非阻塞代码执行

Question

I have a Meteor project that defines certain methods. In those, email is sent. Since that takes noticeable time and slows down the whole thing for end user, I'd like to send the email asynchronously. Whether the email was sent successfully or not has no effect on result of the method call.

From what I've found it's common to simulate async calls using setTimeout . Is that what I should be doing in this case too?

EDIT: Code as requested in comments

export const UpdateMaterial = new ValidatedMethod({
    name: 'material.update',
    validate: new SimpleSchema({
        id: {type: String},
        description: {type: String},
    }).validator(),
    run({id, description}){
        const _id = new Meteor.Collection.ObjectID(id);

        let res;
        if(Meteor.isServer) {
            res = Materials.update({_id}, {
                $set: {
                    'metadata.description': description
                }
            });
         }
        SendHTMLEmailToRoles(Titles.NewMaterial,Texts.NewMaterial, [Roles.Admin]);
        return res;
    }
});

export const SendHTMLEmailToRoles = (subject,html,roles) => {
    if(Meteor.isServer) {
        const users = Meteor.users.find({role: {$in: roles}}).fetch();
        const addresses =  users.map(function(user){
            if(!user.emails)
                return;
            return user.emails.pop().address;
        });
        Email.send({
            to: addresses,
            from: 'test@test.com',
            subject,
            html
        });
    }
}

Answer 1

If my understanding is correct, the entire code that you show is a Meteor method?

In that case, calling it does not block the client at all, as all Meteor calls are asynchronous. That is why you can provide a callback.

However, the Meteor method on the server is synchronous if not carefully designed. So if the client makes further calls, they will not be processed until the email is actually sent.

To restore some asynchronous behaviour on the server for sending emails, pay attention to the this.unblock() line in the example of the reference page provided by Sergio ( https://docs.meteor.com/api/email.html )

Now if you want your Meteor call client callback to be executed right away, without waiting for the Email.send() to complete, you would have to delay that instruction (typically by wrapping it with a setTimeout indeed) to let your Meteor method returning.