spoof 2.2.1

HTTP server for testing environments

Spoof is a simple HTTP server for test environments.

>>> import requests
... import spoof
...
... with spoof.HTTPServer() as httpd:
...     httpd.responses.append([200, [], "This is Spoof 👻👋"])
...     requests.get(httpd.url).text
...
'This is Spoof 👻👋'

A test interface for HTTP

Spoof lets you easily create HTTP servers listening on real network sockets. Designed for test environments, what responses to return can be configured while an HTTP server is running. Requests can be inspected live or after a response is sent.

Unlike a conventional HTTP server, where specific methods and paths are configured in advance, Spoof accepts and records all requests, sending whatever responses are queued, or a default response if the queue is empty.

Why would I want this?

Spoof is all about enabling test-driven development (and refactoring) of HTTP client code. Have you ever felt icky patching a client library to write tests? Ever been burned by this? Ever wanted to refactor a client library, but had no way to check correctness apart from doing live integration testing? Ever wanted mock for HTTP? If you answered yes to any of the above, Spoof might be for you.

Installation and Compatibility

Spoof is available on PyPI:

$ python -m pip install spoof

Spoof is tested on Python 3.10 to 3.14, leverages the http.server module included in the Python standard library, and has no external dependencies. It may work on older versions of Python, but this is not supported.

Multiple Spoof HTTP servers can be run concurrently, and by default, the port number is the next available unused port. With OpenSSL installed, Spoof can also provide an SSL/TLS HTTP server. HTTP proxying and IPv6 are also supported.

Response precedence

Spoof determines what response to send to incoming requests based on the following precedence, highest to lowest:

1. Oldest response queued in .responses using first-in, first-out (FIFO) order

2. Response stored in .defaultResponse if no responses are queued

3. Response stored in .errorResponse if .defaultResponse is None

By default, Spoof will respond with an HTTP 503 Service Unavailable error, because newly created Spoof instances have no responses queued and no default response set. This requires non-error HTTP responses to be explicitly specified.

Response syntax

Spoof expects responses to have the following syntax:

[httpStatus, [(headerName1, value1), (headerName2, value2)], content]

# no content (Content-Length header is *not* sent if content is None)
[200, [], None]

# utf-8 content
[200, [], "This is Spoof 👻👋"]

# bytes content
[200, [("Content-Type", "application/json")], b'{"success": true }']

# responses can also be a callback
def callback(request):
    return [200, [], request.path]

Response queue

Spoof will always try to send a response from .responses first, before falling back to .defaultResponse or .errorResponse if the queue is empty. Backed by a deque instance, the .responses queue supports adding items via .responses.append() and .responses.extend(), similar to a regular list.

Spoof HTTP servers run in a single background thread, so response order should be predictably serial. Tests using Spoof should be able to use the same fixtures, in the same order, and get the same results. Example queueing multiple responses, verifying content, and request paths:

import requests
import spoof

with spoof.HTTPServer() as httpd:
    httpd.responses.extend([
        [200, [("Content-Type", "application/json")], b'{"id": 1111}'],
        [200, [("Content-Type", "application/json")], b'{"id": 2222}'],
    ])
    httpd.defaultResponse = [404, [], "Not found"]

    assert requests.get(httpd.url + "/path").json() == {"id": 1111}
    assert requests.get(httpd.url + "/alt/path").json() == {"id": 2222}
    assert requests.get(httpd.url + "/oops").status_code == 404
    assert [r.path for r in httpd.requests] == ["/path", "/alt/path", "/oops"]

Response callback

Set a callback as the default response (callbacks can also be queued):

import requests
import spoof

with spoof.HTTPServer() as httpd:
    httpd.defaultResponse = lambda request: [200, [], request.path]

    assert requests.get(httpd.url + "/alt").text == "/alt"

Request history

Spoof records each request and appends it to the .requests property, which is backed by a deque instance, the same as the .responses property. Once added to the .requests property, a request instance only exists for historical purposes. Example using request history:

>>> import requests
... import spoof
...
... with spoof.HTTPServer() as httpd:
...     httpd.defaultResponse = [200, [], None]
...
...     [requests.get(httpd.url + path) for path in ["/a", "/b", "/c"]]
...     [f"{r.method} {r.path} {r.protocol}" for r in httpd.requests]
...
[<Response [200]>, <Response [200]>, <Response [200]>]
['GET /a HTTP/1.1', 'GET /b HTTP/1.1', 'GET /c HTTP/1.1']

Request properties

SpoofRequestEnv instances have the following properties:

Property	Description
content	bytes object of request content
contentEncoding	Value of Content-Encoding header, if present
contentLength	Value of Content-Length header, if present
contentType	Value of Content-Type header, if present
headers	http.client.HTTPMessage object of headers
json()	Convenience to call json.loads on content
method	Request method (e.g. GET, POST, HEAD)
path	Decoded URI path, without query string
protocol	Protocol version (e.g. HTTP/1.0)
queryString	Anything in URI after ?
serverName	Host name of HTTP server
serverPort	Port number of HTTP server
uri	Raw URI path and query string, if present

SSL/TLS Mode

Test queued response with a self-signed SSL/TLS certificate:

import requests
import spoof

with spoof.SelfSignedSSLContext() as selfSigned:
    with spoof.HTTPServer(sslContext=selfSigned.sslContext) as httpd:
        httpd.responses.append([200, [], "No self-signed cert warning!"])

        response = requests.get(httpd.url, verify=selfSigned.certFile)
        assert response.text == "No self-signed cert warning!"

If setting the verify option in requests isn’t workable, the REQUESTS_CA_BUNDLE or CURL_CA_BUNDLE environment variables can be set to the path of the self-signed certificate to silence SSL/TLS errors:

import os
import requests
import spoof

with spoof.SelfSignedSSLContext() as selfSigned:
    with spoof.HTTPServer(sslContext=selfSigned.sslContext) as httpd:
        httpd.responses.append([200, [], "No self-signed cert warning!"])

        os.environ["REQUESTS_CA_BUNDLE"] = selfSigned.certFile
        response = requests.get(httpd.url)
        assert response.text == "No self-signed cert warning!"

If OpenSSL 3.5.0 or later is installed, Post-Quantum Cryptography (PQC) key algorithms can be used:

import requests
import spoof

with spoof.SelfSignedSSLContext(keyAlgorithm="mldsa65") as selfSigned:
    with spoof.HTTPServer(sslContext=selfSigned.sslContext) as httpd:
        httpd.responses.append([200, [], "TLS with PQC Key Algorithm"])

        response = requests.get(httpd.url, verify=selfSigned.certFile)
        assert response.text == "TLS with PQC Key Algorithm"

Proxy Mode

Spoof supports proxying by port-forwarding CONNECT requests to a separate upstream Spoof instance when the proxy=True argument is given. Unlike a real proxy server, Spoof won’t try to connect to external services. Example usage:

import requests
import spoof

with spoof.SelfSignedSSLContext(commonName="example.spoof") as selfSigned:
    with spoof.HTTPServer(sslContext=selfSigned.sslContext, proxy=True) as proxy:
        proxy.upstream.defaultResponse = [200, [], "I'm here!"]

        response = requests.get(
            "https://example.spoof/ayt",
            proxies={"https": proxy.url},
            verify=selfSigned.certFile
        )
        assert proxy.requests[0].method == "CONNECT"
        assert proxy.requests[0].path == "example.spoof:443"
        assert proxy.upstream.requests[0].method == "GET"
        assert proxy.upstream.requests[0].path == "/ayt"
        assert response.text == "I'm here!"

If setting the proxies option in requests isn’t workable, the https_proxy environment variable can be set to the URL of the proxy:

import os
import requests
import spoof

with spoof.SelfSignedSSLContext(commonName="example.spoof") as selfSigned:
    with spoof.HTTPServer(sslContext=selfSigned.sslContext, proxy=True) as proxy:
        proxy.upstream.defaultResponse = [200, [], "I'm here!"]

        os.environ["https_proxy"] = proxy.url
        os.environ["REQUESTS_CA_BUNDLE"] = selfSigned.certFile

        response = requests.get("https://example.spoof/ayt")
        assert proxy.requests[0].method == "CONNECT"
        assert proxy.requests[0].path == "example.spoof:443"
        assert proxy.upstream.requests[0].method == "GET"
        assert proxy.upstream.requests[0].path == "/ayt"
        assert response.text == "I'm here!"

IPv6 Mode

Setting the host attribute to an IPv6 address will work as expected. There is also an IPv6-only spoof.HTTPServer6 class that can be used if needed to only listen on IPv6 sockets.

>>> import requests
... import spoof
...
... with spoof.HTTPServer(host="::1") as httpd:
...     httpd.responses.append([200, [], "This is Spoof on IPv6 👀"])
...     requests.get(httpd.url).text
...     httpd.url
...
'This is Spoof on IPv6 👀'
'http://[::1]:51324'

>>> import requests
... import spoof
...
... with spoof.HTTPServer6(host="localhost") as httpd:
...     httpd.responses.append([200, [], "This is also Spoof on IPv6 👀"])
...     requests.get(httpd.url).text
...     httpd.url
...
'This is also Spoof on IPv6 👀'
'http://[::1]:54296'

Debug mode

Setting a callback with a breakpoint() can allow for live HTTP request debugging, including setting custom responses and inspecting requests. Note that callbacks can also be queued.

>>> import requests
... import spoof
...
... def debugCallback(request):
...     response = [200, [], ""]
...     breakpoint()
...     return response
...
... with spoof.HTTPServer() as httpd:
...     httpd.defaultResponse = debugCallback
...     requests.get(httpd.url).text
...
> <python-input-0>(6)debugCallback()
(Pdb) request
SpoofRequestEnv(content=None, contentEncoding=None, contentLength=0, contentType=None, headers=<http.client.HTTPMessage object at 0x10e16bd90>, method='GET', path='/', protocol='HTTP/1.1', queryString=None, serverName='localhost', serverPort=51612, uri='/')
(Pdb) response[2] = "content set from pdb"
(Pdb) c
'content set from pdb'