Django Auxiliary technology Summary [static files, middleware, upload pictures, pagination case]

Static file settings static file Overview:

CSS files used in Web pages , JS files and pictures are called static files.

Setup process:

1. Create a static folder in the project directory
2. Create the Js,css,img folder in the created folder separately
3. Make the following configuration in the setting.py file

Staticfiles_dirs = [Os.path.join (base_dir, ' static ')]  # Sets the physical address of the static file

1. Set the static file path

Static_url = '/abc/'  # and the physical directory is the corresponding relationship, the logical concept

Methods of dynamically acquiring Static_url

• To load a path in a template file

{% load staticfiles%}

• The address of the picture is written

# These two effects are the same

• Eventually rendered in the browser:

Dynamically get Static_url address <br>

Summary :

• /abc/img/mm.jpg hides the directory where the server-side actually saves files
• When static_url = '/abc/' This path is set to/abc/when the picture is loaded, it will go to the physical address Staticfiles_dirs set the project to find, the path of the lookup starts from the IMG folder

Middleware

Click to view middleware in detail: http://www.crazyant.net/1001.html

Get the IP address of the Access browser:

Request. meta[' REMOTE_ADDR ']

Role: Restricts browser user access to the server based on specified IP

Custom middleware Classes

1. Create middleware.py in the app's directory
2. Create middleware functions in this file--class
3. Configure the middleware middleware_classes inside the setting.py to add

Function Call Order Description:

• __INIT__--Service start accepts the first URL request call
• Process_request--Generate Request object, URL match before calling
• After the Prosess_view--url matches, the view function is called before the
• Prosess_response---Call after the view function call is complete and the content is returned to the browser before calling
• Prosess_exception-Called when an exception occurs inside a view function

Attention

Call Order: When there are multiple exception classes, they are all called, and the order of invocation is the opposite of the registration order

classblockedipmiddleware ():"""to create a class that blocks middleware"""    defProcess_view (self, request, Func_view, *view_args, * *View_kwargs):"""is called before the function call after the URL configuration ."""Addr= Request. meta['REMOTE_ADDR']        ifAddr = ='127.0.0.1':            returnHttpResponse ('Middleware block!!!')

block IP Case Code

classtestmiddleware ():"""creating a middleware class for testing"""    def __init__(self):Print('----init----')    defprocess_request (self, request):Print('----process_request----')        #return HttpResponse ('--process_request--')    defProcess_view (self, request, View_func, *view_args, * *View_kwargs):Print('----Process_view----')        #return HttpResponse ('--process_view--')    defProcess_response (self, request, response):Print('----process_response----')        #return HttpResponse ('--process_response--hello--kay--')        returnResponse#If the HttpResponse object is returned in the process of executing the middleware, it will call        #process_response () This function        #whenever a Httpresponsedui object is returned, it is called

Middleware Function Code

class Exceptiontestmiddleware (object):     """ Exception Middleware Class """    def process_exception (self, request, exception):         Print ('----exception_1----')         Print (Exception)     # The parameter exception returns an exception object

exception middle class codeUpload photo configuration upload picture process:

• Make the following configuration in setting.py:

Media_root=os.path.join (Base_dir, "Static/media")

• Create a media folder under the static path
• Create a Booktest folder under the Media folder you created to save photos uploaded from views in the Booktest app
• To create a model class that contains pictures

Class Pictest (models. Model): "" "    Create the Mode class" "That uploads the picture" "    gpic = models. ImageField (upload_to= ' booktest ')  # Specify the path to upload pictures

　

 fromDjango.confImportSettingsdefupload_action (Request):"""functions for uploading pictures"""    #1. Accept the uploaded filepic = Request. Files.get ('pic')    #print (pic.chunks)    #2. Path of stitching SaveSave_path ="%s/booktest/%s"%(settings. Media_root, Pic.name)#3. Open File    #save_file = open (Save_path, ' WB ')    #save_file.close ()    #4. Quick MethodWith open (Save_path,'WB') as Sava_file:#5. The content passed in is chunked, so you have to traverse the write         forFileinchpic.chunks ():#6. Write Datasava_file.write (file)#Save to databasep =pictest () p.gpic='booktest/%s'%pic.name p.save ()returnHttpResponse ('OK')

Upload a picture view in code

<form action= "/upload_action/" method= "post" enctype= "Multipart/form-data" >    {% csrf_token%}     <input type= "file" name= "pic" >    <input type= "Submit" value= "Upload" ></form>

upload a photo template in code

def use_pic (Request):     """ use a local picture    of the database 1. Find the path of the photo corresponding to the image from the data    2. Return to HTTP page    3. Load     "    " "in http page = PicTest.objects.get (id=1)    print(pic_path.gpic)    return ' booktest/use_pic.html ', {"pic_path": Pic_path.gpic})

using the code in the uploaded photos view

use the code in the uploaded photo templatePage out

Django provides classes for data paging, which are defined in django/core/paginator.py. The Paginator object is used to perform a paging operation on a column of n data. The object page is used to represent the data on page m.

Paginator Object

• Method init (list, int): Returns the paging object, the parameter is the list data, the number of bars per polygon.
• Property Count: Returns the total number of objects.
• Property Num_pages: Returns the total number of pages.
• Property Page_range: Returns a list of page numbers, starting with 1, for example [1, 2, 3, 4].
• Method page (M): Returns the Page object that represents the data for page m, with the subscript starting at 1.

Page Object

• Calling the page () method of the Paginator object returns the Page object without the need for manual construction.
• Property object_list: Returns a list of the current page objects.
• Property Number: Returns the current page, starting at 1.
• Property Paginator: The Paginator object that corresponds to the current page.
• Method Has_next (): Returns True if there is a next page.
• Method Has_previous (): Returns True if there is a previous page.
• Method Len (): Returns the number of current page objects.
• Iterate Page objects: Access each object in the current page.

defShow_prov (Request, index):"""Show all provincial area 1. Create a Paged object 2. Gets the contents of the first Page 3. Gets all page number content displayed on the HTML page 4. Process Click to update the displayed content"""areas= AreaInfo.objects.filter (aparent__isnull=True)#areas pagination content every 10 pages create a paginated objectPaginator = paginator (areas, 10)    #How many page numbers are there in total?Page_list =Paginator.page_range#get the contents of the first page    #determine if the URL is Show_prov and the number is empty so make a judgment if it is empty, the first page is displayed.    if  notIndex:index= 1page=paginator.page (Index)#The next page of the number of children    #Pass the page number of the next page to the templatenext_index = Int (index) + 1#to pass the page number of the previous page to a templateprevious_index = Int (index)-1returnRender (Request,'booktest/page_test.html', {'page': page,'page_list': Page_list,"Next_index": Next_index,'Previous_index': Previous_index})

code in Paging view

<body><ul>    {% forAreainchPage%}        <li>{{area.atitle}}</li> {% ENDFOR%}</ul>{# Returns True #}{if there is a next page%ifPage.has_previous%}    <a href= "/show_prov{{Previous_index}" > previous </a>{% endif%}{% forPage_indexinchPage_list%}    {% Comment%} Page.number Returns the current number of pages according to page to determine if there is another page/previous page option {% endcomment%}    {%ifPage_index = = Page.number%} {{Page_index}} {%Else%}        <a href= "/show_prov{{Page_index}}" >{{page_index}}</a> {% ENDIF%}{% ENDFOR%}{# True if there is a next page #}{%ifPage.has_next%}    <a href= "/show_prov{{next_index}" > next </a>{% endif%}</body>

code in the paging template

# location parameter optional URL (r'^show_prov (\d*)/$', Views.show_prov)

Paging URL Configuration code

Django Auxiliary technology Summary [static files, middleware, upload pictures, pagination case]