Django：如何通过views.py更改值

Posted 2023-02-26

【中文标题】Django：如何通过views.py更改值

【英文标题】：Django: How can I changes values via views.py

【发布时间】：2021-09-18 23:25:16

【问题描述】：

我正在尝试制作一个“上传”页面，以便我可以使用 pd.to_sql() 将文件和进程上传到 postgres DB。所有数据已成功记录到数据库中，但无法更改“is_recorded”和“has_issue”的值。这是我目前正在处理的文件。

在上传/models.py中

from django.db import models

class Upload(models.Model):
    file_name = models.FileField(upload_to='uploads', max_length=255)
    uploaded = models.DateTimeField(auto_now_add=True)
    # When uploaded successfully
    is_recorded = models.BooleanField(default=False)
    # When it has a problem to fix
    has_issue = models.BooleanField(default=False)

    def __str__(self):
        return f'self.file_name: self.id'

在views.py中

import os

from django.shortcuts import render

from core.db_implements import upload_csv_to_DB

from upload.forms import UploadForm
from upload.models import Upload


def upload_view(request):

    error_message = None
    success_message = None

    form = UploadForm(request.POST or None, request.FILES or None)

    if form.is_valid():
        form.save()
        form = UploadForm()

        try:

            obj = Upload.objects.get(is_recorded=False)

            recorded, issue, success_message, error_message = ***upload_csv_to_DB***(obj)

            obj.is_recorded = recorded
            obj.has_issue = issue
            obj.save()
            success_message = success_message
            error_message = error_message

        except:

            error_message = 'Something went wrong.'


    context=
        'form': form,
        'success_message': success_message,
        'error_message': error_message,
    

    return render(request, 'upload/upload.html', context)

在forms.py中

from django import forms
from django.db.models import fields
from django.forms.fields import FileField
from django.forms.models import ModelFormMetaclass
from .models import Upload

class UploadForm(forms.ModelForm):

    # file_name = forms.FileField(max_length=255, label=False)

    class Meta:

        model=Upload
        fields = ('file_name',)

        widgets = 
            'file_name': forms.FileInput(
                attrs=
                    'class': 'form-control',
                
            )
        

我将获取文件对象并转换为数据帧并记录到数据库中的函数 (upload_csv_to_DB) 外包。如果成功，recorded=True 应该返回 sucess_message，但是，如果出现问题，issue=True 应该返回 error_message。无论如何，记录和问题总是错误的，并且有来自除子句“出错了。”的 error_message。请给我建议...

【参考方案1】：

我找到了原因。我没有初始化外包函数的返回值upload_csv_to_DB。将返回的值初始化为之后，一切都按预期工作。这是解决问题的代码。

在upload_csv_to_DB.py:

def upload_csv_to_DB(csv_obj):

    recorded = False
    issue = False
    success_message = None
    error_message = None

    upload_file = csv_obj.file_name.path    

    ...

    return (recorded, issue, success_message, error_message)

在views.py:

def upload_view(request):

    error_message = None
    success_message = None
    recorded =False
    issue = False

    if request.method == 'POST':

        form = UploadForm(request.POST, request.FILES)

        if form.is_valid():
            form.save()

            try:

                obj = Upload.objects.get(is_recorded=False)

                recorded, issue, success_message, error_message = upload_csv_to_DB(obj)

                obj.is_recorded = recorded
                obj.has_issue = issue
                obj.save()
                success_message = success_message
                error_message = error_message

            except:

                error_message = 'Something went wrong.'

    else:

        form = UploadForm()


    context=
        'form': form,
        'success_message': success_message,
        'error_message': error_message,
    

    return render(request, 'upload/upload.html', context)