Performance wise, which is better: .get with a block or without a block when parsing JSON?

[postmodern]

I'm curious which is better, in theory, performance wise for parsing JSON responses?

.get without a block where the response body is immediately read/parsed then closed before processing the JSON data:

response = client.get('/endpoint')
json = JSON.parse(response.read)
response.close

json.each do |value|
  ...
end

vs. .get with a block where the response body is read/parsed and kept open while the JSON data is processed:

client.get('/endpoint') do |response|
  json = JSON.parse(response.read)
  json.each do |value|
    ...
  end
end

[ioquatix]

It's generally safer to use the block form if you can since the response will be closed correctly in (almost) every case (except fatal, unrecoverable errors). There should be no difference in performance. However, the code in the first example is unsafe, as you don't have an ensure block to close the connection. If the JSON fails to parse, you may leak the response which is bad.

[postmodern]

So if an exception is raised within the response block, will the response still be automatically closed?

[ioquatix]

Yes.