Django 更新文件到数据库
项目场景：
在Django的一个小项目中，对用户和课程数据进行增删改查，使用到了文件上传的方法
问题描述：
使用了文件上传到数据库的方法，上传各种文件都没问题，但是当我更新文件到数据库时，发现只能更新数据库中的路径，静态资源文件夹中却无法更新，明明和自己写的上传方法没任何区别，就是无法更新，介绍下如何上传文件：
1.肯定是设计数据库，设计的时候upload_to这个属性必须和自己静态文件夹内路径一致，因为我默然将用户资源文件都存放在Meida静态资源文件下，关于如何配置Media，我之前提过。
2.在前端文件中写好input输入框的类型（因为遇到问题是在图片上传上，这里只放上file上传的简单代码）
<div class="form-group">
<h4>文件备注：h4>
<input type="text" id="file_title" class="form-control"
name="file_title">
<input type="file" id="file" name="file">
<span id="result">span>
div>
{# js里面的代码是将所有控件的内容都获取下来，然后再使用Ajax传送到后端 #}
var formdata = new FormData();
var request_data = $("#form").serializeArray();
$.each(request_data, function (index, data) {
formdata.append(data.name, data.value)
});
{#alert($("#file_title").val())#}
formdata.append("file", $("#file")[0].files[0]);
$.ajax({
url: "",
type: "post",
contentType: false,
processData: false,
data: formdata,
success: function (data) {
{#alert(data.user)#}
location.href = "/course_two/{{ course_id }}"
}
})
3.后端接收代码
if request.is_ajax():
form = InformationForm(request.POST)
response = {"user": None, "msg": None}
if form.is_valid():
cour = Course.objects.filter(course_id=pk).first()
teacher_id_id = cour.teacher_id_id
# 生成一条用户纪录
print("teacher_id_id", teacher_id_id)
file_title = request.POST.get("file_title")
file_upload = request.FILES.get("file")
extra = {}
if file_upload:
extra["file_url"] = file_upload
File.objects.create(teacher_id_id=teacher_id_id, file_title=file_title,
course_id_id=pk, download_count=0, **extra)
原因分析：
在搜索了关键字upload_to之后发现，创建后会默认保存到相应的文件夹路径中去，但是没有说更新会保存，那既然这样就重新创建咯，不过这样有点点麻烦，因为用户表的字段比较多，既然是重新，又得更新一些数据，思路肯定是先取出来放字典里，再删除数据库信息，然后将前端传输过来的数据覆盖到字典里，最后将字典直接创建到数据库中。
重点：但是这是一种不周全的方法，如果没有主外键关系可以这样，如果有那只能另寻他路了
解决方案：
数据库ORM model.py里面还是这样的写法
前端如下：
<form id="form">
<span class="error pull-right">span>
{% csrf_token %}
<input type="text" id="pwd" class="form-control" placeholder="输入原密码">
{% for field in c_form %}
<div class="form-group">
<label for="{{ field.auto_id }}" class="text">{{ field.label }}label>
{{ field }} <span class="error pull-right">span>
div>
{% endfor %}
<div class="form-group">
<label for="avatar" class="text">
头像
<img id="avatar_img" width="60" height="60" src="media/{{ control.avatar }}"
alt="">
label>
<input type="file" id="avatar" name="avatar">
div>
<div class="text-center">
<button type="button" class="update_bt btn btn-primary">修改button>
div>
form>
<script>
// 头像预览
$("#avatar").change(function () {
var file_obj = $(this)[0].files[0];
// 获取文件对象的路径
var reader = new FileReader();
reader.readAsDataURL(file_obj);
// 修改img的src属性 ，src=文件对象的路径
reader.onload = function () {
$("#avatar_img").attr("src", reader.result)
};
});
// 基于Ajax提交数据
$(".update_bt").click(function () {
//console.log($("#form").serializeArray());
var formdata = new FormData();
var request_data = $("#form").serializeArray();
$.each(request_data, function (index, data) {
formdata.append(data.name, data.value)
});
formdata.append("avatar", $("#avatar")[0].files[0]);
formdata.append("pwd", $("#pwd").val());
$.ajax({
url: "",
type: "post",
contentType: false,
processData: false,
data: formdata,
success: function (data) {
if (data.user) {
// 更新成功
location.href = "/login/"
} else { // 更新失败
console.log(data.msg)
$("span.error").html(data.msg);
}
}
})
})
script>
后端的结果就是：
def update(request, pk, **kwargs):
control = Control.objects.filter(id=pk).first()
response = {"user": None, "msg": None}
c_form = ControlForm(instance=control)
# print(c_form)
if request.method == 'POST' and request.is_ajax():
# 如果密码正确
if check_password(request.POST['pwd'], control.password):
try:
print(control.username, request.POST['username'])
password = make_password(request.POST['password'])
username = request.POST['username']
email = request.POST['email']
date_joined = str(request.POST['initial-date_joined']).split(" ")[0]
telephone = request.POST['telephone']
address = request.POST['address']
controls = Control.objects.filter(id=pk)# 查询结果
controls_li = controls.values_list() # 将查询到的数据存下来，因为主键是惟一的，所以肯定只能查到一条
control_dict = {}
for i in controls_li: # 将遍历出来的数据放到键值对中，确保一一对应，直接去数据库把字段拿过来
control_dict['password'] = i[0]
control_dict['last_login'] = i[1]
control_dict['is_superuser'] = i[2]
control_dict['username'] = i[3]
control_dict['first_name'] = i[4]
control_dict['last_name'] = i[5]
control_dict['email'] = i[6]
control_dict['is_staff'] = i[7]
control_dict['is_active'] = i[8]
control_dict['date_joined'] = i[9]
control_dict['id'] = i[10]
control_dict['telephone'] = i[11]
control_dict['address'] = i[12]
control_dict['role'] = i[13]
control_dict['avatar'] = i[14]
control_dict['create_time'] = i[15]
# 上面方法可能蠢了点，但是这是普通的我能想到的最直接的方法
# 下面就是判断前端是否传输了这些字段过来，如果传了就更新键值对的值
avatar_obj = request.FILES.get("avatar")
if avatar_obj:
control_dict["avatar"] = avatar_obj
if control.username != request.POST['username']:
control_dict["username"] = username
if control.email != request.POST['email']:
control_dict["email"] = email
if control.telephone != request.POST['telephone']:
control_dict["telephone"] = telephone
if control.password != request.POST['password'] and request.POST['password']:
control_dict["password"] = password
# 搞定之后就删除，然后重新根据保存好的键值对进行创建
controls.delete()
controls.create(**control_dict)
response["user"] = request.POST['username']
print('创建成功阿')
return JsonResponse(response)
except Exception as e:
response["msg"] = "请输入手机号" + str(e)
print(response["msg"], e)
return JsonResponse(response)
else:
response["msg"] = "原密码不正确"
# print(response["msg"])
return JsonResponse(response)
context = {
'control': control,
'c_form': c_form,
}
return render(request, 'lfh/update.html', context)
另一种解决思路：因为即使无法将结果传到后台，但是路径可以保存到数据库，那我们在保存到数据库之前，将图片保存到相应的路径中，就可以解决这种情况了。
if request.method == 'POST' and request.is_ajax():
# 如果密码正确
if check_password(request.POST['pwd'], control.password):
# print("*")
try:
print(control.username, request.POST['username'])
password = make_password(request.POST['password'])
username = request.POST['username']
email = request.POST['email']
date_joined = str(request.POST['initial-date_joined']).split(" ")[0]
telephone = request.POST['telephone']
address = request.POST['address']
# get的东西无法使用update
controls = Control.objects.filter(id=pk)
ddd = 'media' + os.path.join(os.path.join('media', 'avatars'), str(course[0].course_avatar))
os.remove(ddd)
# controls_li = controls.values_list()
# print("---" * 19)
# control_dict = {}
# for i in controls_li:
# control_dict['password'] = i[0]
# control_dict['last_login'] = i[1]
# control_dict['is_superuser'] = i[2]
# control_dict['username'] = i[3]
# control_dict['first_name'] = i[4]
# control_dict['last_name'] = i[5]
# control_dict['email'] = i[6]
# control_dict['is_staff'] = i[7]
# control_dict['is_active'] = i[8]
# control_dict['date_joined'] = i[9]
# control_dict['id'] = i[10]
# control_dict['telephone'] = i[11]
# control_dict['address'] = i[12]
# control_dict['role'] = i[13]
# control_dict['avatar'] = i[14]
# control_dict['create_time'] = i[15]
# 存入文件夹
avatar_obj = request.FILES.get("avatar")
extra = {}
# if avatar_obj:
# control_dict["avatar"] = avatar_obj
# if control.username != request.POST['username']:
# control_dict["username"] = username
# if control.email != request.POST['email']:
# control_dict["email"] = email
# if control.telephone != request.POST['telephone']:
# control_dict["telephone"] = telephone
# if control.password != request.POST['password'] and request.POST['password']:
# control_dict["password"] = password
if avatar_obj:
extra["avatar"] = '/avatars/' + str(avatar_obj)
img = request.FILES.get("avatar")
old_name = img.name
dir = os.path.join(os.path.join('media', 'avatars'), str(old_name))
print(dir, "---------------")
destination = open(dir, 'wb+')
for chunk in img.chunks():
destination.write(chunk)
destination.close()
if control.username != request.POST['username']:
extra["username"] = username
if control.email != request.POST['email']:
extra["email"] = email
if control.telephone != request.POST['telephone']:
extra["telephone"] = telephone
if control.password != request.POST['password'] and request.POST['password']:
extra["password"] = password
# controls.delete()
controls.update(**extra)
response["user"] = request.POST['username']
print('创建成功阿')
return JsonResponse(response)
except Exception as e:
response["msg"] = "请输入手机号" + str(e)
print(response["msg"], e)
return JsonResponse(response)
else:
response["msg"] = "原密码不正确"
# print(response["msg"])
return JsonResponse(response)
context = {
'control': control,
'c_form': c_form,
}
return render(request, 'lfh/update.html', context)