最初在Django表單中填充FileField

Question

我有一個描述網頁的模型。 source_upload字段代表網頁的屏幕截圖。

爲了添加站點對象到我的應用程序，我使用了一個基於django類CreateView。這工作得很好。

現在我試圖添加一個半自動添加網站的方式。您可以將URL傳遞給視圖，視圖會自動填充表單（並製作網頁截圖）。用戶應該能夠查看所有自動提取的字段 - 特別是自動生成的截圖圖像 - 更改它們並點擊保存按鈕以將對象添加到數據庫和圖像（如果獲得批准）添加到其最終位置。

我試圖在視圖的get_initial方法中實現這一點。除屏幕截圖 - FileField外，此功能非常有效。我在initial['source_upload']中設置的路徑未顯示在窗體的FileInput小部件的current: <link>部分中。

我怎樣才能給文件字段初始值？

---

models.py

class Site(models.Model): 

    def get_source_upload_path(instance, filename): 
     now = datetime.datetime.now() 
     return "appname/sites/{}/{}/{}/site_{}_{}".format(now.year, now.month, now.day, instance.pk, filename) 

    creationDate = models.DateTimeField(auto_now_add=True) 
    last_modifiedDate = models.DateTimeField(auto_now=True) 
    creator = models.ForeignKey('auth.User', related_name='siteCreated') 
    last_modifier = models.ForeignKey('auth.User', related_name='siteLast_modified') 

    date = models.DateTimeField(default=datetime.date.today)  
    title = models.CharField(max_length=240, blank=True) 
    body = models.TextField(max_length=3000) 

    source_url = models.URLField(blank=True) 
    source_upload = models.FileField(upload_to=get_source_upload_path, blank=True) 

    keywords = models.ManyToManyField("Keyword") 

urls.py

url(r'site/add/$', views.SiteCreate.as_view(), name='site-add'), 
url(r'site/add/(?P<source_url>[A-Za-z0-9\-._~:/\[\]@!$&\'\(\)\*\+,;=?#]+)/$', views.SiteCreate.as_view(), name='site-add-fromurl'), 

forms.py

class SiteForm(ModelForm): 
    class Meta: 
     model = Site 
     fields = ['date', 'title', 'body', 'source_url', 'source_upload', 'keywords'] 
     widgets = { 
      'keywords' : CheckboxSelectMultiple(), 
     } 

views.py

class SiteCreate(LoginRequiredMixin, CreateView): 
    model = Site 
    template_name = 'appname/site_form.html' 
    form_class = SiteForm 
    success_url = reverse_lazy('appname:index') 

    def form_valid(self, form): 
     form.instance.creator = self.request.user 
     form.instance.last_modifier = self.request.user 
     return super(SiteCreate, self).form_valid(form) 

    def get_initial(self): 
     # Get the initial dictionary from the superclass method 
     initial = super(SiteCreate, self).get_initial() 

     try: 
      #get target url from request 
      fullpath = self.request.get_full_path() 
      fullpath = fullpath.split("/") 
      fullpath, querystring = fullpath[3:-1], fullpath[-1] 
      source_domain = fullpath[2] 
      fullpath = "/".join(fullpath) 
      fullpath += querystring 

      source_url = fullpath 

      if (not source_url.startswith("http://") and not source_url.startswith("https://")): 
       print("ERROR: url does not start with http:// or https://") 
       return initial 

      # ... 
      # extract title, date & others with BeautifulSoup 
      # ... 

      #extract screenshot (is there a better way?) 
      from selenium import webdriver 
      driver = webdriver.Firefox() 
      driver.get(source_url) 
      tmpfilename = "{}_{}.png".format(get_valid_filename(source_domain), get_valid_filename(title[:30])) 
      now = datetime.datetime.now() 
      tmpfilepath_rel = "appname/sites/tmp/{}/{}/{}/{}".format(now.year, now.month, now.day, tmpfilename) 
      tmpfilepath = settings.MEDIA_ROOT + tmpfilepath_rel 

      folder=os.path.dirname(tmpfilepath) 
      if not os.path.exists(folder): 
       os.makedirs(folder) 
      driver.save_screenshot(tmpfilepath) 
      driver.quit() 

      initial = initial.copy() 
      initial['source_url'] = source_url 
      initial['title'] = title 
      initial['date'] = soup_date 
      initial['body'] = body 
      initial['source_upload'] = tmpfilepath_rel 
     except KeyError as e: 
      print("no valid source_url found. zeige also ganz normales add/new template") 
     except IndexError as e: 
      print("no valid source_url found. zeige also ganz normales add/new template") 

     return initial 

site_form.html（用於創建和更新視圖）

{% extends "appname/base.html" %} 
{% load staticfiles %} 
{% block header %} 
    <link rel="stylesheet" type="text/css" href="{% static 'appname/model_forms.css' %}" /> 
{% endblock %} 
{% block body %} 
     <form enctype="multipart/form-data" action="" method="post">{% csrf_token %} 

      <div class="fieldWrapper"> 
       <div class="error">{{ form.date.errors }}</div> 
       <div class="label">{{ form.date.label_tag }}</div> 
       <div class="field">{{ form.date }}<br />{{ form.date.help_text }}</div> 
       <div class="floatclear"></div> 
      </div> 
      <div class="fieldWrapper"> 
       <div class="error">{{ form.title.errors }}</div> 
       <div class="label">{{ form.title.label_tag }}</div> 
       <div class="field">{{ form.title }}<br />{{ form.title.help_text }}</div> 
       <div class="floatclear"></div> 
      </div> 
      <div class="fieldWrapper"> 
       <div class="error">{{ form.body.errors }}</div> 
       <div class="label">{{ form.body.label_tag }}</div> 
       <div class="field">{{ form.body }}<br />{{ form.body.help_text }}</div> 
       <div class="floatclear"></div> 
      </div> 
      <div class="fieldWrapper"> 
       <div class="error">{{ form.source_url.errors }}</div> 
       <div class="label">{{ form.source_url.label_tag }}</div> 
       <div class="field">{{ form.source_url }}<br />{{ form.source_url.help_text }}</div> 
       <div class="floatclear"></div> 
      </div> 
      <div class="fieldWrapper"> 
       <div class="error">{{ form.source_upload.errors }}</div> 
       <div class="label">{{ form.source_upload.label_tag }}</div> 
       <div class="field">{{ form.source_upload }}<br />{{ form.source_upload.help_text }}</div> 
       <div class="floatclear"></div> 
      </div> 
      <div class="fieldWrapper"> 
       <div class="error">{{ form.keywords.errors }}</div> 
       <div class="label">{{ form.keywords.label_tag }}</div> 

       <div class="field"> 
        <ul class="checkbox-grid"> 
         {% for kw in form.keywords %} 
          <li> 
           {{ kw.tag }} 
           <label for="{{ kw.id_for_label }}"> 
            {{ kw.choice_label }} 
           </label> 
          </li> 
         {% endfor %} 
        </ul> 
        <div class="checkbox_help_text"><br />{{ form.keywords.help_text }}</div> 
       </div> 
       <div class="floatclear"></div> 
      </div> 
      <input type="submit" value="Save" /> 
     </form> 
     <div id="ObjectHistory"> 
      {% if site.pk %} 
       <p>Created by: {{ site.creator }}</p> 
       <p>Created on: {{ site.creationDate }}</p> 
       <p>Last modified by: {{ site.last_modifier }}</p> 
       <p>Last modified on: {{ site.last_modifiedDate }}</p> 
       <p>Now: {% now "Y-m-d H:i:s" %} <a href="{% url 'appname:site-delete' site.pk %}"><button>delete</button></a></p> 
      {% else %} 
       <p>This is a new Site!</p> 
       <p>Now: {% now "Y-m-d H:i:s" %}</p> 
      {% endif %} 
     </div> 
{% endblock %} 

Answer 1

這是因爲FileField字段的值，如用你的形式，不僅僅是文件的路徑 - 它是FieldFile的一個實例（請參閱https://docs.djangoproject.com/en/1.10/ref/models/fields/#django.db.models.fields.files.FieldFile）。

我不確定是否可以直接實例化FieldFile，但至少可以通過實例化模型來實現（不需要保存它）。

在views.py：

tmp_site = Site(source_upload=tmpfilepath_rel) 
initial['source_upload'] = tmp_site.source_upload 

另外，您可以渲染HTML時手動添加鏈接到文件：

<div class="currently"><a href="{{ form.source_upload.value }}">{{ form.source_upload.value }}</a></div>