Parsing JSON hash with each generates "can't convert String into Integer"

Question

I am parsing JSON from an API with the following code:

def json_test
    content = open("API URL").read  
    json = JSON.parse(content)
    json.each do |a|
        puts a["first_name"]
    end
end

The reason I'm using each is because the API request will return an array of hashes for multiple users, like this:

[{
  "id": "1",
  "first_name": "John"
},
{
  "id": "2",
  "first_name": "Bob"
}]

However, the API will return just a hash if the request only returns a single user, like thus:

{
  "id": "2",
  "first_name": "Bob"
}

This is where I'm getting the error message: can't convert String into Integer (TypeError)

I've been searching for a good way to be able to parse when it's not returning an array but just a hash and I'm stumped. Any pointers?

mechanicalfish · Accepted Answer · 2013-12-15 00:25:40Z

1

Array.wrap is designed just for this purpose.

Wraps its argument in an array unless it is already an array (or array-like).

Array.wrap({ a: 1 }) # => [{ a: 1 }]
Array.wrap [{ a: 1 }, { b: 2 }] # => [{ a: 1 }, { b: 2 }]

answered Dec 15, 2013 at 0:25

mechanicalfish

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3 Comments

Note: This is rails/active_support only.

Thanks! This is exactly what I needed. I was looking in the Ruby docs instead of Rails docs, hence why I missed the method.

Look at the other extensions in active support too. They contain a lot of useful things that are good to know about.

Guilherme Bernal · Accepted Answer · 2013-12-15 00:20:22Z

0

One way is putting it all inside a single element array and flattening it:

json = [JSON.parse(content)].flatten

If it is not an array, the flatten will be noop. If it is, the extra array layer will be removed.

answered Dec 15, 2013 at 0:20

Guilherme Bernal

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