Is it possible to post data to couch db and return data? - post

Question

For example I would like to send the users score to the database and instead of it returning the typical status, id and rev I would like it to return the users rank. I'm guessing this isn't possible but figured I would ask.

Answer 1

The response to an HTTP POST/PUT should really only be used to help you confirm that it succeeded.
I'm even struggling to see even how you can get the rank of a user returned by a couchdb view, unless you retrieve the data for all users and work out the position of your user.
This use case ...
Simple structured data clearly tabular
The requirement to respond fast to a numerical column (Method to calculate the rank for a score)
OR the requirement to trigger an update a score table each time a rank is submitted.
... very much smells like a classical case where you may want to use a relational DB.

Answer 2

If the result can be calculated from the document you are to change with your http request, then you can use an update handler to PUT a change to the document and return that result:
// 'myhandler' update function
function(doc, req) {
// create a shorthand for json reponses
var json_reponse = function(obj, code) {
return {
headers: { 'Content-Type': 'application/json' }
, body: JSON.stringify(obj)
, code: code
}
}
// assume the incoming body is json and parse it
// needs proper error handling still
var body = JSON.parse(req.body)
// doc is the user document we are patching
// return an error if it isn't there
if(!doc)
return [null, json_response({error: 'user document not found'}, 404)]
// return an error if new_score is missing from body
if(!body.new_score)
return [null, json_response({error: 'missing property new_score'}, 400)
// now patch the user doc
doc.score = body.new_score
// calculate the new rank depending on your own method
var my_rank = my_rank_function(doc.score, Math.PI, 'bananarama')
return [doc, json_response({success: true, rank: my_rank}, 200)
}
Now PUT new data to receive the new rank:
request(
{ method: 'PUT'
, url: httptp://127.0.0.1:5984/mydb/_design/myddoc/_update/myhandler/myuserdocid
, json: {"new_score": 42}
, headers: { "Content-Type: application/json" }
}
, function(err, response, body) {
console.log("user's new rank:", JSON.parse(body).rank)
}
)
should print user's new rank: LEVEL 11 EIGHTIES GIRL GROUP LEADER
nb: I'm not at work so cannot confirm the code works, but you should get the hang of it...