Flask新手求助：如何在get_match函数中复用select_symptoms的symptoms参数

Hey there! Let's work through how to get that symptoms data from your select_symptoms function into get_match in your Flask app. First, let's break down the issue: your two view functions are separate, so get_match can't directly access variables from select_symptoms—they’re in their own scopes. Also, that request.parameter_storage_class(symptoms) line isn’t the right way to handle this.

Here are a few practical solutions depending on your use case:

Solution 1: Pass the symptoms parameter directly to get_match (most straightforward) #

If you want the frontend to call select_symptoms first, then send the same symptom ID to get_match, just update the get_match route to accept the parameter. You can also reuse the database query logic to fetch the symptom data:

@app.route('/organ/id/symptoms/<int:symptoms>', methods=["GET"])
def select_symptoms(symptoms):
    cur = mysql.connect().cursor()
    # Fixed the SQL syntax error (removed extra comma before FROM)
    # Also switched to parameterized query to avoid SQL injection!
    cur.execute('select symptoms, id from symptoms where id in (%s)', (symptoms,))
    symptoms_list = [dict((cur.description[i][0], value) for i, value in enumerate(row)) for row in cur.fetchall()]
    return jsonify({'The Symptoms': symptoms_list})

# Update the route to accept the symptoms parameter
@app.route('/organ/id/symptoms/diagnosis/<int:symptoms>')
def get_match(symptoms):
    # Fetch the symptom data just like in select_symptoms
    cur = mysql.connect().cursor()
    cur.execute('select symptoms, id from symptoms where id in (%s)', (symptoms,))
    symptoms_data = [dict((cur.description[i][0], value) for i, value in enumerate(row)) for row in cur.fetchall()]
    
    # Add your diagnosis logic here using symptoms_data
    return jsonify({'diagnosis_input': symptoms_data})

Important Note: #

Always use parameterized queries (like %s in the example) instead of string concatenation for SQL—this prevents dangerous SQL injection attacks.

Solution 2: Use Flask Session to store data between requests #

If you want users to call select_symptoms first, then access that same data in get_match without re-sending the parameter, use Flask’s session to temporarily store the symptom data. First, you need to set a secret key for your app:

app = Flask(__name__)
app.secret_key = 'your_secure_secret_key_here' # Replace with a real secret key for production

Then update your view functions:

@app.route('/organ/id/symptoms/<int:symptoms>', methods=["GET"])
def select_symptoms(symptoms):
    cur = mysql.connect().cursor()
    cur.execute('select symptoms, id from symptoms where id in (%s)', (symptoms,))
    symptoms_list = [dict((cur.description[i][0], value) for i, value in enumerate(row)) for row in cur.fetchall()]
    
    # Store the symptom data in the user's session
    session['symptoms_data'] = symptoms_list
    return jsonify({'The Symptoms': symptoms_list})

@app.route('/organ/id/symptoms/diagnosis/')
def get_match():
    # Retrieve the stored data from the session
    symptoms_data = session.get('symptoms_data', [])
    
    if not symptoms_data:
        return jsonify({'error': 'No symptom data found—call /organ/id/symptoms/<id> first'}), 400
    
    # Add your diagnosis logic here
    return jsonify({'diagnosis_input': symptoms_data})

Solution 3: Refactor to reuse query logic #

If both functions need to fetch symptom data, pull that logic into a separate helper function to avoid code duplication:

def fetch_symptoms_by_id(symptom_id):
    cur = mysql.connect().cursor()
    cur.execute('select symptoms, id from symptoms where id in (%s)', (symptom_id,))
    return [dict((cur.description[i][0], value) for i, value in enumerate(row)) for row in cur.fetchall()]

@app.route('/organ/id/symptoms/<int:symptoms>', methods=["GET"])
def select_symptoms(symptoms):
    symptoms_list = fetch_symptoms_by_id(symptoms)
    return jsonify({'The Symptoms': symptoms_list})

@app.route('/organ/id/symptoms/diagnosis/<int:symptoms>')
def get_match(symptoms):
    symptoms_data = fetch_symptoms_by_id(symptoms)
    # Add diagnosis logic here
    return jsonify({'diagnosis_input': symptoms_data})

内容的提问来源于stack exchange，提问作者jubey simanjuntak