First draft of full verbs.

This commit is contained in:
Cory Benfield
2012-05-19 21:34:36 +01:00
parent 36fd8da1c0
commit 2b8e01bff7
+156
View File
@@ -319,3 +319,159 @@ You can also configure proxies by environment variables ``HTTP_PROXY`` and ``HTT
$ python
>>> import requests
>>> requests.get("http://example.org")
HTTP Verbs
----------
Requests 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 Requests, 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 Requests. We would get it
like so::
>>> import requests
>>> r = requests.get('https://api.github.com/repos/kennethreitz/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 == requests.codes.ok):
... print r.headers['content-type']
...
application/json; charset=utf-8
So, GitHub returns JSON. That's great, we can use the JSON module to turn it
into Python objects. Because GitHub returned UTF-8, we should use the
``r.text`` method, not the ``r.content`` method. ``r.content`` returns a
bytestring, while ``r.text`` returns a Unicode-encoded string. I have no plans
to perform byte-manipulation on this response, so I want any Unicode code
points encoded.::
>>> import json
>>> commit_data = json.loads(r.text)
>>> print commit_data.keys()
[u'committer', u'author', u'url', u'tree', u'sha', u'parents', u'message']
>>> print commit_data[u'committer']
{u'date': u'2012-05-10T11:10:50-07:00', u'email': u'me@kennethreitz.com', u'name': u'Kenneth Reitz'}
>>> print commit_data[u'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 Requests instead. We can take advantage of the Requests OPTIONS verb to
see what kinds of HTTP methods are supported on the url we just used.::
>>> verbs = requests.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 = requests.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 Requests 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 = requests.get('https://api.github.com/repos/kennethreitz/requests/issues/482')
>>> r.status_code
200
>>> issue = json.loads(r.text)
>>> print issue[u'title']
Feature any http verb in docs
>>> print issue[u'comments']
3
Cool, we have three comments. Let's take a look at the last of them.::
>>> r = requests.get(r.url + u'/comments')
>>> r.status_code
200
>>> comments = json.loads(r.text)
>>> print comments[0].keys()
[u'body', u'url', u'created_at', u'updated_at', u'user', u'id']
>>> print comments[2][u'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][u'user'][u'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/kennethreitz/requests/issues/482/comments"
>>> r = requests.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. Requests makes it easy to use many forms of authentication, including
the very common Basic Auth.::
>>> from requests.auth import HTTPBasicAuth
>>> auth = HTTPBasicAuth('fake@example.com', 'not_a_real_password')
>>> r = requests.post(url=url, data=body, auth=auth)
>>> r.status_code
201
>>> content = json.loads(r.text)
>>> print content[u'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/kennethreitz/requests/issues/comments/5804413"
>>> r = requests.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 = requests.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 = requests.head(url=url, auth=auth)
>>> print r.headers
// ...snip... //
'x-ratelimit-remaining': '4995'
'x-ratelimit-limit': '5000'
// ...snip... //
Excellent. Time to write a Python program that abuses the GitHub API in all
kinds of exciting ways, 4995 more times.