为何控制台返回JSON解析错误，无法将表单数据同步至Mailchimp列表？

我尝试用自制表单提交数据到Mailchimp列表，用body-parser解析表单数据后构造符合Mailchimp批量订阅API格式的JSON，再通过Node.js的https模块发送POST请求。修正request.end为request.end()后，控制台抛出JSON解析错误，且Mailchimp列表里的用户合并字段为空。

原代码 #

app.post("/",function(req,res){
    const fName = req.body.first_name;
    const lName = req.body.last_name;
    const email = req.body.email;

    const data = {
      members: [
          {
              email_address: email,
              status: "subscribed",
              merge_fields: {
               first_name: fName,
                  last_name: lName
              }
          }
      ]     
    }   

    const jsonData = JSON.stringify(data);

    const url = "https://{api-server}.api.mailchimp.com/3.0/lists/{list_id}";

    const options = {
        method:"POST",
        auth: "{my_string}:{my_api_key}"
    }

    const request = https.request(url, options, function(response){
        response.on("data",function(data){
            console.log(JSON.parse(data));
        })
    })

    request.write(jsonData);
    request.end();
})

出现的错误 #

undefined:1
{"new_members":[{"id":"2f0285dfb0337da7ddbc581a5452fd06","email_address":"buchu@luyu.com","unique_email_id":"5b4586e19a","email_type":"html","status":"subscribed","merge_fields":{"FNAME":"","LNAME":"","ADDRESS":"","PHONE":"","BIRTHDAY":""},"stats":{"avg_open_rate":0,"avg_click_rate":0},"ip_signup":"","timestamp_signup":"","ip_opt":"202.51.69.32","timestamp_opt":"2023-12-09T06:40:27+00:00","member_rating":2,"last_changed":"2023-12-09T06:40:27+00:00","language":"","vip":false,"email_client":"","location":{"latitude":0,"longitude":0,"gmtoff":0,"dstoff":0,"country_code":"","timezone":""},"tags_count":0,"tags":[],"list_id":"bd9a1eb732","_links":[{"rel":"self","href":"https://us21.api.mailchimp.com/3.0/lists/{my_list_id}/members/2f0285dfb0337da7ddbc581a5452fd06","method":"GET","targetSchema":"https://us21.api.mailchimp.com/schema/3.0/Definitions/Lists/Members/Response.json"},{"rel":"parent","href":"https://us21.api.mailchimp.com/3.0/lists/{my_list_id}/members","method":"GET","targetSchema":"https://us21.api.mailchimp.com/schema/3.0/Definitions/Lists/Members/CollectionResponse.json","schema":"https://us21.api.mailchimp.com/schema/3.0/Paths/Lists/Members/Collection.json"},{"rel":"update","href":"https://us21.api.mailchimp.com/3.0/lists/{my_list_id}/members/2f0285dfb0337da7ddbc581a5452fd06","method":"PATCH","targetSchema":"https://us21.api.mailchimp.com/schema/3.0

SyntaxError: Unterminated string in JSON at position 1371
    at JSON.parse (<anonymous>)
    at IncomingMessage.<anonymous> (F:\Projects\newsletter-signup\app.js:56:30)
    at IncomingMessage.emit (node:events:514:28)
    at Readable.read (node:internal/streams/readable:758:10)
    at flow (node:internal/streams/readable:1248:53)
    at resume_ (node:internal/streams/readable:1227:3)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)

1. 修复响应数据分段解析问题 #

Node.js的IncomingMessage的data事件会分多次返回响应内容，直接解析单块数据会导致JSON不完整。需要先拼接所有数据块，在end事件触发后再解析：

const request = https.request(url, options, function(response){
    let responseData = '';
    // 拼接所有数据块
    response.on("data",function(chunk){
        responseData += chunk;
    });
    // 数据接收完成后解析
    response.on("end", function(){
        try {
            const result = JSON.parse(responseData);
            console.log(result);
            // 根据返回结果给前端响应
            if(result.new_members){
                res.send("订阅成功");
            } else {
                res.send("订阅失败：" + result.title);
            }
        } catch (err) {
            console.error("JSON解析错误:", err);
            res.send("服务器处理错误");
        }
    });
})

2. 修正Mailchimp合并字段名称 #

从错误返回的merge_fields可以看到，Mailchimp使用的是FNAME和LNAME（大写），而代码里用的是first_name和last_name，导致字段值无法正确传入。需要修改合并字段的键名：

merge_fields: {
    FNAME: fName,
    LNAME: lName
}

3. 验证API端点配置 #

确认url中的{api-server}（比如返回结果里的us21）和{list_id}（比如返回结果里的bd9a1eb732）是否与你的Mailchimp账户信息匹配，替换成实际值。

修正后的完整代码 #

app.post("/",function(req,res){
    const fName = req.body.first_name;
    const lName = req.body.last_name;
    const email = req.body.email;

    const data = {
      members: [
          {
              email_address: email,
              status: "subscribed",
              merge_fields: {
                  FNAME: fName,
                  LNAME: lName
              }
          }
      ]     
    }   

    const jsonData = JSON.stringify(data);

    // 替换为实际的api服务器和列表ID
    const url = "https://us21.api.mailchimp.com/3.0/lists/bd9a1eb732";

    const options = {
        method:"POST",
        auth: "my_string:my_api_key" // 替换为实际的认证信息
    }

    const request = https.request(url, options, function(response){
        let responseData = '';
        response.on("data",function(chunk){
            responseData += chunk;
        });
        response.on("end", function(){
            try {
                const result = JSON.parse(responseData);
                console.log(result);
                if(result.new_members && result.new_members.length > 0){
                    res.send("订阅成功！");
                } else {
                    res.send(`订阅失败：${result.detail || "未知错误"}`);
                }
            } catch (err) {
                console.error("解析响应失败:", err);
                res.send("服务器处理错误");
            }
        });
        // 监听请求错误
        response.on("error", function(err){
            console.error("请求错误:", err);
            res.send("请求失败");
        });
    })

    // 监听请求写入错误
    request.on("error", function(err){
        console.error("发送请求错误:", err);
        res.send("发送请求失败");
    });

    request.write(jsonData);
    request.end();
})

内容的提问来源于stack exchange，提问作者ch_40x