调用OpenTripPlanner API时DateTime参数引发JSON格式错误求助

问题场景 #

使用OpenTripPlanner的transmodel/v3 GraphQL API查询行程时，带dateTime参数的请求持续报错，不带该参数的请求可正常获取响应。尝试过转义字符串、格式化传参等方式，均未解决，不确定dateTime是否需特殊对象传递。

错误信息 #

Unexpected character ('2' (code 50)): was expecting comma to separate Object entries
at [Source: REDACTED (StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION disabled); line: 1, column: 167]

现有代码 #

headers = {
    'Content-Type': 'application/json',
    'OTPTimeout': '180000',
}

data2 = '{"query" :"query {trip(from: {coordinates: {latitude:  27.94942 longitude:  -82.47202 }}to:\
      {coordinates: {latitude: 27.99107 longitude: -82.45619 }} dateTime: "2024-11-18T14:00:00.000Z") \
        {tripPatterns {duration distance legs{ distance duration id mode}}}}"}'
           

response = requests.post('http://localhost:8080/otp/transmodel/v3', headers = headers, data = data2)

json_string = response.text

问题原因 #

核心是JSON嵌套字符串的引号转义错误：

• 外层JSON用双引号包裹query的值，而query内部dateTime的参数值又使用了未转义的双引号，导致JSON解析器误判query字符串提前结束，后续的2024...成为无效的JSON结构。
• OpenTripPlanner的GraphQL API接受dateTime为ISO 8601格式的字符串，无需特殊对象，格式正确即可。

解决方法 #

推荐两种避免手动转义的安全写法：

方法1：用json.dumps自动处理转义 #

import requests
import json

headers = {
    'Content-Type': 'application/json',
    'OTPTimeout': '180000',
}

# 三引号编写原始GraphQL查询，无需手动转义
graphql_query = '''
query {
  trip(
    from: {coordinates: {latitude: 27.94942, longitude: -82.47202}},
    to: {coordinates: {latitude: 27.99107, longitude: -82.45619}},
    dateTime: "2024-11-18T14:00:00.000Z"
  ) {
    tripPatterns {
      duration
      distance
      legs {
        distance
        duration
        id
        mode
      }
    }
  }
}
'''

# 自动处理JSON格式与引号转义
data = json.dumps({"query": graphql_query})

response = requests.post('http://localhost:8080/otp/transmodel/v3', headers=headers, data=data)
json_string = response.text

方法2：用requests的json参数自动序列化 #

import requests

headers = {
    'OTPTimeout': '180000',
}

graphql_query = '''
query {
  trip(
    from: {coordinates: {latitude: 27.94942, longitude: -82.47202}},
    to: {coordinates: {latitude: 27.99107, longitude: -82.45619}},
    dateTime: "2024-11-18T14:00:00.000Z"
  ) {
    tripPatterns {
      duration
      distance
      legs {
        distance
        duration
        id
        mode
      }
    }
  }
}
'''

# 直接传递字典，requests自动转为正确JSON
response = requests.post(
    'http://localhost:8080/otp/transmodel/v3',
    headers=headers,
    json={"query": graphql_query}
)
json_string = response.text

关键说明 #

• 无需手动转义引号，依赖Python的JSON处理库自动处理，避免人为错误。
• dateTime仅需传递ISO 8601格式的字符串即可被API正确解析。

内容的提问来源于stack exchange，提问作者James Polo