Postman请求正常，VB.NET（RestSharp 106.15.0.0）调用报客户端内部错误

问题概述 #

Postman发送请求能正常执行，但通过VB.NET的RestSharp类库（版本106.15.0.0）直接调用时返回客户端错误。

错误信息 #

<?xml version="1.0" encoding="UTF-8"?>
<env:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope/"><env:Body><env:Fault><faultcode>env:Client</faultcode><faultstring>Internal Error (from client)</faultstring></env:Fault></env:Body></env:Envelope>

请求头代码 #

request.AddHeader("Content-Type", "application/json")
request.AddHeader("Accept", "application/json")
request.AddHeader("X-Client-Id", "78a7babff8feb0aed964113c867288b7")
request.AddHeader("Authorization", "Bearer xxxx")
request.AddHeader("Connection", "keep-alive")
request.AddHeader("Content-Length", 1420?)

JSON请求体 #

{
    "billNumber": "R2LEH003776X",
    "internalInvoiceNumber": "6666",
    "paymentMethod": "s",
    "invoiceIssueDate": "2024-05-11",
    "invoiceDueDate": "2024-05-12",
    "invoiceDescription": "",
    "billerVATNumber": 333,
    "companyName": "",
    "companyRegistrationNumber": 1234567890,
    "consumerEmail": "xx@xx.dd",
    "consumerMobile": "",
    "customerVATNumber": "",
    "buildingNumber": 4562,
    "additionalNumber": 7122,
    "street": "INDUSTRIAL STREET",
    "district": "",
    "postalCode": 12333,
    "city": "",
    "province": "",
    "country": "",
    "totalBeforeVAT": 1000.92,
    "totalVAT": 150.14,
    "grandTotal": 1151.06,
     "item":[
        {
          "invoiceLineSerialNo": 1,
          "itemCode": 100,
          "itemDescriptionArabic": "container BGHJ8777",
          "itemDescriptionEnglish": "",
          "unitOfMeasureArabic": "Unit",
          "unitOfMeasureEnglish": "",
          "itemPrice": 500.4586,
          "quantity": 2,
          "lineItemAmount": 1000.92,
          "lineItemDiscount": 0,
          "lineItemDiscountAmount": 0.0,
          "lineItemAmountAfterDiscount": 1000.92,
          "lineItemVAT": 15,
          "lineItemTotalVAT": 150.14,
          "lineItemTotal": 1151.06
        }
    ]
}

排查解决建议 #

• 移除手动设置的Content-Length头：RestSharp会自动计算并设置请求体长度，手动指定的数值（还带问号）大概率和实际请求体长度不匹配，直接删掉request.AddHeader("Content-Length", 1420?)这行代码。
• 检查JSON序列化逻辑：不要手动拼接JSON字符串，优先用request.AddJsonBody(yourModelObject)让RestSharp自动序列化，避免格式或编码错误；如果必须用字符串，用request.AddParameter("application/json", jsonString, ParameterType.RequestBody)明确指定参数类型。
• 确认请求方法一致：核对Postman使用的请求方法（POST/PUT等），确保RestSharp代码里的请求方法完全匹配，比如client.Post(request)或client.Put(request)。
• 升级RestSharp版本：106.15.0是较老的版本，存在一些序列化和请求头处理的已知问题，升级到最新稳定版能解决不少兼容性问题。
• 对比请求细节：用抓包工具（比如Fiddler）分别捕获Postman和VB.NET代码的请求，对比请求头、请求体的字节内容，找出差异点。

内容的提问来源于stack exchange，提问作者adelaraby