如何修复Google Chat推送时的Invalid JSON payload错误

错误原因 #

报错提示Unknown name "content"，说明你构建的卡片JSON结构不符合Google Chat Webhook的API规范，大概率是未提供的buildCard函数在组装widgets时出现了结构错误，或是某个表单响应的格式（比如多选的数组）未正确处理。

修正方案 #

1. 补全符合规范的buildCard函数 #

替换或添加正确的buildCard函数，确保卡片结构完全匹配Google Chat的要求：

function buildCard(title, emailRespondent, widgets, formUrl) {
  return {
    "cardsV2": [
      {
        "cardId": "form-response-card",
        "card": {
          "header": {
            "title": title,
            "subtitle": "提交者邮箱：" + (emailRespondent || "未提供")
          },
          "sections": [
            {
              "widgets": widgets
            },
            {
              "widgets": [
                {
                  "buttonList": {
                    "buttons": [
                      {
                        "text": "查看表单响应",
                        "onClick": {
                          "openLink": {
                            "url": formUrl
                          }
                        }
                      }
                    ]
                  }
                }
              ]
            }
          ]
        }
      }
    ]
  };
}

2. 处理表单响应的数组格式 #

如果表单包含多选类问题，item.getResponse()会返回数组，直接传入keyValue的content会导致JSON格式异常，需要将数组转为字符串：
修改循环中的widgets构建代码：

for(var i = 0; i < items.length; i++) {
  var item = items[i];
  var response = item.getResponse();
  // 处理数组类型的响应（如多选）
  var displayResponse = Array.isArray(response) ? response.join("\n") : response;
  widgets.push({
    "keyValue": {
      "topLabel": item.getItem().getTitle(),
      "content": displayResponse,
      "contentMultiline": true
    }
  });
}

3. 调试建议 #

如果仍报错，添加muteHttpExceptions: true获取完整错误信息，方便定位：

var options = {
  method : "post",
  contentType : "application/json; charset=UTF-8",
  payload : JSON.stringify(card),
  muteHttpExceptions: true // 添加这行
};
var response = UrlFetchApp.fetch(URL_WEBHOOK, options);
Logger.log(response.getContentText()); // 查看完整错误日志

完整修正后的脚本 #

function pushToHangoutsChat(e) {
  var URL_WEBHOOK = "webhookurlgoeshere";
  var form = e.source;
  var emailRespondent = e.response.getRespondentEmail();
  var title = form.getTitle();
  var formUrl = form.getSummaryUrl().replace("viewanalytics","edit#responses")
  var items = e.response.getItemResponses();
  var widgets = [];
  for(var i = 0; i < items.length; i++) {
    var item = items[i];
    var response = item.getResponse();
    var displayResponse = Array.isArray(response) ? response.join("\n") : response;
    widgets.push({
      "keyValue": {
        "topLabel": item.getItem().getTitle(),
        "content": displayResponse,
        "contentMultiline": true
      }
    });
  }
  var card = buildCard(title, emailRespondent, widgets, formUrl);
  var options = {
    method : "post",
    contentType : "application/json; charset=UTF-8",
    payload : JSON.stringify(card),
    muteHttpExceptions: true
  };
  var response = UrlFetchApp.fetch(URL_WEBHOOK, options);
  Logger.log(response.getContentText());
}

function buildCard(title, emailRespondent, widgets, formUrl) {
  return {
    "cardsV2": [
      {
        "cardId": "form-response-card",
        "card": {
          "header": {
            "title": title,
            "subtitle": "提交者邮箱：" + (emailRespondent || "未提供")
          },
          "sections": [
            {
              "widgets": widgets
            },
            {
              "widgets": [
                {
                  "buttonList": {
                    "buttons": [
                      {
                        "text": "查看表单响应",
                        "onClick": {
                          "openLink": {
                            "url": formUrl
                          }
                        }
                      }
                    ]
                  }
                }
              ]
            }
          ]
        }
      }
    ]
  };
}

内容的提问来源于stack exchange，提问作者Scott Stevenson