Merge pull request #16939 from lujun9972/add-MjAyMDAxMDYgSG93IHRvIHdyaXRlIGEgUHl0aG9uIHdlYiBBUEkgd2l0aCBQeXJhbWlkIGFuZCBDb3JuaWNlLm1kCg==

自动选题: 20200106 How to write a Python web API with Pyramid and Cornice

sources/tech/20200106 How to write a Python web API with Pyramid and Cornice.md

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+[#]: collector: (lujun9972)
+[#]: translator: ( )
+[#]: reviewer: ( )
+[#]: publisher: ( )
+[#]: url: ( )
+[#]: subject: (How to write a Python web API with Pyramid and Cornice)
+[#]: via: (https://opensource.com/article/20/1/python-web-api-pyramid-cornice)
+[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
+
+How to write a Python web API with Pyramid and Cornice
+======
+Use Pyramid and Cornice to build and document scalable RESTful web
+services.
+![Searching for code][1]
+
+[Python][2] is a high-level, object-oriented programming language known for its simple syntax. It is consistently among the top-rated programming languages for building RESTful APIs.
+
+[Pyramid][3] is a Python web framework designed to scale up with an application: it's simple for simple applications but can grow for big, complex applications. Among other things, Pyramid powers PyPI, the Python package index. [Cornice][4] provides helpers to build and document REST-ish web services with Pyramid.
+
+This article will use the example of a web service to get famous quotes to show how to use these tools.
+
+### Set up a Pyramid application
+
+Start by creating a virtual environment for your application and a file to hold the code:
+
+
+```
+$ mkdir tutorial
+$ cd tutorial
+$ touch main.py
+$ python3 -m venv env
+$ source env/bin/activate
+(env) $ pip3 install cornice twisted
+```
+
+### Import the Cornice and Pyramid modules
+
+Import these modules with:
+
+
+```
+from pyramid.config import Configurator
+from cornice import Service
+```
+
+### Define the service
+
+Define the quotes service as a **Service** object:
+
+
+```
+QUOTES = Service(name='quotes',
+                 path='/',
+                 description='Get quotes')
+```
+
+### Write the quotes logic
+
+So far, this only supports **GET**ing quotes. Decorate the function with **QUOTES.get**; this is how you can tie in the logic to the REST service:
+
+
+```
+@QUOTES.get()
+def get_quote(request):
+    return {
+        'William Shakespeare': {
+            'quote': ['Love all, trust a few, do wrong to none',
+            'Some are born great, some achieve greatness, and some have greatness thrust upon them.']
+    },
+    'Linus': {
+        'quote': ['Talk is cheap. Show me the code.']
+        }
+    }
+```
+
+Note that unlike in other frameworks, the **get_quote** function is _not_ changed by the decorator. If you import this module, you can still call the function regularly and inspect the result.
+
+This is useful when writing unit tests for Pyramid RESTful services.
+
+### Define the application object
+
+Finally, use **scan** to find all decorated functions and add them to the configuration: 
+
+
+```
+with Configurator() as config:
+    config.include("cornice")
+    config.scan()
+    application = config.make_wsgi_app()
+```
+
+The default for scan is to scan the current module. You can also give the name of a package if you want to scan all modules in a package.
+
+### Run the service
+
+I use Twisted's WSGI server to run the application, but you can use any other [WSGI][5] server, like Gunicorn or uWSGI, if you want:
+
+
+```
+`(env)$ python -m twisted web --wsgi=main.application`
+```
+
+By default, Twisted's WSGI server runs on port 8080. You can test the service with [HTTPie][6]:
+
+
+```
+(env) $ pip install httpie
+...
+(env) $ http GET <http://localhost:8080/>
+HTTP/1.1 200 OK
+Content-Length: 220
+Content-Type: application/json
+Date: Mon, 02 Dec 2019 16:49:27 GMT
+Server: TwistedWeb/19.10.0
+X-Content-Type-Options: nosniff
+
+{
+    "Linus": {
+        "quote": [
+            "Talk is cheap. Show me the code."
+        ]
+    },
+    "William Shakespeare": {
+        "quote": [
+            "Love all,trust a few,do wrong to none",
+            "Some are born great, some achieve greatness, and some greatness thrust upon them."
+        ]
+    }
+}
+```
+
+### Why use Pyramid?
+
+Pyramid is not the most popular framework, but it is used in some high-profile projects like [PyPI][7]. I like Pyramid because it is one of the frameworks that took unit testing seriously: because the decorators do not modify the function and there are no thread-local variables, functions are callable directly from unit tests. For example, functions that need access to the database will get it from the **request** object passed in via **request.config**. This allows a unit tester to put a mock (or real) database object in the request, instead of carefully setting globals, thread-local variables, or other framework-specific things.
+
+If you're looking for a well-tested library to build your next API, give Pyramid a try. You won't be disappointed.
+
+--------------------------------------------------------------------------------
+
+via: https://opensource.com/article/20/1/python-web-api-pyramid-cornice
+
+作者：[Moshe Zadka][a]
+选题：[lujun9972][b]
+译者：[译者ID](https://github.com/译者ID)
+校对：[校对者ID](https://github.com/校对者ID)
+
+本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
+
+[a]: https://opensource.com/users/moshez
+[b]: https://github.com/lujun9972
+[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/search_find_code_python_programming.png?itok=ynSL8XRV (Searching for code)
+[2]: https://opensource.com/resources/python
+[3]: https://opensource.com/article/18/5/pyramid-framework
+[4]: https://cornice.readthedocs.io/en/latest/
+[5]: https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface
+[6]: https://opensource.com/article/19/8/getting-started-httpie
+[7]: https://pypi.org/