Laravel Http发送Discord Webhook报50006空消息错误排查

出现Cannot send an empty message（错误码50006）的核心原因是Discord无法正确解析请求内容，以下是代码中的关键问题及修复方式：

1. 手动设置Content-Type边界导致请求格式错误 #

你手动指定了multipart/form-data的boundary，但Laravel的asMultipart()方法会自动生成并处理正确的boundary，手动添加的边界会和框架生成的冲突，导致Discord无法识别payload_json字段。

修复：删除手动设置的Content-Type头部

// 移除手动设置Content-Type的行
Http::asMultipart()
    ->post($this->webhookUrl, [...]);

2. 图片内容使用Data URI格式，而非原始二进制数据 #

你传递的图片内容是data:image/jpeg;base64,[[encoded image]]这种Data URI字符串，但Discord期望接收的是原始的二进制文件内容，带前缀的字符串会被识别为无效文件内容，同时干扰payload解析。

修复：解码Base64字符串为二进制内容

// 替换图片的contents部分
[
    'name' => 'image1.jpg',
    'contents' => base64_decode(str_replace('data:image/jpeg;base64,', '', '[[encoded image]]')),
    'headers' => [
        'Content-Type' => 'image/jpeg',
    ]
],
[
    'name' => 'image2.jpg',
    'contents' => base64_decode(str_replace('data:image/jpeg;base64,', '', '[[encoded image]]')),
    'headers' => [
        'Content-Type' => 'image/jpeg',
    ]
]

3. 可选优化：payload_json使用数组而非字符串 #

虽非直接错误原因，但用数组传递payload内容，Laravel会自动处理JSON编码，避免手动写JSON字符串可能出现的语法错误：

[
    'name' => 'payload_json',
    'contents' => json_encode([
        'content' => 'Hello, World!',
        'embeds' => [
            [
                'title' => 'Hello, Embed!',
                'description' => 'This is an embedded message.',
                'thumbnail' => ['url' => 'attachment://image1.jpg'],
                'image' => ['url' => 'attachment://image2.jpg']
            ]
        ],
        'attachments' => [
            ['id' => 0, 'description' => 'Image of a cute little cat', 'filename' => 'image1.jpg'],
            ['id' => 1, 'description' => 'Rickroll gif', 'filename' => 'image2.jpg']
        ]
    ]),
    'headers' => ['Content-Type' => 'application/json']
]

修复后的完整代码示例 #

Http::asMultipart()
    ->post(
        $this->webhookUrl,
        [
            [
                'name' => 'payload_json',
                'contents' => json_encode([
                    'content' => 'Hello, World!',
                    'embeds' => [
                        [
                            'title' => 'Hello, Embed!',
                            'description' => 'This is an embedded message.',
                            'thumbnail' => ['url' => 'attachment://image1.jpg'],
                            'image' => ['url' => 'attachment://image2.jpg']
                        ]
                    ],
                    'attachments' => [
                        ['id' => 0, 'description' => 'Image of a cute little cat', 'filename' => 'image1.jpg'],
                        ['id' => 1, 'description' => 'Rickroll gif', 'filename' => 'image2.jpg']
                    ]
                ]),
                'headers' => [
                    'Content-Type' => 'application/json',
                ]
            ],
            [
                'name' => 'image1.jpg',
                'contents' => base64_decode(str_replace('data:image/jpeg;base64,', '', '[[encoded image]]')),
                'headers' => [
                    'Content-Type' => 'image/jpeg',
                ]
            ],
            [
                'name' => 'image2.jpg',
                'contents' => base64_decode(str_replace('data:image/jpeg;base64,', '', '[[encoded image]]')),
                'headers' => [
                    'Content-Type' => 'image/jpeg',
                ]
            ]
        ]
    );

内容的提问来源于stack exchange，提问作者Bird87 ZA