HTTP Posts in Ruby

Sometimes I need to make simple HTTP posts in a Ruby script. Using a 3rd party library may be too clunky for such a simple script.

This post helps a lot, but it doesn't cover all my needs. Specifically, when working with the Switchvox API, the API methods are expected to be a JSON parameter.

Let's start by imply posting some JSON.

Post some JSON

require 'net/http'
require 'uri'
require 'json'

uri = URI.parse("http://localhost:3000/users")

header = {'Content-Type': 'text/json'}
user = {user: {
                   name: 'Bob',
                   email: 'bob@example.com'
                      }
            }

# Create the HTTP objects
http = Net::HTTP.new(uri.host, uri.port)
request = Net::HTTP::Post.new(uri.request_uri, header)
request.body = user.to_json

# Send the request
response = http.request(request)

This will simply submit a POST request with the JSON as the body.

But, there were some methods that required a file be submitted with the JSON? Things get a little more complicated when you do this, but it is still manageable.

Post a file with some JSON

require 'net/http'
require 'uri'
require 'json'
require 'mime/types'

uri = URI.parse("http://localhost:3000/users")
BOUNDARY = "AaB03x"

header = {"Content-Type": "multipart/form-data, boundary=#{BOUNDARY}"}
user = {user: {
                   name: 'Bob',
                   email: 'bob@example.com'
                      }
            }
file = "test_file.xml"

# We're going to compile all the parts of the body into an array, then join them into one single string
# This method reads the given file into memory all at once, thus it might not work well for large files
post_body = []

# Add the file Data
post_body << "--#{BOUNDARY}\r\n"
post_body << "Content-Disposition: form-data; name=\"user[][image]\"; filename=\"#{File.bsename(file)}\"\r\n"
post_body << "Content-Type: #{MIME::Types.type_for(file)}\r\n\r\n"
post_body << File.read(file)

# Add the JSON
post_body << "--#{BOUNDARY}\r\n"
post_body << "Content-Disposition: form-data; name=\"user[]\"\r\n\r\n"
post_body << user.to_json
post_body << "\r\n\r\n--#{BOUNDARY}--\r\n"

# Create the HTTP objects
http = Net::HTTP.new(uri.host, uri.port)
request = Net::HTTP::Post.new(uri.request_uri, header)
request.body = post_body.join

# Send the request
response = http.request(request)

And there you have it! A multipart HTTP Post in Ruby without an external library. You can probably see how you could add multiple files and sets JSON objects.

Is it worth not using a 3rd party library and doing it yourself?