python 34 lines · 6 steps

Paginating articles in a Flask Blueprint

A Flask route reads pagination params, validates them, and serves a page of published articles with SQLAlchemy.

Explained by highlit
Flask Intermediate pagination blueprints input-validation query-building orm
1from flask import Blueprint, render_template, request, abort
2from sqlalchemy import select
3 
4from .models import Article
5from .extensions import db
6 
7bp = Blueprint("articles", __name__)
8 
9 
10@bp.route("/articles")
11def index():
12 page = request.args.get("page", 1, type=int)
13 per_page = request.args.get("per_page", 20, type=int)
14 if page < 1 or per_page < 1 or per_page > 100:
15 abort(400)
16 
17 query = (
18 select(Article)
19 .where(Article.published.is_(True))
20 .order_by(Article.published_at.desc())
21 )
22 
23 pagination = db.paginate(
24 query,
25 page=page,
26 per_page=per_page,
27 error_out=False,
28 )
29 
30 return render_template(
31 "articles/index.html",
32 articles=pagination.items,
33 pagination=pagination,
34 )
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1Blueprints let you group related routes into a self-contained, mountable module.
  2. 2Validate and bound user-supplied pagination input before it ever reaches the database.
  3. 3Building the query separately from paginating it keeps filtering, ordering, and slicing cleanly composable.

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