HTTP client wrapper with URL generation via object notation and argument passing
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ladder
tests
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.travis.yml
CHANGES.md
LICENSE
MANIFEST.in
README.md
makefile
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setup.py
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README.md

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General purpose path generation library with support for URLs, OS paths, delimited paths, and RESTful HTTP client integration.

Inspired by hammock.

Background

The need for ladder came from working with the flask test client during a backend project developing an RESTful API. I wanted an easy way build a test client API that consumed the backend API. I originally started out by having API URLs as class attributes on unittest TestCases which would then get passed to the test client. This worked fine in the beginning, but eventually there was a need for tests to use multiple API endpoints in several places. What I really wanted then was an interface to easily build a test client API which would then be shareable across tests.

With the help of ladder, I was able to implement something similiar to the following:

from ladder import API as APIBase


class API(object):
    def __init__(self, client, route_prefix='/api'):
        endpoint = APIBase(client, url=route_prefix, upper_methods=False)

        self.sessions = endpoint('/sessions')
        self.users = endpoint('/users')
        self.products = endpoint('/products')
        self.product_categories = endpoint('/product/categories')


class Client(ClientBase):
    @cached_property
    def api(self):
        return API(self)

Which allowed me to use the client in the following manner:

def test_some_api(self):
    # Login.
    self.client.api.sessions(login_data).post()

    # Get all users.
    res = self.client.api.users.get()
    self.assertStatus(res, 200)

    # Get a single user.
    user_id = 1
    res = self.client.api.users(user_id).get()

    # Update a singler user.
    res = self.client.api.users(user_id).post(data=data)

For me this made working with the test client easier to manage and more enjoyable.

Compared to Hammock

Hammock can already do most of what ladder does when working with a requests based client. So why use ladder instead of hammock then?

  • No requests dependency. If you're using hammock then you probably already want to use requests. But for those of you who are using another type of HTTP client, then ladder can be your hammock.
  • Since there's no requests dependency, you can generate URLs using ladder.URLPath without having an HTTP client.
  • Inline handling of query string parameters. hammock requires that query parameters be passed into the requests method call (e.g. Hammock(...).GET(params={...}). But with ladder.API, you can provide those via keyword arguments at any time during URL generation (e.g. API(...)(sort='stars').GET()) or you can stick with hammock's style (API(...).GET(params={...}). API even supports extracting query parameters from string urls.
  • You can force the HTTP method functions to be lowercase instead of UPPERCASE, i.e., API(...).GET() or API(..., upper_methods=False).get().

Beyond that the differences between ladder and hammock are under the hood when it comes to being an API client.

Requirements

Compatibility

  • Python 2.6
  • Python 2.7
  • Python 3.2
  • Python 3.3
  • Python 3.4

Dependencies

None.

Installation

pip install ladder

Overview

ladder has several classes for working with various types of path generation:

  • ladder.URLPath: Utility class for generating URLs.
  • ladder.OSPath: Utility class for genearting OS paths.
  • ladder.DelimitedPath: Utility class for generating delimited paths.
  • ladder.API: HTTP client wrapper which uses URLPath to generate URLs that can be passed to the client when making HTTP method calls (e.g. GET, POST, etc).

URLPath

Ever wanted to generate URLs using object notation? Well now you can:

from ladder import URLPath

github = URLPath('https://api.github.com')
print(github)
# https://api.github.com

search = github.search
print(search)
# https://api.github.com/search

repositories = search.repositories(q='ladder', sort='stars')
print(repositories)
# https://api.github.com/search/repositories?q=ladder&sort=stars

Don't want to use object notation? You don't have to:

URLPath('https://api.github.com')('users')('dgilland/repos', sort='updated')
# or all in one
URLPath('https://api.github.com', 'users/dgilland', 'repos', sort='updated')

Mix-and-match:

URLPath('https://api.github.com').search('repositories', q='ladder')

You can even pass in URL paths as a list:

URLPath('https://api.github.com')(['search', 'repositories'], q='ladder')

And lists of lists (because URLPath supports flattening):

URLPath('https://api.github.com')([['search', ['repositories']]], q='ladder')

Need that slash at the end?

print(URLPath('/').search)
# /search
# ...well that isn't what you want

print(URLPath('/', append_slash=True).search)
# /search/
# ...ah, that's better!

Create partial URL paths:

print(URLPath('/path/to/resource').subresource)
# /path/to/resource/subresource

Supply query string parameters in a variety of ways:

print(URLPath('/path/with?a=1')('query?so=cool', foo='bar')(b=2, c=3)(d=4)(a=2))
# /path/with/query?so=cool&a=1&foo=bar&b=2&c=3&d=4&a=2

print(URLPath('/')(a=[1, 2, 3])(b=4)(b=5)(c=(6,7))
# /?a=1&a=2&a=3&b=4&b=5&c=6&c=7

Convert URLPath to string:

url = str(URLPath('/foo/bar/baz'))

Concatenate using + and / (because, hey, why not!):

start = '/start/of/path'
middle = URLPath('middle')
end = '/end/of/path'

# supports both URLPath and string concatenation

URLPath(start) + middle + URLPath(end)
URLPath(start) + middle + end
start + middle + URLPath(end)

URLPath(start) / middle / URLPath(end)
URLPath(start) / middle / end
start / middle / URLPath(end)

OSPath

See all the stuff URLPath can do above? If you limit it to the path generation parts, then OSPath works the same way but instead of creating fancy URLs, it creates awesome OS paths!

from ladder import OSPath

var = OSPath('/var')
print(var.www.mydir)
# /var/www/mydir (on Unix)

DelimitedPath

Take OSPath and tell it to use any string delimiter you'd like and you get something like DelimitedPath.

from ladder import DelimitedPath

PeriodPath = DelimitedPath(delimiter='.')

mypath = PeriodPath('foo').bar.baz('qux')
print(mypath)
# foo.bar.baz.qux

API

Do what URLPath does but make an HTTP request at the end (provided you give it a client)! Now we're really trying to be like hammock.

After installing requests:

import requests
from ladder import API

# If you need to configure your requests session,
# it's best to do it before passing it into API().
Hammock = API(requests.session())

# However, if you can't preconfigure the requests session...
Hammock.__client__.auth = ('user', 'pass')
Hammock.__client__.headers.update({'x-test': True})

github = Hammock('https://api.github.com')
results = github.search.repositories(q='ladder').GET().json()

api = Hammock('https://api.example.com')
data = {'a': 1, 'b': 2}
api.users.POST(data, headers={}, auth=()).json()
api.users(1).PUT(data).json()
api.users(1).DELETE().json()
api.users.HEAD()
api.users.OPTIONS()

Don't like having to use UPPERCASE HTTP METHODS? No problem! API has you covered:

github = API(requests.session(), 'https://api.github.com', upper_methods=False)
results = github.search.repositories(q='ladder').get().json()

Just remember you'll need to pass a string for any of the lowercase HTTP methods that are in the URL path:

api = API(requests.session(), '/api/', upper_methods=False)
api.item('get').details.get()