# PyConES17
![Title](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/title.png)
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) Workshop: Vigilante de Wallapop (Application to monitor prices in Wallapop)
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Taller: Vigilante de Wallapop (Aplicación para vigilar precios en Wallapop)
## Demo
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) Currently implemented on a real site:
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Actualmente esta implementado en un sitio real:
[wallaviso.com](http://wallaviso.com)
## Run (Ejecutar)
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) For the impatient, you can play with the finished exercise. You should download the code and execute the following commands.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Para los impacientes, podéis jugar con el ejercicio acabado. Debéis descargar el código y ejecutar los siguientes comandos.
```bash
cd flask-wallapop-watcher
pip3 install virtualenv
virtualenv --python=python3 .venv
source .venv/bin/activate
pip3 install -r requirements.txt
python3 models.py db init
python3 models.py db migrate
python3 models.py db upgrade
python3 app.py
````
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) Then open in your favorite browser, which will possibly be the fantastic Firefox, a new tab with [http://127.0.0.1:5000](http://127.0.0.1:5000)
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Después abrir en tu navegador favorito, que posiblemente será el fantástico Firefox, una pestaña nueva con [http://127.0.0.1:5000](http://127.0.0.1:5000)
---
## Workshop (Taller)
### Minimum requirements (Requisitos mínimos)
* python3
* wget
* Editor de texto enriquecido: Vim, Sublime Text, VSCode, Atom...
* sqlite3
* Conexión a internet
### We checked everything (Comprobamos que tenemos todo)
```bash
python3 --help
wget --help
sqlite3 --help
ping -c 5 google.com
```
---
### Part 1 - Flask Core y Search (Parte 1 - Nucleo de Flask y Buscador) 50 min
#### 1.1 Ready?
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We prepare our virtual environment.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Preparamos nuestro entorno virtual.
```bash
mkdir flask-wallapop-watcher
cd flask-wallapop-watcher
pip3 install virtualenv
virtualenv --python=python3 .venv
source .venv/bin/activate
wget https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/requirements.txt
pip3 install -r requirements.txt
```
---
#### 1.1 Hello PyConES17
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) Template Flask. We created a new file called **app.py**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Plantilla Flask. Creamos un nuevo archivo llamado **app.py**.
```python3
from flask import Flask
# Flask
app = Flask(__name__)
app.config['DEBUG'] = True
app.config['SECRET_KEY'] = 'mi secreto'
@app.route('/')
def buscador():
return 'Hello PyConES17 !!!'
if __name__ == '__main__':
app.run()
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We run and check that everything works.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Ejecutamos y comprobamos que todo funciona.
```bash
python3 app.py
```
```bash
http://127.0.0.1:5000
```
---
#### 1.2 Templates
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We created a folder called **templates**. Inside we make two more folders: **layouts** and **items**. In **layouts** we will make a new one with the name **master.html**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Creamos una carpeta llamada **templates**. Dentro dos más: **layouts** y **items**. En **layouts** haremos uno nuevo con el nombre **master.html**.
```jinja2
{% block title %}{% endblock %} | Vigilador de Wallapop
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) In **items** we are going to have our first real page that will inherit from **master.html**. Within **items** we create **searcher.html**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) En **items** vamos a tener nuestra primera página real que va a heredar de **master.html**. Dentro de **items** creamos **buscador.html**.
```jinja2
{% extends 'layouts/master.html' %}
{% set active_page = "buscador" %}
{% block title %}Buscador{% endblock %}
{% block body %}
Buscador
{% endblock %}
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) You update **app.py** to work with our template engine.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Actulizamos **app.py** para que trabaje nuestro motor de plantillas.
```python3
from flask import Flask, render_template
# Flask
app = Flask(__name__)
app.config['DEBUG'] = True
app.config['SECRET_KEY'] = 'mi secreto'
@app.route('/')
def buscador():
return render_template('items/buscador.html')
if __name__ == '__main__':
app.run()
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We create the second page where we will have our searches stored. Within **items** we create a new file with the name of **programadas.html**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Creamos la segunda página donde tendremos nuestras busquedas almacenadas. Dentro de **items** creamos un fichero nuevo con el nombre de **programadas.html**.
```jinja2
{% extends 'layouts/master.html' %}
{% set active_page = "programadas" %}
{% block title %}Programadas{% endblock %}
{% block body %}
Soy la página donde estará las programadas
{% endblock %}
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We update **app.py** with the new page.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Actulizamos **app.py** con la nueva página.
```python3
from flask import Flask, render_template
# Flask
app = Flask(__name__)
app.config['DEBUG'] = True
app.config['SECRET_KEY'] = 'mi secreto'
@app.route('/')
def buscador():
return render_template('items/buscador.html')
@app.route('/programadas')
def programadas():
return render_template('items/programadas.html')
if __name__ == '__main__':
app.run()
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) As a final detail we will make our browser buttons have the correct routes.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Como último detalle haremos que nuestros botones del navegador tengan las rutas correctas.
```jinja2
{% block title %}{% endblock %} | Vigilador de Wallapop
```
---
#### 1.3 Forms
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We make the new file **forms.py**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Realizamos el nuevo archivo **forms.py**.
```python3
from flask_wtf import FlaskForm
from wtforms import StringField, IntegerField
from wtforms.validators import DataRequired, Length, NumberRange, Optional
class SearchForm(FlaskForm):
name = StringField('Nombre', [Length(min=1, max=100, message='Es demasiado largo'), DataRequired(message='Campo obligatorio')])
price_max = IntegerField('Precio', [NumberRange(1, message='No puede ser inferior a 1'), Optional()])
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We load it and pass it to the template.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Lo cargamos y se lo pasamos a la plantilla.
```python3
from flask import Flask, render_template
from forms import SearchForm
# Flask
app = Flask(__name__)
app.config['DEBUG'] = True
app.config['SECRET_KEY'] = 'mi secreto'
@app.route('/', methods=('GET', 'POST'))
def buscador():
form = SearchForm()
if form.validate_on_submit():
pass
return render_template('items/buscador.html', form=form)
@app.route('/programadas')
def programadas():
return render_template('items/programadas.html')
if __name__ == '__main__':
app.run()
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We print the fields with a **loop** in our template **buscador.html**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Imprimimos los campos con un **bucle** en nuestra plantilla **buscador.html**.
```jinja2
{% extends 'layouts/master.html' %}
{% set active_page = "buscador" %}
{% block title %}Buscador{% endblock %}
{% block body %}
Buscador
{% endblock %}
```
---
#### 1.4 Search
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) It's time for fun. First we update our **app.py** to get the form data if you pass the validations. Then, with that information, we will make a call to the Wallapop API. We will only need the URL that they use in your APP. With **urllib3** we will have all the results in a simple dictionary. Which is great, since it is easy to iterate within our template.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Ha llegado la hora de lo divertido. Primero actulizamos nuestro **app.py** para obtener los datos del formulario si pasa las validaciones. Después, con esa información, haremos una llamada al API de Wallapop. Solo necesitaremos la URL que utilizan en su APP. Con *urllib3* tendremos todos los resultados en un sencillo diccionario. Lo cual es magnífico, ya que es fácil de iterar dentro de nuestra plantilla.
```python3
from flask import Flask, render_template, request
from forms import SearchForm
# Get data Wallapop
import json
from urllib3 import PoolManager
import urllib.parse
# Flask
app = Flask(__name__)
app.config['DEBUG'] = True
app.config['SECRET_KEY'] = 'mi secreto'
@app.route('/', methods=('GET', 'POST'))
def buscador():
form = SearchForm()
results = None
if form.validate_on_submit():
name = form.name.data
price_max = form.price_max.data or ''
# Search in Wallapop
results = get_resultados(name, price_max)
return render_template('items/buscador.html', form=form, results=results)
@app.route('/programadas')
def programadas():
return render_template('items/programadas.html')
def get_resultados(name='', price_max=''):
http = PoolManager()
url_api = 'http://es.wallapop.com/rest/items?minPrice=&maxPrice={price_max}&dist=&order=creationDate-des&lat=41.398077&lng=2.170432&kws={kws}'.format(
kws=urllib.parse.quote(name, safe=''),
price_max=price_max
)
results = http.request('GET', url_api)
results = json.loads(
results.data.decode('utf-8')
)
return results['items']
if __name__ == '__main__':
app.run()
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) And in our template of **buscador.html**.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Y en nuestra plantilla de **buscador.html**.
```jinja2
{% extends 'layouts/master.html' %}
{% set active_page = "buscador" %}
{% block title %}Buscador{% endblock %}
{% block body %}
{% endif %}
{% endblock %}
```
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) And ... *Voilá*.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Y... *Voilá*.
### Break (Descanso) - 10 min
![English](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/en.png) We debug bugs and prepare for the next point.
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Depuramos bugs y nos preparamos para el siguiente punto.
---
### Part 2 - Databases and CRUD with Flask (Bases de datos y CRUD elementos con Flask)
#### 2.1 Models
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Con **Flask-alquemy** vamos a definir la estructura de nuestra base de datos. En este caso tendremos una única tabla llamada *Programado* con los campos: *id*, *title* y *last_item*. Para ello crearemos un nuevo archivo con el nombre **models.py**.
```python3
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.sqlite'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
class Programado(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(128))
last_item = db.Column(db.Integer)
```
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Esta forma de trabajar tan limpia carece de varias funcionalidades básicas, como migraciones o la posibilidad de ejecutar ordenes por medio del terminal. Para ello le sumaremos **Flask-Migrate** para las migraciones automáticas y **Flask-Script** para su gestión.
```python3
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_script import Manager
from flask_migrate import Migrate, MigrateCommand
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.sqlite'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
migrate = Migrate(app, db)
manager = Manager(app)
manager.add_command('db', MigrateCommand)
class Programado(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(128))
last_item = db.Column(db.Integer)
if __name__ == "__main__":
manager.run()
```
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Abrimos nuestro terminal e iniciamos la base de datos, creamos la primera migración y actualizamos la base de datos.
```bash
python3 models.py db init
python3 models.py db migrate
python3 models.py db upgrade
```
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Comprobamos que todo ha ido bien.
```bash
sqlite3 database.sqlite
.schema Programado
.exit
```
---
#### 2.2 Save item
![Castellano](https://raw.githubusercontent.com/tanrax/flask-wallapop-watcher/master/workshop/es.png) Para guarda un elemento necesitamos modificar nuestra plantilla **buscador.html**. Enviaremos un *POST*. Qué sencillamente será un **