我如何从mongodb解析此json以与流星助手一起使用

Question

i have this json data in a collection and i need to get all the fiels/values of first_yr, second_yr_sem_1 , second_yr_sem_2 ....

  {
    "first_yr": [
                  {
                   "subject_name": "Subject1",
                   "subject_val": "subject1"
                 },
                 {
                   "subject_name": "Subject2",
                   "subject_val": "subject2"
                 },
                 {
                   "subject_name": "Subject3",
                   "subject_val": "subject3"
                 },
                 {
                   "subject_name": "Subject4",
                   "subject_val": "subject4"
                 },
                 {
                   "subject_name": "Subject5",
                   "subject_val": "subject5"
                 },
                 {
                   "subject_name": "Subject6",
                   "subject_val": "subject6"
                 }
              ]

  },
  {
    "second_yr_sem_1":
              [
                {
                 "subject_name": "Subject1",
                 "subject_val": "subject1"
               },
               {
                 "subject_name": "Subject2",
                 "subject_val": "subject2"
               },
               {
                 "subject_name": "Subject3",
                 "subject_val": "subject3"
               },
               {
                 "subject_name": "Subject4",
                 "subject_val": "subject4"
               },
               {
                 "subject_name": "Subject5",
                 "subject_val": "subject5"
               },
               {
                 "subject_name": "Subject6",
                 "subject_val": "subject6"
               }
              ]

  },
  {
    "second_yr_sem_2":
                [
                  {
                   "subject_name": "Subject1",
                   "subject_val": "subject1"
                 },
                 {
                   "subject_name": "Subject2",
                   "subject_val": "subject2"
                 },
                 {
                   "subject_name": "Subject3",
                   "subject_val": "subject3"
                 },
                 {
                   "subject_name": "Subject4",
                   "subject_val": "subject4"
                 },
                 {
                   "subject_name": "Subject5",
                   "subject_val": "subject5"
                 },
                 {
                   "subject_name": "Subject6",
                   "subject_val": "subject6"
                 }
              ]

  }

to use with this meteor helper

<select name="subject">
         {{#each subjects}}
         <option value="{{subject_val}}">{{subject_name}}</option>
         {{/each}}
</select>

So, what should be the mongodb query i should return to the helper(subjects) ?! Im stuck,anything could help me! Thanks!!

Answer 1

Sorry, I don't know what you mean exactly. So I suppose that you save the Json directly in your collection, and I think you could use cursor.forEach to parse each string to object in your template.helpers:

Template["myTemplate"].helpers({
  var subjects = [];
  var myDataCursor = MyCollection.find();
  myDataCursor.forEach(function(eachSubject) {
    subjects.push(JSON.parse(eachSubject));  // parse str to object, and save it in an array.
  });
  return subjects;
})

You can find more detail here

I wish this can solve your problem perfectly :-)

Answer 2

To get all data back from mongoDB you need use the in-built ".find" method. For example:

app.get('/user/all', function(req, res) {

     // use mongoose to get all users in the database
    User.find(function(err, user) 
    {
            // if there is an error retrieving, send the err 
    if (err)
    {
        res.send(err);
    }

    // return all users in JSON format
    res.json(user);

});
});

User is the name of your schema in MongoDB. All your data is not currently in "user". You will need to parse this data, as your JSON is an array of objects you cause a use a for-loop to parse and then pass the values to your variables on the front it.

I haven't used meteor that much so I am sure about that. I hope this helps.

Answer 3

Template.myTemplate.helpers({ subjects: function() { return YourCollection.find(); } });