Update an existing ROI

Description: Update an existing ROI in dataset
URI: /datasets/ROI/<name>
http method: PUT

@app.route('/datasets/ROI/<string:name>', methods=['PUT'])
def modify_roi(name):
    if not request.json or 'rid' not in request.json:
        return('',400)
    cur = conn.cursor()
    constraint = []
    rid = str(request.json['rid'])

    if 'density' in request.json:
        constraint.append("density = "+str(request.json['density']))
    if 'score' in request.json:
        constraint.append("score = "+str(request.json['score']))
    if 'range' in request.json:
        bound = request.json['range']
        try:
            range = "'"+str(bound['east'])+","+str(bound['north'])+","+str(bound['west'])+","+str(bound['south'])+"'"
        except KeyError: 
            return('',400)
        constraint.append("range = "+range)
    query = "UPDATE roi."+name+" SET "+",".join(constraint)+" where rid = "+rid+";"

    try: 
        cur.execute(query)
        conn.commit()
        cur.close()
    except psycopg2.Error as e:
        conn.rollback()
        cur.close()
        return(e.pgerror,400)

    return('',200)