20.7. httplib — HTTP protocol client

注解

The httplib module has been renamed to http.client in Python 3. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.

Source code: Lib/httplib.py

This module defines classes which implement the client side of the HTTP and HTTPS protocols. It is normally not used directly — the module urllib uses it to handle URLs that use HTTP and HTTPS.

参见

The Requests package is recommended for a higher-level HTTP client interface.

注解

HTTPS support is only available if the socket module was compiled with SSL support.

注解

The public interface for this module changed substantially in Python 2.0. The HTTP class is retained only for backward compatibility with 1.5.2. It should not be used in new code. Refer to the online docstrings for usage.

The module provides the following classes:

class httplib.HTTPConnection(host[, port[, strict[, timeout[, source_address]]]])

An HTTPConnection instance represents one transaction with an HTTP server. It should be instantiated passing it a host and optional port number. If no port number is passed, the port is extracted from the host string if it has the form host:port, else the default HTTP port (80) is used. When true, the optional parameter strict (which defaults to a false value) causes BadStatusLine to be raised if the status line can’t be parsed as a valid HTTP/1.0 or 1.1 status line. If the optional timeout parameter is given, blocking operations (like connection attempts) will timeout after that many seconds (if it is not given, the global default timeout setting is used). The optional source_address parameter may be a tuple of a (host, port) to use as the source address the HTTP connection is made from.

For example, the following calls all create instances that connect to the server at the same host and port:

>>> h1 = httplib.HTTPConnection('www.cwi.nl')
>>> h2 = httplib.HTTPConnection('www.cwi.nl:80')
>>> h3 = httplib.HTTPConnection('www.cwi.nl', 80)
>>> h3 = httplib.HTTPConnection('www.cwi.nl', 80, timeout=10)

2.0 新版功能.

在 2.6 版更改: timeout was added.

在 2.7 版更改: source_address was added.

class httplib.HTTPSConnection(host[, port[, key_file[, cert_file[, strict[, timeout[, source_address[, context]]]]]]])

A subclass of HTTPConnection that uses SSL for communication with secure servers. Default port is 443. If context is specified, it must be a ssl.SSLContext instance describing the various SSL options.

key_file and cert_file are deprecated, please use ssl.SSLContext.load_cert_chain() instead, or let ssl.create_default_context() select the system’s trusted CA certificates for you.

Please read Security considerations for more information on best practices.

2.0 新版功能.

在 2.6 版更改: timeout was added.

在 2.7 版更改: source_address was added.

在 2.7.9 版更改: context was added.

This class now performs all the necessary certificate and hostname checks by default. To revert to the previous, unverified, behavior ssl._create_unverified_context() can be passed to the context parameter.

class httplib.HTTPResponse(sock, debuglevel=0, strict=0)

Class whose instances are returned upon successful connection. Not instantiated directly by user.

2.0 新版功能.

class httplib.HTTPMessage

An HTTPMessage instance is used to hold the headers from an HTTP response. It is implemented using the mimetools.Message class and provides utility functions to deal with HTTP Headers. It is not directly instantiated by the users.

The following exceptions are raised as appropriate:

exception httplib.HTTPException

The base class of the other exceptions in this module. It is a subclass of Exception.

2.0 新版功能.

exception httplib.NotConnected

A subclass of HTTPException.

2.0 新版功能.

exception httplib.InvalidURL

A subclass of HTTPException, raised if a port is given and is either non-numeric or empty.

2.3 新版功能.

exception httplib.UnknownProtocol

A subclass of HTTPException.

2.0 新版功能.

exception httplib.UnknownTransferEncoding

A subclass of HTTPException.

2.0 新版功能.

exception httplib.UnimplementedFileMode

A subclass of HTTPException.

2.0 新版功能.

exception httplib.IncompleteRead

A subclass of HTTPException.

2.0 新版功能.

exception httplib.ImproperConnectionState

A subclass of HTTPException.

2.0 新版功能.

exception httplib.CannotSendRequest

A subclass of ImproperConnectionState.

2.0 新版功能.

exception httplib.CannotSendHeader

A subclass of ImproperConnectionState.

2.0 新版功能.

exception httplib.ResponseNotReady

A subclass of ImproperConnectionState.

2.0 新版功能.

exception httplib.BadStatusLine

A subclass of HTTPException. Raised if a server responds with a HTTP status code that we don’t understand.

2.0 新版功能.

The constants defined in this module are:

httplib.HTTP_PORT

The default port for the HTTP protocol (always 80).

httplib.HTTPS_PORT

The default port for the HTTPS protocol (always 443).

and also the following constants for integer status codes:

Constant

Value

Definition

CONTINUE

100

HTTP/1.1, RFC 2616, Section 10.1.1

SWITCHING_PROTOCOLS

101

HTTP/1.1, RFC 2616, Section 10.1.2

PROCESSING

102

WEBDAV, RFC 2518, Section 10.1

OK

200

HTTP/1.1, RFC 2616, Section 10.2.1

CREATED

201

HTTP/1.1, RFC 2616, Section 10.2.2

ACCEPTED

202

HTTP/1.1, RFC 2616, Section 10.2.3

NON_AUTHORITATIVE_INFORMATION

203

HTTP/1.1, RFC 2616, Section 10.2.4

NO_CONTENT

204

HTTP/1.1, RFC 2616, Section 10.2.5

RESET_CONTENT

205

HTTP/1.1, RFC 2616, Section 10.2.6

PARTIAL_CONTENT

206

HTTP/1.1, RFC 2616, Section 10.2.7

MULTI_STATUS

207

WEBDAV RFC 2518, Section 10.2

IM_USED

226

Delta encoding in HTTP, RFC 3229, Section 10.4.1

MULTIPLE_CHOICES

300

HTTP/1.1, RFC 2616, Section 10.3.1

MOVED_PERMANENTLY

301

HTTP/1.1, RFC 2616, Section 10.3.2

FOUND

302

HTTP/1.1, RFC 2616, Section 10.3.3

SEE_OTHER

303

HTTP/1.1, RFC 2616, Section 10.3.4

NOT_MODIFIED

304

HTTP/1.1, RFC 2616, Section 10.3.5

USE_PROXY

305

HTTP/1.1, RFC 2616, Section 10.3.6

TEMPORARY_REDIRECT

307

HTTP/1.1, RFC 2616, Section 10.3.8

BAD_REQUEST

400

HTTP/1.1, RFC 2616, Section 10.4.1

UNAUTHORIZED

401

HTTP/1.1, RFC 2616, Section 10.4.2

PAYMENT_REQUIRED

402

HTTP/1.1, RFC 2616, Section 10.4.3

FORBIDDEN

403

HTTP/1.1, RFC 2616, Section 10.4.4

NOT_FOUND

404

HTTP/1.1, RFC 2616, Section 10.4.5

METHOD_NOT_ALLOWED

405

HTTP/1.1, RFC 2616, Section 10.4.6

NOT_ACCEPTABLE

406

HTTP/1.1, RFC 2616, Section 10.4.7

PROXY_AUTHENTICATION_REQUIRED

407

HTTP/1.1, RFC 2616, Section 10.4.8

REQUEST_TIMEOUT

408

HTTP/1.1, RFC 2616, Section 10.4.9

CONFLICT

409

HTTP/1.1, RFC 2616, Section 10.4.10

GONE

410

HTTP/1.1, RFC 2616, Section 10.4.11

LENGTH_REQUIRED

411

HTTP/1.1, RFC 2616, Section 10.4.12

PRECONDITION_FAILED

412

HTTP/1.1, RFC 2616, Section 10.4.13

REQUEST_ENTITY_TOO_LARGE

413

HTTP/1.1, RFC 2616, Section 10.4.14

REQUEST_URI_TOO_LONG

414

HTTP/1.1, RFC 2616, Section 10.4.15

UNSUPPORTED_MEDIA_TYPE

415

HTTP/1.1, RFC 2616, Section 10.4.16

REQUESTED_RANGE_NOT_SATISFIABLE

416

HTTP/1.1, RFC 2616, Section 10.4.17

EXPECTATION_FAILED

417

HTTP/1.1, RFC 2616, Section 10.4.18

UNPROCESSABLE_ENTITY

422

WEBDAV, RFC 2518, Section 10.3

LOCKED

423

WEBDAV RFC 2518, Section 10.4

FAILED_DEPENDENCY

424

WEBDAV, RFC 2518, Section 10.5

UPGRADE_REQUIRED

426

HTTP Upgrade to TLS, RFC 2817, Section 6

INTERNAL_SERVER_ERROR

500

HTTP/1.1, RFC 2616, Section 10.5.1

NOT_IMPLEMENTED

501

HTTP/1.1, RFC 2616, Section 10.5.2

BAD_GATEWAY

502

HTTP/1.1 RFC 2616, Section 10.5.3

SERVICE_UNAVAILABLE

503

HTTP/1.1, RFC 2616, Section 10.5.4

GATEWAY_TIMEOUT

504

HTTP/1.1 RFC 2616, Section 10.5.5

HTTP_VERSION_NOT_SUPPORTED

505

HTTP/1.1, RFC 2616, Section 10.5.6

INSUFFICIENT_STORAGE

507

WEBDAV, RFC 2518, Section 10.6

NOT_EXTENDED

510

An HTTP Extension Framework, RFC 2774, Section 7
httplib.responses

This dictionary maps the HTTP 1.1 status codes to the W3C names.

Example: httplib.responses[httplib.NOT_FOUND] is 'Not Found'.

2.5 新版功能.

20.7.1. HTTPConnection Objects

HTTPConnection instances have the following methods:

HTTPConnection.request(method, url[, body[, headers]])

This will send a request to the server using the HTTP request method method and the selector url. If the body argument is present, it should be a string of data to send after the headers are finished. Alternatively, it may be an open file object, in which case the contents of the file is sent; this file object should support fileno() and read() methods. The headers argument should be a mapping of extra HTTP headers to send with the request.

If one is not provided in headers, a Content-Length header is added automatically for all methods if the length of the body can be determined, either from the length of the str representation, or from the reported size of the file on disk. If body is None the header is not set except for methods that expect a body (PUT, POST, and PATCH) in which case it is set to 0.

在 2.6 版更改: body can be a file object.

HTTPConnection.getresponse()

Should be called after a request is sent to get the response from the server. Returns an HTTPResponse instance.

注解

Note that you must have read the whole response before you can send a new request to the server.

HTTPConnection.set_debuglevel(level)

Set the debugging level (the amount of debugging output printed). The default debug level is 0, meaning no debugging output is printed.

HTTPConnection.set_tunnel(host, port=None, headers=None)

Set the host and the port for HTTP Connect Tunnelling. Normally used when it is required to do HTTPS Connection through a proxy server.

The headers argument should be a mapping of extra HTTP headers to send with the CONNECT request.

2.7 新版功能.

HTTPConnection.connect()

Connect to the server specified when the object was created.

HTTPConnection.close()

Close the connection to the server.

As an alternative to using the request() method described above, you can also send your request step by step, by using the four functions below.

HTTPConnection.putrequest(request, selector[, skip_host[, skip_accept_encoding]])

This should be the first call after the connection to the server has been made. It sends a line to the server consisting of the request string, the selector string, and the HTTP version (HTTP/1.1). To disable automatic sending of Host: or Accept-Encoding: headers (for example to accept additional content encodings), specify skip_host or skip_accept_encoding with non-False values.

在 2.4 版更改: skip_accept_encoding argument added.

HTTPConnection.putheader(header, argument[, ...])

Send an RFC 822-style header to the server. It sends a line to the server consisting of the header, a colon and a space, and the first argument. If more arguments are given, continuation lines are sent, each consisting of a tab and an argument.

HTTPConnection.endheaders(message_body=None)

Send a blank line to the server, signalling the end of the headers. The optional message_body argument can be used to pass a message body associated with the request. The message body will be sent in the same packet as the message headers if it is string, otherwise it is sent in a separate packet.

在 2.7 版更改: message_body was added.

HTTPConnection.send(data)

Send data to the server. This should be used directly only after the endheaders() method has been called and before getresponse() is called.

20.7.2. HTTPResponse Objects

HTTPResponse instances have the following methods and attributes:

HTTPResponse.read([amt])

Reads and returns the response body, or up to the next amt bytes.

HTTPResponse.getheader(name[, default])

Get the contents of the header name, or default if there is no matching header.

HTTPResponse.getheaders()

Return a list of (header, value) tuples.

2.4 新版功能.

HTTPResponse.fileno()

Returns the fileno of the underlying socket.

HTTPResponse.msg

A mimetools.Message instance containing the response headers.

HTTPResponse.version

HTTP protocol version used by server. 10 for HTTP/1.0, 11 for HTTP/1.1.

HTTPResponse.status

Status code returned by server.

HTTPResponse.reason

Reason phrase returned by server.

20.7.3. Examples

Here is an example session that uses the GET method:

>>> import httplib
>>> conn = httplib.HTTPSConnection("www.python.org")
>>> conn.request("GET", "/")
>>> r1 = conn.getresponse()
>>> print r1.status, r1.reason
200 OK
>>> data1 = r1.read()
>>> conn.request("GET", "/")
>>> r2 = conn.getresponse()
>>> print r2.status, r2.reason
404 Not Found
>>> data2 = r2.read()
>>> conn.close()

Here is an example session that uses the HEAD method. Note that the HEAD method never returns any data.

>>> import httplib
>>> conn = httplib.HTTPSConnection("www.python.org")
>>> conn.request("HEAD","/")
>>> res = conn.getresponse()
>>> print res.status, res.reason
200 OK
>>> data = res.read()
>>> print len(data)
0
>>> data == ''
True

Here is an example session that shows how to POST requests:

>>> import httplib, urllib
>>> params = urllib.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
>>> headers = {"Content-type": "application/x-www-form-urlencoded",
...            "Accept": "text/plain"}
>>> conn = httplib.HTTPConnection("bugs.python.org")
>>> conn.request("POST", "", params, headers)
>>> response = conn.getresponse()
>>> print response.status, response.reason
302 Found
>>> data = response.read()
>>> data
'Redirecting to <a href="http://bugs.python.org/issue12524">http://bugs.python.org/issue12524</a>'
>>> conn.close()

Client side HTTP PUT requests are very similar to POST requests. The difference lies only the server side where HTTP server will allow resources to be created via PUT request. Here is an example session that shows how to do PUT request using httplib:

>>> # This creates an HTTP message
>>> # with the content of BODY as the enclosed representation
>>> # for the resource http://localhost:8080/foobar
...
>>> import httplib
>>> BODY = "***filecontents***"
>>> conn = httplib.HTTPConnection("localhost", 8080)
>>> conn.request("PUT", "/file", BODY)
>>> response = conn.getresponse()
>>> print response.status, response.reason
200, OK