Slack SDK：如何为Blocks添加类似Attachments的左侧颜色条

Slack Blocks没有原生的左侧颜色条属性，但可以通过Columns布局结合纯色小图片来模拟Attachments的color效果，同时保留Blocks对文件URL的正常渲染能力。

实现方式 #

1. 准备纯色小图片的Base64编码（避免外链，加载更稳定）：

   • 红色（错误状态）：data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAAXNSR0IArs4c6QAAADFJREFUKFNj/P//PwOtARMDHQBdLGFBYtMq3BiHT3DRPU4YR4NrNAmPJuHRJDyahEeT8Ii3BCDAAA7UUpfdW5uQAAAAASUVORK5CYII=
   • 绿色（成功状态）：data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH5gMVESkqQzkfSwAAABl0RVh0Q29tbWVudABDcmVhdGVkIHdpdGggR0lNUFeBDhcAAAAUSURBVBjTY2RgYNgHxGAAYuwAAVA8AAE3gAA4egAABS0AAAdmwAAOvsAAIdvgAA3egAAOvwAAJtvgAA3ewAAOvwAAJtvAAAAAElFTkSuQmCC

2. 用Columns块组合色条和内容：
   根据errors变量动态切换色条颜色，右侧区块放置带文件链接的任务内容：

# 动态选择色条的Base64编码
color_bar = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAAXNSR0IArs4c6QAAADFJREFUKFNj/P//PwOtARMDHQBdLGFBYtMq3BiHT3DRPU4YR4NrNAmPJuHRJDyahEeT8Ii3BCDAAA7UUpfdW5uQAAAAASUVORK5CYII=" if errors else "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH5gMVESkqQzkfSwAAABl0RVh0Q29tbWVudABDcmVhdGVkIHdpdGggR0lNUFeBDhcAAAAUSURBVBjTY2RgYNgHxGAAYuwAAVA8AAE3gAA4egAABS0AAAdmwAAOvsAAIdvgAA3egAAOvwAAJtvgAA3ewAAOvwAAJtvAAAAAElFTkSuQmCC"

# 构建Blocks
blocks = [
    {
        "type": "columns",
        "columns": [
            {
                "type": "section",
                "text": {"type": "mrkdwn", "text": f"![color bar]({color_bar})"}
            },
            {
                "type": "section",
                "text": {
                    "type": "mrkdwn",
                    "text": "任务输出内容\n文件链接：<https://example.com/your-file.pdf|点击查看>"
                }
            }
        ]
    }
]

# 直接发送blocks，无需嵌套在attachments中

注意事项 #

• 调整Base64图片的尺寸可以改变色条的高度和宽度，适配不同的内容长度
• Slack对Base64图片的支持稳定，不会出现外链加载失败的问题
• 这种布局完全兼容Blocks的所有组件，包括文件链接、按钮等交互元素

内容的提问来源于stack exchange，提问作者Muhammad Magdi Youssif