how to parse and iterate a json using ruby - json

Question

Im a beginner with ruby and learning to iterate and parse json file. The contents inside input.json
[
{
"scheme": "http",
"domain_name": "www.example.com",
"path": "path/to/file",
"fragment": "header2"
},
{
"scheme": "http",
"domain_name": "www.example2.org",
"disabled": true
},
{
"scheme": "https",
"domain_name": "www.stack.org",
"path": "some/path",
"query": {
"key1": "val1",
"key2": "val2"
}
}
]
ho do I parse print the output as:
http://www.example.com/path/to/file#header2
https://www.stack.org/some/path?key1=val1&key2=val2
Any learning references would be very helpful.

Answer 1

Hopefully this code is self-explanatory:
require 'URI'
require 'json'
entries = JSON.parse(File.read('input.json'))
entries.reject { |entry| entry["disabled"] }.each do |entry|
puts URI::Generic.build({
:scheme => entry["scheme"],
:host => entry["domain_name"],
:fragment => entry["fragment"],
:query => entry["query"] && URI.encode_www_form(entry["query"]),
:path => entry["path"] && ("/" + entry["path"])
}).to_s
end
# Output:
# http://www.example.com/path/to/file#header2
# https://www.stack.org/some/path?key1=val1&key2=val2

Answer 2

The first step is to turn this JSON into Ruby data:
require 'json'
data = JSON.load(DATA)
Then you need to iterate over this and reject all those that are flagged as disabled:
data.reject do |entry|
entry['disabled']
end
Which you can chain together with an operation that leverages the URI library to build your output:
require 'uri'
uris = data.reject do |entry|
entry['disabled']
end.map do |entry|
case (entry['scheme'])
when 'https'
URI::HTTPS
else
URI::HTTP
end.build(
host: entry['domain_name'],
path: normalized_path(entry['path']),
query: entry['query'] && URI.encode_www_form(entry['query'])
).to_s
end
#=> ["http://www.example.com/path/to/file", "http://www.stack.org/some/path?key1=val1&key2=val2"]
This requires a function called normalized_path to deal with nil or invalid paths and fix them:
def normalized_path(path)
case (path and path[0,1])
when nil
'/'
when '/'
path
else
"/#{path}"
end
end