如何修复Python中hyper库的FRAME_SIZE_ERROR连接错误

问题场景 #

需要向单元测试REST API服务器发送HTTP/2的GET和POST请求，使用requests库结合hyper的HTTP20Adapter实现，但运行时抛出帧大小错误。

原始代码如下：

import requests
from hyper.contrib import HTTP20Adapter

s = requests.Session()
data={
    "param1": 3000,
    "param2": 10,
    "param3": 2,
    "param4": "2200",
    "param5": "800",
    "param6": "2200",
    "param7": "2000",
    "param8": "1700",
    "param9": "1200",
    "param10": 60,
    "param11": "23:00-22:59",
    "param12": 3,
    "param13": True,
    "param14": 85
}
s.verify="/path to ca-cert file"
s.mount('https://', HTTP20Adapter())
r = s.post('https://localhost:1000/config', data=data)
print(r.status_code)
print(r.url)

报错信息 #

Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 635, in post
        return self.request("POST", url, data=data, json=json, **kwargs)
      File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 587, in request
        resp = self.send(prep, **send_kwargs)
      File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 701, in send
        r = adapter.send(request, **kwargs)
      File "/usr/local/lib/python3.9/site-packages/hyper/contrib.py", line 118, in send
        resp = conn.get_response()
      File "/usr/local/lib/python3.9/site-packages/hyper/common/connection.py", line 136, in get_response
        return self._conn.get_response(*args, **kwargs)
      File "/usr/local/lib/python3.9/site-packages/hyper/http20/connection.py", line 305, in get_response
        return HTTP20Response(stream.getheaders(), stream)
      File "/usr/local/lib/python3.9/site-packages/hyper/http20/stream.py", line 240, in getheaders
        self._recv_cb(stream_id=self.stream_id)
      File "/usr/local/lib/python3.9/site-packages/hyper/http20/connection.py", line 787, in _recv_cb
        self._single_read()
      File "/usr/local/lib/python3.9/site-packages/hyper/http20/connection.py", line 738, in _single_read
        raise ConnectionError(error_string)
hyper.http20.exceptions.ConnectionError: Encountered error FRAME_SIZE_ERROR 0x6: Frame size incorrect

解决方法 #

这个错误是因为HTTP/2连接的帧大小不匹配，需要自定义流量控制管理器来适配服务器的帧大小设置。具体步骤如下：

1. 导入BaseFlowControlManager类，自定义流量控制管理器；
2. 继承HTTP20Adapter，重写build_connection方法，在创建HTTP20连接时传入自定义的流量控制管理器；
3. 将自定义的适配器挂载到requests Session上。

修改后的完整代码：

import requests
from hyper.contrib import HTTP20Adapter
from hyper.http20.window import BaseFlowControlManager

# 自定义流量控制管理器
class StupidFlowControlManager(BaseFlowControlManager):
    def increase_window_size(self, frame_size):
        return frame_size

# 继承HTTP20Adapter，自定义连接创建逻辑
class CustomHTTP20Adapter(HTTP20Adapter):
    def build_connection(self, host, port, secure):
        # 创建连接时传入自定义的window_manager
        conn = super().build_connection(host, port, secure)
        conn._conn.window_manager = StupidFlowControlManager()
        return conn

s = requests.Session()
data={
    "param1": 3000,
    "param2": 10,
    "param3": 2,
    "param4": "2200",
    "param5": "800",
    "param6": "2200",
    "param7": "2000",
    "param8": "1700",
    "param9": "1200",
    "param10": 60,
    "param11": "23:00-22:59",
    "param12": 3,
    "param13": True,
    "param14": 85
}
s.verify="/path to ca-cert file"
# 挂载自定义的适配器
s.mount('https://', CustomHTTP20Adapter())

# 发送POST请求
r = s.post('https://localhost:1000/config', json=data)  # 建议用json参数自动序列化，避免表单编码问题
print(r.status_code)
print(r.url)

补充说明 #

• 代码中把data=data改为json=data，因为大多数REST API期望接收JSON格式的请求体，而data参数默认会以表单形式编码，可能不符合服务器要求；
• 如果自定义的流量控制管理器仍不生效，可以尝试调整帧大小的具体数值，比如返回一个固定的较大值（如return 65535，HTTP/2最大帧大小）。

内容的提问来源于stack exchange，提问作者user5759780