python - In Flask, what is "request.args" and how is it used?

Question

As a Flask beginner, I can't understand how request.args is used. I read somewhere that it is used to return values of query string (correct me if I'm wrong) and how many parameters request.args.get() takes.

I know that when I have to store submitted form data, I can use fname = request.form.get("firstname"). Here, only one parameter is passed, whereas the code below takes two parameters.

@app.route("/")
def home():
    cnx = db_connect()
    cur = cnx.cursor()
    output = []

    page = request.args.get('page', 1)

    try:
        page = int(page)
        skip = (page-1)*4
    except:
        abort(404)
   
    stmt_select = "select * from posts limit %s, 4;"
    values=[skip]

    cur.execute(stmt_select,values)
    x=cur.fetchall()

    for row in reversed(x):
        data = {
           "uid":row[0],
           "pid":row[1],
           "subject":row[2],
           "post_content":row[3],
           "date":datetime.fromtimestamp(row[4]),
        }
        output.append(data)
    
    next = page + 1
    previous = page-1
    if previous<1:
    previous=1
    return render_template("home.html", persons=output, next=next, previous=previous)

Please explain why it takes two parameters, and then what its use is.

Answer 1

According to the flask.Request.args documents.

flask.Request.args
A MultiDict with the parsed contents of the query string. (The part in the URL after the question mark).

So the args.get() is method get() for MultiDict, whose prototype is as follows:

get(key, default=None, type=None)

---

In newer version of flask (v1.0.x and v1.1.x), flask.Request.args is an ImmutableMultiDict(an immutable MultiDict), so the prototype and specific method above are still valid.