1. Introduction<\/h2>\n
REST<\/strong> stands for Representational state transfer and it fits in the HTTP protocol designed worldwide for the users. RESTful is \u2013<\/p>\n To start with this tutorial we will need to install Python and set up some of the third-party Python libraries. Let us go ahead and install them one by one.<\/p>\n If someone needs to go through the Python installation on Windows, please watch this<\/a> link. You can download the Python from this<\/a> link.<\/p>\n Once the python is successfully installed on your system you can install the Flask<\/strong> using a simple Installation command<\/em><\/span><\/p>\n Once the python is successfully installed on your system you can install the connexion<\/strong> and connexion-swagger<\/strong> modules using a simple Installation commands<\/em><\/span><\/p>\n Before going any deeper into the practice I am assuming that you are aware of the Python and OpenAPI basics. Let us dive in with the programming stuff now.<\/p>\n Add the following code to the OpenAPI\/Swagger configuration file<\/a> which will contain all the necessary information to define the application endpoints. The YML configuration file is written in a hierarchical manner where the indentation level represents the level of scope and ownership. The file consists of the following information \u2013 swagger.yml<\/em><\/span><\/p>\n Add the following code to the handler script containing the methods that will handle the request from the application endpoints. Each method name corresponds to the employees.py<\/em><\/span><\/p>\n Add the following code to the main script where will specify the swagger configuration file details to incorporate the connexion into the server. The application will create a connexion instance which in turn will create a Flask app internally but it will have some added functionalities.<\/p>\n app.py<\/em><\/span><\/p>\n Run this python script and let us understand the output.<\/p>\n To bring up the swagger on the browser hit the following endpoint – The page displays the initial swagger interface and shows the list of endpoints supported by our application at the following endpoints – In this tutorial, we learned:<\/p>\n You can download the source code of this tutorial from the Downloads<\/a> section.<\/p>\n This was a python programming tutorial to understand the connexion in python programming. This is extremely useful as it gives you and your API users a way to explore and experiment with the API without having to write any code.<\/p>\n\n
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1.1 Setting up Python<\/h3>\n
1.2 Setting up Flask<\/h3>\n
pip<\/code> command. You can fire the below command from the command prompt and it will successfully download the module from pypi.org<\/a> and install it.<\/p>\npip install -U Flask\n<\/pre>\n
1.3 Setting up Connexion & Connexion Swagger<\/h3>\n
pip<\/code> command. You can fire the below commands from the command prompt and it will successfully download the modules from pypi.org and install it.<\/p>\npip install -U connexion\n\npip install -U connexion[swagger-ui]\n<\/pre>\n
2. Introduction to Python REST API<\/h2>\n
![\"Python](\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2021\/05\/python-project-structure-guide-img1.jpg\")
<\/a><\/a>2.1 Creating an OpenAPI configuration<\/h3>\n
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swagger<\/code>: Tells which version of Swagger API is to be used<\/li>\ninfo<\/code>: Tells the API information such as API version, documentation title, etc<\/li>\nconsumes<\/code>: Tells the mime-type<\/a> which is to be expected by the API<\/li>\nproduces<\/code>: Tells what content type is expected by the API caller<\/li>\nbasePath<\/code>: Defines the API root\n\n
\/api<\/code><\/li>\n<\/ul>\n<\/li>\npaths<\/code>: Defines the application endpoints configuration<\/li>\nget<\/code>: Defines the HTTP method for the given endpoint<\/li>\noperationId<\/code>: Defines the python import path\/function (i.e. a handler file) that will respond to the given endpoint request. In our case,\n\n
\/api\/employee<\/code> endpoint will be responded by the read_all(\u2026)<\/code> method written in the employees.py<\/code> file<\/li>\n\/api\/employee\/{employee_id}<\/code> endpoint will be responded by the read_one(\u2026)<\/code> method written in the employees.py<\/code> file<\/li>\n<\/ul>\n<\/li>\ntags<\/code>: Define a grouping for the UI interface<\/li>\ndescription<\/code>: Defines the implementation notes for the UI interface<\/li>\nresponse<\/code>: Defines the beginning of the expected response section<\/li>\n<\/ul>\nswagger: '2.0'\ninfo:\n version: 1.0.0\n title: Python Swagger REST article\n description: Swagger file that works in parallel with server to generate endpoints\nconsumes:\n - application\/json\nproduces:\n - application\/json\nbasePath: \/api\n# Paths supported by the server application\npaths:\n \/employee:\n get:\n operationId: employees.read_all\n tags:\n - Employee\n description: Read the list of employee\n responses:\n '200':\n description: Successful read employee list operation\n schema:\n type: array\n items:\n properties:\n id:\n type: string\n first_name:\n type: string\n last_name:\n type: string\n joined_on:\n type: string\n '\/employee\/{employee_id}':\n get:\n operationId: employees.read_one\n tags:\n - Employee\n description: Read one employee from the list\n parameters:\n - name: employee_id\n in: path\n description: Employee id of the employee\n type: string\n required: true\n responses:\n '200':\n description: Successful read employee from list operation\n schema:\n properties:\n id:\n type: string\n first_name:\n type: string\n last_name:\n type: string\n joined_on:\n type: string\n<\/pre>\n2.2 Creating a Handler for Application endpoints<\/h3>\n
operationId<\/code> defined in the swagger configuration file<\/a>. We are skipping the other REST operations (like POST, PUT, and DELETE) and only focusing on HTTP GET operation for brevity. You are free to add new endpoints and play around with them.<\/p>\n# Modules\nfrom datetime import datetime\n\nfrom flask import abort\n\n\ndef get_timestamp():\n return datetime.now().strftime('%Y-%m-%d %H:%M:%S')\n\n\n# Mock employees data\nEMPLOYEES = {\n '101': {\n 'id': '101',\n 'first_name': 'John',\n 'last_name': 'Doe',\n 'joined_on': get_timestamp()\n },\n '102': {\n 'id': '102',\n 'first_name': 'Maxim',\n 'last_name': 'Klee',\n 'joined_on': get_timestamp()\n },\n '103': {\n 'id': '103',\n 'first_name': 'Nonnah',\n 'last_name': 'Kirkland',\n 'joined_on': get_timestamp()\n },\n '104': {\n 'id': '104',\n 'first_name': 'Kit',\n 'last_name': 'Tite',\n 'joined_on': get_timestamp()\n },\n '105': {\n 'id': '105',\n 'first_name': 'Grannie',\n 'last_name': 'Coulman',\n 'joined_on': get_timestamp()\n }\n}\n\n\n# Return all employees\ndef read_all():\n print('Fetching all employees')\n return [EMPLOYEES[key] for key in EMPLOYEES.keys()]\n\n\n# Return employee by id\ndef read_one(employee_id):\n print('Finding employee id = {}'.format(employee_id))\n for key in EMPLOYEES.keys():\n if key == employee_id:\n return EMPLOYEES[key]\n else:\n abort(404, 'Employee id = {} not found'.format(employee_id))\n<\/pre>\n2.3 Adding Connexion to the Server<\/h3>\n
# Modules\nimport connexion\nfrom flask import jsonify\n\n# Creating the application instance\napp = connexion.App(__name__, specification_dir='.\/configure')\n\n# Reading the swagger.yml file to configure the application endpoints\napp.add_api('swagger.yml')\n\n\n# Index endpoint\n# URL - http:\/\/localhost:5000\/\n@app.route('\/', methods=['GET'])\ndef home():\n print('Showing the index message')\n return jsonify({'message': 'Application is up and running'})\n\n\n# Driver code\nif __name__ == '__main__':\n app.run(debug=False)\n<\/pre>\n3. Swagger UI<\/h2>\n
http:\/\/localhost:5000\/api\/ui<\/code> and the application will bring up a page as shown in Fig. 2.<\/p>\n![\"Python](\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2021\/05\/python-flask-connexion-demo-img-guide-1.jpg\")
<\/a>http:\/\/localhost:5000<\/code>. This is built automatically by connexion when it parses the swagger.yml<\/code> file. You are free to try the endpoints and play with them too. That is all for this tutorial and I hope the article served you with whatever you were looking for. Happy Learning and do not forget to share!<\/p>\n4. Summary<\/h2>\n
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<\/a>5. More articles<\/h2>\n
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6. Download the Project<\/h2>\n