Pagination issue while using Flask-WTF in Flask with Flask-Bootstrap and Flask-SQLAlchemy

form_test.py

from flask import Flask, render_template_string, request
from flask_bootstrap import Bootstrap
from jinja2 import Template
from flask_wtf import Form
from wtforms import StringField
from wtforms.validators import DataRequired
from flask_sqlalchemy import SQLAlchemy


# Build the app along with its extensions and the route
app = Flask(__name__)
app.config['SECRET_KEY'] = 'foobarbaz'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite://'

bs = Bootstrap(app)
db = SQLAlchemy(app)

# Define some module constants and the search form
search_template = """
{% extends 'bootstrap/base.html' %}
{% from 'bootstrap/wtf.html' import form_errors, form_field %}
{% from "bootstrap/pagination.html" import render_pagination %}

{% block content %}
    <div style="padding:2em">
    <p>Form:</p>

    {% if form %}
        <form class="form form-horizontal" method="get" role="form">
          {{ form_errors(form, hiddens="only") }}
          {{ form_field(form.search) }}
        </form>
    {% endif %}

    <p>Data:</p>

    {% if query_results %}
    {{ render_pagination(query_results) }}
    <ul>
        {% for item in query_results.items %}
        <li>{{ item }}</li>
        {% endfor %}
    </ul>
    {% endif %}
    </div>
{% endblock %}
"""

class SearchForm(Form):
        search = StringField('search', validators=[DataRequired()])

class Example(db.Model):
    __tablename__ = 'examples'

    id = db.Column(db.Integer, primary_key=True)

    def __repr__(self):
        return "%03d" % self.id

db.create_all()
for i in range(50):
    db.session.add(Example())
db.session.commit()


@app.route('/')
def index():
    form = SearchForm()

    search = request.args.get('search')
    if search:
        match = '%' + str(search) + '%'
        query_results = Example.query.filter(Example.id.like(match))

    else:
        query_results = Example.query

    query_results = query_results.paginate(per_page=10)
    return render_template_string(search_template, form=form, query_results=query_results)

from flask import Flask, render_template_string, request
from flask_bootstrap import Bootstrap
from jinja2 import Template
from flask_wtf import Form
from wtforms import StringField
from wtforms.validators import DataRequired
from flask_sqlalchemy import SQLAlchemy
from flask_wtf.csrf import CsrfProtect

# Build the app along with its extensions and the route
app = Flask(__name__)
app.config['SECRET_KEY'] = 'foobarbaz'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite://'

Bootstrap(app)
db = SQLAlchemy(app)
CsrfProtect(app)

# Define some module constants and the search form
search_template = """
{% extends 'bootstrap/base.html' %}
{% from 'bootstrap/wtf.html' import form_errors, form_field %}
{% from "bootstrap/pagination.html" import render_pagination %}
{% block content %}
    <div style="padding:2em">
    <p>Form:</p>
    {% if form %}
        <form class="form form-horizontal" method="get" role="form">
          {{ form.csrf_token }}
          {{ form_errors(form, hiddens="only") }}
          {{ form_field(form.search) }}
        </form>
    {% endif %}
    <p>Data:</p>
    {% if query_results %}
    {{ render_pagination(query_results) }}
    <ul>
        {% for item in query_results.items %}
        <li>{{ item.id }}</li>
        {% endfor %}
    </ul>
    {% endif %}
    </div>
{% endblock %}
"""

class SearchForm(Form):
        search = StringField('search', validators=[DataRequired()])

class Example(db.Model):
    __tablename__ = 'examples'

    id = db.Column(db.Integer, primary_key=True)

    def __repr__(self):
        return "%03d" % self.id

db.create_all()
for i in range(50):
    db.session.add(Example())
db.session.commit()


@app.route('/', methods=['GET'])
def index():
    form = SearchForm(request.args)

    if request.method == 'GET' and form.validate():
        search = form.search.data
        match = '%' + str(search) + '%'
        query_results = Example.query.filter(Example.id.like(match))
    else:
        query_results = Example.query

    query_results = query_results.paginate(per_page=10)
    return render_template_string(search_template, form=form, query_results=query_results)

if __name__ == "__main__":
    app.run(debug=True)

I don't get the logic of that edit, the

request.method == 'GET'

in the if condition is unnecessary since the view is only registered for GET method, also the validation will fail at first loading.

This example doesn't need CSRF anyway, why going through the hassle of rendering it in the form?