How to construct URI with query arguments from hash in Ruby

Question

How to construct URI object with query arguments by passing hash?

I can generate query with:

URI::HTTPS.build(host: 'example.com', query: "a=#{hash[:a]}, b=#{[hash:b]}")

which generates

https://example.com?a=argument1&b=argument2

however I think constructing query string for many arguments would be unreadable and hard to maintain. I would like to construct query string by passing hash. Like in example below:

hash = {
  a: 'argument1',
  b: 'argument2'
  #... dozen more arguments
}
URI::HTTPS.build(host: 'example.com', query: hash)

which raises

NoMethodError: undefined method `to_str' for {:a=>"argument1", :b=>"argument2"}:Hash

Is it possible to construct query string based on hash using URI api? I don't want to monkey patch hash object...

David Moles · Accepted Answer · 2019-09-19 22:24:01Z

29

If you have ActiveSupport, just call '#to_query' on hash.

hash = {
  a: 'argument1',
  b: 'argument2'
  #... dozen more arguments
}
URI::HTTPS.build(host: 'example.com', query: hash.to_query)

=> https://example.com?a=argument1&b=argument2

If you are not using rails remember to require 'uri'

edited Sep 19, 2019 at 22:24

David Moles

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answered Oct 21, 2015 at 10:51

Filip Bartuzi

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3 Comments

marc_ferna Over a year ago

to_query is a Rails only method. It does not exist in Ruby.

Filip Bartuzi Over a year ago

@marc_ferna questions has ruby on rails tag. You can include : ActiveSupport in non-rails projects

David Moles Jul 23 at 23:43

This is OK if you're constructing URLs for querying a Rails app; for anything else, use URI.encode_www_form as per Grizz's answer. Compare for instance {q: [1, 2]}.to_query vs URI.encode_www_form({q: [1, 2]}) — the former injects square brackets into the parameter names, a weird Rails-ism, producing q%5B%5D=1&q%5B%5D=2; while the second produces the web-standard (and much more legible) "q=1&q=2". It will also sort the keys first, which while not a showstopper, can be unnecessarily annoying to debug.

Grizz · Accepted Answer · 2017-04-19 21:46:30Z

27

For those not using Rails or Active Support, the solution using the Ruby standard library is

hash = {
  a: 'argument1',
  b: 'argument2'
}
URI::HTTPS.build(host: 'example.com', query: URI.encode_www_form(hash))
=> #<URI::HTTPS https://example.com?a=argument1&b=argument2>

answered Apr 19, 2017 at 21:46

Grizz

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1 Comment

David Moles Jul 23 at 23:45

This should be the accepted answer, much better than ActiveSupport's quirky to_query for anything other than querying a Rails server.

yegor256 · Accepted Answer · 2024-06-13 11:07:20Z

0

You can try my iri gem, which is exactly the builder of URI/URL:

require 'iri'
uri = Iri.new
  .host('example.com')
  .add(a: 'argument1')
  .add(b: 'argument2')
  .to_s

answered Jun 13, 2024 at 11:07

yegor256

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