【Django】【五】开发Web接口

【HTTP协议与JSON】

1. HTTP协议

特点如下：

（1）支持客户/服务器模式。

简单快速：客户向服务器请求服务时，只需传送请求方法和路径。请求方法常用的有GET、POST。每种方法规定了客户与服务器联系的类型不同。由于HTTP协议简单，使得HTTP服务器的程序规模小，因而通信速度很快。

（2）灵活：HTTP允许传输任意类型的数据对象。正在传输的类型由Content-Type标记。

（3）无连接：限制每次连接只处理一个请求。服务器处理完客户的请求，并收到客户的应答后，即断开连接。采用这种方式可节省传输时间。

（4）无状态：协议对于事物处理没有记忆能力。缺少状态意味着如果后续处理需要前面的信息，则它必须重传，这样可能导致每次连接传送的数据量增大。另一方面，在服务器不需要前面信息时它的应答就较快。

 

8.3 开发系统Web接口

8.3.1 配置接口路径

开发Web接口的访问方式与开发系统的访问方式相同， 为了进行区分， 这里设置Web接口的根目录为'/api/' 通过二级目录表示实现具体功能的接口

.../ guest/urls.py

...

from django.conf.urls import url, include
...

url(r'^api/', include('sign.urls', namespace='sign')),

在sign应用下创建urls.py 即 .../sign/urls.py 用来配置具体接口的二级目录

from django.conf.urls import url
from sign import views_if

urlpatterns = [
    # sign system interface:
    # ex: /api/add_event/
    #url(r'^add_event/', views_if.add_event, name='add_event'),
    # ex: /api/add_guest/
    #url(r'^add_guest/', views_if.add_guest, name='add_guest'),
    # ex: /api/get_event_list/
    #url(r'^get_event_list/', views_if.get_event_list, name='get_event_list'),
    # ex: /api/get_guest_list/
    #url(r'^get_guest_list/', views_if.get_guest_list, name='get_guest_list'),
    # ex: /api/user_sign/

    #url(r'^api/', include(('sign.urls', 'sign'), namespace='sign')),

]

首先 为了避免Web接口代码与views.py文件中的系统功能代码混在一起，因此需要重新在sign应用下创建views_if.py 用于Web接口的开发。
其次，这里定义的接口路径暂时还未实现，当启动项目时会引起报错，所以，需要将他们先全部注释。接下来每开发一个接口，这里就去掉一个接口的注释，直到所有接口开发完成。

8.3.2 添加发布会接口
.../sign/views_if.py 

from django.http import JsonResponse
from sign.models import Event
from django.core.exceptions import ValidationError

#添加发布会接口
def add_event(request):
    eid = request.POST.get('eid', '')
    name = request.POST.get('name', '')
    limit = request.POST.get('limit', '')
    status = request.POST.get('status', '')
    address = request.POST.get('address', '')
    start_time = request.POST.get('start_time', '')
    
    if eid == '' or name == '' or limit == '' or address == '' or start_time == '':
        return JsonResponse({'status': 10021, 'message': 'parameter error'})
    
    result = Event.objects.filter(id=eid)
    if result:
        return JsonResponse({'status': 10022, 'message': 'event id already exists'})
    
    result = Event.objects.filter(name=name)
    if result:
        return JsonResponse({'status': 10023, 'message': 'event name already exists'})
    
    if status == '':
        status = 1
        
    try:
        Event.objects.create(id=eid, name=name, limit=limit, address=address,
                             status=int(status), start_time=start_time)
    except ValidationError as e:
        error = 'start_time format error. It must be in YYYY-MM-DD HH:MM:SS format.'
        return JsonResponse({'status': 10024, 'message': error})
    
    return JsonResponse({'status': 200, 'message': 'add event success'})
    
8.3.3 查询发布会接口
.../sign/views_if.py

# 查询发布会接口
def get_event_list(request):
    eid = request.GET.get('eid', '')
    name = request.GET.get('name', '')

    if eid == '' and name == '':
        return JsonResponse({'status': 10021, 'message': 'parameter error'})

    if eid != '':
        event = {}
        try:
            result = Event.objects.get(id=eid)
        except ObjectDoesNotExist :
            return JsonResponse({'status': 10022, 'message': 'query result is empty'})
        else:
            event['name'] = result.name
            event['limit'] = result.limit
            event['status'] = result.status
            event['address'] = result.address
            event['start_time'] = result.start_time
            return JsonResponse({'status': 200, 'message': 'success', 'data': event})

    if name != '':
        datas = []
        results = Event.objects.filter(name__contains=name)
        if results:
            for r in results:
                event = {}
                event['name'] = r.name
                event['limit'] = r.limit
                event['status'] = r.status
                event['address'] = r.address
                event['start_time'] = r.start_time
                datas.append(event)
        return JsonResponse({'status': 200, 'message': 'success', 'data': datas})

    else:
        return JsonResponse({'status': 10022, 'message': 'query result is empty'})


8.3.4 添加嘉宾接口
.../ sign/views_if.py 

# 添加嘉宾接口
def add_guest(request):
    eid = request.POST.get('eid', '')
    realname = request.POST.get('realname', '')
    phone = request.POST.get('phone', '')
    email = request.POST.get('email', '')

    if eid == '' or realname == '' or phone == '':
        return JsonResponse({'status': 10021, 'message': 'parameter error'})

    result = Event.objects.filter(id=eid)
    if not result:
        return JsonResponse({'status': 10022, 'message': 'event id null'})

    result = Event.objects.get(id=eid).status
    if not result:
        return JsonResponse({'status': 10023, 'message': 'event status is not available'})

    event_limit = Event.objects.get(id=eid).limit    # 发布会限制人数
    guest_limit = Guest.objects.filter(event_id=eid) # 发布会已添加的嘉宾数

    if len(guest_limit) >= event_limit:
        return JsonResponse({'status': 10024, 'message': 'event number is full'})

    event_time = Event.objects.get(id=eid).start_time
    etime = str(event_time).split('.')[0]
    timeArray = time.strptime(etime, '%Y-%m-%d %H:%M:%S')
    e_time = int(time.mktime(timeArray))

    now_time = str(time.time())
    ntime = now_time.split('.')[0]
    n_time = int(ntime)

    if n_time >= e_time:
        return JsonResponse({'status': 10025, 'message': 'event has started'})

    try:
        Guest.objects.create(realname=realname, phone=int(phone), email=email,
                             sign=0, event_id=int(eid))
    except IntegrityError:
        return JsonResponse({'status': 10026, 'message': 'the event guest phone number repeat'})
    
    return JsonResponse({'status': 200, 'message': 'add guest success'})

8.3.5 查询嘉宾接口
.../sign/views_if.py

# 查询嘉宾接口
def get_guest_list(request):
    eid = request.GET.get('eid', '')
    phone = request.GET.get('phone', '')

    if eid == '':
        return JsonResponse({'status': 10021, 'message': 'eid cannot be empty'})

    if eid != '' and phone == '':
        datas = []
        results = Guest.objects.filter(event_id=eid)
        if results:
            for r in results:
                guest = []
                guest['realname'] = r.realname
                guest['phone'] = r.phone
                guest['email'] = r.email
                guest['sign'] = r.sign
                datas.append(guest)
            return JsonResponse({'status': 200, 'message': 'success', 'data': datas})
        else:
            return JsonResponse({'status': 10022, 'message': 'query result is empty'})

    if eid != '' and phone != '':
        guest = {}
        try:
            result = Guest.objects.get(phone=phone, event_id=eid)
        except ObjectDoesNotExist:
            return JsonResponse({'status': 10022, 'message': 'query result is empty'})
        else:
            guest['realname'] = result.realname
            guest['phone'] = result.phone
            guest['email'] = result.email
            guest['sign'] = result.sign
            return JsonResponse({'status': 200, 'message': 'success', 'data': guest})


8.发布会签到接口
.../sign/views_if.py

# 发布会签到接口
def user_sign(request):
    eid = request.POST.get('eid', '')
    phone = request.POST.get('phone', '')

    if eid == '' or phone == '':
        return JsonResponse({'status': 10021, 'message': 'parameter error'})

    result = Event.objects.filter(id=eid)
    if not result:
        return JsonResponse({'status': 10022, 'message': 'event id null'})

    result = Event.objects.get(id=eid).status
    if not result:
        return JsonResponse({'status': 10023, 'message': 'event status is not available'})

    event_time = Event.objects.get(id=eid).start_time
    etime = str(event_time).split('.')[0]
    timeArray = time.strptime(etime, '%Y-%m-%d %H:%M:%S')
    e_time = int(time.mktime(timeArray))

    new_time = str(time.time())
    ntime = new_time.split('.')[0]
    n_time = int(ntime)

    if n_time >= e_time:
        return JsonResponse({'status': 10024, 'message': 'event has started'})

    result = Guest.objects.filter(phone=phone)
    if not result:
        return JsonResponse({'status': 10025, 'message': 'user phone null'})

    result = Guest.objects.filter(event_id=eid, phone=phone)
    if not result:
        return JsonResponse({'status': 10026, 'message': 'user did not participate in the conference'})

    result = Guest.objects.get(event_id=eid, phone=phone).sign
    if result:
        return JsonResponse({'status': 10027, 'message': 'user has sign in'})

    else:
        Guest.objects.filter(event_id=eid, phone=phone).update(sign=1)
        return JsonResponse({'status': 200, 'message': 'sign success'})


8.4 编写Web接口文档