Javascript Ajax 到 Flask request.get_json : TypeError: string indices must be integers

标签 javascript python flask

我正在尝试使用我的 javascript 文件中的 ajax 调用将信息(字典)从 Javascript 传递到 Flask。

我在 CentOS7 上运行 Python 2.7。

Flask 路由通过 request.get_json('data') 获取数据，字典由 python 获取，因为我的控制台打印出请求的字典。我可以访问字典，但我不知道为什么会出现 typeError。

这是我的 flask 代码:

# import the Flask class from the flask module
from flask import Flask, render_template, redirect, url_for, request, jsonify
import json
from ev import EventViewer

# create the application object
app = Flask(__name__, )
app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 0
app.run(debug=True, host='localhost:5000')


@app.route('/')
def main():
    return render_template('charts.html')  # render a template


@app.route('/python_portal', methods=['GET', 'POST'])
def python_portal():

    if request.method == "POST":
        print 'STEP 1'
        request_data = request.get_json('data')
        print "query: %s" % request_data
        page = request_data['page']
        payload = request_data['data_to_pass']
        print 'STEP 2'
        print page, request_data
        return "Python portal"


# start the server with the 'run()' method
if __name__ == '__main__':
    app.run(debug=True)

这是我的 Javascript:

function build(query){
    var qu = query
    console.log(qu)
    $.ajax(
    {
      type: "POST",
      async: true,
      contentType: "application/json; charset=utf-8",
      url: "/python_portal",
      data: JSON.stringify(query),
      dataType: "json",
      failure: function () {
        console.log("failure");                                                                                                  
      },
      success: function (data) {
        console.log("success");

        for(i=0; i < 3; i++){
         console.log(i);
        };

        }
    })
};



$('#submit').on('click', function() {
        var event_name = document.getElementById("schools").value;
        var symbol_name = document.getElementById("vacations").value;
        var instances = document.getElementById("instances").value;
        var payload = {
            "page": "project",
            "data_to_pass": [event_name, symbol_name, instances]
        }
        build(payload)
})

这是我的 html:

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

<!-- Load c3.css -->
<link href="https://cdnjs.cloudflare.com/ajax/libs/c3/0.7.2/c3.css" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<link rel="stylesheet" type="text/css" href="//cdnjs.cloudflare.com/ajax/libs/c3/0.4.10/c3.min.css"/>

<link rel="stylesheet" type="text/css" href="../static/css/style.css" >
<!-- Load d3.js and c3.js -->

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.9.7/d3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/c3/0.7.2/c3.js"></script>
<script src="https://cdn.plot.ly/plotly-latest.min.js"></script>
<script src="http://code.jquery.com/jquery-latest.js"></script>

</head>

<body>

<div class="container">
    <div class="row">
        <div class="col-8">
            <div class="form-group w-50">
                <input type="text" class="form-control" id="schools" placeholder="schools" >
                <input type="text" class="form-control" id="vacations" placeholder="vacations">
            </div>
        </div>
    </div>
    <div class="row">
        <div class="col-2">
            <div class="form-group">
                <label>Instances to lookback</label>
                <select class="form-control" id="instances">
                  <option>1</option>
                  <option>2</option>
                  <option>3</option>
                  <option>4</option>
                  <option>5</option>
                </select>
            </div>
        </div>
    </div>
    <div class="row">
        <div class="col-4">
    <button id="submit" class="btn btn-primary btn-sm" type="submit" onclick=build('chart') >Generate</button>
        <div class="spinner-border spinner-border-sm d-none text-light" role="status" aria-hidden="true" id="spin0"></div>
        </div>
    </div>
</div>
<div class="container">
    <div class="row">
        <div class="col-md-12">
            <div id="event_chart"></div>
        </div>
    </div>
    <div class="row">
        <div class="col-md-6">
            <div id="event_chart2"></div>
        </div>
        <div class="col-md-6">
            <div id="event_chart3"></div>
        </div>
    </div>
    <div class="row">
        <div class="col-md-6">
            <div id="event_chart4"></div>
        </div>
        <div class="col-md-6">
            <div id="event_chart5"></div>
        </div>
    </div>
</div>


<script type="text/javascript" src="../static/js/chart.js"></script>
<script src="http://code.jquery.com/ui/1.10.2/jquery-ui.js" ></script>


</body>
</html>

问题是我得到了一个

“类型错误:字符串索引必须是整数”

字典上。奇怪的是，尽管有这个错误，字典似乎没问题，我可以访问(键，值)——我只是在我的 flask 控制台中得到了那个类型错误。

这是显示数据和错误的 Flask 控制台日志:

 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 125-816-613
STEP 1STEP 1

query: chart
query: {u'data_to_pass': [u'', u'', u'1'], u'page': u'project'}
STEP 2
project {u'data_to_pass': [u'', u'', u'1'], u'page': u'project'}
127.0.0.1 - - [12/Jul/2019 10:35:51] "POST /python_portal HTTP/1.1" 200 -
127.0.0.1 - - [12/Jul/2019 10:35:51] "POST /python_portal HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 2328, in __call__
    return self.wsgi_app(environ, start_response)
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 2314, in wsgi_app
    response = self.handle_exception(e)
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 1760, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 2311, in wsgi_app
    response = self.full_dispatch_request()
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 1834, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 1737, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 1832, in full_dispatch_request
    rv = self.dispatch_request()
  File "/data/4/dfs/eqo/env/envs/py2/lib/python2.7/site-packages/flask/app.py", line 1818, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/ssohn/py/projects/flask_error/app.py", line 24, in python_portal
    page = request_data['page']
TypeError: string indices must be integers

最佳答案

发布一个答案，因为这不适合评论。

根据输出，有时 request.get_json('data') 会返回一个字符串(例如“chart”)。
我不知道为什么会这样，所以我建议解决这个问题，将函数更改为:

@app.route('/python_portal', methods=['GET', 'POST'])
def python_portal():

    if request.method == "POST":
        print 'STEP 1'
        request_data = request.get_json('data')
        print "query: %s" % request_data
        if isinstance(request_data, (dict,)):
            page = request_data['page']
            payload = request_data['data_to_pass']
            print 'STEP 2'
            print page, request_data
        return "Python portal - POST"
    # ...

关于Javascript Ajax 到 Flask request.get_json : TypeError: string indices must be integers，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57008276/

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