'JSON.parse' error handling invalid/non JSON format - ruby

Question

I request information from an HTTP streaming service. It provides data in JSON format. Here is the documentation. Here is a part of the code I am using:
require 'uri'
require 'net/https'
require 'json'
uri = URI("https://api.tradier.com/v1/markets/events/session")
http = Net::HTTP.new(uri.host, uri.port)
request = Net::HTTP::Post.new(uri.request_uri)
http.read_timeout = 30
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_PEER
# Headers
request["Accept"] = "application/json"
request["Authorization"] = "Bearer xxx"
# Send synchronously
response = http.request(request)
# parses response
parse = JSON.parse(response.body)
#out puts values only from response
sessionid = parse.values[0]["sessionid"]
url = parse.values[0]["url"]
uri = URI("#{url}?sessionid=#{sessionid}&symbols=aapl")
http = Net::HTTP.new(uri.host, uri.port)
request = Net::HTTP::Post.new(uri.request_uri)
http.read_timeout = 30
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_PEER
# Headers
request["Accept"] = "application/json"
request["Authorization"] = "Bearer xxx"
http.request request do |response|
response.read_body do |data|
puts data.class
# info = JSON.parse(data, :quirks_mode => true)
# puts info.values
end
end
I want to have the system continue the program. It seems that I need to use begin and rescue, but I cannot get them to work. When I request data, I get the following error:
`parse': 757: unexpected token at '{"type":"trade","symbol":"AAPL","exch":"Q","price":"191.23","size":"1081622","cvol":"18308460","date":"1528747200000","last":"191.23"}{"type":"summary","symbol":"AAPL","open":"191.35","high":"191.97","low":"190.21","prevClose":"191.7","close":"191.23"}' (JSON::ParserError)

Answer 1

The endpoint you are using is documented in Tradier API docs and it's a streaming endpoint.
It appears that the response is not chunked to contain just one JSON document per chunk. It however does appear that the documents are separated by linefeeds, making the response look like:
{ "json": "data" }
{ "more": "data" }
And that is not valid JSON. You probably need to parse them one by one by doing something like:
http.request request do |response|
response.read_body do |data|
data.each_line do |chunk|
info = JSON.parse(chunk)
puts info.inspect
end
end
end
If the response chunking happens in the middle of JSON documents, you must use some kind of buffered reader.