如何在 CherryPy 中设置 CORS
How to set up CORS in CherryPy
概览
当创建从我的网站到我的 Python 服务器 运行ning CherryPy 的 post 请求时，我收到错误 Access to XMLHttpRequest has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.。我能够使用 "CORS Everywhere" 浏览器扩展程序之一暂时解决问题，但是
- 由于最近的更新，扩展尚未更新以再次运行。
- 所涉及的网站最终需要在没有浏览器扩展的情况下被我当地的许多人使用，所以一旦扩展得到更新，无论哪种方式都无关紧要，因为我不能依赖这些扩展，并且强制每个人都使用它们（当显然有一个不需要扩展的修复程序时）。
我想也许这些解决方案已经过时了，但我不确定。
相关代码如下：
在服务器端（CherryPy/Python）：
正在调用 CherryPy Python 函数，来自网站 post 请求
@cherrypy.expose
@cherrypy.tools.json_in()
def add_meeting(self):
data = None
id = None
start_time = None
end_time = None
title = None
userlist = None
result = {"operation": "request", "result": "success"}
if cherrypy.request.method == "POST":
data = cherrypy.request.json
id = data["id"]
start_time = data["start_time"]
end_time = data["end_time"]
title = data["title"]
userlist = data["userlist"]
# Rest of relevant code in function is left out, to take up less
# space and not post irrelevant code. That being said, I am
# positive the logic is correct, as it originally ran smoothly
# with a "Cors Everywhere" Browser Extension.
return result
这里是我设置的区域和运行CherryPy
def main():
# Create the configuration file parser object and start the CherryPy server
config = ConfigParser.ConfigParser()
config.read(CONFIG_FILE)
port = config.getint('Meta', 'port')
host = config.get('Meta', 'host')
cherrypy.config.update({'server.socket_port': port,
'server.socket_host': host,
'tools.CORS.on': True})
cherrypy.quickstart(Coordinator(config))
main()
这里是上面代码中提到的配置文件(CONFIG_FILE)
[Meta]
host = 0.0.0.0
port = 3000
# Rest is left out, as it is irrelevant with problem
我尝试实施的解决方案
- 在main函数之上包含以下函数：
def CORS():
cherrypy.response.headers["Access-Control-Allow-Origin"] = "*"
与 cherrypy.tools.CORS = cherrypy.Tool('before_handler', CORS)
2.在
上方的cherrypy.config.update中添加“'cors.expose.on': True”
3. 使用我在网上找到的 cherrypy-cors Python 库：https://pypi.org/project/cherrypy-cors/
4. headers 包含在 Python 文件的 config.update 部分
5.在"def add_meeting"
前添加“@cherrypy.tools.accept(media='application/json')”
结论
我已经分别尝试了上述解决方案，有的有，有的没有，但我仍然卡住了。也许其中一些解决方案是部分正确的，我的代码还需要一些额外的东西。我不知道;我就是无法让它工作。在此之前我没有太多的 Web 开发经验，所以也许（并且希望）解决方案非常简单。我知道该代码有效，但如果没有为每个用户提供有效的 "Cors Everywhere" 浏览器扩展，我就无法获得它 运行ning。
至于我运行ning的版本：我使用的是CherryPy 14.2.0和Python 2.7.6
任何帮助对我来说都意味着绝对的世界，谢谢。
所以首先，你需要在处理OPTIONS请求时设置pre-flight headers，你可以在那里列出允许的方法。
然后，您还需要启用 cors.expose 工具。
有一些使用提示 in the docstring of cherrypy-cors. For example, when using a MethodDispatcher，您可以用 @cherrypy_cors.tools.preflight() 修饰 OPTIONS 处理程序方法，而不是在每个 HTTP 处理程序中都这样做。
这是一个简单的遍历示例（没有方法调度程序）。要对其进行测试，请访问 http://127.0.0.1/ and it will make requests against http://localhost:3333/add_meeting，就 CORS ('localhost' != '127.0.0.1') 而言，这是一个不同的 Origin。
"""Example of CORS setup using cherrypy-cors library."""
import cherrypy
import cherrypy_cors
# Python 2 compat: make all classes new-style by default
__metaclass__ = type # pylint: disable=invalid-name
class WebRoot:
"""Root node for HTTP handlers."""
@cherrypy.expose
def index(self): # pylint: disable=no-self-use
"""Render a web page handling request against ``/``.
Contains client JS snippet which will query the API endpoint.
It will be executed by the browser while loading the page.
"""
return """<html>
<script type="text/javascript">
async function addMeeting() {
/*
* Example coroutine for querying /add_meeing
* HTTP endpoint. It uses localhost as in the URL.
* For testing CORS, make sure to visit
* http://127.0.0.1/ which is a different origin
* from browser's perspective.
* /
const request_payload = {
some: 'data',
listed: ['h', 'er', 'e'],
}
try {
const resp = await fetch(
'http://localhost:3333/add_meeting',
{
method: 'POST',
mode: 'cors', // Required for customizing HTTP request headers
credentials: 'same-origin',
headers: {
'Content-Type': 'application/json; charset=UTF-8', // Required for ``cherrypy.tools.json_in`` to identify JSON payload and parse it automatically
},
body: JSON.stringify(request_payload),
},
)
const json_resp = await resp.json()
console.log(json_resp) // Will print: {"method": "POST", "payload": {"listed": ["h", "er", "e"], "some": "data"}}
} catch (e) {
console.warn('Exception: ' + e)
}
}
async function main() {
await addMeeting()
}
main() // Entry point
</script>
</html>""" # noqa: E501
@cherrypy.expose
@cherrypy.tools.json_in() # turn HTTP payload into an object; also checking the Content-Type header
@cherrypy.tools.json_out() # turn ``return``ed Python object into a JSON string; also setting corresponding Content-Type
def add_meeting(self):
"""Handle HTTP requests against ``/add_meeting`` URI."""
if cherrypy.request.method == 'OPTIONS':
# This is a request that browser sends in CORS prior to
# sending a real request.
# Set up extra headers for a pre-flight OPTIONS request.
cherrypy_cors.preflight(allowed_methods=['GET', 'POST'])
if cherrypy.request.method == 'POST':
return {'method': 'POST', 'payload': cherrypy.request.json}
return {'method': 'non-POST'}
def main():
"""Set up and run the web app.
Initializes CORS tools.
Sets up web server socket.
Enables the CORS tool.
"""
cherrypy_cors.install()
cherrypy.config.update({
'server.socket_host': '127.0.0.1',
'server.socket_port': 3333,
'cors.expose.on': True,
})
cherrypy.quickstart(WebRoot())
__name__ == '__main__' and main() # pylint: disable=expression-not-assigned
概览
当创建从我的网站到我的 Python 服务器 运行ning CherryPy 的 post 请求时，我收到错误 Access to XMLHttpRequest has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.。我能够使用 "CORS Everywhere" 浏览器扩展程序之一暂时解决问题，但是
- 由于最近的更新，扩展尚未更新以再次运行。
- 所涉及的网站最终需要在没有浏览器扩展的情况下被我当地的许多人使用，所以一旦扩展得到更新，无论哪种方式都无关紧要，因为我不能依赖这些扩展，并且强制每个人都使用它们（当显然有一个不需要扩展的修复程序时）。 我想也许这些解决方案已经过时了，但我不确定。
相关代码如下：
在服务器端（CherryPy/Python）：
正在调用 CherryPy Python 函数，来自网站 post 请求
@cherrypy.expose
@cherrypy.tools.json_in()
def add_meeting(self):
data = None
id = None
start_time = None
end_time = None
title = None
userlist = None
result = {"operation": "request", "result": "success"}
if cherrypy.request.method == "POST":
data = cherrypy.request.json
id = data["id"]
start_time = data["start_time"]
end_time = data["end_time"]
title = data["title"]
userlist = data["userlist"]
# Rest of relevant code in function is left out, to take up less
# space and not post irrelevant code. That being said, I am
# positive the logic is correct, as it originally ran smoothly
# with a "Cors Everywhere" Browser Extension.
return result
这里是我设置的区域和运行CherryPy
def main():
# Create the configuration file parser object and start the CherryPy server
config = ConfigParser.ConfigParser()
config.read(CONFIG_FILE)
port = config.getint('Meta', 'port')
host = config.get('Meta', 'host')
cherrypy.config.update({'server.socket_port': port,
'server.socket_host': host,
'tools.CORS.on': True})
cherrypy.quickstart(Coordinator(config))
main()
这里是上面代码中提到的配置文件(CONFIG_FILE)
[Meta]
host = 0.0.0.0
port = 3000
# Rest is left out, as it is irrelevant with problem
我尝试实施的解决方案
- 在main函数之上包含以下函数：
def CORS():
cherrypy.response.headers["Access-Control-Allow-Origin"] = "*"
与 cherrypy.tools.CORS = cherrypy.Tool('before_handler', CORS)
2.在
上方的cherrypy.config.update中添加“'cors.expose.on': True”
3. 使用我在网上找到的 cherrypy-cors Python 库：https://pypi.org/project/cherrypy-cors/
4. headers 包含在 Python 文件的 config.update 部分
5.在"def add_meeting"
结论
我已经分别尝试了上述解决方案，有的有，有的没有，但我仍然卡住了。也许其中一些解决方案是部分正确的，我的代码还需要一些额外的东西。我不知道;我就是无法让它工作。在此之前我没有太多的 Web 开发经验，所以也许（并且希望）解决方案非常简单。我知道该代码有效，但如果没有为每个用户提供有效的 "Cors Everywhere" 浏览器扩展，我就无法获得它 运行ning。
至于我运行ning的版本：我使用的是CherryPy 14.2.0和Python 2.7.6
任何帮助对我来说都意味着绝对的世界，谢谢。
所以首先，你需要在处理OPTIONS请求时设置pre-flight headers，你可以在那里列出允许的方法。
然后，您还需要启用 cors.expose 工具。
有一些使用提示 in the docstring of cherrypy-cors. For example, when using a MethodDispatcher，您可以用 @cherrypy_cors.tools.preflight() 修饰 OPTIONS 处理程序方法，而不是在每个 HTTP 处理程序中都这样做。
这是一个简单的遍历示例（没有方法调度程序）。要对其进行测试，请访问 http://127.0.0.1/ and it will make requests against http://localhost:3333/add_meeting，就 CORS ('localhost' != '127.0.0.1') 而言，这是一个不同的 Origin。
"""Example of CORS setup using cherrypy-cors library."""
import cherrypy
import cherrypy_cors
# Python 2 compat: make all classes new-style by default
__metaclass__ = type # pylint: disable=invalid-name
class WebRoot:
"""Root node for HTTP handlers."""
@cherrypy.expose
def index(self): # pylint: disable=no-self-use
"""Render a web page handling request against ``/``.
Contains client JS snippet which will query the API endpoint.
It will be executed by the browser while loading the page.
"""
return """<html>
<script type="text/javascript">
async function addMeeting() {
/*
* Example coroutine for querying /add_meeing
* HTTP endpoint. It uses localhost as in the URL.
* For testing CORS, make sure to visit
* http://127.0.0.1/ which is a different origin
* from browser's perspective.
* /
const request_payload = {
some: 'data',
listed: ['h', 'er', 'e'],
}
try {
const resp = await fetch(
'http://localhost:3333/add_meeting',
{
method: 'POST',
mode: 'cors', // Required for customizing HTTP request headers
credentials: 'same-origin',
headers: {
'Content-Type': 'application/json; charset=UTF-8', // Required for ``cherrypy.tools.json_in`` to identify JSON payload and parse it automatically
},
body: JSON.stringify(request_payload),
},
)
const json_resp = await resp.json()
console.log(json_resp) // Will print: {"method": "POST", "payload": {"listed": ["h", "er", "e"], "some": "data"}}
} catch (e) {
console.warn('Exception: ' + e)
}
}
async function main() {
await addMeeting()
}
main() // Entry point
</script>
</html>""" # noqa: E501
@cherrypy.expose
@cherrypy.tools.json_in() # turn HTTP payload into an object; also checking the Content-Type header
@cherrypy.tools.json_out() # turn ``return``ed Python object into a JSON string; also setting corresponding Content-Type
def add_meeting(self):
"""Handle HTTP requests against ``/add_meeting`` URI."""
if cherrypy.request.method == 'OPTIONS':
# This is a request that browser sends in CORS prior to
# sending a real request.
# Set up extra headers for a pre-flight OPTIONS request.
cherrypy_cors.preflight(allowed_methods=['GET', 'POST'])
if cherrypy.request.method == 'POST':
return {'method': 'POST', 'payload': cherrypy.request.json}
return {'method': 'non-POST'}
def main():
"""Set up and run the web app.
Initializes CORS tools.
Sets up web server socket.
Enables the CORS tool.
"""
cherrypy_cors.install()
cherrypy.config.update({
'server.socket_host': '127.0.0.1',
'server.socket_port': 3333,
'cors.expose.on': True,
})
cherrypy.quickstart(WebRoot())
__name__ == '__main__' and main() # pylint: disable=expression-not-assigned