快速设置多部分/表单数据错误：“身体必须是对象”

Question

我正在使用Fastify-multer和JSON模式提交可能包含文件的多部分表单数据。不管我做什么，factify都会给我一个不好的响应错误：

{
  "statusCode": 400,
  "error": "Bad Request",
  "message": "body must be object"
}

这是我的index.ts：

const server = fastify();
server.register(require("@fastify/cors"));
server.register(multer.contentParser).after(() => {
    if (!isProdEnv) {
        server.register(require("@fastify/swagger"), {
            /* ... */
        });
    }
    server.register(require("@fastify/auth")).after(() => {
        server.decorate("authenticateRequest", authenticateRequest);
        server.decorate("requireAuthentication", requireAuthentication);
        server.addHook("preHandler", server.auth([server.authenticateRequest]));
        server.register(indexRouter);
        server.register(authRouter, { prefix: "/auth" });
        server.register(usersRouter, { prefix: "/users" });
        server.register(listsRouter, { prefix: "/lists" });
        server.register(postsRouter, { prefix: "/posts" });
        server.register(searchRouter, { prefix: "/search" });
        server.register(settingsRouter, { prefix: "/settings" });
    });
});
server.setErrorHandler((err, req, res) => {
    req.log.error(err.toString());
    res.status(500).send(err);
});

和/posts/create/create endpoint：

const postsRouter = (server: FastifyInstance, options: FastifyPluginOptions, next: HookHandlerDoneFunction) => {
    server.post(
        "/create",
        {
            schema: {
                consumes: ["multipart/form-data"],
                body: {
                    content: {
                        type: "string"
                    },
                    media: {
                        type: "string",
                        format: "binary"
                    },
                    "media-description": {
                        type: "string"
                    }
                }
            },
            preHandler: [server.auth([server.requireAuthentication]), uploadMediaFileToCloud]
        },
        postsController.createPost
    );
    next();
};

export default postsRouter;

request curl：

curl -X 'POST' \
  'http://localhost:3072/posts/create' \
  -H 'accept: */*' \
  -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJoYW5kbGUiOiJ1bGtrYSIsInVzZXJJZCI6IjYyNGQ5NmY4NzFhOTI2OGY2YzNjZWExZCIsImlhdCI6MTY1NzEwNTg5NCwiZXhwIjoxNjU3NDA1ODk0fQ.A5WO3M-NhDYGWkILQLVCPfv-Ve-e_Dlm1UYD2vj5UrQ' \
  -H 'Content-Type: multipart/form-data' \
  -F 'content=Test.' \
  -F '[email protected];type=image/png' \
  -F 'media-description=' \

为什么是这样不起作用？

Answer 1

编辑2：显然，有一个非常简单的解决方案：在prevalidation挂钩中使用multer，而不是prehandler。因此，一个工作代码看起来像这样：

server.register(multer.contentParser).after(() => {
    server.register(
        (instance: FastifyInstance, options: FastifyPluginOptions, next: HookHandlerDoneFunction) => {
            instance.post(
                "/create",
                {
                    schema: {
                        consumes: ["multipart/form-data"],
                        body: {
                            type: "object",
                            properties: {
                                content: {
                                    type: "string"
                                },
                                media: {
                                    type: "string",
                                    format: "binary"
                                }
                            }
                        }
                    },
                    preValidation: multer({
                        limits: {
                            fileSize: 1024 * 1024 * 5
                        },
                        storage: multer.memoryStorage()
                    }).single("media")
                },
                (request: FastifyRequest, reply: FastifyReply) => {
                    const content = (request.body as any).content as string;
                    const file = (request as any).file as File;
                    if (file) {
                        delete file.buffer;
                    }
                    reply.send({
                        content,
                        file: JSON.stringify(file) || "No file selected"
                    });
                }
            );
            next();
        },
        { prefix: "/posts" }
    );
});

---

编辑：在下面发布答案后，我可以找到解决方案。为可能遇到同一问题的其他人更新我的答案。

首先，我从fastify-multer切换到@fastify/multipart。然后，我从媒体字段中删除了type属性。

media: {
    format: "binary"
}

之后，我在注册@fastify/multipart时添加了Option {AddTobody：true}。

import fastifyMultipart from "@fastify/multipart";

server.register(fastifyMultipart, { addToBody: true }).after(() => { ... });

这些更改后，字段媒体在request.body中可用。

---

旧答案：

似乎如今，我必须在这里回答自己的问题。无论如何，我弄清楚了发生了什么。 Fastify的内置模式验证与Multipart/form-data相关。我玩了架构规范，以确保情况如此。因此，我从所有路线中删除了模式验证。我的用例是从Expressjs移植API以进行快速化，所以我使用 Express-Oas-Generator 躺在周围。我用它来产生Swagger UI，一切正常。我希望Fastify将其行为共同解决，并解决这个问题。

Answer 2

您现在可以使用@fastify/multipart来完成此操作，要求它将所有多部分表单字段连接到对象上，就像是JSON一样，使用魔术值“ keyValues”：

server.register(multipart, {
  attachFieldsToBody: "keyValues",
  ...
});

将文件标记为文件（s）在架构中键入“对象”：

const SCHEMA_API_UPLOAD = {
  consumes: [ "multipart/form-data" ],
  body: {
    type: "object",
    properties: {
      file: { type: "object" },
      description: { type: "string" },
    }
  }
};

然后，每个表单字段将是request.body对象的字段：

server.post("/upload", { schema: SCHEMA_API_UPLOAD }, async (request, reply) => {
    console.log(request.body);
});

您可以通过curl：

$ curl -v localhost:8080/upload -F description="something good" -F [email protected]

...

[20250109-20:02:50.501] INF (uy33kj8cjzw6) [127.0.0.1:48898] POST /upload
[20250109-20:02:50.502] DEB (uy33kj8cjzw6) starting multipart parsing
[20250109-20:02:50.502] TRA (uy33kj8cjzw6) Providing options to busboy
{
  description: 'something good',
  file: <Buffer ff d8 ff e0 ... 61483 more bytes>
}