Malformed servers to test your HTTP client
Hamms is designed to elicit failures in your HTTP Client. Connection failures,
malformed response data, slow servers, fat headers, and more!
You can either install hamms via pip:
pip install hamms
Or clone this project:
git clone https://github.com/kevinburke/hamms.git
Start hamms by running it from the command line:
python -m hamms
Or use the HammsServer class to start and stop the server on command.
from hamms import HammsServer
class MyTest(object):
def setUp(self):
self.hs = HammsServer()
self.hs.start(beginning_port=5500)
def tearDown(self):
self.hs.stop()
Make requests and test your client. See the reference below for a list of
supported failure modes.
By default, Hamms uses ports 5500-5600. You can customize the port range by
passing the beginning_port parameter to HammsServer.start().
Connect to the ports listed below to enact the various failure modes.
5500 - Nothing is listening on the port. Note, your machine will likely
send back a TCP reset (closing the connection) immediately.
To simulate a connection failure that just hangs forever (a connection
timeout), connect to a bad host on a real server, for example
www.google.com:81, or use a port in the 10.* range, for example
10.255.255.1.
5501 - The port accepts traffic but never sends back data
5502 - The port sends back an empty string immediately upon connection
5503 - The port sends back an empty string after the client sends data
5504 - The port sends back a malformed response (“foo bar”) immediately upon connection
5505 - The port sends back a malformed response (“foo bar”) after the client sends data
5506 - The client accepts the request, and sends back one byte every 5 seconds
5507 - The client accepts the request, and sends back one byte every 30 seconds
5508 - Send a request to localhost:5508?sleep=<float> to sleep
for float number of seconds. If no value is provided, sleep for 5 seconds.
5509 - Send a request to localhost:5509?status=<int> to return
a response with HTTP status code status. If no value is provided, return
status code 200.
5510 - The server will send a response with a Content-Length: 3 header,
however the response is actually 1 MB in size. This can break clients that
reuse a socket.
5511 - Send a request to localhost:5511?size=<int> to return a Cookie
header that is n bytes long. By default, return a 63KB header. 1KB larger
will break many popular clients (curl, requests, for example)
5512 - Use this port to test retry logic in your client - to ensure that
it retries on failure.
The server maintains a counter for incoming requests. Each time a new
request is made, a 500 error is served and the counter is decremented. When
the counter reaches zero, a 200 response is served. This server accepts two
query arguments:
key to create a new counter. Continue makingkey=<key> to decrement that particular counter. If noThe server will let you know the key and how many tries are remaining until
you get a successful response. Example error response:
HTTP/1.1 500 INTERNAL SERVER ERROR
Content-Length: 116
Content-Type: application/json
Date: Wed, 19 Nov 2014 00:59:19 GMT
Server: TwistedWeb/14.0.2
{
"error": "The server had an error. Try again 1 more time",
"key": "foobar",
"success": false,
"tries_remaining": 1
}
Example usage:
r = requests.get('http://localhost:5512?key=special-key')
assert_equal(r.status_code, 500)
r = requests.get('http://localhost:5512?key=special-key')
assert_equal(r.status_code, 500)
# Third time is the charm
r = requests.get('http://localhost:5512?key=special-key')
assert_equal(r.status_code, 200)
# Set tries=1 to serve a 200 right away.
r = requests.get('http://localhost:5512?key=my-key&tries=1')
assert_equal(r.status_code, 200)
You can see the status of all available counters by making a GET request
to http://localhost:5512/counters, or reset a counter by making a POST
request to http://localhost:5512/counters with the key you want to
reset.
5513 - Send a request to localhost:5513?failrate=<float>. The server
will drop requests with a frequency of failrate.
5514 - The server will try as hard as it can to return a content type
that is not parseable by the Accept header provided by the request. Specify
a Accept: application/json header in your request and the server will return
data with the text/morse content type. The server will try these
content-types in turn:
text/morse
application/json
text/html
text/csv
If your Accept header indicates it can accept all of these content-types, the
server will return text/morse.
5515 - The server will return a response with a content-type that matches
the request, but it will be incomplete. The server will advertise an incorrect,
too long Content-Length, and the response body will not be complete. The
practical effect is that the server will hang halfway through the response
download. The server can return partial responses with the following
content-types:
application/json
text/html
text/plain
text/xml
If your server indicates an Accept header value of */*, or the server cannot
find a matching content-type, the server will returnn an incomplete json
response.
Donations free up time to make improvements to the library, and respond to
bug reports. You can send donations via Paypal’s “Send Money” feature to
[email protected]. Donations are not tax deductible in the USA.