Debugging a failed request

In the previous example you saw that I had to set :use_ssl => true, but it took some time to figure it out. The main problem was that in case of failure my previous code only printed the HTTP status code that was 400.

I read the documentation several times and tried various combinations of the code till it occurred to be that maybe there is some hint in the body of the response. So I changed the code to print that in case of failure.

require 'net/http'

url = 'https://httpbin.org/post'
uri = URI(url)

req = Net::HTTP::Post.new(uri)
req.set_form_data(
   "name" => "Foo Bar",
   "height" => 175,
)
req['User-Agent'] = "Internet Explorer 6.0"

response = Net::HTTP.start(uri.hostname, uri.port) do |http|
  http.request(req)
end


if response.is_a?(Net::HTTPSuccess)
    puts response.body
else
    #puts response.code
    puts response.body
end

This was the response:

<html>
<head><title>400 The plain HTTP request was sent to HTTPS port</title></head>
<body>
<center><h1>400 Bad Request</h1></center>
<center>The plain HTTP request was sent to HTTPS port</center>
</body>
</html>

That allowed me to understand that the issue is around the use of ssl: http vs https. First I tried the same code replacing the URL by one that uses http:

url = 'http://httpbin.org/post'

This worked.

At this point I understood I need to search for something about ssl, and that's how I found out that I had to pass :use_ssl => true.

So remember, at least for debugging, it can be useful to print the content of the body even in the case of error.

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Debugging a failed request