21.12. `http.client` — cliente de protocolo HTTP¶

Código Fonte: Lib/http/client.py

Este módulo define classes que implementam o lado do cliente nos protocolos HTTP e HTTPS. Normalmente não é utilizada diretamente – o módulo urllib.request o utiliza para manipular URLs que utilizam HTTP e HTTPS.

Ver também

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

Nota

Suporte HTTPS está disponível somente se Python foi compilado com suporte SSL (através do módulo ssl).

O módulo fornece as seguintes classes:

class http.client.HTTPConnection(host, port=None, [timeout, ]source_address=None)¶

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. 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.

Por exemplo, todas as seguintes chamadas criam instâncias que conectam ao servidor com o mesmo host e porta:

>>> h1 = http.client.HTTPConnection('www.python.org')
>>> h2 = http.client.HTTPConnection('www.python.org:80')
>>> h3 = http.client.HTTPConnection('www.python.org', 80)
>>> h4 = http.client.HTTPConnection('www.python.org', 80, timeout=10)

Alterado na versão 3.2: source_address foi adicionado.

Alterado na versão 3.4: O argumento strict foi removido. “Respostas Simples” HTTP com o estilo 0.9 não são mais suportadas.

class http.client.HTTPSConnection(host, port=None, key_file=None, cert_file=None, [timeout, ]source_address=None, *, context=None, check_hostname=None)¶

Uma subclasse de HTTPConnection que utiliza SSL para comunicação com servidores seguros. A porta padrão é 443. Se context for especificado, ele deve ser uma instância de ssl.SSLContext descrevendo as várias opções do SSL.

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. The check_hostname parameter is also deprecated; the ssl.SSLContext.check_hostname attribute of context should be used instead.

Por favor leia Security considerations para mais informações sobre as melhores práticas.

Alterado na versão 3.2: source_address, context e check_hostname foram adicionados.

Alterado na versão 3.2: Esta classe agora suporta hosts virtuais HTTPS se possível (isto é, se ssl.HAS_SNI é true).

Alterado na versão 3.4: O argumento strict foi removido. “Respostas Simples” HTTP com o estilo 0.9 não são mais suportadas.

Alterado na versão 3.4.3: Essa classe agora executa todos os certificados e verificação de hostnames necessários por padrão. Para reverter ao comportamento anterior, sem verificação, ssl._create_unverified_context() pode ser fornecida ao argumento context.

class http.client.HTTPResponse(sock, debuglevel=0, method=None, url=None)¶: Classe em que instâncias são retornadas mediante de conexão bem-sucedida. Não é instanciável diretamente pelo usuário.

Alterado na versão 3.4: O argumento strict foi removido. “Respostas Simples” HTTP com o estilo 0.9 não são mais suportadas.

As seguintes exceções são lançadas conforme apropriado:

exception http.client.HTTPException¶: A classe base das outras exceções neste módulo. É uma subclasse de Exception.

exception http.client.NotConnected¶: Uma subclasse de HTTPException.

exception http.client.InvalidURL¶: Uma subclasse de HTTPException, lançada se uma porta é fornecida e esta é não-numérica ou vazia.

exception http.client.UnknownProtocol¶: Uma subclasse de HTTPException.

exception http.client.UnknownTransferEncoding¶: Uma subclasse de HTTPException.

exception http.client.UnimplementedFileMode¶: Uma subclasse de HTTPException.

exception http.client.IncompleteRead¶: Uma subclasse de HTTPException.

exception http.client.ImproperConnectionState¶: Uma subclasse de HTTPException.

exception http.client.CannotSendRequest¶: Uma subclasse de ImproperConnectionState.

exception http.client.CannotSendHeader¶: Uma subclasse de ImproperConnectionState.

exception http.client.ResponseNotReady¶: Uma subclasse de ImproperConnectionState.

exception http.client.BadStatusLine¶: Uma subclasse de HTTPException. Lançada se um servidor responde com um código de status HTTP que não é entendido.

exception http.client.LineTooLong¶: Uma subclasse de HTTPException. Lançada se uma linha excessivamente longa é recebida, do servidor, no protocolo HTTP.

exception http.client.RemoteDisconnected¶: Uma subclasse de ConnectionResetError e BadStatusLine. Lançada por HTTPConnection.getresponse() quando a tentativa de ler a resposta resulta na não leitura dos dados pela conexão, indicando que o fim remoto fechou a conexão.

Novo na versão 3.5: Anteriormente, a exceção BadStatusLine('') foi lançada.

As constantes definidas neste módulo são:

http.client.HTTP_PORT¶: A porta padrão para o protocolo HTTP (sempre 80).

http.client.HTTPS_PORT¶: A porta padrão para o protocolo HTTPS (sempre 443).

http.client.responses¶

Este dicionário mapeia os códigos de status HTTP 1.1 para os nomes em W3C.

Exemplo: http.client.responses[http.client.NOT_FOUND] é 'Not Found'.

Ver códigos de status HTTP para uma lista de códigos de status HTTP que estão disponíveis neste módulo como constantes.

21.12.1. Objetos de HTTPConnection¶

Instâncias HTTPConnection contêm os seguintes métodos:

HTTPConnection.request(method, url, body=None, headers={})¶

Isto irá enviar uma requisição para o servidor utilizando o método de requisição HTTP method e o seletor url.

If body is specified, the specified data is sent after the headers are finished. It may be a string, a bytes-like object, an open file object, or an iterable of bytes-like objects. If body is a string, it is encoded as ISO-8859-1, the default for HTTP. If it is a bytes-like object the bytes are sent as is. If it is a file object, the contents of the file is sent; this file object should support at least the read() method. If the file object has a mode attribute, the data returned by the read() method will be encoded as ISO-8859-1 unless the mode attribute contains the substring b, otherwise the data returned by read() is sent as is. If body is an iterable, the elements of the iterable are sent as is until the iterable is exhausted.

O argumento headers deve ser um mapeamento de cabeçalhos HTTP extras a serem enviados com a requisição.

If headers does not contain a Content-Length item, one is added automatically if possible. If body is None, the Content-Length header is set to 0 for methods that expect a body (PUT, POST, and PATCH). If body is a string or bytes object, the Content-Length header is set to its length. If body is a file object and it works to call fstat() on the result of its fileno() method, then the Content-Length header is set to the st_size reported by the fstat call. Otherwise no Content-Length header is added.

Novo na versão 3.2: body pode agora ser um iterável.

HTTPConnection.getresponse()¶: Should be called after a request is sent to get the response from the server. Returns an HTTPResponse instance.

Nota

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

Alterado na versão 3.5: Se uma ConnectionError ou subclasse for levantada, o objeto HTTPConnection estará pronto para se reconectar quando uma nova solicitação for enviada.

HTTPConnection.set_debuglevel(level)¶: Set the debugging level. The default debug level is 0, meaning no debugging output is printed. Any value greater than 0 will cause all currently defined debug output to be printed to stdout. The debuglevel is passed to any new HTTPResponse objects that are created.

Novo na versão 3.1.

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

Set the host and the port for HTTP Connect Tunnelling. This allows running the connection through a proxy server.

The host and port arguments specify the endpoint of the tunneled connection (i.e. the address included in the CONNECT request, not the address of the proxy server).

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

For example, to tunnel through a HTTPS proxy server running locally on port 8080, we would pass the address of the proxy to the HTTPSConnection constructor, and the address of the host that we eventually want to reach to the set_tunnel() method:

>>> import http.client
>>> conn = http.client.HTTPSConnection("localhost", 8080)
>>> conn.set_tunnel("www.python.org")
>>> conn.request("HEAD","/index.html")

Novo na versão 3.2.

HTTPConnection.connect()¶: Connect to the server specified when the object was created. By default, this is called automatically when making a request if the client does not already have a connection.

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(method, url, skip_host=False, skip_accept_encoding=False)¶: 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 method string, the url 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.

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.

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.

21.12.2. Objetos HTTPResponse¶

An HTTPResponse instance wraps the HTTP response from the server. It provides access to the request headers and the entity body. The response is an iterable object and can be used in a with statement.

Alterado na versão 3.5: The io.BufferedIOBase interface is now implemented and all of its reader operations are supported.

HTTPResponse.read([amt])¶: Reads and returns the response body, or up to the next amt bytes.

HTTPResponse.readinto(b)¶: Reads up to the next len(b) bytes of the response body into the buffer b. Returns the number of bytes read.

Novo na versão 3.3.

HTTPResponse.getheader(name, default=None)¶: Return the value of the header name, or default if there is no header matching name. If there is more than one header with the name name, return all of the values joined by ‘, ‘. If ‘default’ is any iterable other than a single string, its elements are similarly returned joined by commas.

HTTPResponse.getheaders()¶: Return a list of (header, value) tuples.

HTTPResponse.fileno()¶: Return the fileno of the underlying socket.

HTTPResponse.msg¶: A http.client.HTTPMessage instance containing the response headers. http.client.HTTPMessage is a subclass of email.message.Message.

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.

HTTPResponse.debuglevel¶: A debugging hook. If debuglevel is greater than zero, messages will be printed to stdout as the response is read and parsed.

HTTPResponse.closed¶: Is True if the stream is closed.

21.12.3. Exemplos¶

Here is an example session that uses the GET method:

>>> import http.client
>>> conn = http.client.HTTPSConnection("www.python.org")
>>> conn.request("GET", "/")
>>> r1 = conn.getresponse()
>>> print(r1.status, r1.reason)
200 OK
>>> data1 = r1.read()  # This will return entire content.
>>> # The following example demonstrates reading data in chunks.
>>> conn.request("GET", "/")
>>> r1 = conn.getresponse()
>>> while not r1.closed:
...     print(r1.read(200))  # 200 bytes
b'<!doctype html>\n<!--[if"...
...
>>> # Example of an invalid request
>>> conn.request("GET", "/parrot.spam")
>>> 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 http.client
>>> conn = http.client.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 == b''
True

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

>>> import http.client, urllib.parse
>>> params = urllib.parse.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
>>> headers = {"Content-type": "application/x-www-form-urlencoded",
...            "Accept": "text/plain"}
>>> conn = http.client.HTTPConnection("bugs.python.org")
>>> conn.request("POST", "", params, headers)
>>> response = conn.getresponse()
>>> print(response.status, response.reason)
302 Found
>>> data = response.read()
>>> data
b'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. It should be noted that custom HTTP methods +are also handled in urllib.request.Request by sending the appropriate +method attribute.Here is an example session that shows how to do PUT request using http.client:

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

21.12.4. HTTPMessage Objects¶

An http.client.HTTPMessage instance holds the headers from an HTTP response. It is implemented using the email.message.Message class.

21.12. `http.client` — cliente de protocolo HTTP¶

21.12.1. Objetos de HTTPConnection¶

21.12.2. Objetos HTTPResponse¶

21.12.3. Exemplos¶

21.12.4. HTTPMessage Objects¶

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21.12. http.client — cliente de protocolo HTTP¶

21.12.1. Objetos de HTTPConnection¶

21.12.2. Objetos HTTPResponse¶

21.12.3. Exemplos¶

21.12.4. HTTPMessage Objects¶

21.12. `http.client` — cliente de protocolo HTTP¶