Export valid json from mongodb collection

Question

I am trying to export valid json from a mongodb collection I created using node and instagram\'s api. I must be missing something as it seems like it should be super simple.

Answer 1

As mentioned in the comments, parsing the result of mongodump directly probably isn't a good idea. Mongo doesn't give you any guarantee that the elements in the dump will be a valid json (and they're not).

But if you're so inclined to do this you can use event-stream to read newline delimited stream of objects and a parser that allows your json to have single quotes instead of double quotes (i.e. hanson).

Then your code might look something like this:

var es = require('event-stream'),
    hanson = require('hanson'),
    in = process.stdin,
    out = process.stdout;


in //read the input stream
    .pipe(es.split()) //split it on newline
    .pipe(es.map(function(data, cb) {
        if (data === '') { //necessary due to the last element produced by split
            cb();
        } else {
            cb(null, hanson.parse(data)); //parse the line with hanson
        }
    }))
    .pipe(es.writeArray(function (err, array){ //convert resulting objects to array
        var strArray = JSON.stringify(array);
        out.write(strArray + '\n'); //write the resulting array to output stream
    }));

If you had a stream of valid json objects (with double quotes), the same code would get shortened to:

var es = require('event-stream'),
    hanson = require('hanson'),
    in = process.stdin,
    out = process.stdout;


in
    .pipe(es.split()) 
    .pipe(es.parse())
    .pipe(es.writeArray(function (err, array){ 
        var strArray = JSON.stringify(array);
        out.write(strArray + '\n'); 
    }));

Skipped error handling for clarity.

Answer 2

using themongoexport util use --jsonArray

http://docs.mongodb.org/manual/reference/program/mongoexport/#cmdoption--jsonArray