如何在不使用 forms 的情况下将客户端参数传递给服务器端路由？

Question

I have a simple Flask web app. My index template has various ways of interacting with clients using javascript and HTML . I am also have a form that, upon submission, routes to another flask process and uses the request.form command to retrieve user-submitted data.

However, I want to do something a little different. I would like to initiate a Flask redirection upon javascript event but include a parameter, and not use form .

For example, my index.html file would display something like this after template rendering:

function startRedirect(parameter) {
    window.location.pathname = '/myRedirect';
}

<input type="checkbox" id="sample" name="sample" onChange="startRedirect(parameter);">

And part of my Flask script would have:

@app.route('/myRedirect')
def myRedirectFunction():
    # do something with the parameter here
    return render_template('index.html')

I realize this can be done with using a form , but I am interested in accomplishing this task without having a form . I was thinking about somehow using request.args , but don't quite understand what to do.

Answer 1

You can use a dynamic route to capture a simple input and pass it to the route's function.

app.route('/myRedirect/<param>')
def myRedirectFunction(param='hello world'):
    return render_template('index.html', param=param)

Using this route as a redirect, you can pass a single param (or multiple if you serialize them) that you can use to do something . From there, you can either display or you can redirect again to a common endpoint so the user does not see the param in the url.

Answer 2

There's no need for a form or an explicit redirect , just attach a route and some parameter to the dynamic route.

Let's say you have a model to list the departments in your company:

class Departments(db.Model):

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), unique=True)

Now you have a department selection page:

@app.route('/departments_home', methods=['GET'])
def departments_home():
    departments = Departments.query.all()
    return render_template('departments_home.html',
                           departments=departments)

On the frontend you might have a variety of selections, each giving a link to the same route but with a different department_id:

{% for department in departments %}
<a href="{{ url_for('load_department', department_id=department.id) }}" class="button">Click to go to {{ department.name }}</a>
{% endfor %}

Now you just need another route to handle this, taking the variable department_id that was passed in the GET request:

@app.route('/load_department/<department_id>', methods=['GET'])
def load_department(department_id):
   department = Departments.query.get(int(department_id))
   department_data = # do stuff here with the specific department