如何从JavaScript调用Python脚本？
我有一个后台的Python脚本，它从sqlalchemy引擎中获取数据。我想把这些数据展示在一个搜索框里，用户可以在里面滚动查看数据并进行选择。我看了一些类似问题的回答，比如用ajax来调用Python脚本，但我还是不太明白。以下是我的Python脚本。
# models.py
from sqlalchemy import create_engine
from sqlalchemy.engine.url import URL
from sqlalchemy.ext.declarative import declarative_base
import pandas as pd
aURL = URL(drivername='mysql', username='chlee021690', database = 'recommender')
engine = create_engine(aURL, echo=True)
sql_command = 'SELECT product_id FROM bestbuy_data'
results = pd.read_sql(sql = sql_command, con = engine)
有没有人能告诉我怎么写JavaScript代码来获取这些结果并把它们显示在我的表单里？谢谢。
2 个回答
0
你的Python服务器需要做两件事：
- 提供AJAX的JavaScript文件（通过GET请求）
- 响应来自网页客户端的请求（通过POST请求）。
另外，它还应该支持多线程，这样可以同时处理多个连接。
下面是一个示例，展示了如何使用内置的BaseHTTPServer来完成以上所有功能。
JavaScript（放在static/hello.html中，以便通过Python提供）：
<html><head><meta charset="utf-8"/></head><body>
Hello.
<script>
var xhr = new XMLHttpRequest();
xhr.open("POST", "/postman", true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify({
value: 'value'
}));
xhr.onload = function() {
console.log("HELLO")
console.log(this.responseText);
var data = JSON.parse(this.responseText);
console.log(data);
}
</script></body></html>
Python服务器（用于测试）：
import time, threading, socket, SocketServer, BaseHTTPServer
import os, traceback, sys, json
log_lock = threading.Lock()
log_next_thread_id = 0
# Local log functiondef
def Log(module, msg):
with log_lock:
thread = threading.current_thread().__name__
msg = "%s %s: %s" % (module, thread, msg)
sys.stderr.write(msg + '\n')
def Log_Traceback():
t = traceback.format_exc().strip('\n').split('\n')
if ', in ' in t[-3]:
t[-3] = t[-3].replace(', in','\n***\n*** In') + '(...):'
t[-2] += '\n***'
err = '\n*** '.join(t[-3:]).replace('"','').replace(' File ', '')
err = err.replace(', line',':')
Log("Traceback", '\n'.join(t[:-3]) + '\n\n\n***\n*** ' + err + '\n***\n\n')
os._exit(4)
def Set_Thread_Label(s):
global log_next_thread_id
with log_lock:
threading.current_thread().__name__ = "%d%s" \
% (log_next_thread_id, s)
log_next_thread_id += 1
class Handler(BaseHTTPServer.BaseHTTPRequestHandler):
def do_GET(self):
Set_Thread_Label(self.path + "[get]")
try:
Log("HTTP", "PATH='%s'" % self.path)
with open('static' + self.path) as f:
data = f.read()
Log("Static", "DATA='%s'" % data)
self.send_response(200)
self.send_header("Content-type", "text/html")
self.end_headers()
self.wfile.write(data)
except:
Log_Traceback()
def do_POST(self):
Set_Thread_Label(self.path + "[post]")
try:
length = int(self.headers.getheader('content-length'))
req = self.rfile.read(length)
Log("HTTP", "PATH='%s'" % self.path)
Log("URL", "request data = %s" % req)
req = json.loads(req)
response = {'req': req}
response = json.dumps(response)
Log("URL", "response data = %s" % response)
self.send_response(200)
self.send_header("Content-type", "application/json")
self.send_header("content-length", str(len(response)))
self.end_headers()
self.wfile.write(response)
except:
Log_Traceback()
# Create ONE socket.
addr = ('', 8000)
sock = socket.socket (socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(addr)
sock.listen(5)
# Launch 10 listener threads.
class Thread(threading.Thread):
def __init__(self, i):
threading.Thread.__init__(self)
self.i = i
self.daemon = True
self.start()
def run(self):
httpd = BaseHTTPServer.HTTPServer(addr, Handler, False)
# Prevent the HTTP server from re-binding every handler.
# https://stackoverflow.com/questions/46210672/
httpd.socket = sock
httpd.server_bind = self.server_close = lambda self: None
httpd.serve_forever()
[Thread(i) for i in range(10)]
time.sleep(9e9)
控制台日志（Chrome浏览器）：
HELLO
hello.html:14 {"req": {"value": "value"}}
hello.html:16
{req: {…}}
req
:
{value: "value"}
__proto__
:
Object
控制台日志（Firefox浏览器）：
GET
http://XXXXX:8000/hello.html [HTTP/1.0 200 OK 0ms]
POST
XHR
http://XXXXX:8000/postman [HTTP/1.0 200 OK 0ms]
HELLO hello.html:13:3
{"req": {"value": "value"}} hello.html:14:3
Object { req: Object }
控制台日志（Edge浏览器）：
HTML1300: Navigation occurred.
hello.html
HTML1527: DOCTYPE expected. Consider adding a valid HTML5 doctype: "<!DOCTYPE html>".
hello.html (1,1)
Current window: XXXXX/hello.html
HELLO
hello.html (13,3)
{"req": {"value": "value"}}
hello.html (14,3)
[object Object]
hello.html (16,3)
{
[functions]: ,
__proto__: { },
req: {
[functions]: ,
__proto__: { },
value: "value"
}
}
Python日志：
HTTP 8/postman[post]: PATH='/postman'
URL 8/postman[post]: request data = {"value":"value"}
URL 8/postman[post]: response data = {"req": {"value": "value"}}
另外，你可以通过在将套接字传递给BaseHTTPServer之前进行包装，轻松添加SSL加密。