Overriding pageBeforeSend in apostrophe-pieces-pages doesn't work

[puntnomads]

I can successfully overridden pageBeforeSend to get data from the database and send it to a template. I did this in apostrophe-pages using the example in https://stackoverflow.com/questions/40011205/injecting-backend-data-into-view-for-use-in-client-side-js. However, when I try to do the same thing in apostrophe-pieces-pages, the data is not received in the template. This happens when I update the data within the callback of the database call. However, If I update the data outside of the callback of the database call, the data is received in the template.

module.exports = {
  extend: "apostrophe-pieces-pages",
  construct: function(self, options) {
    var superPageBeforeSend = self.pageBeforeSend;
    self.pageBeforeSend = function(req) {
      var pieces = req.data.pieces;
      console.log("page type: ", req.data.page.type);
      if (
        !req.data.pieces &&
        req.data.page.type.replace(/\s/g, "") === "news-page"
      ) {
        // this works
        req.data.relatedNews = "Hello World";
        return self.apos.modules["news"]
          .find(req, {})
          .sort({ title: 1 })
          .toArray(function(err, pieces) {
            if (err) {
              throw err;
            }
            // this doesn't work
            req.data.relatedNews = pieces;
            return superPageBeforeSend(req);
          });
      } else {
        return superPageBeforeSend(req);
      }
    };
  }
};

[boutell]

Your pageBeforeSend method must take a callback (and invoke it when it's finished, too) if it does async work.

Complicating matters, apostrophe-pieces-pages already has one which does not take a callback. That's fine but bear in mind that you'll need to take that into account when invoking superPageBeforeSend, before invoking your callback.

[puntnomads]

@boutell I haven't quite understood what I need to do to resolve this problem.

[boutell]

You're invoking things that take callbacks, and your code is meanwhile returning, so apostrophe goes its merry way and renders your page. Then, later, your data arrives. Oops, too late.

So your pageBeforeSend method must take an additional argument, callback, and must invoke it only when your work is complete.