Advanced Usage#

This document covers some of Niquests more advanced features.

Session Objects#

The Session object allows you to persist certain parameters across niquests. It also persists cookies across all requests made from the Session instance, and will use urllib3.future’s connection pooling. So if you’re making several requests to the same host, the underlying TCP connection will be reused, which can result in a significant performance increase (see HTTP persistent connection).

A Session object has all the methods of the main Niquests API.

Let’s persist some cookies across requests:

s = niquests.Session()

s.get('https://httpbin.org/cookies/set/sessioncookie/123456789')
r = s.get('https://httpbin.org/cookies')

print(r.text)
# '{"cookies": {"sessioncookie": "123456789"}}'

Sessions can also be used to provide default data to the request methods. This is done by providing data to the properties on a Session object:

s = niquests.Session()
s.auth = ('user', 'pass')
s.headers.update({'x-test': 'true'})

# both 'x-test' and 'x-test2' are sent
s.get('https://httpbin.org/headers', headers={'x-test2': 'true'})

Any dictionaries that you pass to a request method will be merged with the session-level values that are set. The method-level parameters override session parameters.

Note, however, that method-level parameters will not be persisted across requests, even if using a session. This example will only send the cookies with the first request, but not the second:

s = niquests.Session()

r = s.get('https://httpbin.org/cookies', cookies={'from-my': 'browser'})
print(r.text)
# '{"cookies": {"from-my": "browser"}}'

r = s.get('https://httpbin.org/cookies')
print(r.text)
# '{"cookies": {}}'

If you want to manually add cookies to your session, use the Cookie utility functions to manipulate Session.cookies.

Sessions can also be used as context managers:

with niquests.Session() as s:
    s.get('https://httpbin.org/cookies/set/sessioncookie/123456789')

This will make sure the session is closed as soon as the with block is exited, even if unhandled exceptions occurred.

Remove a Value From a Dict Parameter

Sometimes you’ll want to omit session-level keys from a dict parameter. To do this, you simply set that key’s value to None in the method-level parameter. It will automatically be omitted.

All values that are contained within a session are directly available to you. See the Session API Docs to learn more.

The Session class takes two (optional) named arguments for your convenience.

quic_cache_layer Specify a MutableMapping that can memorize Alt-Svc capabilities (when a server is HTTP/3 compatible).
retries Determine the retry strategy across the Session lifetime.

Request and Response Objects#

Whenever a call is made to niquests.get() and friends, you are doing two major things. First, you are constructing a Request object which will be sent off to a server to request or query some resource. Second, a Response object is generated once Niquests gets a response back from the server. The Response object contains all of the information returned by the server and also contains the Request object you created originally. Here is a simple request to get some very important information from Wikipedia’s servers:

>>> r = niquests.get('https://en.wikipedia.org/wiki/Monty_Python')

If we want to access the headers the server sent back to us, we do this:

>>> r.headers
{'content-length': '56170', 'x-content-type-options': 'nosniff', 'x-cache':
'HIT from cp1006.eqiad.wmnet, MISS from cp1010.eqiad.wmnet', 'content-encoding':
'gzip', 'age': '3080', 'content-language': 'en', 'vary': 'Accept-Encoding,Cookie',
'server': 'Apache', 'last-modified': 'Wed, 13 Jun 2012 01:33:50 GMT',
'connection': 'close', 'cache-control': 'private, s-maxage=0, max-age=0,
must-revalidate', 'date': 'Thu, 14 Jun 2012 12:59:39 GMT', 'content-type':
'text/html; charset=UTF-8', 'x-cache-lookup': 'HIT from cp1006.eqiad.wmnet:3128,
MISS from cp1010.eqiad.wmnet:80'}

However, if we want to get the headers we sent the server, we simply access the request, and then the request’s headers:

>>> r.request.headers
{'Accept-Encoding': 'identity, deflate, compress, gzip',
'Accept': '*/*', 'User-Agent': 'python-requests/1.2.0'}

Prepared Requests#

Whenever you receive a Response object from an API call or a Session call, the request attribute is actually the PreparedRequest that was used. In some cases you may wish to do some extra work to the body or headers (or anything else really) before sending a request. The simple recipe for this is the following:

from niquests import Request, Session

s = Session()

req = Request('POST', url, data=data, headers=headers)
prepped = req.prepare()

# do something with prepped.body
prepped.body = 'No, I want exactly this as the body.'

# do something with prepped.headers
del prepped.headers['Content-Type']

resp = s.send(prepped,
    stream=stream,
    verify=verify,
    proxies=proxies,
    cert=cert,
    timeout=timeout
)

print(resp.status_code)

Since you are not doing anything special with the Request object, you prepare it immediately and modify the PreparedRequest object. You then send that with the other parameters you would have sent to niquests.* or Session.*.

However, the above code will lose some of the advantages of having a Requests Session object. In particular, Session-level state such as cookies will not get applied to your request. To get a PreparedRequest with that state applied, replace the call to Request.prepare() with a call to Session.prepare_request(), like this:

from niquests import Request, Session

s = Session()
req = Request('GET',  url, data=data, headers=headers)

prepped = s.prepare_request(req)

# do something with prepped.body
prepped.body = 'Seriously, send exactly these bytes.'

# do something with prepped.headers
prepped.headers['Keep-Dead'] = 'parrot'

resp = s.send(prepped,
    stream=stream,
    verify=verify,
    proxies=proxies,
    cert=cert,
    timeout=timeout
)

print(resp.status_code)

When you are using the prepared request flow, keep in mind that it does not take into account the environment. This can cause problems if you are using environment variables to change the behaviour of niquests. For example: Self-signed SSL certificates specified in REQUESTS_CA_BUNDLE will not be taken into account. As a result an SSL: CERTIFICATE_VERIFY_FAILED is thrown. You can get around this behaviour by explicitly merging the environment settings into your session:

from niquests import Request, Session

s = Session()
req = Request('GET', url)

prepped = s.prepare_request(req)

# Merge environment settings into session
settings = s.merge_environment_settings(prepped.url, {}, None, None, None)
resp = s.send(prepped, **settings)

print(resp.status_code)

SSL Cert Verification#

Niquests verifies SSL certificates for HTTPS requests, just like a web browser. By default, SSL verification is enabled, and Niquests will throw a SSLError if it’s unable to verify the certificate:

>>> niquests.get('https://requestb.in')
niquests.exceptions.SSLError: hostname 'requestb.in' doesn't match either of '*.herokuapp.com', 'herokuapp.com'

I don’t have SSL setup on this domain, so it throws an exception. Excellent. GitHub does though:

>>> niquests.get('https://github.com')
<Response HTTP/2 [200]>

You can pass verify the path to a CA_BUNDLE file or directory with certificates of trusted CAs:

>>> niquests.get('https://github.com', verify='/path/to/certfile')

or persistent:

s = niquests.Session()
s.verify = '/path/to/certfile'

Note

If verify is set to a path to a directory, the directory must have been processed using the c_rehash utility supplied with OpenSSL.

This list of trusted CAs can also be specified through the REQUESTS_CA_BUNDLE environment variable. If REQUESTS_CA_BUNDLE is not set, CURL_CA_BUNDLE will be used as fallback.

Niquests can also ignore verifying the SSL certificate if you set verify to False:

>>> niquests.get('https://kennethreitz.org', verify=False)
<Response HTTP/2 [200]>

Note that when verify is set to False, requests will accept any TLS certificate presented by the server, and will ignore hostname mismatches and/or expired certificates, which will make your application vulnerable to man-in-the-middle (MitM) attacks. Setting verify to False may be useful during local development or testing.

By default, verify is set to True. Option verify only applies to host certs.

Client Side Certificates#

You can also specify a local cert to use as client side certificate, as a single file (containing the private key and the certificate) or as a tuple of both files’ paths:

>>> niquests.get('https://kennethreitz.org', cert=('/path/client.cert', '/path/client.key'))
<Response HTTP/2 [200]>

or persistent:

s = niquests.Session()
s.cert = '/path/client.cert'

If you specify a wrong path or an invalid cert, you’ll get a SSLError:

>>> niquests.get('https://kennethreitz.org', cert='/wrong_path/client.pem')
SSLError: [Errno 336265225] _ssl.c:347: error:140B0009:SSL routines:SSL_CTX_use_PrivateKey_file:PEM lib

Warning

The private key to your local certificate must be unencrypted in above example.

You may specify the private key passphrase using the following example:

>>> niquests.get('https://kennethreitz.org', cert=('/path/client.cert', '/path/client.key', 'my_key_password'))
<Response HTTP/2 [200]>

DNS with mTLS#

You can pass your client side certificate to authenticate yourself against the given resolver. To do so, you will have to do as follow:

from urllib3 import ResolverDescription
from niquests import Session

rd = ResolverDescription.from_url("doq://my-resolver.tld")
rd["cert_data"] = in_memory_cert  # not a path, it should contain your cert content PEM format directly
rd["cert_key"] = ...
rd["key_password"] = ...

with Session(resolver=rd) as s:
    ...

Note

Instead of in-memory cert, you can pass file path instead with cert_file, key_file.

This method of authentication is broadly used with DNS over TLS, QUIC, and HTTPS.

In-memory Certificates#

The cert=... and verify=... can actually take the certificates themselves. Niquests support in-memory certificates instead of file paths.

CA Certificates#

Niquests uses certificates provided by the package wassima. This allows for users to not care about root CAs. By default it is expected to use your operating system root CAs. You have nothing to do.

Body Content Workflow#

By default, when you make a request, the body of the response is downloaded immediately. You can override this behaviour and defer downloading the response body until you access the Response.content attribute with the stream parameter:

tarball_url = 'https://github.com/jawah/niquests/tarball/main'
r = niquests.get(tarball_url, stream=True)

At this point only the response headers have been downloaded and the connection remains open, hence allowing us to make content retrieval conditional:

if int(r.headers['content-length']) < TOO_LONG:
  content = r.content
  ...

You can further control the workflow by use of the Response.iter_content() and Response.iter_lines() methods. Alternatively, you can read the undecoded body from the underlying urllib3 urllib3.HTTPResponse at Response.raw.

If you set stream to True when making a request, Niquests cannot release the connection back to the pool unless you consume all the data (HTTP/1.1 only) or call Response.close. This can lead to inefficiency with connections. If you find yourself partially reading request bodies (or not reading them at all) while using stream=True, you should make the request within a with statement to ensure it’s always closed:

with niquests.get('https://httpbin.org/get', stream=True) as r:
    # Do things with the response here.

Keep-Alive#

Excellent news — thanks to urllib3.future, keep-alive is 100% automatic within a session! Any requests that you make within a session will automatically reuse the appropriate connection!

Note that connections are only released back to the pool for reuse once all body data has been read; be sure to either set stream to False or read the content property of the Response object.

Streaming Uploads#

Niquests supports streaming uploads, which allow you to send large streams or files without reading them into memory. To stream and upload, simply provide a file-like object for your body:

with open('massive-body', 'rb') as f:
    niquests.post('http://some.url/streamed', data=f)

Warning

It is recommended that you open files in binary mode.

Chunk-Encoded Requests#

Niquests also supports Chunked transfer encoding for outgoing and incoming niquests. To send a chunk-encoded request, simply provide a generator (or any iterator without a length) for your body:

def gen():
    yield 'hi'
    yield 'there'

niquests.post('http://some.url/chunked', data=gen())

For chunked encoded responses, it’s best to iterate over the data using Response.iter_content(). In an ideal situation you’ll have set stream=True on the request, in which case you can iterate chunk-by-chunk by calling iter_content with a chunk_size parameter of None. If you want to set a maximum size of the chunk, you can set a chunk_size parameter to any integer.

POST Multiple Multipart-Encoded Files#

You can send multiple files in one request. For example, suppose you want to upload image files to an HTML form with a multiple file field ‘images’:

<input type="file" name="images" multiple="true" required="true"/>

To do that, just set files to a list of tuples of (form_field_name, file_info):

>>> url = 'https://httpbin.org/post'
>>> multiple_files = [
...     ('images', ('foo.png', open('foo.png', 'rb'), 'image/png')),
...     ('images', ('bar.png', open('bar.png', 'rb'), 'image/png'))]
>>> r = niquests.post(url, files=multiple_files)
>>> r.text
{
  ...
  'files': {'images': 'data:image/png;base64,iVBORw ....'}
  'Content-Type': 'multipart/form-data; boundary=3131623adb2043caaeb5538cc7aa0b3a',
  ...
}

Warning

It is recommended that you open files in binary mode. Errors may occur if you open the file in text mode. This because it is going to be re-encoded later in the process.

Event Hooks#

Niquests has a hook system that you can use to manipulate portions of the request process, or signal event handling.

Available hooks:

response:: The response generated from a Request.
pre_send:: The prepared request got his ConnectionInfo injected. This event is triggered just after picking a live connection from the pool.
on_upload:: Permit to monitor the upload progress of passed body. This event is triggered each time a block of data is transmitted to the remote peer. Use this hook carefully as it may impact the overall performance.
pre_request:: The prepared request just got built. You may alter it prior to be sent through HTTP.

You can assign a hook function on a per-request basis by passing a {hook_name: callback_function} dictionary to the hooks request parameter:

hooks={'response': print_url}

That callback_function will receive a chunk of data as its first argument.

def print_url(r, *args, **kwargs):
    print(r.url)

Your callback function must handle its own exceptions. Any unhandled exception won’t be passed silently and thus should be handled by the code calling Niquests.

If the callback function returns a value, it is assumed that it is to replace the data that was passed in. If the function doesn’t return anything, nothing else is affected.

def record_hook(r, *args, **kwargs):
    r.hook_called = True
    return r

Let’s print some request method arguments at runtime:

>>> niquests.get('https://httpbin.org/', hooks={'response': print_url})
https://httpbin.org/
<Response HTTP/2 [200]>

You can add multiple hooks to a single request. Let’s call two hooks at once:

>>> r = niquests.get('https://httpbin.org/', hooks={'response': [print_url, record_hook]})
>>> r.hook_called
True

You can also add hooks to a Session instance. Any hooks you add will then be called on every request made to the session. For example:

>>> s = niquests.Session()
>>> s.hooks['response'].append(print_url)
>>> s.get('https://httpbin.org/')
 https://httpbin.org/
 <Response HTTP/2 [200]>

A Session can have multiple hooks, which will be called in the order they are added.

You can find a example of how to retrieve the connection information just before the request is sent:

>>> r = niquests.get("https://1.1.1.1", hooks={"pre_send": [lambda r: print(r.conn_info)]}

Here, r is the PreparedRequest and conn_info contains a ConnectionInfo. You can explore the following data in it.

certificate_der: The peer certificate in DER format (binary)
certificate_dict: The peer certificate as a dictionary like ssl.SSLSocket.getpeercert(binary_from=False) output it.
tls_version: TLS version.
cipher: Cipher used.
http_version: Http version that is about to be used.
destination_address: The remote peer address given to us by the DNS resolver.
issuer_certificate_der: Immediate issuer (in the TLS certificate chain) in DER format (binary)
issuer_certificate_dict: Immediate issuer (in the TLS certificate chain) as a dictionary
established_latency: The amount of time consumed to get an ESTABLISHED network link.
resolution_latency: The amount of time consumed for the hostname resolution.
tls_handshake_latency: The amount of time consumed for the TLS handshake completion.
request_sent_latency: The amount of time consumed to encode and send the whole request through the socket.

Warning

Depending on your platform and interpreter, some key element might not be available and be assigned None everytime. Like certificate_dict on MacOS.

List of tangible use-cases:

Displaying cool stuff on the screen for CLI based tools.
Also debugging, obviously.
Among others thing.

Note

In a asynchronous HTTP request, you may pass awaitable functions in addition to the usual synchronous ones.

Track upload progress#

You may use the on_upload hook to track the upload progress of a request. The callable will receive the PreparedRequest that will contain a property named upload_progress.

Note

upload_progress is a TransferProgress instance.

You may find bellow a plausible example:

import niquests

if __name__ == "__main__":
    def track(req):
        print(req.upload_progress)

    with niquests.Session() as s:
        s.post("https://pie.dev/post", data=b"foo"*16800*1024, hooks={"on_upload": [track]})

Note

Niquests recommend the excellent tqdm library to create progress bars with ease.

upload_progress contains the following properties:

percentage (optional) Basic percentage expressed via float from 0% to 100%
content_length (optional) The expected total bytes to be sent (may be unset due to some body formats, e.g. blind iterator / generator)
total : Amount of bytes sent to the remote peer
is_completed : Determine if the transfer ended
any_error : Simple boolean that indicate whenever a error occurred during transfer (like early response from peer)

Custom Authentication#

Niquests allows you to specify your own authentication mechanism.

Any callable which is passed as the auth argument to a request method will have the opportunity to modify the request before it is dispatched.

Authentication implementations are subclasses of AuthBase, and are easy to define. Niquests provides two common authentication scheme implementations in niquests.auth: HTTPBasicAuth and HTTPDigestAuth.

Let’s pretend that we have a web service that will only respond if the X-Pizza header is set to a password value. Unlikely, but just go with it.

from niquests.auth import AuthBase

class PizzaAuth(AuthBase):
    """Attaches HTTP Pizza Authentication to the given Request object."""
    def __init__(self, username):
        # setup any auth-related data here
        self.username = username

    def __call__(self, r):
        # modify and return the request
        r.headers['X-Pizza'] = self.username
        return r

Then, we can make a request using our Pizza Auth:

>>> niquests.get('http://pizzabin.org/admin', auth=PizzaAuth('kenneth'))
<Response HTTP/2 [200]>

Note

In case you want a clever shortcut to passing a Bearer token, you can pass directly (as a string) the token to auth=... instead.

Streaming Requests#

With Response.iter_lines() you can easily iterate over streaming APIs such as the Twitter Streaming API. Simply set stream to True and iterate over the response with iter_lines:

import json
import requests

r = niquests.get('https://httpbin.org/stream/20', stream=True)

for line in r.iter_lines():

    # filter out keep-alive new lines
    if line:
        decoded_line = line.decode('utf-8')
        print(json.loads(decoded_line))

When using decode_unicode=True with Response.iter_lines() or Response.iter_content(), you’ll want to provide a fallback encoding in the event the server doesn’t provide one:

r = niquests.get('https://httpbin.org/stream/20', stream=True)

if r.encoding is None:
    r.encoding = 'utf-8'

for line in r.iter_lines(decode_unicode=True):
    if line:
        print(json.loads(line))

Warning

iter_lines is not reentrant safe. Calling this method multiple times causes some of the received data being lost. In case you need to call it from multiple places, use the resulting iterator object instead:

lines = r.iter_lines()
# Save the first line for later or just skip it

first_line = next(lines)

for line in lines:
    print(line)

Proxies#

If you need to use a proxy, you can configure individual requests with the proxies argument to any request method:

import requests

proxies = {
  'http': 'http://10.10.1.10:3128',
  'https': 'http://10.10.1.10:1080',
}

niquests.get('http://example.org', proxies=proxies)

Alternatively you can configure it once for an entire Session:

import requests

proxies = {
  'http': 'http://10.10.1.10:3128',
  'https': 'http://10.10.1.10:1080',
}
session = niquests.Session()
session.proxies.update(proxies)

session.get('http://example.org')

Warning

Setting session.proxies may behave differently than expected. Values provided will be overwritten by environmental proxies (those returned by urllib.request.getproxies). To ensure the use of proxies in the presence of environmental proxies, explicitly specify the proxies argument on all individual requests as initially explained above.

See #2018 for details.

When the proxies configuration is not overridden per request as shown above, Niquests relies on the proxy configuration defined by standard environment variables http_proxy, https_proxy, no_proxy, and all_proxy.

IPv6 in NO_PROXY

Available since version 3.1.2

Uppercase variants of these variables are also supported. You can therefore set them to configure Niquests (only set the ones relevant to your needs):

$ export HTTP_PROXY="http://10.10.1.10:3128"
$ export HTTPS_PROXY="http://10.10.1.10:1080"
$ export ALL_PROXY="socks5://10.10.1.10:3434"

$ python
>>> import requests
>>> niquests.get('http://example.org')

To use HTTP Basic Auth with your proxy, use the http://user:password@host/ syntax in any of the above configuration entries:

$ export HTTPS_PROXY="http://user:pass@10.10.1.10:1080"

$ python
>>> proxies = {'http': 'http://user:pass@10.10.1.10:3128/'}

Warning

Storing sensitive username and password information in an environment variable or a version-controlled file is a security risk and is highly discouraged.

To give a proxy for a specific scheme and host, use the scheme://hostname form for the key. This will match for any request to the given scheme and exact hostname.

proxies = {'http://10.20.1.128': 'http://10.10.1.10:5323'}

Note that proxy URLs must include the scheme.

Finally, note that using a proxy for https connections typically requires your local machine to trust the proxy’s root certificate. By default the list of certificates trusted by Niquests can be found with:

from wassima import generate_ca_bundle
print(generate_ca_bundle)  # it is a single concatenated list of PEM (string)

You override this default certificate bundle by setting the REQUESTS_CA_BUNDLE (or CURL_CA_BUNDLE) environment variable to another file path:

$ export REQUESTS_CA_BUNDLE="/usr/local/myproxy_info/cacert.pem"
$ export https_proxy="http://10.10.1.10:1080"

$ python
>>> import niquests
>>> niquests.get('https://example.org')

SOCKS#

New in version 2.10.0.

In addition to basic HTTP proxies, Niquests also supports proxies using the SOCKS protocol. This is an optional feature that requires that additional third-party libraries be installed before use.

You can get the dependencies for this feature from pip:

$ python -m pip install niquests[socks]

Once you’ve installed those dependencies, using a SOCKS proxy is just as easy as using a HTTP one:

proxies = {
    'http': 'socks5://user:pass@host:port',
    'https': 'socks5://user:pass@host:port'
}

Using the scheme socks5 causes the DNS resolution to happen on the client, rather than on the proxy server. This is in line with curl, which uses the scheme to decide whether to do the DNS resolution on the client or proxy. If you want to resolve the domains on the proxy server, use socks5h as the scheme.

Compliance#

Niquests is intended to be compliant with all relevant specifications and RFCs where that compliance will not cause difficulties for users. This attention to the specification can lead to some behaviour that may seem unusual to those not familiar with the relevant specification.

Encodings#

When you receive a response, Niquests makes a guess at the encoding to use for decoding the response when you access the Response.text attribute. Niquests will first check for an encoding in the HTTP header, and if none is present or if specified is invalid, will use charset_normalizer to attempt to guess the encoding.

If you require a different encoding, you can manually set the Response.encoding property, or use the raw Response.content.

You should keep in mind that if Niquests fail to choose a suitable encoding, the text method from Response will return None. This is the default since the version 3. We choose to return None in those cases because of numerous things, like for example:

Avoid accidentally decoding a large binary.
Avoid rare type of attacks where hacker expect you to decode an invalid payload and expect you to be non-strict.

HTTP Verbs#

Niquests provides access to almost the full range of HTTP verbs: GET, OPTIONS, HEAD, POST, PUT, PATCH and DELETE. The following provides detailed examples of using these various verbs in Niquests, using the GitHub API.

We will begin with the verb most commonly used: GET. HTTP GET is an idempotent method that returns a resource from a given URL. As a result, it is the verb you ought to use when attempting to retrieve data from a web location. An example usage would be attempting to get information about a specific commit from GitHub. Suppose we wanted commit a050faf on Niquests. We would get it like so:

>>> import niquests
>>> r = niquests.get('https://api.github.com/repos/psf/requests/git/commits/a050faf084662f3a352dd1a941f2c7c9f886d4ad')

We should confirm that GitHub responded correctly. If it has, we want to work out what type of content it is. Do this like so:

>>> if r.status_code == niquests.codes.ok:
...     print(r.headers['content-type'])
...
application/json; charset=utf-8

So, GitHub returns JSON. That’s great, we can use the r.json method to parse it into Python objects.

>>> commit_data = r.json()

>>> print(commit_data.keys())
['committer', 'author', 'url', 'tree', 'sha', 'parents', 'message']

>>> print(commit_data['committer'])
{'date': '2012-05-10T11:10:50-07:00', 'email': 'me@kennethreitz.com', 'name': 'Kenneth Reitz'}

>>> print(commit_data['message'])
makin' history

So far, so simple. Well, let’s investigate the GitHub API a little bit. Now, we could look at the documentation, but we might have a little more fun if we use Niquests instead. We can take advantage of the Niquests OPTIONS verb to see what kinds of HTTP methods are supported on the url we just used.

>>> verbs = niquests.options(r.url)
>>> verbs.status_code
500

Uh, what? That’s unhelpful! Turns out GitHub, like many API providers, don’t actually implement the OPTIONS method. This is an annoying oversight, but it’s OK, we can just use the boring documentation. If GitHub had correctly implemented OPTIONS, however, they should return the allowed methods in the headers, e.g.

>>> verbs = niquests.options('http://a-good-website.com/api/cats')
>>> print(verbs.headers['allow'])
GET,HEAD,POST,OPTIONS

Turning to the documentation, we see that the only other method allowed for commits is POST, which creates a new commit. As we’re using the Niquests repo, we should probably avoid making ham-handed POSTS to it. Instead, let’s play with the Issues feature of GitHub.

This documentation was added in response to Issue #482. Given that this issue already exists, we will use it as an example. Let’s start by getting it.

>>> r = niquests.get('https://api.github.com/repos/psf/requests/issues/482')
>>> r.status_code
200

>>> issue = json.loads(r.text)

>>> print(issue['title'])
Feature any http verb in docs

>>> print(issue['comments'])
3

Cool, we have three comments. Let’s take a look at the last of them.

>>> r = niquests.get(r.url + '/comments')
>>> r.status_code
200

>>> comments = r.json()

>>> print(comments[0].keys())
['body', 'url', 'created_at', 'updated_at', 'user', 'id']

>>> print(comments[2]['body'])
Probably in the "advanced" section

Well, that seems like a silly place. Let’s post a comment telling the poster that he’s silly. Who is the poster, anyway?

>>> print(comments[2]['user']['login'])
kennethreitz

OK, so let’s tell this Kenneth guy that we think this example should go in the quickstart guide instead. According to the GitHub API doc, the way to do this is to POST to the thread. Let’s do it.

>>> body = json.dumps({u"body": u"Sounds great! I'll get right on it!"})
>>> url = u"https://api.github.com/repos/psf/requests/issues/482/comments"

>>> r = niquests.post(url=url, data=body)
>>> r.status_code
404

Huh, that’s weird. We probably need to authenticate. That’ll be a pain, right? Wrong. Niquests makes it easy to use many forms of authentication, including the very common Basic Auth.

>>> from niquests.auth import HTTPBasicAuth
>>> auth = HTTPBasicAuth('fake@example.com', 'not_a_real_password')

>>> r = niquests.post(url=url, data=body, auth=auth)
>>> r.status_code
201

>>> content = r.json()
>>> print(content['body'])
Sounds great! I'll get right on it.

Brilliant. Oh, wait, no! I meant to add that it would take me a while, because I had to go feed my cat. If only I could edit this comment! Happily, GitHub allows us to use another HTTP verb, PATCH, to edit this comment. Let’s do that.

>>> print(content[u"id"])
5804413

>>> body = json.dumps({u"body": u"Sounds great! I'll get right on it once I feed my cat."})
>>> url = u"https://api.github.com/repos/psf/requests/issues/comments/5804413"

>>> r = niquests.patch(url=url, data=body, auth=auth)
>>> r.status_code
200

Excellent. Now, just to torture this Kenneth guy, I’ve decided to let him sweat and not tell him that I’m working on this. That means I want to delete this comment. GitHub lets us delete comments using the incredibly aptly named DELETE method. Let’s get rid of it.

>>> r = niquests.delete(url=url, auth=auth)
>>> r.status_code
204
>>> r.headers['status']
'204 No Content'

Excellent. All gone. The last thing I want to know is how much of my ratelimit I’ve used. Let’s find out. GitHub sends that information in the headers, so rather than download the whole page I’ll send a HEAD request to get the headers.

>>> r = niquests.head(url=url, auth=auth)
>>> print(r.headers)
...
'x-ratelimit-remaining': '4995'
'x-ratelimit-limit': '5000'
...

Excellent. Time to write a Python program that abuses the GitHub API in all kinds of exciting ways, 4995 more times.

Custom Verbs#

From time to time you may be working with a server that, for whatever reason, allows use or even requires use of HTTP verbs not covered above. One example of this would be the MKCOL method some WEBDAV servers use. Do not fret, these can still be used with Niquests. These make use of the built-in .request method. For example:

>>> r = niquests.request('MKCOL', url, data=data)
>>> r.status_code
200 # Assuming your call was correct

Utilising this, you can make use of any method verb that your server allows.

Link Headers#

Many HTTP APIs feature Link headers. They make APIs more self describing and discoverable.

GitHub uses these for pagination in their API, for example:

>>> url = 'https://api.github.com/users/kennethreitz/repos?page=1&per_page=10'
>>> r = niquests.head(url=url)
>>> r.headers['link']
'<https://api.github.com/users/kennethreitz/repos?page=2&per_page=10>; rel="next", <https://api.github.com/users/kennethreitz/repos?page=6&per_page=10>; rel="last"'

Niquests will automatically parse these link headers and make them easily consumable:

>>> r.links["next"]
{'url': 'https://api.github.com/users/kennethreitz/repos?page=2&per_page=10', 'rel': 'next'}

>>> r.links["last"]
{'url': 'https://api.github.com/users/kennethreitz/repos?page=7&per_page=10', 'rel': 'last'}

Transport Adapters#

As of v1.0.0, Niquests has moved to a modular internal design. Part of the reason this was done was to implement Transport Adapters, originally described here. Transport Adapters provide a mechanism to define interaction methods for an HTTP service. In particular, they allow you to apply per-service configuration.

Niquests ships with a single Transport Adapter, the HTTPAdapter. This adapter provides the default Niquests interaction with HTTP and HTTPS using the powerful urllib3.future library. Whenever a Niquests Session is initialized, one of these is attached to the Session object for HTTP, and one for HTTPS.

Niquests enables users to create and use their own Transport Adapters that provide specific functionality. Once created, a Transport Adapter can be mounted to a Session object, along with an indication of which web services it should apply to.

>>> s = niquests.Session()
>>> s.mount('https://github.com/', MyAdapter())

The mount call registers a specific instance of a Transport Adapter to a prefix. Once mounted, any HTTP request made using that session whose URL starts with the given prefix will use the given Transport Adapter.

Note

The adapter will be chosen based on a longest prefix match. Be mindful prefixes such as http://localhost will also match http://localhost.other.com or http://localhost@other.com. It’s recommended to terminate full hostnames with a /.

Many of the details of implementing a Transport Adapter are beyond the scope of this documentation, but take a look at the next example for a simple SSL use- case. For more than that, you might look at subclassing the BaseAdapter.

Example: Specific SSL Version#

The Niquests team has made a specific choice to use whatever SSL version is default in the underlying library (urllib3.future). Normally this is fine, but from time to time, you might find yourself needing to connect to a service-endpoint that uses a version that isn’t compatible with the default.

You can use Transport Adapters for this by taking most of the existing implementation of HTTPAdapter, and adding a parameter ssl_version that gets passed-through to urllib3.future. We’ll make a Transport Adapter that instructs the library to use SSLv3:

import ssl
from urllib3.poolmanager import PoolManager

from niquests.adapters import HTTPAdapter


class Ssl3HttpAdapter(HTTPAdapter):
    """"Transport adapter" that allows us to use SSLv3."""

    def init_poolmanager(self, connections, maxsize, block=False):
        self.poolmanager = PoolManager(
            num_pools=connections, maxsize=maxsize,
            block=block, ssl_version=ssl.PROTOCOL_SSLv3)

Example: Automatic Retries#

By default, Niquests does not retry failed connections. However, it is possible to implement automatic retries with a powerful array of features, including backoff, within a Niquests Session using the urllib3.util.Retry class:

from urllib3.util import Retry
from niquests import Session

retries = Retry(
    total=3,
    backoff_factor=0.1,
    status_forcelist=[502, 503, 504],
    allowed_methods={'POST'},
)

s = Session(retries=retries)
s.get("https://1.1.1.1")

Blocking Or Non-Blocking?#

The Response.content property will block until the entire response has been downloaded by default in HTTP/1.1 In HTTP/2 onward, non-consumed response (body, aka. stream=True) will no longer block the connection.

But if you leverage a full multiplexed connection, Niquests no longer block your synchronous loop. You are free of the IO blocking per request.

You may also use the AsyncSession that provide you with the same methods as the regular Session but with asyncio support.

Header Ordering#

In unusual circumstances you may want to provide headers in an ordered manner. If you pass an OrderedDict to the headers keyword argument, that will provide the headers with an ordering. However, the ordering of the default headers used by Niquests will be preferred, which means that if you override default headers in the headers keyword argument, they may appear out of order compared to other headers in that keyword argument.

If this is problematic, users should consider setting the default headers on a Session object, by setting Session.headers to a custom OrderedDict. That ordering will always be preferred.

Timeouts#

Most requests to external servers should have a timeout attached, in case the server is not responding in a timely manner. By default, requests do not time out unless a timeout value is set explicitly. Without a timeout, your code may hang for minutes.

The connect timeout is the number of seconds Niquests will wait for your client to establish a connection to a remote machine (corresponding to the connect()) call on the socket. It’s a good practice to set connect timeouts to slightly larger than a multiple of 3, which is the default TCP packet retransmission window.

Once your client has connected to the server and sent the HTTP request, the read timeout is the number of seconds the client will wait for the server to send a response. (Specifically, it’s the number of seconds that the client will wait between bytes sent from the server. In 99.9% of cases, this is the time before the server sends the first byte).

If you specify a single value for the timeout, like this:

r = niquests.get('https://github.com', timeout=5)

The timeout value will be applied to both the connect and the read timeouts. Specify a tuple if you would like to set the values separately:

r = niquests.get('https://github.com', timeout=(3.05, 27))

If the remote server is very slow, you can tell Niquests to wait forever for a response, by passing None as a timeout value and then retrieving a cup of coffee.:

r = niquests.get('https://github.com', timeout=None)

It is also possible to use the Timeout class from urllib3 directly:

from urllib3 import Timeout

r = niquests.get('https://github.com', timeout=Timeout(3, 9))

OCSP or Certificate Revocation#

Difficult subject. Short story, when a HTTP client establish a secure connection, it verify that the certificate is valid. The problem is that a certificate can be both valid and revoked due its immutability, the revocation status must be taken from an outside source, most of the revocation are linked to a hack/security violation.

Niquests try to protect you from the evoked problem by doing a post-handshake verification using the OCSP protocols via plain HTTP.

Unfortunately, at this moment, no bullet proof solution has emerged against revoked certificate. We are aware of this. But still, it is better than nothing!

By default, Niquests operate a soft-fail verification, or non-strict if you prefer.

This feature is broadly available and is enabled by default when verify=True. We decided to follow what browsers do by default, so Niquests follows by being non-strict. OCSP responses are expected to arrive in less than 200ms, otherwise ignored (e.g. OCSP is dropped). Niquests keeps in-memory the results until the size exceed 2,048 entries, then an algorithm choose an entry to be deleted (oldest request or the first one that ended in error).

You can at your own discretion enable strict OCSP checks by passing the environment variable NIQUESTS_STRICT_OCSP with anything inside but 0. In strict mode the maximum delay for response passes from 200ms to 1,000ms and raises an error or explicit warning.

In non-strict mode, this security measure will be deactivated automatically if your usage is unreasonable. e.g. Making a hundred of requests to a hundred of domains, thus consuming resources that should have been allocated to browser users. This was made available for users with a limited target of domains to get a complementary security measure.

Unless in strict-mode, the proxy configuration will be respected when given, as long as it specify a plain http proxy. This is meant for people who want privacy.

This feature may not be available if the qh3 package is missing from your environment. Verify the availability by running python -m niquests.help.

Note

Access property ocsp_verified in both PreparedRequest, and Response to have information about this post handshake verification.

Specify HTTP/3 capable endpoint preemptively#

Preemptively register a website to be HTTP/3 capable prior to the first TLS over TCP handshake. You can do so by doing like:

from niquests import Session

s = Session()
s.quic_cache_layer.add_domain("cloudflare.com")

This will prevent the first request being made with HTTP/2 or HTTP/1.1.

Note

You can also specify an alternate destination port if QUIC is being served on anything else than 443.

Sample:

s.quic_cache_layer.add_domain("cloudflare.com", alt_port=8544)

This would mean that attempting to request https://cloudflare.com/a/b will be routed through https://cloudflare.com:8544/a/b over QUIC.

Warning

You cannot specify another hostname for security reasons.

Note

Using a custom DNS resolver can solve the problem as we can probe the HTTPS record for the given hostname and connect directly using HTTP/3 over QUIC.

Increase the default Alt-Svc cache size#

When a server yield its support for HTTP/3 over QUIC, the information is stored within a local thread safe in-memory storage.

That storage is limited to 12,288 entries by default, and you can override this by passing a custom QuicSharedCache instance like so:

import niquests

cache = niquests.structures.QuicSharedCache(max_size=128_000)
session = niquests.Session(quic_cache_layer=cache)

Note

Passing None to max size actually permit the cache to grow indefinitely. This is unwise and can lead to significant RAM usage.

When the cache is full, the oldest entry is removed.

Disable HTTP/2, and/or HTTP/3#

You can at your own discretion disable a protocol by passing disable_http2=True or disable_http3=True within your Session constructor.

Warning

It is actually forbidden to disable HTTP/1.1 as the underlying library (urllib3.future) does not permit it for now.

Having a session without HTTP/2 enabled should be done that way:

import niquests

session = niquests.Session(disable_http2=True)

Thread Safety#

Niquests is meant to be thread and task safe. Any error or unattended behaviors are covered by our support for bug policy. Both main scenarios are eligible, meaning Thread and Async, with Thread and Sync.

Support include notable performance issues like abusive lock.

Use a custom CA without loosing the official ones#

There’s an interesting use-case where a user may want to be able to request both private and public HTTP endpoints without doing some gymnastic with verify=....

Thanks to our underlying library wassima you can register globally your own set of certificate authorities like so:

import wassima

wassima.register_ca(my_own_ca_pem_str)

That’s it! Niquests will now automatically recognize it and use it to verify your secure endpoints. You’ll have to register it prior to your HTTP requests.

Note

While doing local development with HTTPS, we recommend using tool like mkcert that will register the CA into your local machine trust store. Niquests is natively capable of picking them up.

Disable either IPv4 or IPv6#

You may be interested in controlling what kind of address you would accept connecting to. Since Niquests 3.4+, you can configure that aspect per Session instance.

Having a session without IPv6 enabled should be done that way:

import niquests

session = niquests.Session(disable_ipv6=True)

Warning

You cannot set both disable_ipv4 and disable_ipv6 at the cost of receiving a RuntimeError exception.

Setting the source network adapter#

In a complex scenario, you could face the following: “I have multiple network adapters, some can access this and other that..” Since Niquests 3.4+, you can configure that aspect per Session instance.

Having a session that explicitly bind to “10.10.4.1” on port 4444 should be done that way:

import niquests

session = niquests.Session(source_address=("10.10.4.1", 4444))

It will be passed down the the lower stack. No effort required.

Note

You can set 0 instead of 4444 to select a random port.

Note

You can set 0.0.0.0 to select the network adapter automatically instead, if you wish to set the port only.

Inspect network timings#

You are probably used to calling response.elapsed to get a rough estimate on how long did the request took to complete.

It is likely that you may be interested in knowing:

How long did the TCP/UDP established connection took?
How long did the DNS resolution cost me?

… and so on.

Here is a simple example:

import niquests

session = niquests.Session()

response = session.get("https://pie.dev/get")

print(response.conn_info.resolution_latency)  # output the DNS resolution latency
print(response.conn_info.tls_handshake_latency)  # the TLS handshake completion

Here, conn_info is a urllib3.ConnectionInfo instance. The complete list of attributes is listed on the Hook bottom section.

Note

Each response and request are linked to a unique ConnectionInfo.

Verify Certificate Fingerprint#

Note

Available since Niquests 3.5.4

An alternative to the certificate verification can be asserting its fingerprint. We (absolutely) do not recommend using it unless you are left with no other alternative.

Here is a simple example:

import niquests

session = niquests.Session()
session.get("https://pie.dev/get", verify="sha256_8fff956b66667ffe5801c8432b12c367254727782d91bc695b7a53d0b512d721")

Warning

Supported fingerprinting algorithms are sha256, and sha1. The prefix is mandatory.