Generate an HTTP response in Ruby

Question

I'm working on an application that reaches out to a web service. I'd like to develop a proxy class that returns a fake response from the service, so I don't have to constantly be hitting it with requests while I'm developing/testing other parts of the app.

My application is expecting a response generated via Net::HTTP.

response = Net::HTTP.get(URI.parse('http://foo.com')) case response when Net::HTTPOK # do something fun when Net::HTTPUnauthorized # you get the idea

How can I manufacture a response object, give it all the right headers, return a body string, etc?

response = ProxyClass.response_object case response when Net::HTTPOk # my app doesn't know it's being lied to

Thanks.

lambshaanxy · Accepted Answer · 2010-07-30 01:50:33Z

It's actually not that hard to roll your own fake responses directly with Net::HTTP. Here's a simple 200 OK with a cookie header:

def fake_response net_http_resp = Net::HTTPResponse.new(1.0, 200, "OK") net_http_resp.add_field 'Set-Cookie', 'Monster' RestClient::Response.create("Body goes here", net_http_resp, nil) end

Since few of us are using raw Net::HTTP anymore, the (optional) last line wraps it up as a RestClient::Response, which can then be stubbed into RestClient:

stub(RestClient).post(anything) { fake_response }

Thanks, sometimes people rely on strange libraries even though http is supposed to be so darn simple. Good to know ruby has built in to generate the bare minimum http response.
FYI, Net::HTTP uses strings to represent HTTP response codes the the 200 response should be '200'
you could see a good use of that in the HTTParty library github.com/jnunemaker/httparty/blob/master/spec/support/…

gtd · Accepted Answer · 2009-04-21 06:25:26Z

I would start with FakeWeb and see if that meets your needs. If it doesn't you can probably gut whatever you need out of the internals and create your own solution.

David van Geest · Accepted Answer · 2012-05-11 21:12:29Z

I know this post is old, but instead of FakeWeb which seems to be largely dead, try webmock. It seems to be more full-featured and very active.

Thom A · Accepted Answer · 2022-08-26 14:27:56Z

I would look into a mocking library like mocha.

Then you should be able to setup a mock object to help test:

Then following example is from Tim Stephenson's RaddOnline blog, which also includes a more complete tutorial:

def setup @http_mock = mock('Net::HTTPResponse') @http_mock .stubs(:code => '200', :message => "OK", :content_type => > "text/html", :body => '<title>Test</title><body>Body of the page</body>') end

Velizar Hristov · Accepted Answer · 2020-10-24 20:52:23Z

I ended up using a Struct.

FakeHttpResponse = Struct.new(:status, :body) http = FakeHttpResponse.new('success', 'body goes here') http['status'] # = 'success' http.body # = 'body goes here'

The drawback is that .status and ['body'] are also valid, but I don't think that matters much.

Can be a little shorter with: OpenStruct.new(status: 'success', body: 'body goes here')

Brian Campbell · Accepted Answer · 2009-04-21 14:50:16Z

For testing a web service client, we use Sinatra, a lovely little lightweight web framework that lets you get something up and running very quickly and easily. Check out the home page; it has an entire Hello World app in 5 lines of code, and two commands to install and run the whole thing.

Jules Glegg · Accepted Answer · 2009-04-21 14:43:33Z

I would either use FakeWeb as mentioned above, or have my rake test task start a Webrick instance to a little sinatra app which mocks the various test responses you're hoping to see.

nkassis · Accepted Answer · 2009-04-21 16:56:34Z

0

You could look into using Rack for this which should allow you to do everything you need.

answered Apr 21, 2009 at 16:56

nkassis

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