使用Python调用eBay API发布商品时遇Error ID 2004问题求助

问题现象 #

• 调用eBay sell/inventory/v1/inventory_item API发布商品时，返回错误：

  {"errors":[{"errorId":2004,"domain":"ACCESS","category":"REQUEST","message":"Invalid request","longMessage":"The request has errors. For help, see the documentation for this API."}]}
  

• 确认未达调用限额，access code有效
• 在API Explorer测试时，得到更详细错误提示：

  {
    "errors": [
      {
        "errorId": 2004,
        "domain": "ACCESS",
        "category": "REQUEST",
        "message": "Invalid request",
        "longMessage": "The request has errors. For help, see the documentation for this API.",
        "parameters": [
          {
            "name": "reason",
            "value": "Can not instantiate value of type [simple type, class com.ebay.raptor.slrinvapi.app.entities.InventoryItem] from JSON String; no single-String constructor/factory method"
          }
        ]
      }
    ]
  }
  

问题根源 #

错误提示的核心是API无法解析请求体，本质原因是请求方法和URL不符合API规范：

• eBay创建/更新inventory item的接口要求使用PUT方法，且必须在URL中指定唯一SKU（格式为https://api.ebay.com/sell/inventory/v1/inventory_item/{sku}）
• 你当前使用POST请求不带SKU的URL，API会错误地将请求体当作字符串解析，导致无法实例化InventoryItem对象

修复方案 #

1. 修正请求方法与URL #

将请求方法从POST改为PUT，并在URL末尾拼接自定义的唯一SKU：

# 替换为你的商品唯一SKU
sku = "BLUETOOTH_SPEAKER_001"
response = requests.put(f"{api_url}/{sku}", headers=headers, json=data)

2. 完善请求体必填字段 #

根据eBay API文档，补充availability等必填字段（原代码中直接用quantity不符合规范）：

data = {
    "title": "Bluetooth Speaker",
    "condition": "NEW",
    "description": "This is a very good speaker and sounds amazing",
    "imageUrls": [
        "https://amazon.adamkhattab.co.uk/photo.jpg"
    ],
    "price": {
        "value": "20.00",
        "currency": "GBP"
    },
    "availability": {
        "shipToLocationAvailability": {
            "quantity": 1
        }
    }
}

3. 优化请求写法 #

使用requests的json参数替代手动序列化，自动处理Content-Type头：

response = requests.put(f"{api_url}/{sku}", headers=headers, json=data)

完整修复后的代码 #

import requests
import json
import base64

client_id = '#################################'
client_secret = '#################################'
redirect_uri = 'https://amazon.adamkhattab.co.uk/callback.php'

auth_url = 'https://auth.ebay.com/oauth2/authorize'
token_url = 'https://api.ebay.com/identity/v1/oauth2/token'
api_url = 'https://api.ebay.com/sell/inventory/v1/inventory_item'

def get_access_token(client_id, client_secret, redirect_uri):
    auth_code = input('Please enter the authorization code: ')
    headers = {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Authorization': f'Basic {base64.b64encode(f"{client_id}:{client_secret}".encode()).decode()}'
    }
    data = {
        'grant_type': 'authorization_code',
        'code': auth_code,
        'redirect_uri': redirect_uri
    }
    response = requests.post(token_url, headers=headers, data=data)
    # 添加token获取失败的错误处理
    if response.status_code != 200:
        print(f"获取token失败: {response.text}")
        return None
    access_token = json.loads(response.text)['access_token']
    return access_token

def list_item(access_token):
    if not access_token:
        return
    headers = {
        'Authorization': f'Bearer {access_token}',
        'Content-Type': 'application/json',
        'Accept': 'application/json'
    }

    data = {
        "title": "Bluetooth Speaker",
        "condition": "NEW",
        "description": "This is a very good speaker and sounds amazing",
        "imageUrls": [
            "https://amazon.adamkhattab.co.uk/photo.jpg"
        ],
        "price": {
            "value": "20.00",
            "currency": "GBP"
        },
        "availability": {
            "shipToLocationAvailability": {
                "quantity": 1
            }
        }
    }
    sku = "BLUETOOTH_SPEAKER_001"
    response = requests.put(f"{api_url}/{sku}", headers=headers, json=data)
    print(response.text)

auth_url += f'?client_id={client_id}&redirect_uri={redirect_uri}&response_type=code&scope=https://api.ebay.com/oauth/api_scope/sell.inventory'

print(f'Please visit the following URL and authorize the application:\n{auth_url}')
access_token = get_access_token(client_id, client_secret, redirect_uri)
list_item(access_token)

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