SN verification support

[Gujiawei-Edinburgh]

I read the python code in this repo. I think currently, it directly uses the AK for http calls. However, from the offical website, if SN verification is enabled, it should calculate the SN value and append SN in the request. Therefore, in this way, it will get "APP SN 校验失败" message.

From issue12, IP white list is prefered.
But I am still confused why SN is not prefered here. I think wrap the following code can support SN verification.

import asyncio
import hashlib
import urllib
import httpx

ak = $AK
sk = $SK

host = "https://api.map.baidu.com"


async def map_weather(name: str, arguments: dict):
    """
    From map.py map_weather
    """
    try:
        uri = "/weather_abroad/v1/"
        location = arguments.get("location", "")
        district_id = arguments.get("district_id", "")

        params = {
            "data_type": "all",
            "ak": ak,
            "from": "py_mcp"
        }

        if not location:
            params["district_id"] = f"{district_id}"
        else:
            params["location"] = f"{location}"

        paramsArr = []
        for key in params:
            paramsArr.append(key + "=" + params[key])

        queryStr = uri + "?" + "&".join(paramsArr)

        encodedStr = urllib.request.quote(queryStr, safe="/:=&?#+!$,;'@()*[]")

        rawStr = encodedStr + sk

        sn = hashlib.md5(urllib.parse.quote_plus(rawStr).encode("utf8")).hexdigest()

        queryStr = queryStr + "&sn=" + sn

        url = host + queryStr

        async with httpx.AsyncClient() as client:
            response = await client.get(url)
            response.raise_for_status()
            result = response.json()

        if result.get("status") != 0:
            error_msg = result.get("message", "unknown error")
            raise Exception(f"API response error: {error_msg}")

        return [response.text]

    except httpx.HTTPError as e:
        raise Exception(f"HTTP request failed: {str(e)}") from e
    except KeyError as e:
        raise Exception(f"Failed to parse reponse: {str(e)}") from e


if __name__ == '__main__':
    asyncio.get_event_loop().run_until_complete(map_weather(name="weather", arguments={"district_id": "JPN10041030001"}))

[Pineapple274]

Thank you very much for your attention to Baidu Maps MCP Server, you may be able to ask the question in the form of PR, which will be more clear 🤓

Here we answer your query about the main reason we don't provide SN checksum: the method can be provided, but the usage scenario is too specific.

As you can see in #12 , the main reason we don't add the sn checksum is that MCP Server is usually called by Agent, which leads to the fact that there is no way for MCP to predict the parameters passed in by Agent. So any slight change in the number of coordinate parameters will cause the SN checksum to detect a change in the hash value of the original request string, which will cause the SN checksum to fail, resulting in the message “APP SN 校验失败”.

We generally believe that this kind of verification is not suitable for widely used Agent interaction scenarios, but if you use Baidu Maps MCP Server by developing your own MCP client, you can control the fixed input parameters to ensure that the Hash value of the original request string remains unchanged, which naturally allows SN verification.

For your request, we will submit the corresponding modifications later, if your needs are more urgent, you are also very welcome to participate in the modification of the submission of PR. of course, these modifications must not have an impact on the existing ak checksum scenarios.

Thanks again for your feedback ❤️❤️☺️

[Gujiawei-Edinburgh]

Thanks for your reply. I will try to submit a PR for SN verification in the near future.