i just create a migration like this
def change
add_column :articles, : information, :json,
default: '[{ "type:c":"12", "temperature":12 }]', null: false
end
i just migrated that table
right now, to create a new article, i am sending this in my request with postman, i am sending properly the 'information' as string?
{
"section":"139",
"information":"[{ type:c, temperature:9 }]" //string
}
so far every thing is ok
now i want to get the param information as a array not string
I want to convert information in an array of json object, how can i do that?
This can be achieved in two ways.
require 'yaml'
input_params = {"section":"139","information":"[{ type: c, temperature: 9 }]"}
#=> {"section"=>"139", "information"=>"[{ type: c, temperature: 9 }]"}
YAML.load(input_params['information'])
#=> [{"type"=>"c", "temperature"=>9}]
or If you want to use JSON.parse then input_params should be as below:
require 'json'
input_params = {"section"=> "139", "information" =>'[{ "type":"c", "temperature":"9" }]'}
#=> {"section"=>"139", "information"=>"[{ \"type\":\"c\", \"temperature\":\"9\" }]"}
JSON.parse(input_params['information'])
#=> [{"type"=>"c", "temperature"=>9}]
I hope this will help you
Related
a little help with getting data out of a string.
Assuming I executed a sql query and now have a string(which set as hash on db):
"{\"users_associated\":{\"User:4\":6,\"User:22\":28,\"User:30\":36}}"
(Which stands for User:ID : User.display_id)
How can I get a substring the includes all users ids or all their display ids, so I'll have something like 4,22,30 or 6,22,36)?
Thanks!
It's common for data systems to return data in a serialized form, i.e. using data types that facilitate transmission of data. One of these serializable data types is String, which is how your JSON data object has been received.
The first step would be to de-serialize (or parse) this String into a Hash object using JSON.parse and tease out just the data value for key "users_associated".
your_string = "{\"users_associated\":{\"User:4\":6,\"User:22\":28,\"User:30\":36}}"
hash = JSON.parse(your_string)
data = hash["users_associated"]
#=> {"User:4":6, "User:22": 28, "User:30": 36}
Hash#keys gives you an array of a hash's keys.
Hash#values gives you an array of a hash's data values.
keys = data.keys
#=> ["User:4", "User:22", "User:30"]
values = data.values
#=> [6, 28, 36]
Array#join lets you string together the contents of an array with a defined separator, , in this case.
display_ids = keys.join(',')
#=> "6,28,36"
For the User IDs, you could Array#map every element of the values array to replace every string occurrence of "User:" with "", using String#gsub.
user_ids = values.map{|user_id| user_id.gsub("User:", "")}
#=> ["4", "22", "30"]
Then, in a similar way to display_ids, we can Array#join the contents of the user_ids array to a single string.
user_ids = user_ids.join(",")
#=> "4,22,30"
You can create two helper methods. I'm leaving return values as arrays because I assume you would need to iterate on them at some point and also converting the user id's to integers.
def extract_display_ids(json)
json['users_associated'].values
end
def extract_user_ids(some_data)
json['users_associated'].keys.map{ |key| key.split(':').last.to_i }
end
some_data = JSON.parse("{\"users_associated\":{\"User:4\":6,\"User:22\":28,\"User:30\":36}}")
extract_display_ids(some_data)
#=> [6, 28, 36]
extract_user_ids(some_data)
#=> [4, 22, 30]
If possible though, I would recommend trying to get a better data format:
{ users_associated:
[{ user_id : 4, display_id:6 }, { user_id : 4, display_id:6 }]
}
I wrote class for this. If you want, you can add it to your project and use it as follows:
require 'json'
class UserSubstringExtractor
def initialize(user_json_data)
#user_json_data = user_json_data
end
def display_ids
user_data.dig('users_associated').values
end
def user_ids
user_data.dig('users_associated').keys.map { |u| u.split(':').last.to_i }
end
private
def user_data
JSON.parse(#user_json_data)
end
end
user_json_data = '{"users_associated":{"User:4":6,"User:22":28,"User:30":36}}'
extractor = UserSubstringExtractor.new(user_json_data)
p extractor.display_ids
#=> [6, 28, 36]
p extractor.user_ids
#=> [4, 22, 30]
I've got some issue with DateTime in Ruby
I've got line which looks like this (it's in .txt file)
DateTime.new(1979,1,1) DateTime.new(2012,3,29)
And my function to get this looks like this
def split_line
array = line.split(' ')
#date_of_birth = array[0]
#date_of_death = array[1]
end
But #date_of_birth and #date_of_death class are String. How can I get them as DateTime?
Assuming your string is in the correct format, then you're probably looking for:
#date_of_birth = array[0].to_datetime
#date_of_death = array[1].to_datetime
See here for more info:
https://apidock.com/rails/String/to_datetime
This:
DateTime.new(1979,1,1) DateTime.new(2012,3,29)
Is not code. What do you expect that to do?
If you want two DateTimes as a space-separated string, do something like:
"#{DateTime.new(1979,1,1)} #{DateTime.new(2012,3,29)}"
When you have something like #{...} inside a set of double quotation marks (they must be double, not single quotation marks), it's called string interpolation. Learn it. Love it. Live it.
But, for the life of me, I don't know why you wouldn't do:
[DateTime.new(1979,1,1), DateTime.new(2012,3,29)]
Which gives you an array, so no split needed. Just:
def split_line
#date_of_birth = array[0]
#date_of_death = array[1]
end
If you want DateTime values, grab the numbers and create them:
require 'date'
'DateTime.new(1979,1,1) DateTime.new(2012,3,29)'.split.map { |s|
DateTime.new(*s.scan(/\d+/).map(&:to_i) )
}
# => [#<DateTime: 1979-01-01T00:00:00+00:00 ((2443875j,0s,0n),+0s,2299161j)>,
# #<DateTime: 2012-03-29T00:00:00+00:00 ((2456016j,0s,0n),+0s,2299161j)>]
The values aren't DateTime though, they're Dates:
'DateTime.new(1979,1,1) DateTime.new(2012,3,29)'.split.map { |s|
Date.new(*s.scan(/\d+/).map(&:to_i) )
}
# => [#<Date: 1979-01-01 ((2443875j,0s,0n),+0s,2299161j)>,
# #<Date: 2012-03-29 ((2456016j,0s,0n),+0s,2299161j)>]
Breaking it down:
'DateTime.new(1979,1,1) DateTime.new(2012,3,29)'.split # => ["DateTime.new(1979,1,1)", "DateTime.new(2012,3,29)"]
.map { |s|
Date.new(
*s.scan(/\d+/) # => ["1979", "1", "1"], ["2012", "3", "29"]
.map(&:to_i) # => [1979, 1, 1], [2012, 3, 29]
)
}
# => [#<Date: 1979-01-01 ((2443875j,0s,0n),+0s,2299161j)>,
# #<Date: 2012-03-29 ((2456016j,0s,0n),+0s,2299161j)>]
* (AKA "splat"), used like this, explodes an array into its elements, which is useful when you have an array but the method only takes separate parameters.
The bigger question is why you're getting values like that in a text file.
I need to build a json object inside a loop using params.
My params look like this...
params[:answers]
returns => {"1"=>"answer1", "2"=>"answer2"}
The keys in this json object are the id's of the survey question.
So I planed to loop through the keys to build the json object like this...
def build_answersheet_json(params[:answers], params[:survey_id])
params[:answers].keys.each do |question_id|
current_question = question_id
current_answer = params[:answers][question_id]
end
end
Since im using "t.json" in my migration to save json to postgres, I wanted to use the extracted question_id and answer to build a json object that looks something like this...
{
survey_id: '1',
answers: {
question: [{
question_id: 1,
answer: 'answer1'
}, {
question_id: 2,
answer: 'answer2'
}]
}
}
Ive been trying to do this using a method that looks somthing like this...
build_answersheet_json(params[:answers], params[:survey_id])
Ive tried JSON.parse() and Ive tried to just logically work through it but I cant seem to figure this out.
Any help is appreciated.
Maybe you can try something like that:
/* fake params (to test) */
params = {
survey_id: '1',
answers: {
"1"=>"answer1",
"2"=>"answer2",
"3"=>"answer3",
"4"=>"answer4"
}
}
def build_answersheet_json(answers, survey_id)
{
survey_id: survey_id,
answers: answers.map { |k,v| { question_id: k.to_i, answer: v } }
}
end
survey = build_answersheet_json(params[:answers], params[:survey_id])
puts survey.class
#Hash
puts survey.to_json
# formated JSON string:
# {
# "survey_id":"1",
# "answers":[
# {"question_id":1,"answer":"answer1"},
# {"question_id":2,"answer":"answer2"},
# {"question_id":3,"answer":"answer3"},
# {"question_id":4,"answer":"answer4"}
# ]
# }
In order to save to a t.json postgress column type, just pass the Hash survey object, like that:
YourModel.create(survey: survey)
Source: http://edgeguides.rubyonrails.org/active_record_postgresql.html
Try
{
survey: ¯\_༼◉ل͟◉༽_/¯,
}
Json may not be parsed if json have construction like this:
survey = {
}
Json may not contain = and assignment
Check real variables values with puts varname.inspect near at code lines where you meet unexpected behaviour.
I have a JSON string as pulled from some API
[{"_id"=>"56aefb3b653762000b400000",
"checkout_started_at"=>"2016-02-01T07:32:09.120+01:00",
"created_at"=>"2016-02-01T07:29:15.695+01:00", ...}]
I want to filter data in this string based on created_at, e.g. letting the user chose a specific date-range and then only show the data from this range.
E.g.
#output = my_json.where(created_at: start_date..end_date)
My first thought was to somehow transfer the JSON string to Hashie, to interact with JSON as the data were objects:
my_json = (my_json).map { |hash| Hashie::Mash.new(hash) }
but that didn't work out
undefined method `where' for Array:0x007fd0bdeb84e0
How can I filter out data from a JSON string based on specific criteria or even SQL queries?
This simplest possible way would be to use Enumberable#select directly on the array of hashes:
require 'time'
myjson.select { |o| Time.iso8601(o["created_at"]).between?(start_date, end_date) }
If you want a fancy interface surrounding the raw data:
require 'time' # not needed in rails
class Order < Hashie::Mash
include Hashie::Extensions::Coercion
coerce_key :created_at, ->(v) do
return Time.iso8601(v)
end
end
class OrderCollection
def initialize(json)
#storage = json.map { |j| Order.new(j) }
end
def between(min, max)
#storage.select { |t| t.created_at.between?(min, max) }
end
end
orders = OrderCollection.new(myjson)
orders.between(Time.yesterday, Time.now)
Need to submit an HTTP POST request of a json string.
Have all of the RESTful parts working, and verified correctly.
This works if I hard code the elements inside the array. I am wanting to loop through one of the arrays in the JSON string, the "Attachments Array".
The loop would look something like:
#days = Daily.all
#days[0..11] do |dailys|
#loop that builds json to post
end
#RESTful HTTP POST request
The only problem is, I don't know how to implement a loop inside of a JSON string for only one array.
My code so far for testing out the HTTP POST
#!/usr/bin/ruby
require 'net/http'
require 'uri'
require 'json'
require 'jbuilder'
uri = URI.parse("<POST URL>")
header = {'Content-Type' => 'text/json'}
payload = {
channel: "<channel>",
username: "<username>",
# Wish to loop through the "Attachments" Array
attachments: [
{
param: "Text",
text: "Text",
pretext: "Optional Text",
color: 'good',
fields: [
{
Title: "Title field",
value: "First Value",
short: false
},
{
title: "Field Title",
value: "Field Value",
short: true
},
{
title: "Second Field Title",
value: "Second Field Value",
short: true
}
]
}
]
}
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
req = Net::HTTP::Post.new(uri.request_uri, header)
req.body = payload.to_json
resp = http.request(req)
puts resp
Your code is looping through a bunch of Daily objects (though you're calling each one 'dailys' inside the loop which is confusing). You don't really explain what you want to do, but if you wanted to make a json object using some of the attributes of the Daily objects you have, you could do it like this.
hash = Daily.find(:all, :limit => 12).map{|daily| {:foo => daily.bar, :chunky => daily.chicken}}.to_json
If you give some details of the json string you want to make from your daily objects then i could give you some less silly code, but the approach is correct: build a ruby data structure then convert it to json with to_json
EDIT: following on from your comment, i would do this.
hash = Daily.find(:all, :limit => 12, :order => "id desc").map{|daily| {param: daily.title, fields: [{title: "Task Completed?", value: daily.completed, short: true}]} }
json = hash.to_json
Couple of notes:
1) Daily is a class, not an object (while classes are also objects in Ruby, i think that in rails it's better to refer to it as the class.
2) By the last 12 elements i assume you mean the most recently saved records: this is what the :order option is for.