* Close redirect responses

* History should not be reverse-order

* History should not be reverse-order

* Docs updates

2019-06-13 16:19:39 +01:00

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QuickStart

!!! note This page closely follows the layout of the requests QuickStart documentation. The http3 library is designed to be API compatible with requests wherever possible.

First start by importing HTTP3:

>>> import http3

Now, let’s try to get a webpage.

>>> r = http3.get('https://httpbin.org/get')

Similarly, to make an HTTP POST request:

>>> r = http3.post('https://httpbin.org/post', data={'key': 'value'})

The PUT, DELETE, HEAD, and OPTIONS requests all follow the same style:

>>> r = http3.put('https://httpbin.org/put', data={'key': 'value'})
>>> r = http3.delete('https://httpbin.org/delete')
>>> r = http3.head('https://httpbin.org/get')
>>> r = http3.options('https://httpbin.org/get')

Passing Parameters in URLs

To include URL query parameters in the request, use the params keyword:

>>> params = {'key1': 'value1', 'key2': 'value2'}
>>> r = http3.get('https://httpbin.org/get', params=params)

To see how the values get encoding into the URL string, we can inspect the resulting URL that was used to make the request:

>>> r.url
URL('https://httpbin.org/get?key2=value2&key1=value1')

You can also pass a list of items as a value:

>>> params = {'key1': 'value1', 'key2': ['value2', 'value3']}
>>> r = http3.get('https://httpbin.org/get', params=params)
>>> r.url
URL('https://httpbin.org/get?key1=value1&key2=value2&key2=value3')

Response Content

HTTP3 will automatically handle decoding the response content into unicode text.

>>> r = http3.get('https://www.example.org/')
>>> r.text
'<!doctype html>\n<html>\n<head>\n<title>Example Domain</title>...'

You can inspect what encoding has been used to decode the response.

>>> r.encoding
'UTF-8'

If you need to override the standard behavior and explicitly set the encoding to use, then you can do that too.

>>> r.encoding = 'ISO-8859-1'

Binary Response Content

The response content can also be accessed as bytes, for non-text responses:

>>> r.content
b'<!doctype html>\n<html>\n<head>\n<title>Example Domain</title>...'

Any gzip and deflate HTTP response encodings will automatically be decoded for you. If brotlipy is installed, then the brotli response encoding will also be supported.

For example, to create an image from binary data returned by a request, you can use the following code:

>>> from PIL import Image
>>> from io import BytesIO
>>> i = Image.open(BytesIO(r.content))

JSON Response Content

Often Web API responses will be encoded as JSON.

>>> r = http3.get('https://api.github.com/events')
>>> r.json()
[{u'repository': {u'open_issues': 0, u'url': 'https://github.com/...' ...  }}]

Custom Headers

To include additional headers in the outgoing request, use the headers keyword argument:

>>> url = 'http://httpbin.org/headers'
>>> headers = {'user-agent': 'my-app/0.0.1'}
>>> r = http3.get(url, headers=headers)

Sending Form Encoded Data

Some types of HTTP requests, such as POST and PUT requests, can include data in the request body. One common way of including that is as form encoded data, which is used for HTML forms.

>>> data = {'key1': 'value1', 'key2': 'value2'}
>>> r = http3.post("https://httpbin.org/post", data=data)
>>> print(r.text)
{
  ...
  "form": {
    "key2": "value2",
    "key1": "value1"
  },
  ...
}

Form encoded data can also include multiple values form a given key.

>>> data = {'key1': ['value1', 'value2']}
>>> r = http3.post("https://httpbin.org/post", data=data)
>>> print(r.text)
{
  ...
  "form": {
    "key1": [
      "value1",
      "value2"
    ]
  },
  ...
}

Sending JSON Encoded Data

Form encoded data is okay if all you need is simple key-value data structure. For more complicated data structures you'll often want to use JSON encoding instead.

>>> data = {'integer': 123, 'boolean': True, 'list': ['a', 'b', 'c']}
>>> r = http3.post("https://httpbin.org/post", json=data)
>>> print(r.text)
{
  ...
  "json": {
    "boolean": true,
    "integer": 123,
    "list": [
      "a",
      "b",
      "c"
    ]
  },
  ...
}

Sending Binary Request Data

For other encodings you should use either a bytes type, or a generator that yields bytes.

You'll probably also want to set a custom Content-Type header when uploading binary data.

## Response Status Codes

We can inspect the HTTP status code of the response:

>>> r = http3.get('https://httpbin.org/get')
>>> r.status_code
<StatusCode.OK: 200>

The status code is an integer enum, meaning that the Python representation gives use some descriptive information, but the value itself can be used as a regular integer.

>>> r.status_code == 200
True

HTTP3 also includes an easy shortcut for accessing status codes by their text phrase.

>>> r.status_code == requests.codes.OK
True

We can raise an exception for any Client or Server error responses (4xx or 5xx status codes):

>>> not_found = http3.get('https://httpbin.org/status/404')
>>> not_found.status_code
<StatusCode.NOT_FOUND: 404>
>>> not_found.raise_for_status()
Traceback (most recent call last):
  File "/Users/tomchristie/GitHub/encode/httpcore/http3/models.py", line 776, in raise_for_status
    raise HttpError(message)
http3.exceptions.HttpError: 404 Not Found

Any successful response codes will simply return None rather than raising an exception.

>>> r.raise_for_status()

Response Headers

The response headers are available as a dictionary-like interface.

>>> r.headers
Headers({
    'content-encoding': 'gzip',
    'transfer-encoding': 'chunked',
    'connection': 'close',
    'server': 'nginx/1.0.4',
    'x-runtime': '148ms',
    'etag': '"e1ca502697e5c9317743dc078f67693f"',
    'content-type': 'application/json'
})

The Headers data type is case-insensitive, so you can use any capitalization.

>>> r.headers['Content-Type']
'application/json'

>>> r.headers.get('content-type')
'application/json'

Multiple values for a single response header are represented as a single comma separated value, as per RFC 7230:

A recipient MAY combine multiple header fields with the same field name into one “field-name: field-value” pair, without changing the semantics of the message, by appending each subsequent field value to the combined field value in order, separated by a comma.

Cookies

Any cookies that are set on the response can be easily accessed:

>>> r = http3.get('http://httpbin.org/cookies/set?chocolate=chip', allow_redirects=False)
>>> r.cookies['chocolate']
'chip'

To include cookies in an outgoing request, use the cookies parameter:

>>> cookies = {"peanut": "butter"}
>>> r = http3.get('http://httpbin.org/cookies', cookies=cookies)
>>> r.json()
{'cookies': {'peanut': 'butter'}}

Cookies are returned in a Cookies instance, which is a dict-like data structure with additional API for accessing cookies by their domain or path.

>>> cookies = http3.Cookies()
>>> cookies.set('cookie_on_domain', 'hello, there!', domain='httpbin.org')
>>> cookies.set('cookie_off_domain', 'nope.', domain='example.org')
>>> r = http3.get('http://httpbin.org/cookies', cookies=cookies)
>>> r.json()
{'cookies': {'cookie_on_domain': 'hello, there!'}}

Redirection and History

By default HTTP3 will follow redirects for anything except HEAD requests.

The history property of the response can be used to inspect any followed redirects. It contains a list of all any redirect responses that were followed, in the order in which they were made.

For example, GitHub redirects all HTTP requests to HTTPS.

>>> r = http3.get('http://github.com/')
>>> r.url
URL('https://github.com/')
>>> r.status_code
<StatusCode.OK: 200>
>>> r.history
[<Response [301]>]

You can modify the default redirection handling with the allow_redirects parameter:

>>> r = http3.get('http://github.com/', allow_redirects=False)
>>> r.status_code
301
>>> r.history
[]

If you’re making a HEAD request, you can use this to enable redirection:

>>> r = http3.head('http://github.com/', allow_redirects=True)
>>> r.url
'https://github.com/'
>>> r.history
[<Response [301]>]

Timeouts

HTTP3 defaults to including reasonable timeouts for all network operations, meaning that if a connection is not properly established then it should always raise an error rather than hanging indefinitely.

The default timeout for network inactivity is five seconds. You can modify the value to be more or less strict:

>>> http3.get('https://github.com/', timeout=0.001)

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