Querying multiple models from a controller action in Sails

query-multiple-models-in-sails-controller-action.js

//...
showSchoolDetailPage: function (req, res) {
  
  if (!req.param('id')) {
    return res.badRequest('The id of the school (`id`) is a required parameter!');
  }
  
  // Look up the school, it's associated image, and the associated list of students.
  School.findOne({
    id: req.param('id')
  })
  .populate('image')
  .populate('students')
  .exec(function (err, school) {
    if (err) {
      return res.negotiate(err);
    }
    // Always be careful to do checks like these!  In Node.js, if you throw an error
    // in a callback, it will crash your server!
    if (!school) {
      return res.notFound();
    }
    
    // Let's say we also want to fetch the image for each student.
    // Waterline doesn't support nested populate, but we can still just do things the
    // ole fashioned way. We could either cache the image src URL as an attribute on the
    // Student model, or do an additional "IN" query here.  For the sake of demonstration,
    // I'll do the latter:
    File.find({
      // This means we'll find files whose `photoOfStudent` attribute (a "model" association)
      // is pointed at one of the students we just found associated with our school.
      photoOfStudent: _.pluck(school.students, 'id')
    }).exec(function (err, studentPhotos){
      if (err) {
        return res.negotiate(err);
      }
      
      
      // Now render the view, mashing together the different result sets into the locals
      // we need for our view (if this was an API endpoint instead of a web page, we'd do 
      // the same thing, but call `res.json()`)
      return res.view({
        
        // It's a good idea to explicitly lay out the properties you're passing through to the response.
        // Otherwise, it's just too easy to mess up and accidentally send down an encrypted password, etc.
        // In other words, avoid doing `return res.view(school);`
        name: school.name,
        
        // If we didn't do this check, and the school _didn't_ have an image association, the server could crash.
        imageSrc: school.image ? school.image.srcUrl : null,
        
        allStudents: _.map(students, function (student){
          
          // Figure out the source image URL for the student's photo.
          var studentPhotoFileRecord = _.find(studentPhotos, {photoOfStudent: student.id});
          var studentPhotoUrl;
          if (studentPhotoFileRecord) { studentPhotoUrl = studentPhotoFileRecord.srcUrl; }
          else { studentPhotoUrl = 'http://placeponi.es/150/150'; } // << default image src URL (sometimes it's better to take care of this kind of thing in the action where the student is updated or created-- but putting it here in this case for demonstration purposes)
          
          return {
            name: student.name,
            slug: student.slug,
            imageSrc: studentPhotoUrl,
            studentDetailPageUrl: require('util').format('https://my-app.com/%s/%d', school.slug, student.slug)
          };
        })
      });
    });
    
  });
    
}
// ...

Hi @mikermcneil do you know callback hell?