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// a simple node server
/* TO DO:
* 1. get all exams given course code -- order by year desc ? PENDING
* 2. add upload date and user name ? DONE
* 3. remove exam ? PENDING
* 4. questions ? PENDING
* 5. ....TBD
* */
var debug_mode = false;
Object.assign = require('object-assign');
var mongodb = require('mongodb');
var mongoFactory = require('mongo-factory');
// Standard URI format: mongodb://[dbuser:dbpassword@]host:port/dbname
var uri = 'mongodb://general:assignment4@ds057862.mlab.com:57862/solutions_repo';
// sample exam data
// hopefully this will be collected when an admin user fills out a form to create an exam.
// this looks something like...
/*
* var exam =
{
course_code: "CSC240",
year: 2016,
term: "fall",
type: "midterm",
page_count: 20,
questions_count: 2,
questions_list: [],
upload_date: "some date",
uploaded_by: "some user name"
};
*/
var fields = ["CSC240", 2016, "fall", "midterm", ["Faith Ellen", "Tom F."], 20, 2, "some date", "some user name"];
var questions_array = ["this is q1", "this is q2"];
// Eventually this will be a better idea in the long run
/*var offering = {
course_code: "CSC240",
year: 2016,
term: "fall",
instructors: ["Faith Ellen", "Tom Fairgreve"]
};*/
// test adding of exams to the database functionality
add_exam(fields, questions_array);
/*
* This function will add an exam to the database UNLESS the exams already exists.
* If the exams table is empty, this will create one and then add the data.
* Note: this assumes that (course_code + year + term + type) together form a unique exam.
* i.e there can't be two exams occurring for the same course in the same year in the same term with the same type.
* Params: fields - an array of format ["course_code", year, "term",
* ["instructor1",...,"instructor n"], page_count, question_count
* "upload_date", "user_name"]
* questions_array - a array by format ["q_1", "q_2", ... , "q_question_count"]
* */
function add_exam(fields, questions_array) {
// first see if the exam already exists
find_exam(fields, questions_array, function(result, Data) {
if (result == true) { // meaning that the exam was found
console.log("This exam already exists in the database");
}
else { // add Data to the database
// make a connection
mongoFactory.getConnection(uri)
.then(function(db) {
// find the exams table
var exam_collection = db.collection('exams');
// insert data into table
exam_collection.insert(Data, function(err) {
if (err) throw err;
else {
console.log("exam added");
db.close(function (err) { // close the connection when done
if (err) throw err;
});
}
});
})
.catch(function(err) {
console.error(err);
});
}
});
}
/*
* This function will return TRUE if the provided exam info already exists in the database
* OR FALSE if it does not exist in the database.
* Params: fields - an array of format ["course_code", year, "term", "type"
* ["instructor1",...,"instructor n"], page_count, question_count,
* "upload_data", "user_name"]
* questions_array - a array by format ["q_1", "q_2", ... , "q_question_count"]
* */
function find_exam(fields, questions_array, callback) {
// construct an exam object
var Data =
{
course_code: fields[0],
year: fields[1],
term: fields[2],
type: fields[3],
instructors: fields[4],
page_count: fields[5],
questions_count: fields[6],
questions_list: [],
upload_date: fields[7],
uploaded_by: fields[8]
};
// create the questions objects
for (var i = 1; i <= Data.questions_count; i++) {
Data.questions_list.push(
{
q_id: i,
question: questions_array[i - 1]
}
);
}
// console.log(Data);
// check the data to see if this exam exists...
// first make a connection
mongoFactory.getConnection(uri)
.then(function(db) {
// fetch the exams table
var exams = db.collection('exams');
// look for the exam
exams.find(
{
course_code: Data.course_code,
year: Data.year,
term: Data.term,
type: Data.type
}
).toArray(function (err, docs) {
if (err) throw err;
if (docs.length == 0) { // if this exam doesnt exist.... add it
callback(false, Data);
}
else { // exam was found
callback(true);
}
});
/* db.close(function (err) {
if (err) throw err;
});*/
})
.catch(function(err) {
console.error(err);
});
}
/* IGNORE BELOW **************
ONLY FOR SYNTAX REFERENCE
/!*
* Then we need to give Boyz II Men credit for their contribution
* to the hit "One Sweet Day".
*!/
songs.update(
{ song: 'One Sweet Day' },
{ $set: { artist: 'Mariah Carey ft. Boyz II Men' } },
function (err, result) {
if(err) throw err;
/!*
* Finally we run a query which returns all the hits that spend 10 or
* more weeks at number 1.
*!/
songs.find({ weeksAtOne : { $gte: 10 } }).sort({ decade: 1 }).toArray(function (err, docs) {
if(err) throw err;
docs.forEach(function (doc) {
console.log(
'In the ' + doc['decade'] + ', ' + doc['song'] + ' by ' + doc['artist'] +
' topped the charts for ' + doc['weeksAtOne'] + ' straight weeks.'
);
});
// Since this is an example, we'll clean up after ourselves.
songs.drop(function (err) {
if(err) throw err;
// Only close the connection when your app is terminating.
db.close(function (err) {
if(err) throw err;
});
});
});
}
);
});
});*/
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