问题描述
在客户端通过AJAX发布帖子之后，我正在尝试从服务器向客户端返回json响应.
I'm trying to return a json response from server to client after client makes a post via AJAX.
就像这样，它有效:
@app.route("/test", methods=["GET", "POST"])
@login_required
def test():
if request.is_xhr:
try:
json_response = {
"result": "success"
}
except Exception as e:
err = _except(line=sys.exc_info()[-1].tb_lineno, error=e, function_name=what_func(), script_name=__file__)
json_response = {"result": "failure", "msg": err}
return jsonify(json_response)
else:
return redirect("/not-found")
return ''
如果我这样做，那就行不通了:
If I do like this, it doesn't works:
@app.route("/test", methods=["GET", "POST"])
@login_required
def test():
if request.is_xhr:
try:
_dict = {
"key1": "value1",
"key2": "value2"
}
if not "my_dict" in session:
session["my_dict"] = [_dict]
else:
session["my_dict"] = session["my_dict"] + [_dict]
session.modified = True
json_response = {
"result": "success"
}
except Exception as e:
err = _except(line=sys.exc_info()[-1].tb_lineno, error=e, function_name=what_func(), script_name=__file__)
json_response = {"result": "failure", "msg": err}
return jsonify(json_response)
else:
return redirect("/not-found")
return ''
我收到以下错误，客户端未收到json响应:
I get the following error and client doesn't receives json response:
File "~/myprojectenv/lib/python3.8/site-packages/flask/json/__init__.py", line 100, in default
return _json.JSONEncoder.default(self, o)
File "/usr/lib/python3.8/json/encoder.py", line 179, in default
raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type cycle is not JSON serializable
[2020-09-26 19:01:14,091] ERROR in app: Request finalizing failed with an error while handling an error
如果我取消拉伸:
if not "my_dict" in session:
session["my_dict"] = [_dict]
else:
session["my_dict"] = session["my_dict"] + [_dict]
session.modified = True
它再次起作用.客户端收到json响应.
It works again. Client receives json response.
推荐答案
我发现了麻烦.
检查以下功能:
@app.route("/test", methods=["GET", "POST"])
def test():
if request.is_xhr:
try:
licycle = cycle(files)
nextelem = next(licycle)
_dict = {
"sid": session["_id"],
"licycle": licycle,
"nextelem": nextelem,
"licycle2": licycle2,
"nextelem2": nextelem2,
"mon_id": _id,
"sch_id": 0
}
if not "all_submons" in session:
session["all_submons"] = [_dict]
else:
session["all_submons"] = session["all_submons"] + [_dict]
session.modified = True
all_submons.setdefault("sub_mons", []).append(_dict)
json_response = {"result": "success"}
except Exception as e:
err = _except(line=sys.exc_info()[-1].tb_lineno, error=e, function_name=what_func(), script_name=__file__)
json_response = {"result": "failure", "err": err}
finally:
try:
print("exiting...")
except Exception as e:
pass
return jsonify(json_response)
else:
return redirect("/not-found")
return ""
原因是licycle变量的类型为< class'itertools.cycle'>会话可能不接受"如您在all_submons dict变量中所见，这种类型的变量(如字典)可以接受.
The reason is that type of licycle variable is <class 'itertools.cycle'> and session "probably doesn't accepts" that type of variable like a dictionary accepts as you can see in my all_submons dict variable.
重点是:
执行不会失败._dict存储在会话中，如下所示.
The execution DOESN'T FALLS in exception. And _dict is stored on session as you can see to next.
print(f"Session before: {session}")
print(f"all_submons before: {all_submons}")
if not "all_submons" in session:
session["all_submons"] = [_dict]
else:
session["all_submons"] = session["all_submons"] + [_dict]
session.modified = True
all_submons.setdefault("sub_mons", []).append(_dict)
print(f"Session after: {session}")
print(f"all_submons after: {all_submons}\n")
您可以检查输出:
Session before: <SecureCookieSession {'_fresh': True, '_id': 'e253a950...', 'all_submons': [], 'user_id': '1'}>
all_submons before: {}
Session after: <SecureCookieSession {'_fresh': True, '_id': 'e253a...', 'all_submons': [{'sid': 'e253a95...', 'licycle': <itertools.cycle object at 0x7fc989237280>, 'nextelem': ('1a4add0f275c7275.jpg',), 'licycle2': None, 'nextelem2': None, 'mon_id': 1, 'sch_id': 0}], 'user_id': '1'}>
all_submons after: {'sub_mons': [{'sid': 'e253a...', 'licycle': <itertools.cycle object at 0x7fd6f1a17b80>, 'nextelem': ('1a4add0f275c7275.jpg',), 'licycle2': None, 'nextelem2': None, 'mon_id': 1, 'sch_id': 0}]}
我不确定会话可能不接受"那种类型的变量-< class'itertools.cycle'>
I'm not sure about session "probably doesn't accepts" that type of variable - <class 'itertools.cycle'>
但是我用其他变量创建了其他词典，但没有itertools.cycle类型，并且可以正常工作.
But I created other dictionary with others variables, without type of itertools.cycle and it worked.
这篇关于Flask-TypeError:类型为cycle的对象不可JSON序列化的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！