法拉第宝石未定义方法“bytesize”= Hash`

Question

I want to send a POST request to an API. Here's my code:

conn = Faraday.new(url: BASE) do |faraday|
  faraday.response :logger
  faraday.request  :url_encoded
  faraday.headers['Content-Type'] = 'application/json'
  faraday.headers["Authorization"] = "bearer #{AppConfig.instance.access_token}"
  faraday.adapter Faraday.default_adapter
end
form_data = {a: 1, b: 2}
conn.post("/api/test", form_data)

But I get this error:

NoMethodError (undefined method `bytesize' for {:a=>1, :b=>2}:Hash)

I've also tried:

conn.post("/api/test", form_data.to_json)

but it doesn't work either.

Answer 1

Official faraday repo provides next description:

# post payload as JSON instead of "www-form-urlencoded" encoding:
conn.post do |req|
  req.url '/nigiri'
  req.headers['Content-Type'] = 'application/json'
  req.body = '{ "name": "Unagi" }'
end

So, content type 'application/json' can't resolve hash. Gem doesn't convert the body data to needed format by itself.

You need to convert your form_data to string( json ) format:

form_data = {a: 1, b: 2}.to_json

Note. Don't convert by .to_s when using symbol keys format because that will cause the parsing error.

With provided by you faraday configuration I can't cause any error after converting format_data to json. So, new error not related to faraday gem or provided code.

Answer 2

Use to_json to convert it to json, It fails with as_json as well.

{ key: value }.as_json.respond_to?(:bytesize) => false

{ key: value }.to_json.respond_to?(:bytesize) => true