Rails params to array - ruby-on-rails

I am sending a list of checkbox selected from PHP file to our Rails API server. All checked items' ID's will be sent in json format (campaign_ids in json_encode from PHP):
I got a URL being passed to our API like this
Started PUT "/campaigns/function.json?campaign_ids=["6","7"]&user_id=0090000007"
I need to get the campaign_ids ["6","7"] and process it like any other array using array.each do || end
How can I convert this to an array so I can use array.each?
The following sample code can achieve it but I think there could be a better way?
campaign_ids = params[:campaign_ids].to_s # [\"6\",\"7\"]
campaign_ids = campaign_ids.gsub(/[^0-9,]/,'') # 6,7
if campaign_ids.size.to_i > 0 # 3 ??
campaign_ids.split(",").each do |campaign_id|
...
end
end

The correct format of the URL should've been campaign_ids[]=6&campaign_ids[]=7. That would automatically yield an array of [6, 7] when you do params[:campaign_ids].
But assuming you can't change the format of the incorrect parameters, you can still get it via JSON.parse(params[:campaign_ids])

Try this
campaign_ids = JSON.parse(params[:campaign_ids])
You get params[:campaign_ids] as a string.
So, you will have to parse that json string to get array elements.

params[:campaign_ids] is already in your desired array format, you need not convert that to string using to_s.
You can do something like this
campaign_ids = params[:campaign_ids]
campaign_ids.each do |campaign_id|
# do the computation here
end

Related

Generation of table and accessing elements of a Array of Hashes

I have the following Array of hashes in a rails application:
a = ["{\"ROW1\"=>{\"correct\"=>{\"h\"=>\"10\", \"m\"=>\"11\", \"l\"=>
\"12\"}, \"wrong\"=>{\"h\"=>\"2\", \"m\"=>\"2\", \"l\"=>\"4\"}, \"blank
\"=>{\"h\"=>\"2\", \"m\"=>\"4\", \"l\"=>\"3\"}}, \"ROW2\"=>{\"correct
\"=>{\"h\"=>\"2\", \"m\"=>\"4\", \"l\"=>\"4\"}, \"wrong\"=>{\"h
\"=>\"4\", \"m\"=>\"6\", \"l\"=>\"6\"}, \"blank\"=>{\"h\"=>\"7\",
\"m\"=>\"5\", \"l\"=>\"6\"}}, \"ROW3\"=>{\"correct\"=>{\"h\"=>\"4\",
\"m\"=>\"6\", \"l\"=>\"7\"}, \"wrong\"=>{\"h\"=>\"6\", \"m\"=>\"7\",
\"l\"=>\"5\"}, \"blank\"=>{\"h\"=>\"7\", \"m\"=>\"9\", \"l\"=>
\"3\"}}}"]
I want to access its elements and create a database table from it, in the following format
ROW1 correct h=10, m=11,l=12
wrong h=2, m=2,l=4
blank h=2, m=4,l=3
...and similar for ROW2 and ROW3.
How can I do that?
I tried to access a value using
a["ROW1"]["Correct"]["h"]
...but it returns a nil value.
How to access the values of this array of hashes?
you need to first convert the string to hash which can be done as follows:
require 'json'
a = ["{\"ROW1\"=>{\"correct\"=>{\"h\"=>\"10\", \"m\"=>\"11\", \"l\"=>
\"12\"}, \"wrong\"=>{\"h\"=>\"2\", \"m\"=>\"2\", \"l\"=>\"4\"}, \"blank
\"=>{\"h\"=>\"2\", \"m\"=>\"4\", \"l\"=>\"3\"}}, \"ROW2\"=>{\"correct
\"=>{\"h\"=>\"2\", \"m\"=>\"4\", \"l\"=>\"4\"}, \"wrong\"=>{\"h
\"=>\"4\", \"m\"=>\"6\", \"l\"=>\"6\"}, \"blank\"=>{\"h\"=>\"7\",
\"m\"=>\"5\", \"l\"=>\"6\"}}, \"ROW3\"=>{\"correct\"=>{\"h\"=>\"4\",
\"m\"=>\"6\", \"l\"=>\"7\"}, \"wrong\"=>{\"h\"=>\"6\", \"m\"=>\"7\",
\"l\"=>\"5\"}, \"blank\"=>{\"h\"=>\"7\", \"m\"=>\"9\", \"l\"=>
\"3\"}}}"
]
hash_string = a[0]
hash = JSON.parse hash_string.gsub("\n", '').gsub('=>', ':')
# you access the hash now:
hash["ROW1"]["correct"]["h"]
# => 10
Btw, please note that there is a typo. Instead of Correct, the key is correct with small c instead of capital C.
Hope it helps : )

Ruby, accessing a nested value in a hash

I have the following hash. Using ruby, I want to get the value of "runs". I can't figure out how to do it. If I do my_hash['entries'], I can dig down that far. If I take that value and dig down lower, I get this error:
no implicit conversion of String into Integer:
{"id"=>2582, "entries"=>[{"id"=>"7", "runs"=>[{"id"=>2588, ...
Assuming that you want to lookup values by id, Array#detect comes to the rescue:
h = {"id"=>2582, "entries"=>[{"id"=>"7", "runs"=>[{"id"=>2588}]}]}
# ⇓⇓⇓⇓⇓⇓⇓ lookup element with id = 7
h['entries'].detect { |e| e['id'] == 7 }['runs']
.detect { |e| e['id'] == 2588 }
#⇒ { "id" => 2588 }
As you have an array inside the entries so you can access it using an index like this:
my_hash["entries"][0]["runs"]
You need to follow the same for accessing values inside the runs as it is also an array.
Hope this helps.
I'm not sure about your hash, as it's incomplete. So , guessing you have multiple run values like:
hash = {"id"=>2582, "entries"=>[{"id"=>"7", "runs"=>[{"id"=>2588}]},
{"id"=>"8", "runs"=>[{"id"=>2589}]},
{"id"=>"9", "runs"=>[{"id"=>2590}]}]}
Then, you can do
hash["entries"].map{|entry| entry["runs"]}
OUTPUT
[[{"id"=>2588}], [{"id"=>2589}], [{"id"=>2590}]]

How do I access a hash value that only exists in 1 attribute out of many?

So this one is a bit tricky.
I have an attribute that looks like this:
[22] pry(main)> n.media.meta_info[:response][:outputs]
=> [{"id"=>486,
"url"=>"http://some-video.com/by-fire.mp4",
"label"=>"webmp4",
"state"=>"finished",
"format"=>"mpeg4",
"type"=>"standard",
"frame_rate"=>30.06,
{"id"=>488848287,
"url"=>"http://some-video.com/by-fire.webm",
"label"=>"webwebm",
"state"=>"finished",
"format"=>"webm",
"type"=>"standard",
"frame_rate"=>30.06,
{"id"=>488848288,
"url"=>"http://some-video.com/by-fire.ogv",
"label"=>"webogv",
"state"=>"finished",
"format"=>"ogg",
"type"=>"standard",
"frame_rate"=>30.059,
{"id"=>488848289,
"url"=>
"https://zencoder-temp-storage-us-east-1.s3.amazonaws.com/",
"label"=>nil,
"state"=>"finished",
"format"=>"mpeg4",
"type"=>"standard",
"frame_rate"=>30.06,
"thumbnails"=>
[{"label"=>nil,
"images"=>
[{"dimensions"=>"56x100",
"file_size_bytes"=>15142,
"format"=>"PNG",
"url"=>"https://some-video.s3.amazonaws.com/uploads/video/video_file/id/by-fire.png"}]}],
"md5_checksum"=>nil}]
I am trying to access the thumbnails info, specifically the URL for the thumbnails.
I can't figure out how to get there though.
When I try to go the nested hash key of thumbnails it doesn't work:
[23] pry(main)> n.media.meta_info[:response][:outputs][:thumbnails]
TypeError: no implicit conversion of Symbol into Integer
from (pry):22:in `[]'
Thoughts?
The [{ at the beginning of the output indicates that an array is returned. You first need to find a element in the array that contains a thumbnails key:
outputs = n.media.meta_info[:response][:outputs]
output_with_thumbnail = outputs.find { |elem| elem.keys.include?('thumbnails') }
Then continue like this:
output_with_thumbnail['thumbnails']
If you're just trying to find the thumbnail, and don't care about the rest of the outputs, you can use #find like so:
thumbnails = n.media.meta_info[:response][:outputs].find {|it| it[:thumbnails] }[:thumbnails]
You have an array of hashes, thumbnails are in the 3rd:
n.media.meta_info[:response][:outputs][3][:thumbnails]
It looks like
outputs = n.media.meta_info[:response][:outputs]
is an Array of hashes. So, you need to iterate over them first:
outputs.each do |output|
# deal with each output here
end
You can check for :thumbnails like so:
if (thumbnails = output[:thumbnails])
# we've got thumbnails, deal with it here
end

Extracting JSON objects from JSON string

I want to break down a JSON string into smaller objects. I have two servers, one acting as the web-app interface to the whole application and the other is a repository/database.
I'm able to retrieve information from the repository to the web-app as JSON, but after that I don't know how to return it.
Here's a sample of the JSON being returned:
{"respPages":[{"page":{"page_url":"http://www.google.com/","created_at":"2011-08-10T11:00:19Z","website_id":1,"updated_at":"2011-08-10T11:00:19Z","id":1}},{"page":{"page_url":"http://www.blank.com/services/content_services/","created_at":"2011-08-10T11:02:46Z","website_id":1,"updated_at":"2011-08-10T11:02:46Z","id":2}}],"respSite":{"website":{"created_at":"2011-08-10T11:00:19Z","website_id":null,"updated_at":"2011-08-10T11:00:19Z","website_url":null,"id":1}},"respElementTypes":[{"element_type":{"created_at":"2011-08-10T11:00:19Z","updated_at":"2011-08-10T11:00:19Z","id":1,"tag_name":"head"}},
There are four tags in the JSON:
page
website
elementType
elementData
I would like to create four arrays and populate them with the object that matches these tags.
I would image the code is something like this:
#Get the json from repo using net/http
uri = URI.parse("http://127.0.0.1:3007/repository/infoid/1.json")
http = Net::HTTP.new(uri.host, uri.port)
response = http.request(Net::HTTP::Get.new(uri.request_uri))
#x = response.to_hash
#pages = Array.new
#websites= Array.new
#elementDatas = Array.new
#elementTypes = Array.new
#enter code here`#For every bit of the hash, find out what it is and allocate it accordingly
#x.each_with_index do |e,index|
if e.tagName == pages #Getting real javascripty here. There must be someway to check the tag or title of the element
#pages[index]=e
end
My goal for the returned value is to have four arrays, each containing different types of objects:
#pagesArray[1]
should contain the first occurrence of a page object in the JSON string. Then do the same for the other ones.
Of course I'd need to break down the object further but once I can break down the top level and categorize them, then I can go deeper.
In the JSON there are already tag titles respPages and respWebsites which group all the objects.
How do I turn JSON back into objects in Ruby and reference them using something like the tag name?
You should be able to decode anything in JSON format using the standard JSON library:
JSON.load(...)
It will throw exceptions on malformed JSON data, so be sure to test it thoroughly and make sure it can handle all the important cases.
If you're trying to navigate the structure of the JSON itself, you probably need to write a series of recursive methods that handle each case along the way. A good pattern to start with is this:
#data.each do |key, value|
case (key)
when 'someKey'
handle_some_key(value)
when 'otherKey'
handle_other_key(value)
end
end
You can either break out the behavior into methods as in this example, or inline it if the logic is fairly straightforward.
As a note, an alternative to Array.new is simply [ ] as it is in JavaScript. For example:
#pages = [ ]
You'll see this used frequently in most Ruby examples. The alternative to Hash.new is { }.
The following works:
json = {"respPages"=>[{"page"=>{"page_url"=>"http://www.google.com", "created_at"=>"2011-08-10T11:00:19Z", "website_id"=>1, "updated_at"=>"2011-08-10T11:00:19Z", "id"=>1}}, {"page"=>{"page_url"=>"http://www.blank.com/services/content_services/", "created_at"=>"2011-08-10T11:02:46Z", "website_id"=>1, "updated_at"=>"2011-08-10T11:02:46Z", "id"=>2}}],
"respSite"=>{"website"=>{"created_at"=>"2011-08-10T11:00:19Z", "website_id"=>nil, "updated_at"=>"2011-08-10T11:00:19Z", "website_url"=>nil, "id"=>1}},
"respElementTypes"=>[{"element_type"=>{"created_at"=>"2011-08-10T11:00:19Z", "updated_at"=>"2011-08-10T11:00:19Z", "id"=>1, "tag_name"=>"head"}}]}
#respPages, #respSite, #respElementTypes = [], [], []
json.each do |key_category, group_category|
group_category.each do |hash|
if group_category.is_a? Array
eval("##{key_category}") << hash.values.first
elsif group_category.is_a? Hash
eval("##{key_category}") << hash[1]
end
end
end
there weren't any respData in your sample but you've got the idea.

How to parse a yaml file into ruby hashs and/or arrays?

I need to load a yaml file into Hash,
What should I do?
I would use something like:
hash = YAML.load(File.read("file_path"))
A simpler version of venables' answer:
hash = YAML.load_file("file_path")
Use the YAML module:
http://ruby-doc.org/stdlib-1.9.3/libdoc/yaml/rdoc/YAML.html
node = YAML::parse( <<EOY )
one: 1
two: 2
EOY
puts node.type_id
# prints: 'map'
p node.value['one']
# prints key and value nodes:
# [ #<YAML::YamlNode:0x8220278 #type_id="str", #value="one", #kind="scalar">,
# #<YAML::YamlNode:0x821fcd8 #type_id="int", #value="1", #kind="scalar"> ]'
# Mappings can also be accessed for just the value by accessing as a Hash directly
p node['one']
# prints: #<YAML::YamlNode:0x821fcd8 #type_id="int", #value="1", #kind="scalar">
http://yaml4r.sourceforge.net/doc/page/parsing_yaml_documents.htm
You may run into a problem mentioned at this related question, namely, that the YAML file or stream specifies an object into which the YAML loader will attempt to convert the data into. The problem is that you will need a related Gem that knows about the object in question.
My solution was quite trivial and is provided as an answer to that question. Do this:
yamltext = File.read("somefile","r")
yamltext.sub!(/^--- \!.*$/,'---')
hash = YAML.load(yamltext)
In essence, you strip the object-classifier text from the yaml-text. Then you parse/load it.

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