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Diffstat (limited to 'requests/sessions.py')
| -rw-r--r-- | requests/sessions.py | 637 |
1 files changed, 637 insertions, 0 deletions
diff --git a/requests/sessions.py b/requests/sessions.py new file mode 100644 index 0000000..df85a25 --- /dev/null +++ b/requests/sessions.py @@ -0,0 +1,637 @@ +# -*- coding: utf-8 -*- + +""" +requests.session +~~~~~~~~~~~~~~~~ + +This module provides a Session object to manage and persist settings across +requests (cookies, auth, proxies). + +""" +import os +from collections import Mapping +from datetime import datetime + +from .auth import _basic_auth_str +from .compat import cookielib, OrderedDict, urljoin, urlparse, builtin_str +from .cookies import ( + cookiejar_from_dict, extract_cookies_to_jar, RequestsCookieJar, merge_cookies) +from .models import Request, PreparedRequest, DEFAULT_REDIRECT_LIMIT +from .hooks import default_hooks, dispatch_hook +from .utils import to_key_val_list, default_headers, to_native_string +from .exceptions import ( + TooManyRedirects, InvalidSchema, ChunkedEncodingError, ContentDecodingError) +from .structures import CaseInsensitiveDict + +from .adapters import HTTPAdapter + +from .utils import ( + requote_uri, get_environ_proxies, get_netrc_auth, should_bypass_proxies, + get_auth_from_url +) + +from .status_codes import codes + +# formerly defined here, reexposed here for backward compatibility +from .models import REDIRECT_STATI + + +def merge_setting(request_setting, session_setting, dict_class=OrderedDict): + """ + Determines appropriate setting for a given request, taking into account the + explicit setting on that request, and the setting in the session. If a + setting is a dictionary, they will be merged together using `dict_class` + """ + + if session_setting is None: + return request_setting + + if request_setting is None: + return session_setting + + # Bypass if not a dictionary (e.g. verify) + if not ( + isinstance(session_setting, Mapping) and + isinstance(request_setting, Mapping) + ): + return request_setting + + merged_setting = dict_class(to_key_val_list(session_setting)) + merged_setting.update(to_key_val_list(request_setting)) + + # Remove keys that are set to None. + for (k, v) in request_setting.items(): + if v is None: + del merged_setting[k] + + merged_setting = dict((k, v) for (k, v) in merged_setting.items() if v is not None) + + return merged_setting + + +def merge_hooks(request_hooks, session_hooks, dict_class=OrderedDict): + """ + Properly merges both requests and session hooks. + + This is necessary because when request_hooks == {'response': []}, the + merge breaks Session hooks entirely. + """ + if session_hooks is None or session_hooks.get('response') == []: + return request_hooks + + if request_hooks is None or request_hooks.get('response') == []: + return session_hooks + + return merge_setting(request_hooks, session_hooks, dict_class) + + +class SessionRedirectMixin(object): + def resolve_redirects(self, resp, req, stream=False, timeout=None, + verify=True, cert=None, proxies=None): + """Receives a Response. Returns a generator of Responses.""" + + i = 0 + + while resp.is_redirect: + prepared_request = req.copy() + + try: + resp.content # Consume socket so it can be released + except (ChunkedEncodingError, ContentDecodingError, RuntimeError): + resp.raw.read(decode_content=False) + + if i >= self.max_redirects: + raise TooManyRedirects('Exceeded %s redirects.' % self.max_redirects) + + # Release the connection back into the pool. + resp.close() + + url = resp.headers['location'] + method = req.method + + # Handle redirection without scheme (see: RFC 1808 Section 4) + if url.startswith('//'): + parsed_rurl = urlparse(resp.url) + url = '%s:%s' % (parsed_rurl.scheme, url) + + # The scheme should be lower case... + parsed = urlparse(url) + url = parsed.geturl() + + # Facilitate non-RFC2616-compliant 'location' headers + # (e.g. '/path/to/resource' instead of 'http://domain.tld/path/to/resource') + # Compliant with RFC3986, we percent encode the url. + if not urlparse(url).netloc: + url = urljoin(resp.url, requote_uri(url)) + else: + url = requote_uri(url) + + prepared_request.url = to_native_string(url) + + # http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.4 + if (resp.status_code == codes.see_other and + method != 'HEAD'): + method = 'GET' + + # Do what the browsers do, despite standards... + # First, turn 302s into GETs. + if resp.status_code == codes.found and method != 'HEAD': + method = 'GET' + + # Second, if a POST is responded to with a 301, turn it into a GET. + # This bizarre behaviour is explained in Issue 1704. + if resp.status_code == codes.moved and method == 'POST': + method = 'GET' + + prepared_request.method = method + + # https://github.com/kennethreitz/requests/issues/1084 + if resp.status_code not in (codes.temporary, codes.resume): + if 'Content-Length' in prepared_request.headers: + del prepared_request.headers['Content-Length'] + + prepared_request.body = None + + headers = prepared_request.headers + try: + del headers['Cookie'] + except KeyError: + pass + + extract_cookies_to_jar(prepared_request._cookies, prepared_request, resp.raw) + prepared_request._cookies.update(self.cookies) + prepared_request.prepare_cookies(prepared_request._cookies) + + # Rebuild auth and proxy information. + proxies = self.rebuild_proxies(prepared_request, proxies) + self.rebuild_auth(prepared_request, resp) + + # Override the original request. + req = prepared_request + + resp = self.send( + req, + stream=stream, + timeout=timeout, + verify=verify, + cert=cert, + proxies=proxies, + allow_redirects=False, + ) + + extract_cookies_to_jar(self.cookies, prepared_request, resp.raw) + + i += 1 + yield resp + + def rebuild_auth(self, prepared_request, response): + """ + When being redirected we may want to strip authentication from the + request to avoid leaking credentials. This method intelligently removes + and reapplies authentication where possible to avoid credential loss. + """ + headers = prepared_request.headers + url = prepared_request.url + + if 'Authorization' in headers: + # If we get redirected to a new host, we should strip out any + # authentication headers. + original_parsed = urlparse(response.request.url) + redirect_parsed = urlparse(url) + + if (original_parsed.hostname != redirect_parsed.hostname): + del headers['Authorization'] + + # .netrc might have more auth for us on our new host. + new_auth = get_netrc_auth(url) if self.trust_env else None + if new_auth is not None: + prepared_request.prepare_auth(new_auth) + + return + + def rebuild_proxies(self, prepared_request, proxies): + """ + This method re-evaluates the proxy configuration by considering the + environment variables. If we are redirected to a URL covered by + NO_PROXY, we strip the proxy configuration. Otherwise, we set missing + proxy keys for this URL (in case they were stripped by a previous + redirect). + + This method also replaces the Proxy-Authorization header where + necessary. + """ + headers = prepared_request.headers + url = prepared_request.url + scheme = urlparse(url).scheme + new_proxies = proxies.copy() if proxies is not None else {} + + if self.trust_env and not should_bypass_proxies(url): + environ_proxies = get_environ_proxies(url) + + proxy = environ_proxies.get(scheme) + + if proxy: + new_proxies.setdefault(scheme, environ_proxies[scheme]) + + if 'Proxy-Authorization' in headers: + del headers['Proxy-Authorization'] + + try: + username, password = get_auth_from_url(new_proxies[scheme]) + except KeyError: + username, password = None, None + + if username and password: + headers['Proxy-Authorization'] = _basic_auth_str(username, password) + + return new_proxies + + +class Session(SessionRedirectMixin): + """A Requests session. + + Provides cookie persistence, connection-pooling, and configuration. + + Basic Usage:: + + >>> import requests + >>> s = requests.Session() + >>> s.get('http://httpbin.org/get') + 200 + """ + + __attrs__ = [ + 'headers', 'cookies', 'auth', 'timeout', 'proxies', 'hooks', + 'params', 'verify', 'cert', 'prefetch', 'adapters', 'stream', + 'trust_env', 'max_redirects'] + + def __init__(self): + + #: A case-insensitive dictionary of headers to be sent on each + #: :class:`Request <Request>` sent from this + #: :class:`Session <Session>`. + self.headers = default_headers() + + #: Default Authentication tuple or object to attach to + #: :class:`Request <Request>`. + self.auth = None + + #: Dictionary mapping protocol to the URL of the proxy (e.g. + #: {'http': 'foo.bar:3128'}) to be used on each + #: :class:`Request <Request>`. + self.proxies = {} + + #: Event-handling hooks. + self.hooks = default_hooks() + + #: Dictionary of querystring data to attach to each + #: :class:`Request <Request>`. The dictionary values may be lists for + #: representing multivalued query parameters. + self.params = {} + + #: Stream response content default. + self.stream = False + + #: SSL Verification default. + self.verify = True + + #: SSL certificate default. + self.cert = None + + #: Maximum number of redirects allowed. If the request exceeds this + #: limit, a :class:`TooManyRedirects` exception is raised. + self.max_redirects = DEFAULT_REDIRECT_LIMIT + + #: Should we trust the environment? + self.trust_env = True + + #: A CookieJar containing all currently outstanding cookies set on this + #: session. By default it is a + #: :class:`RequestsCookieJar <requests.cookies.RequestsCookieJar>`, but + #: may be any other ``cookielib.CookieJar`` compatible object. + self.cookies = cookiejar_from_dict({}) + + # Default connection adapters. + self.adapters = OrderedDict() + self.mount('https://', HTTPAdapter()) + self.mount('http://', HTTPAdapter()) + + def __enter__(self): + return self + + def __exit__(self, *args): + self.close() + + def prepare_request(self, request): + """Constructs a :class:`PreparedRequest <PreparedRequest>` for + transmission and returns it. The :class:`PreparedRequest` has settings + merged from the :class:`Request <Request>` instance and those of the + :class:`Session`. + + :param request: :class:`Request` instance to prepare with this + session's settings. + """ + cookies = request.cookies or {} + + # Bootstrap CookieJar. + if not isinstance(cookies, cookielib.CookieJar): + cookies = cookiejar_from_dict(cookies) + + # Merge with session cookies + merged_cookies = merge_cookies( + merge_cookies(RequestsCookieJar(), self.cookies), cookies) + + + # Set environment's basic authentication if not explicitly set. + auth = request.auth + if self.trust_env and not auth and not self.auth: + auth = get_netrc_auth(request.url) + + p = PreparedRequest() + p.prepare( + method=request.method.upper(), + url=request.url, + files=request.files, + data=request.data, + headers=merge_setting(request.headers, self.headers, dict_class=CaseInsensitiveDict), + params=merge_setting(request.params, self.params), + auth=merge_setting(auth, self.auth), + cookies=merged_cookies, + hooks=merge_hooks(request.hooks, self.hooks), + ) + return p + + def request(self, method, url, + params=None, + data=None, + headers=None, + cookies=None, + files=None, + auth=None, + timeout=None, + allow_redirects=True, + proxies=None, + hooks=None, + stream=None, + verify=None, + cert=None): + """Constructs a :class:`Request <Request>`, prepares it and sends it. + Returns :class:`Response <Response>` object. + + :param method: method for the new :class:`Request` object. + :param url: URL for the new :class:`Request` object. + :param params: (optional) Dictionary or bytes to be sent in the query + string for the :class:`Request`. + :param data: (optional) Dictionary or bytes to send in the body of the + :class:`Request`. + :param headers: (optional) Dictionary of HTTP Headers to send with the + :class:`Request`. + :param cookies: (optional) Dict or CookieJar object to send with the + :class:`Request`. + :param files: (optional) Dictionary of 'filename': file-like-objects + for multipart encoding upload. + :param auth: (optional) Auth tuple or callable to enable + Basic/Digest/Custom HTTP Auth. + :param timeout: (optional) Float describing the timeout of the + request in seconds. + :param allow_redirects: (optional) Boolean. Set to True by default. + :param proxies: (optional) Dictionary mapping protocol to the URL of + the proxy. + :param stream: (optional) whether to immediately download the response + content. Defaults to ``False``. + :param verify: (optional) if ``True``, the SSL cert will be verified. + A CA_BUNDLE path can also be provided. + :param cert: (optional) if String, path to ssl client cert file (.pem). + If Tuple, ('cert', 'key') pair. + """ + + method = builtin_str(method) + + # Create the Request. + req = Request( + method = method.upper(), + url = url, + headers = headers, + files = files, + data = data or {}, + params = params or {}, + auth = auth, + cookies = cookies, + hooks = hooks, + ) + prep = self.prepare_request(req) + + proxies = proxies or {} + + # Gather clues from the surrounding environment. + if self.trust_env: + # Set environment's proxies. + env_proxies = get_environ_proxies(url) or {} + for (k, v) in env_proxies.items(): + proxies.setdefault(k, v) + + # Look for configuration. + if not verify and verify is not False: + verify = os.environ.get('REQUESTS_CA_BUNDLE') + + # Curl compatibility. + if not verify and verify is not False: + verify = os.environ.get('CURL_CA_BUNDLE') + + # Merge all the kwargs. + proxies = merge_setting(proxies, self.proxies) + stream = merge_setting(stream, self.stream) + verify = merge_setting(verify, self.verify) + cert = merge_setting(cert, self.cert) + + # Send the request. + send_kwargs = { + 'stream': stream, + 'timeout': timeout, + 'verify': verify, + 'cert': cert, + 'proxies': proxies, + 'allow_redirects': allow_redirects, + } + resp = self.send(prep, **send_kwargs) + + return resp + + def get(self, url, **kwargs): + """Sends a GET request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + kwargs.setdefault('allow_redirects', True) + return self.request('GET', url, **kwargs) + + def options(self, url, **kwargs): + """Sends a OPTIONS request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + kwargs.setdefault('allow_redirects', True) + return self.request('OPTIONS', url, **kwargs) + + def head(self, url, **kwargs): + """Sends a HEAD request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + kwargs.setdefault('allow_redirects', False) + return self.request('HEAD', url, **kwargs) + + def post(self, url, data=None, **kwargs): + """Sends a POST request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + return self.request('POST', url, data=data, **kwargs) + + def put(self, url, data=None, **kwargs): + """Sends a PUT request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + return self.request('PUT', url, data=data, **kwargs) + + def patch(self, url, data=None, **kwargs): + """Sends a PATCH request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + return self.request('PATCH', url, data=data, **kwargs) + + def delete(self, url, **kwargs): + """Sends a DELETE request. Returns :class:`Response` object. + + :param url: URL for the new :class:`Request` object. + :param \*\*kwargs: Optional arguments that ``request`` takes. + """ + + return self.request('DELETE', url, **kwargs) + + def send(self, request, **kwargs): + """Send a given PreparedRequest.""" + # Set defaults that the hooks can utilize to ensure they always have + # the correct parameters to reproduce the previous request. + kwargs.setdefault('stream', self.stream) + kwargs.setdefault('verify', self.verify) + kwargs.setdefault('cert', self.cert) + kwargs.setdefault('proxies', self.proxies) + + # It's possible that users might accidentally send a Request object. + # Guard against that specific failure case. + if not isinstance(request, PreparedRequest): + raise ValueError('You can only send PreparedRequests.') + + # Set up variables needed for resolve_redirects and dispatching of hooks + allow_redirects = kwargs.pop('allow_redirects', True) + stream = kwargs.get('stream') + timeout = kwargs.get('timeout') + verify = kwargs.get('verify') + cert = kwargs.get('cert') + proxies = kwargs.get('proxies') + hooks = request.hooks + + # Get the appropriate adapter to use + adapter = self.get_adapter(url=request.url) + + # Start time (approximately) of the request + start = datetime.utcnow() + + # Send the request + r = adapter.send(request, **kwargs) + + # Total elapsed time of the request (approximately) + r.elapsed = datetime.utcnow() - start + + # Response manipulation hooks + r = dispatch_hook('response', hooks, r, **kwargs) + + # Persist cookies + if r.history: + + # If the hooks create history then we want those cookies too + for resp in r.history: + extract_cookies_to_jar(self.cookies, resp.request, resp.raw) + + extract_cookies_to_jar(self.cookies, request, r.raw) + + # Redirect resolving generator. + gen = self.resolve_redirects(r, request, + stream=stream, + timeout=timeout, + verify=verify, + cert=cert, + proxies=proxies) + + # Resolve redirects if allowed. + history = [resp for resp in gen] if allow_redirects else [] + + # Shuffle things around if there's history. + if history: + # Insert the first (original) request at the start + history.insert(0, r) + # Get the last request made + r = history.pop() + r.history = history + + if not stream: + r.content + + return r + + def get_adapter(self, url): + """Returns the appropriate connnection adapter for the given URL.""" + for (prefix, adapter) in self.adapters.items(): + + if url.lower().startswith(prefix): + return adapter + + # Nothing matches :-/ + raise InvalidSchema("No connection adapters were found for '%s'" % url) + + def close(self): + """Closes all adapters and as such the session""" + for v in self.adapters.values(): + v.close() + + def mount(self, prefix, adapter): + """Registers a connection adapter to a prefix. + + Adapters are sorted in descending order by key length.""" + + self.adapters[prefix] = adapter + keys_to_move = [k for k in self.adapters if len(k) < len(prefix)] + + for key in keys_to_move: + self.adapters[key] = self.adapters.pop(key) + + def __getstate__(self): + return dict((attr, getattr(self, attr, None)) for attr in self.__attrs__) + + def __setstate__(self, state): + for attr, value in state.items(): + setattr(self, attr, value) + + +def session(): + """Returns a :class:`Session` for context-management.""" + + return Session() |