809: unexpected token at '' (JSON parser error ruby3.0.4 mac os catalina - json

Question

I have just started learning ruby and trying to learn extracting web data. I am using samplewebapp code given in a sites API documentation
On executing the test.rb file as given below it generates a token.
The token.json file contains the following
{"access_token":"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJhdWQiOiIzY2U1NjFhMC01ZmE5LTQ5NjUtYTQ2Mi01NmI2MzEzNjRlZGMiLCJqdGkiOiJmMjc0ZTgwM2FmZjVlMTFiMTAzNzIwMzAwNzRlNDRhZDE3ODg3ZjAzOGQ2ODk0OWIwNzVkMmQ5N2E2MjAwYzc5ZWRhNzU4MmQ3MTg1MTc1YiIsImlhdCI6MTY1NDU2OTc0MS41MjgxNTUsIm5iZiI6MTY1NDU2OTc0MS41MjgxNTcsImV4cCI6MTY1NDU3MzM0MS41MjgwMzksInN1YiI6IjE5NGFlNTU5LTU5OWMtNDQ2ZC1hOTRhLWM2MTIyYjZkMTA2ZiIsInNjb3BlcyI6W10sImNyZWRpdHNfcmVtYWluaW5nIjo0NzAwLCJyYXRlX2xpbWl0cyI6W3sicmF0ZSI6NSwiaW50ZXJ2YWwiOjYwfV19.XoN5A-H8Z7d8p_0e2rCcyV4yWO9MAF3TZlHk5VP5NjUEqtTXTVYKfKuzidYDs7K8ZzAtWzyt3aR5VSUG0_nw-uPd7Z3_Y75alQMqa2b5rHGn5JFWH7nuAriskr26WSCqAdj4cNjccPORryRr5sYKwpE4Y4kTG0IX_8frvwYxwp-8wFpLLj98K3axwN7CCpWdnPDSzuMqmH6tSpF0XhdYxB5LTVH0AyH7lN0S0_Lftq0b3sOLIvEaTfNkuRGNqwLkBYFkHFuPqwrKd8RJhC2W1QZhrmUw3eYnh-0iQABGk2V0skIqDlb6BbQ5GFX6MXgiXAc-h5Ndda7pZ5N5UCQU3g","expires_at":1654573341}
However it also generates a JSON parser error as under
/Users/mm/.rbenv/versions/3.0.4/lib/ruby/3.0.0/json/common.rb:216:in `parse': 809: unexpected token at '' (JSON::ParserError)
from /Users/mm/.rbenv/versions/3.0.4/lib/ruby/3.0.0/json/common.rb:216:in `parse'
from /Users/mm/Desktop/prokerala/client.rb:21:in `parseResponse'
from /Users/mm/Desktop/prokerala/client.rb:99:in `get'
I googled around for a while and some of the responses talk about the issues between double and single quotes.. I tried changing those also but it doesn't work.
I have also tried running it with system ruby - which gives a different error
Would appreciate very much if someone could explain what the error is / logic behind this.. Also I am not clear about the error message itself. The message talks about parse error 809:"unexpected token" on column no 809 of the token there is nothing.. Am i reading it wrong?
code used in test.rb file
client = ApiClient.new('YOUR CLIENT_ID', 'YOUR CLIENT_SECRET');
result = client.get('v2/astrology/thirumana-porutham/advanced', {
:girl_nakshatra => 4,
:girl_nakshatra_pada => 2,
:boy_nakshatra => 26,
:boy_nakshatra_pada => 3
})
puts JSON.pretty_generate(result)
code used in client.rb file
require 'net/http'
require 'json'
class ApiError < StandardError
end
class ApiClient
BASE_URL = "https://api.prokerala.com/"
# Make sure that the following file path is set to a location that is not publicly accessible
TOKEN_FILE = "./token.json"
def initialize(clientId, clientSecret)
# Instance variables
#clientId = clientId
#clientSecret = clientSecret
end
def parseResponse(response)
content = response.body
res = JSON.parse(content)
if res.key?('access_token')
return res
end
if res['status'] == "error"
raise ApiError, res['errors'].map {|e| e['detail']}.join("\n")
end
if res['status'] != "ok"
raise "HTTP request failed"
end
return res
end
def saveToken(token)
# Cache the token until it expires.
File.open(ApiClient::TOKEN_FILE,"w") do |f|
token = {
:access_token => token['access_token'],
:expires_at => Time.now.to_i + token['expires_in']
}
f.write(token.to_json)
end
end
def getTokenFromCache
if not File.file?(ApiClient::TOKEN_FILE)
return nil
end
begin
# Fetch the cached token, and return if not expired
text = File.read(ApiClient::TOKEN_FILE)
token = JSON.parse(text)
if token['expires_at'] < Time.now.to_i
return nil
end
return token['access_token']
rescue JSON::ParserError
return nil
end
end
def fetchNewToken
params = {
:grant_type => 'client_credentials',
:client_id => #clientId,
:client_secret => #clientSecret
}
res = Net::HTTP.post_form(URI(ApiClient::BASE_URL + 'token'), params)
token = parseResponse(res)
saveToken(token)
return token['access_token']
end
def get(endpoint, params)
# Try to fetch the access token from cache
token = getTokenFromCache
# If failed, request new token
token ||= fetchNewToken
uri = URI(ApiClient::BASE_URL + endpoint)
uri.query = URI.encode_www_form(params)
req = Net::HTTP::Get.new(uri.to_s, {'Authorization' => 'Bearer ' + token})
res = Net::HTTP.start(uri.hostname) do |http|
http.request(req)
end
return parseResponse(res)
end
end
running the test file using ruby 3.0.4 gives the a JSON parse error. Full error reproduced as below
/Users/mm/.rbenv/versions/3.0.4/lib/ruby/3.0.0/json/common.rb:216:in `parse': 809: unexpected token at '' (JSON::ParserError)
from /Users/mm/.rbenv/versions/3.0.4/lib/ruby/3.0.0/json/common.rb:216:in `parse'
from /Users/mm/Desktop/prokerala/client.rb:21:in `parseResponse'
from /Users/mm/Desktop/prokerala/client.rb:99:in `get'
from test.rb:11:in `<main>'

Answer 1

I executed the above code and from this, we are getting
#<Net::HTTPMovedPermanently 301 Moved Permanently readbody=true> as response
and response body as empty string '', which results in error in parsing the body.
Since, API endpoint is secure with https, we need set use_ssl: true before starting the session. Try below code and it will fix the issue.
res = Net::HTTP.start(uri.hostname, use_ssl: true) do |http|
http.request(req)
end