In Ruby, how can I traverse an arbitrary document retrieved from a collection using something like mongomapper? Let's say the document looks something like this:
mydocs = [{
"title": "my title",
"description": "hello world",
"comments": [{
"user": "me",
"text": "this"
}, {
"user": "him",
"text": "that"
}]
},
{
.....
}
]
def traverse(obj, level=0, name='root')
s = " "*level + name.to_s + ": "
if obj.is_a?(Array)
puts s
obj.each_with_index{ |child,idx| traverse(child,level+1,idx) }
elsif obj.is_a?(Hash)
puts s
obj.each{ |k,v| traverse(v,level+1,k) }
else
puts s + obj.inspect
end
end
traverse mydocs
After fetch a document from MongoMapper/Mongoid or even mongo-ruby-driver, it's like you generate an Hash.
So you can tranverse it like all hash in Ruby World
Related
I am building a Rails 5 app.
In this app I have connected to the Google Calendar API.
The connection works fine and I get a list of calendars back.
What I need to do is to get the Id and Summary of this JSON object that I get back from Google.
This is what I get
[{
"kind": "calendar#calendarListEntry",
"etag": "\"1483552200690000\"",
"id": "xxx.com_asae#group.calendar.google.com",
"summary": "My office calendar",
"description": "For office meeting",
"location": "344 Common st",
"colorId": "8",
"backgroundColor": "#16a765",
"foregroundColor": "#000000",
"accessRole": "owner",
"defaultReminders": [],
"conferenceProperties": {
"allowedConferenceSolutionTypes": [
"hangoutsMeet"
]
}
},
{
"kind": "calendar#calendarListEntry",
"etag": "\"1483552200690000\"",
"id": "xxx.com_asae#group.calendar.google.com",
"summary": "My office calendar",
"description": "For office meeting",
"location": "344 Common st",
"colorId": "8",
"backgroundColor": "#16a765",
"foregroundColor": "#000000",
"accessRole": "owner",
"defaultReminders": [],
"conferenceProperties": {
"allowedConferenceSolutionTypes": [
"hangoutsMeet"
]
}
}]
This is what I want to end up with
[{
"id": "xxx.com_asae#group.calendar.google.com",
"title": "My office calendar",
}]
The purpose of this is that I want to populate a selectbox using Selectize plugin
Another way to achieve removing of certain keys in your hash is by using Hash#reject method:
response = { your_json_response }
expected = [response[0].reject {|k| k != :id && k != :summary}]
The original response remains unchanged while a mutated copy of the original response is returned.
You can filter the desierd keys with the select method:
responde = {your_json_response}
expected = [response[0].select{|k,v| ['id','title'].include?(k)}]
response[0] retrieves the hash, and the select compares each key with the ones you want and returns a hash with only those key: value pairs.
EDIT: I missed that you don't have a "title" key on the original response, I would do this then:
response = {your_json_response}
h = response[0]
expected = [{'id' => h['id'], 'title' => h['summary']}]
EDIT 2: Sorry, the first example was not clear that there would be multiple hashes
expected = response.map{|h| {'id' => h['id'], 'title' => h['summary']}}
map iterates over each element of response and returns the result of the block applied for each iteration as an array, so the blocks is apllied to each h and it generates a new hash from it
I suggest this approach.
expected = response.each { |h| h.keep_if { |k, _| k == :id || k == :summary } }
It returns just the required pairs:
# => [{:id=>"xxx.com_asae#group.calendar.google.com", :summary=>"My office calendar"}, {:id=>"xxx.com_asae#group.calendar.google.com", :summary=>"My office calendar"}]
To remove duplicates, just do expected.uniq
If you need to change the key name :summary to :title do:
expected = expected.each { |h| h[:title] = h.delete(:summary) }
One liner
expected = response.each { |h| h.keep_if { |k, _| k == :id || k == :summary } }.each { |h| h[:title] = h.delete(:summary) }.uniq
Of course, maybe it is better to move .uniq as first method expected = response.uniq.each { .....
Can anyone help me with this problem?
So, here is the problem, I want to merge this query response:
#energy = Alert.where(["alert_type = ?", "Energy"]).last.as_json
#cost = Alert.where(["alert_type = ?", "Cost"]).last.as_json
Then I merge those object with:
#current_notif = #energy.merge(#cost)
But those just give me #cost object like this:
{
"alert_type": "Cost",
"value": 30000000,
"status": "Cost exceeds limit",
"created_at": "2017-06-03T15:31:21.156+07:00",
"updated_at": "2017-06-03T15:31:21.156+07:00",
"home_id": 2
}
Rather than a merged #energy + #cost like this:
{ {"alert_type": "Energy",
"value": 384455.813978742,
"status": "Energy too high",
"created_at": "2017-05-31T11:31:12.907+07:00",
"updated_at": "2017-05-31T11:31:12.907+07:00",
"home_id": 2 },
{
"alert_type": "Cost",
"value": 30000000,
"status": "Cost exceeds limit",
"created_at": "2017-06-03T15:31:21.156+07:00",
"updated_at": "2017-06-03T15:31:21.156+07:00",
"home_id": 2
}
}
If you want you could "join" both values, and then over that use as_json:
[#energy, #cost].as_json
# [{"alert_type": "Energy", ... }, {"alert_type": "Cost", ... }]
Or if you want you could use the IN expression, in order to deal with ActiveRecord instead having to customize the result this gives you:
Alert.where(alert_type: ['Energy', 'Cost']).as_json
# [{"alert_type": "Energy", ... }, {"alert_type": "Cost", ... }]
This is happening because that's how merge works.
hash = {:name => "Ade", :gender => "Male"}.merge(:name => "Bob")
puts hash # {:name=>"Bob", :gender=>"Male"}
Solution:
results = [ #energy, #cost ]
results.each do |result|
puts result['alert_type'] # Energy, Cost
end
I'm parsing a JSON result into a Ruby hash. The JSON result looks like this:
{
"records": [
{
"recordName": "7DBC4FAD-D18C-476A-89FB-14A515098F34",
"recordType": "Media",
"fields": {
"data": {
"value": {
"fileChecksum": "ABCDEFGHIJ",
"size": 9633842,
"downloadURL": "https://cvws.icloud-content.com/B/ABCDEF"
},
"type": "ASSETID"
}
},
"recordChangeTag": "ii23box2",
"created": {
"timestamp": 1449863552482,
"userRecordName": "_abcdef",
"deviceID": "12345"
},
"modified": {
"timestamp": 1449863552482,
"userRecordName": "_abcdef",
"deviceID": "12345"
}
}
]
}
I can't guarantee that it'll return with any/all those values, or that each value will be of a certain type (e.g. Array, Hash, string, number), and if I call it incorrectly then I get a crash.
Right now I need the downloadURL for the first item in the 'records' array, or to write it as I might with the Swift library SwiftyJSON (which I'm far more familiar with):
json["records"][0]["fields"]["data"]["value"]["downloadURL"]
I'm wondering what the safest/best/standard way to do this safely in Ruby is. Perhaps I'm thinking about it wrong?
In ruby 2.3 and above you can use Hash#dig and Array#dig
json = JSON.parse(...)
json.dig('records', 0, 'fields', 'data', 'value', 'downloadURL')
You'll get nil if any of the intermediate values is nil. If one of the intermediate values doesn't have a dig method, for example if `json['records'][0]['fields'] was unexpectedly an integer this will raise TypeError.
From the documentation (http://ruby-doc.org/stdlib-2.2.3/libdoc/json/rdoc/JSON.html):
require 'json'
my_hash = JSON.parse('{"hello": "goodbye"}')
puts my_hash["hello"] => "goodbye"
If you're worried that you might not have some data. See this question:
Equivalent of .try() for a hash to avoid "undefined method" errors on nil?
You can recursively search each object contained in the json object using
the recurse_proc method of the JSON module.
Here is an example using the data you provided.
require 'json'
json_string = '{
"records": [
{
"recordName": "7DBC4FAD-D18C-476A-89FB-14A515098F34",
"recordType": "Media",
"fields": {
"data": {
"value": {
"fileChecksum": "ABCDEFGHIJ",
"size": 9633842,
"downloadURL": "https://cvws.icloud-content.com/B/ABCDEF"
},
"type": "ASSETID"
}
},
"recordChangeTag": "ii23box2",
"created": {
"timestamp": 1449863552482,
"userRecordName": "_abcdef",
"deviceID": "12345"
},
"modified": {
"timestamp": 1449863552482,
"userRecordName": "_abcdef",
"deviceID": "12345"
}
}
]
}'
json_obj = JSON.parse(json_string)
JSON.recurse_proc(json_obj) do |obj|
if obj.is_a?(Hash) && obj['downloadURL']
puts obj['downloadURL']
end
end
Update Based on Frederick's answer and Cary's comment
I originally assumed you just wanted to find the downloadURL somewhere in the json without crashing, but based on Frederick's answer and Cary's comment, it's reasonable to assume that you only want to find the downloadURL if it is at the exact path, rather than if it just exists. Building on Frederick's answer and Cary's comment here are a couple of other options that should safely find the downloadURL at the expected path.
path = ['records', 0, 'fields', 'data', 'value', 'downloadURL']
parsed_json_obj = JSON.parse(json_string)
node_value = path.reduce(parsed_json_obj) do |json,node|
if json.is_a?(Hash) || (json.is_a?(Array) && node.is_a?(Integer))
path = path.drop 1
json[node]
else
node unless node == path.last
end
end
puts node_value || "not_found"
path = ['records', 0, 'fields', 'data', 'value', 'downloadURL']
begin
node_value = parsed_json_obj.dig(*path)
rescue TypeError
node_value = "not_found"
end
puts node_value || "not_found"
BTW, this assumes the json is at least valid, if that is not a given you might want to wrap the JSON.parse in a begin-rescue-end block as well.
These is sample response of hashes in ruby.
Eg:-
find abcd1234
should give me
i was able to find by but it's not sufficent
I have response of sth like these and list keep on going different value but same structure
[
{
"addon_service": {
"id": "01234567-89ab-cdef-0123-456789abcdef",
"name": "heroku-postgresql"
},
"config_vars": [
"FOO",
"BAZ"
],
"created_at": "2012-01-01T12:00:00Z",
"id": "01234567-89ab-cdef-0123-456789abcdef",
"name": "acme-inc-primary-database",
"plan": {
"id": "01234567-89ab-cdef-0123-456789abcdef",
"name": "heroku-postgresql:dev"
},
"app": {
"id"=>"342uo23iu4io23u4oi2u34",
"name"=>"heroku-staging"},
},
"provider_id": "abcd1234",
"updated_at": "2012-01-01T12:00:00Z",
"web_url": "https://postgres.heroku.com/databases/01234567-89ab-cdef-0123-456789abcdef"
} .........
]
can anyone know how to grab those?
You can iterate all array element (a hash) and display its content if the hash meet your requirement:
element_found = 0
YOUR_DATA.each do |element|
if element["provider_id"].match(/abcd1234/)
element_found += 1
puts "addon_service: #{element['addon_service']['name']}"
puts "app: #{element['app']['name']}"
end
end
if element_found == 0 puts "Sorry match didn't found"
Since the elements of the array are hashes you can select the appropriate ones by matching the desired key.
select {|app| app[:provider_id] == "abcd1234"}
Do you know what to do with the element once you select it?
I think you want some of the items from the hash, but not all of them.
That might look like:
select {|app| app[:provider_id] == "abcd1234"}.map {|app| app.select {|key, v| [:addon_service, :app].include?(key) } }
I have some JSON that looks like this. I have it stored and read into an object, #items.
[
{
{
"id": "A",
"description": "a_description"
},
{
"id": "B",
"description": "b_description"
}
},
{
{
"id": "A",
"description": "a_description"
},
{
"id": "B",
"description": "b_description"
}
}
]
My goal is to display a table with two columns, one labeled A and the other labeled B, in which each row gives the "a_description" and "b_description". I'm not sure how to go about doing this.
Ah, the ol' array of hashes and hashes of arrays problem.
To get around your "out of order" problem you first have to convert
{
"id": "A",
"description": "foo"
},
{
"id": "B",
"description": "bar"
}
into {"A" : "foo", "B" : "bar" }.
#new_items = #items.map do |item|
output = {}
item.each do |hash|
output.merge!(hash["id"] => hash["description"])
end
end
Then #new_items becomes (intentionally presented out of order since hash elements are not ordered)
[
{
"A": "a1_description",
"B": "b1_description"
},
{
"B": "b2_description",
"A": "a2_description"
}
]
From there, each line is simply a hash, so you can just dereference the value you need based on the column you're in.
#new_items.each do |item|
puts "#{item['A']} is paired with #{item['B']}"
end
Keys, of course could be retrieved dynamically if you don't want to hard code "A" and "B" using .keys
Something like this maybe
<tr><th>A</th><th>B</th></tr>
<% #items.each do |item| %>
<tr><td><%=item[0].description%></td><td><%=item[1].description%></td></tr>
<% end %>