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const superagent = require('superagent')
const config={'couchdb':{}}
const config_okay = require('config_okay')
// wrap call to config_okay, if needed
function config_wrapper(opts,cb,fn){
if(config.couchdb.host === undefined && opts.config_file !== undefined){
return config_okay(opts.config_file)
.then(c => {
config.couchdb = c.couchdb
return fn(opts,cb)
})
}else{
return fn(opts,cb)
}
}
function couchdb_check_state(opts,cb){
const req = config_wrapper(opts,cb,_couchdb_check_state)
if(!cb){
return req
}
}
function couchdb_check_exists(opts,cb){
const req = config_wrapper(opts,cb,_couchdb_check_exists)
if(!cb){
return req
}
}
/**
* make_state_getter
*
* I made this into a function generator because I see that one use
* case is to grab several states with one call.
*
* @param {integer} year the year to inspect, or undefined
* @returns {function} a function that will get the desired state(s)
*/
function make_state_getter(year){
if(!year || year===undefined){
return (state,doc) =>{
return doc[state]
}
}else{
return (state,doc) =>{
if(doc[year] !== undefined ){
return doc[year][state]
}else{
return doc[year]
}
}
}
}
function get_query(c){
const db = c.db
if(db === undefined ){
throw('db is required in options object under \'db\' key')
}
const id = c.doc
if(id === undefined ){
throw('document id is required in options object under \'doc\' key')
}
const cport = c.port || 5984
const host = c.host || '127.0.0.1'
let cdb = host+':'+cport
if(! /http/.test(cdb)){
cdb = 'http://'+cdb
}
return cdb+'/'+db+'/'+id
}
function cb_or_promise( cb, req ) {
if(!cb || cb === undefined){
return req // send back the promise object
}else{
// wait here for promise object
req.then(res =>{
return cb(null,res)
}).catch(e =>{
return cb(e)
})
return null
}
}
/**
* couchdb_check_state(opts,cb)
* opts = {'db': the couchdb holding the document,
* 'doc': the document holding the state,
* 'year': the year to check (any sub key in the doc, really),
* 'state': the state to get from the doc under the 'year' key,
* 'config_file': where to look for options like HOST,PORT
* }
* cb = a callback
*
* See docs for config_okay to see what to put into config_file
* make sure config_file is chmod 0600
*
* cb will be called as cb(error,value)
*
* The error will contain any error passed from accessing couchdb
*
* The value can be null if there is nothing in the document, or will
* equal the value of doc[year][state]
*
* in a special case, if there is doc[state], but nothing at doc[year]
* and/or if opts.year is not defined, then I will return doc[state]
*
* So for example, if you want to check 'rawimpute' in the year 2008
* for detector 1212432, in a couchdb called 'tracking', you would
* call with
*
* {'db':'tracking',doc':'1212432','year':2008,'state':'rawimpute'}
*
* If you want to check 'rawimpute' in the year 2008 for detector
* 1212432, in a couchdb database named vds_detector/tracking/D12, you
* could call with
*
* {'db':'vds_detector%2ftracking%2f/D12','doc':'1212432',
* 'year':2008,'state':'rawimpute'}
*
*
*
* note that I don't make any assumptions about the db or year, aside
* from the fact that I expect that there will be a couchdb document
* with that name. Typically this means the detector id should
* resolve to some string. If you have a couchdb with slashes, you
* should remember to escape those properly, etc
*
* If you pass dbroot, it is presumed that the separator is a slash,
* and if you don't want that, then do not use dbroot, use a full
* couchdb name passed as detector_id
*
*/
function _couchdb_check_state(opts,cb){
if(opts.couchdb !== undefined){
throw new Error('hey, you are using an old way of doing this')
}
let c = {}
Object.assign(c,config.couchdb,opts)
const year = c.year
const query = get_query(c)
const state_getter = make_state_getter(year)
const state = c.state
const req = superagent
.get(query)
.set('accept','application/json')
.set('followRedirect',true)
.then( res => {
const doc = res.body
// let state be an array
let result
let _state = state
if(! Array.isArray(state)){
_state = [state]
}
result = _state.map(function(s){
return state_getter(s,doc)
})
// for backwards compatibility, if array is length 1, make
// it not array
if(result.length === 1) result = result[0]
return result
})
return cb_or_promise(cb,req)
}
/**
* couchdb_check_exists(opts,cb)
* opts = {'db': the couchdb holding the document,
* 'doc': the document, does it exist or not,
* 'config_file': where to look for options like HOST,PORT
* }
* cb = a callback
*
* See docs for config_okay to see what to put into config_file
* make sure config_file is chmod 0600
*
* cb will be called as cb(error,value)
*
* The error will contain any error passed from accessing couchdb
*
* The value will be undefined if HEAD does not come back with an etag
* in the header
*
* If HEAD returns an etag, then the result will equal that (the
* revision number of the document)
*
*/
function _couchdb_check_exists(opts,cb){
const c = {}
Object.assign(c,config.couchdb,opts)
const query = get_query(c)
const req = superagent.head(query)
.then( res => {
let result
if(res.header.etag){
result = JSON.parse(res.headers.etag)
}
return result
})
return cb_or_promise(cb,req)
}
module.exports=couchdb_check_state
module.exports.check_exists=couchdb_check_exists