AJAX准备知识:JSON
什么是 JSON ？
- JSON 指的是 JavaScript 对象表示法（JavaScript Object Notation）
- JSON 是轻量级的文本数据交换格式
- JSON 独立于语言 *
- JSON 具有自我描述性，更易理解
* JSON 使用 JavaScript 语法来描述数据对象，但是 JSON 仍然独立于语言和平台。JSON 解析器和 JSON 库支持许多不同的编程语言
正确的json对象：
["one", "two", "three"]{ "one": 1, "two": 2, "three": 3 }{"names": ["张三", "李四"] }[ { "name": "张三"}, {"name": "李四"} ] 不正确的json对象：
{ name: "张三", ‘age‘: 32 } ? // 属性名必须使用双引号[32, 64, 128, 0xFFF] ?// 不能使用十六进制值{ "name": "张三", "age": undefined } ???// 不能使用undefined{ "name": "张三", ?"birthday": new Date(‘Fri, 26 Aug 2011 07:13:10 GMT‘), ?"getName": ?function() {return this.name;} ?// 不能使用函数和日期对象}stringify与parse方法
JavaScript中关于JSON对象和字符串转换的两个方法：
JSON.parse(): 用于将一个 JSON 字符串转换为 JavaScript 对象
JSON.parse(‘{"name":"wl"}‘);JSON.parse(‘{name:"wl"}‘) ; ?????// 错误JSON.parse(‘[18,undefined]‘) ; ????// 错误JSON.stringify(): 用于将 JavaScript 值转换为 JSON 字符串。
JSON.stringify({"name":"wl"})AJAX简介
AJAX（Asynchronous Javascript And XML）翻译成中文就是“异步的Javascript和XML”。即使用Javascript语言与服务器进行异步交互，传输的数据为XML（当然，传输的数据不只是XML）。
AJAX 不是新的编程语言，而是一种使用现有标准的新方法。
AJAX 最大的优点是在不重新加载整个页面的情况下，可以与服务器交换数据并更新部分网页内容。（这一特点给用户的感受是在不知不觉中完成请求和响应过程）
AJAX 不需要任何浏览器插件，但需要用户允许JavaScript在浏览器上执行。
- 同步交互：客户端发出一个请求后，需要等待服务器响应结束后，才能发出第二个请求；
- 异步交互：客户端发出一个请求后，无需等待服务器响应结束，就可以发出第二个请求。
示例
页面输入两个整数，通过AJAX传输到后端计算出结果并返回
views.py代码
from django.shortcuts import render, HttpResponsedef index(request): ???if request.method == ‘POST‘: ???????i1 = request.POST.get(‘i1‘) ???????i2 = request.POST.get(‘i2‘) ???????i3 = int(i1) + int(i2) ???????return render(request, ‘index.html‘, {‘i1‘: i1, ‘i2‘: i2, ‘i3‘: i3}) ???return render(request, ‘index.html‘)def calc(request): ???i1 = request.POST.get(‘i1‘) ???i2 = request.POST.get(‘i2‘) ???i3 = int(i1) + int(i2) ???return HttpResponse(i3)HTML代码
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Title</title></head><body><input type="text" name="i1">+<input type="text" name="i2">=<input type="text" name="i3"><button id="b1">计算</button><script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script><script> ???$(‘#b1‘).click(function () { ???????$.ajax({ ???????????url:‘/calc/‘, ???????????type:‘post‘, ???????????data:{ ???????????????i1:$(‘[name="i1"]‘).val(), ???????????????i2:$(‘[name="i2"]‘).val(), ???????????}, ???????????success:function (res) { ????????????????$(‘[name = "i3"]‘).val(res) ???????????} ???????}) ???})</script></body></html>urls.py
from app01 import viewsurlpatterns = [ ???url(r‘^admin/‘, admin.site.urls), ???url(r‘^index/‘, views.index), ???url(r‘^calc/‘, views.calc),]
参数
$.ajax({ ???url: ‘/ajax_test/‘, ??# ?提交的地址 ???type: ‘post‘, ?????????# 提交的方式 ???data: { ?????????????????# ?数据 ???????name: ‘alex‘, ???????age: 73, ???????hobby: JSON.stringify([‘大保健‘, ‘cnb‘, ‘画大饼‘]) ?#提交多个数据 ???}, ???success: function (res) { ???# 回调函数 ???????$(‘[name="ii3"]‘).val(res) ???}， ???error: function (res) { ??????#错误 ???????????????console.log(res) ???}})#viewsimport jsondef ajax_test(request): ???print(request.POST) ???# hobby = request.POST.getlist(‘hobby[]‘) ???hobby = request.POST.get(‘hobby‘) ???hobby = json.loads(hobby) ???print(hobby, type(hobby)) ???# int(‘a‘) ???return HttpResponse(‘OK‘)AJAX上传文件
urls.py
from app01 import viewsurlpatterns = [ ???url(r‘^admin/‘, admin.site.urls), ???url(r‘^index/‘, views.index), ???url(r‘^calc/‘, views.calc), ???url(r‘^upload/‘, views.upload),]
upload.html
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Title</title></head><body><input type="file" id="f1"><button id="b1">上传</button><script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script><script> ???$(‘#b1‘).click(function () { ???????var form_obj = new FormData(); #组建FormData对象 ???????form_obj.append(‘x1‘,$(‘#f1‘)[0].files[0]) ???????$.ajax({ ???????????url:‘/upload/‘, ???????????type : ‘post‘, ???????????data: form_obj, ???????????processData:false, # 不处理编码方式 ???????????contentType:false, ?#不处理contentType请求头 ???????????success:function (res) { ???????????????alert(‘ok‘) ???????????????????????????} ???????}) ???})</script></body>views.py
def upload(requset): ???if requset.is_ajax(): ???????file_obj = requset.FILES.get(‘x1‘) ???????with open(file_obj.name,‘wb‘) as f: ???????????for i in file_obj.chunks(): ???????????????f.write(i) ???return render(requset,‘upload.html‘)
AJAX通过CSRF校验
一.模板中使用csrf_token 标签
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Title</title></head><body><input type="text" name="i1">+<input type="text" name="i2">=<input type="text" name="i3"><button id="b1">计算</button><script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>{% csrf_token %}<script> ???$(‘#b1‘).click(function () { ???????$.ajax({ ???????????url:‘/calc/‘, ???????????type:‘post‘, ???????????data:{ ???????????????csrfmiddlewaretoken: ?$(‘[name="csrfmiddlewaretoken"]‘).val(), ???????????????i1:$(‘[name="i1"]‘).val(), ???????????????i2:$(‘[name="i2"]‘).val(), ???????????}, ???????????success:function (res) { ????????????????$(‘[name = "i3"]‘).val(res) ???????????} ???????}) ???})</script></body></html>二.获取请求头
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Title</title></head><body><input type="text" name="i1">+<input type="text" name="i2">=<input type="text" name="i3"><button id="b1">计算</button><script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>{% csrf_token %}<script> ???$(‘#b1‘).click(function () { ???????$.ajax({ ???????????url:‘/calc/‘, ???????????type:‘post‘, ??????????????headers:{ ??????????‘X-csrftoken‘: $(‘[name="csrfmiddlewaretoken"]‘).val(), ???????}, ???????????data:{ ???????????????i1:$(‘[name="i1"]‘).val(), ???????????????i2:$(‘[name="i2"]‘).val(), ???????????}, ???????????success:function (res) { ????????????????$(‘[name = "i3"]‘).val(res) ???????????} ???????}) ???})</script></body></html>三.文件(常用)
function getCookie(name) { ???var cookieValue = null; ???if (document.cookie && document.cookie !== ‘‘) { ???????var cookies = document.cookie.split(‘;‘); ???????for (var i = 0; i < cookies.length; i++) { ???????????var cookie = jQuery.trim(cookies[i]); ???????????// Does this cookie string begin with the name we want? ???????????if (cookie.substring(0, name.length + 1) === (name + ‘=‘)) { ???????????????cookieValue = decodeURIComponent(cookie.substring(name.length + 1)); ???????????????break; ???????????} ???????} ???} ???return cookieValue;}var csrftoken = getCookie(‘csrftoken‘);function csrfSafeMethod(method) { ???// these HTTP methods do not require CSRF protection ???return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method));}$.ajaxSetup({ ???beforeSend: function (xhr, settings) { ???????if (!csrfSafeMethod(settings.type) && !this.crossDomain) { ???????????xhr.setRequestHeader("X-CSRFToken", csrftoken); ???????} ???}});settings.py 静态文件配置
STATICFILES_DIRS = [ ???os.path.join(BASE_DIR,‘static‘)]
模板
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Title</title></head><body><input type="text" name="i1">+<input type="text" name="i2">=<input type="text" name="i3"><button id="b1">计算</button><script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script><script src="/static/js/ajax_setup.js"></script><script> ???$(‘#b1‘).click(function () { ???????$.ajax({ ???????????url:‘/calc/‘, ???????????type:‘post‘, ???????????data:{ ???????????????i1:$(‘[name="i1"]‘).val(), ???????????????i2:$(‘[name="i2"]‘).val(), ???????????}, ???????????success:function (res) { ????????????????$(‘[name = "i3"]‘).val(res) ???????????} ???????}) ???})</script></body></html>AJAX
原文地址：https://www.cnblogs.com/wanglan/p/10381396.html