如何修复返回“Invalid JSON primitive: .”的POST请求

架构老林

2026-6-29

问题描述

尝试通过POST请求爬取starbet.rs的投注数据时，返回Invalid JSON primitive: .错误。请求头和请求体均直接取自网站原有请求的cURL内容，修改POST返回类型后只能拿到网站HTML页面，无法获取目标JSON数据。

网站地址：https://www.starbet.rs/Bet

原代码：

import requests
import json

url = "https://www.starbet.rs/Oblozuvanje.aspx/GetLiga"

payload = "{LigaID:^[494^],filter:0,parId:0}"
###LigaID is the ID of the chosen leagues not really of importance
headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:122.0) Gecko/20100101 Firefox/122.0",
    "Accept": "application/json, text/javascript, */*; q=0.01",
    "Accept-Language": "en-US,en;q=0.5",
    "Accept-Encoding": "gzip, deflate, br",
    "Content-Type": "application/json; charset=utf-8",
    "X-Requested-With": "XMLHttpRequest",
    "Origin": "https://www.starbet.rs",
    "DNT": "1",
    "Sec-GPC": "1",
    "Connection": "keep-alive",
    "Referer": "https://www.starbet.rs/Bet",
    "Cookie": "ASP.NET_SessionId=jsjbtw2gizig2sh3mfrrqyje; style=null",
    "Sec-Fetch-Dest": "empty",
    "Sec-Fetch-Mode": "cors",
    "Sec-Fetch-Site": "same-origin",
    "TE": "trailers"
}

response = requests.request("POST", url, data=payload, headers=headers)

print(response.text)

错误信息（中文翻译）：

"Message": "无效的JSON原语: .",
"StackTrace": "在 System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializePrimitiveObject()\r\n 在 System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)\r\n 在 System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeDictionary(Int32 depth)\r\n 在 System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)\r\n 在 System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)\r\n 在 System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit)\r\n 在 System.Web.Script.Serialization.JavaScriptSerializer.Deserialize[T](String input)\r\n 在 System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)",
"ExceptionType": "System.ArgumentException"

解决方案

问题根源在于请求体的JSON格式不合法：

原payload中的^[494^]是网站请求中的特殊编码，并非标准JSON格式，需要改成正常的数组[494]
JSON要求键名必须用双引号包裹，原payload的键名（如LigaID）没有加双引号
使用data参数传递字符串payload容易出现格式错误，推荐用json参数直接传递Python字典，requests会自动完成JSON序列化并设置正确的请求头

修改后的代码：

import requests

url = "https://www.starbet.rs/Oblozuvanje.aspx/GetLiga"

# 用Python字典构造合法的请求体，自动序列化为JSON
payload = {
    "LigaID": [494],
    "filter": 0,
    "parId": 0
}

headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:122.0) Gecko/20100101 Firefox/122.0",
    "Accept": "application/json, text/javascript, */*; q=0.01",
    "Accept-Language": "en-US,en;q=0.5",
    "X-Requested-With": "XMLHttpRequest",
    "Origin": "https://www.starbet.rs",
    "DNT": "1",
    "Sec-GPC": "1",
    "Connection": "keep-alive",
    "Referer": "https://www.starbet.rs/Bet",
    "Cookie": "ASP.NET_SessionId=jsjbtw2gizig2sh3mfrrqyje; style=null",
    "Sec-Fetch-Dest": "empty",
    "Sec-Fetch-Mode": "cors",
    "Sec-Fetch-Site": "same-origin",
    "TE": "trailers"
}

# 使用json参数传递payload，无需手动设置Content-Type（requests会自动处理）
response = requests.post(url, json=payload, headers=headers)

print(response.text)

关键改动说明

把字符串格式的payload改成Python字典，确保结构符合JSON规范
移除了原payload中的^符号，将^[494^]修正为标准数组[494]
用requests.post替代requests.request，代码更简洁
使用json参数传递请求体，替代data参数，避免手动构造JSON字符串的错误

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

如何修复返回“Invalid JSON primitive: .”的POST请求

关键改动说明 #

关键改动说明