Flask で JSON ファイルを読む

次のプログラムの入力ソースを、MariaDB から JSON に変更。

flask で MariaDB を使う

フォルダー構成

$ tree
.
├── data
│   └── cities.json
├── json_read.py
└── templates
    ├── hello.html
    └── layout.html

json_read.py

# --------------------------------------------------------------------
#	json_read.py
#
#						May/10/2019
#
# --------------------------------------------------------------------
from flask import Flask, render_template
import sys
import json

app = Flask(__name__)

@app.route('/')
def hello():
	name = "皆さんこんにちは"
	return name


@app.route('/json_pp')
def json_pp():
	file_json = "data/cities.json"
	fp_in = open (file_json,encoding='utf-8')
	json_str = fp_in.read()
	fp_in.close()
	dict_aa = json.loads(json_str)
#
	rows = []
	for key in sorted (dict_aa.keys()):
		unit = dict_aa[key]
		unit['id'] = key
		rows.append(unit)
#
	return render_template('hello.html', title='json', cities=rows)

#
if __name__ == "__main__":
	app.run(host='0.0.0.0',debug=True)
# --------------------------------------------------------------------

data/cities.json

{
  "t0921": {
    "name": "宇都宮",
    "population": 41295,
    "date_mod": "2003-8-12"
  },
  "t0922": {
    "name": "小山",
    "population": 38756,
    "date_mod": "2003-5-15"
  },
  "t0923": {
    "name": "佐野",
    "population": 71294,
    "date_mod": "2003-6-8"
  },
  "t0924": {
    "name": "足利",
    "population": 27138,
    "date_mod": "2003-7-21"
  },
  "t0925": {
    "name": "日光",
    "population": 74682,
    "date_mod": "2003-4-19"
  },
  "t0926": {
    "name": "下野",
    "population": 82951,
    "date_mod": "2003-10-14"
  }
}

サーバー起動

python json_read.py

クライアント

http://localhost:5000/json_pp

にアクセスする。

確認したバージョン

$ flask --version
Python 3.12.3
Flask 3.0.2
Werkzeug 3.0.1