Robotframework POST多对象请求报400错误，求技术解决方案

正在进行API自动化测试，需要构造Postman中的多对象POST请求（请求示例如下），尝试编写Robotframework代码构造请求后，发送时出现HTTPError: 400 Client Error错误，附上代码请求协助解决。

Postman请求示例 #

{
    "affordability": {
        "grossIncome": 100000,
        "netIncome": 80000,
        "capitalRequired": 25000,
        "groceries": 200,
        "utilities": 300,
        "savings": 400,
        "services": 500,
        "transport": 600,
        "support": 800,
        "housing": 700,
        "other": 900
    },
    "employment": {
        "sector": "CentralGovernmentSocial",
        "status": "Contract",
        "startDate": "2010-08-01",
        "endDate": "2030-08-01"
    },
    "declarations": {
        "debtLiability": "None",
        "pendingRetrenchment": "false",
        "knownMedicalCondition": "false"
    },
    "bank": "ABSA"
}

我的Robotframework代码 #

#    &{baseURL}=          this is a url
#    ${offer}=           /offer
#    ${URL}=             Catenate           This is a url          ${appID}              /offer
#    log to console      ${URL}
#    Create Session      httpbin             this is a url
    &{affordability}=      Create Dictionary    grossIncome=60000     netIncome=30000      capitalRequired=25000       groceries=500        utilities=400     savings=300     services=200     transport=100     support=100       housing=500      other=100
    ${affordabilityobject}=    Catenate     {'affordability':      ${affordability}
#    log to console          ${affordabilityobject}
    &{employment}=       Create Dictionary      sector=CentralGovernmentSocial         status=Contract        startDate=2019-08-01           endDate=2023-08-01
    ${employmentobject}=        Catenate     'employment':      ${employment}
#    log to console          ${employmentobject}
    &{declarations}=      Create Dictionary     debtLiability=None      pendingRetrenchment=false      knownMedicalCondition=false
    ${declarationsobject}=      Catenate     'declarations':      ${declarations}
#    log to console          ${declarationsobject}
#    &{bank}=              Create Dictionary     bank=FirstNationalBank
    ${bank}=              Catenate     'bank':'FirstNationalBank'}
    log to console      ${bank}
    ${fullrequest}=             Catenate        SEPARATOR=,        ${affordabilityobject}      ${employmentobject}       ${declarationsobject}     ${bank}
    log to console      ${fullrequest}
    ${resp}=    Post      this is a url/${appID}/offer         json=${fullrequest}

问题原因及修正方案 #

错误原因 #

你现在的代码用Catenate手动拼接字符串构造请求体，会生成格式非法的JSON：

• 直接拼接Robotframework字典会保留框架自身的格式（比如{grossIncome:60000 ...}），不是标准JSON的键值对格式
• 拼接过程缺少必要的括号、引号，整体结构混乱，接口无法解析请求体，因此返回400错误

修正后的代码 #

Robotframework的Post关键字的json参数可直接接收嵌套字典，框架会自动将其序列化为合法JSON，无需手动拼接：

# 定义各个子字典
&{affordability}=      Create Dictionary    grossIncome=60000     netIncome=30000      capitalRequired=25000       groceries=500        utilities=400     savings=300     services=200     transport=100     support=100       housing=500      other=100
&{employment}=         Create Dictionary    sector=CentralGovernmentSocial         status=Contract        startDate=2019-08-01           endDate=2023-08-01
&{declarations}=       Create Dictionary    debtLiability=None      pendingRetrenchment=false      knownMedicalCondition=false

# 构造顶层请求体字典，整合所有字段
&{full_request}=       Create Dictionary    affordability=${affordability}    employment=${employment}    declarations=${declarations}    bank=FirstNationalBank

# 发送POST请求，直接传入顶层字典即可
${resp}=               Post                this is a url/${appID}/offer         json=${full_request}
log to console         ${resp.json()}

关键说明 #

1. 先创建所有子字典，再用一个顶层字典整合所有请求字段，结构和Postman示例完全对应
2. Post关键字会自动处理字典到JSON的转换，生成接口可识别的合法请求体
3. 可以通过${resp.json()}打印响应内容，方便后续排查问题

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