File upload 拒绝&；GraphQL文件上载的错误处理

我有一个带有接受单个文件的解析器的express GraphQL端点。解析程序包括对接收到的文件进行简单的验证

问题是，当验证失败时，无法立即将错误返回到前端，因为抛出错误不会强制中断上载请求

一个过于简化的例子：

fileUpload: async (parent, { file, otherdata }) => {
    const isValid = (some logic here)
    if(!isValid)
        throw new ApolloError('upload parameters not valid')

    //No need to get this far,
    //we could have rejected the request already by examining otherdata,
    //or the stream could be already created for max time utilization

    const { createReadStream, filename, mimetype, encoding } = await file;
    const readStream = await createReadStream()
    ...
 }

预期行为：解析程序根据错误策略选项返回通常的{errors:[]，data:null}对象或错误本身

实际行为：错误在后端抛出，但请求在前端仍处于挂起状态

我已经尝试了以下方法，但未成功：

• 仍要初始化readStream并对其调用.destroy（）。结果是读取流停止，请求永远挂起
• 在解析器上下文中包括请求对象（也尝试了响应对象）并对其调用.destroy（）。这将结束请求，但会导致前端出现网络错误，因此没有机会进行特定于错误的处理

一些澄清：

• 显然还有客户端验证，但这并不意味着服务器端验证是不必要的
• 等待上传完成，然后抛出错误显然是可行的，但从时间和带宽角度看，这并不是一个真正的选项

我知道使用GraphQL上传文件是受支持的边缘功能，但在本例中，我们讨论的是一个相当基本的操作

---

如果有任何建议，我将不胜感激

事实证明，这是默认的express行为，与GraphQL接口完全无关。 可以找到该解决方案的纯express版本

请求和响应对象应传递到解析器上下文：

const apollo = new ApolloServer({
    typeDefs,
    resolvers,
    context: ({ req, res }) => {
        return {
            req,
            res
        };
    }
});

然后在分解器中，根据示例：

fileUpload: async (parent, { file, otherdata }, {req, res}) => {
    const isValid = (some logic here)
    if(!isValid){
        res.send(403).send("Some message")
        // Throwing ApolloError could also work,
        // in which case response object would not be required, but not tested.
        // throw new ApolloError('upload parameters not valid')
        return req.destroy()
    }
        

    //No need to get this far,
    //we could have rejected the request already by examining otherdata,
    //or the stream could be already created for max time utilization

    const { createReadStream, filename, mimetype, encoding } = await file;
    const readStream = await createReadStream()
    ...
 }

---

事实证明，这是默认的express行为，与GraphQL接口完全无关。 可以找到该解决方案的纯express版本

请求和响应对象应传递到解析器上下文：

const apollo = new ApolloServer({
    typeDefs,
    resolvers,
    context: ({ req, res }) => {
        return {
            req,
            res
        };
    }
});

然后在分解器中，根据示例：

fileUpload: async (parent, { file, otherdata }, {req, res}) => {
    const isValid = (some logic here)
    if(!isValid){
        res.send(403).send("Some message")
        // Throwing ApolloError could also work,
        // in which case response object would not be required, but not tested.
        // throw new ApolloError('upload parameters not valid')
        return req.destroy()
    }
        

    //No need to get this far,
    //we could have rejected the request already by examining otherdata,
    //or the stream could be already created for max time utilization

    const { createReadStream, filename, mimetype, encoding } = await file;
    const readStream = await createReadStream()
    ...
 }