)
thread.start()
def start_server():
"""Start the server."""
httpd = make_server("", PORT, test_app)
httpd.serve_forever()
if __name__ == "__main__":
open_browser()
start_server()
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