Django学习笔记（二）

将创建的app配置到setting.py文件中去，app需要在settings里的INSTALLED_APPS注册

一级路由

添加一个app下的路由

创建二级路由

在app下创建一个路由文件urls.py文件

# Create your models here.
from py2neo import Graph, Node, Relationship, cypher, Path
from django.db import models
class Neo4j(models.Model):
    graph = None

    def __init__(self):
        print("create neo4j class ...")
        #self.graph = Graph("http://localhost:7474", username="neo4j", password="chang1978")

    def connectDB(self):
        self.graph = Graph(
            # "http://localhost:7474/db/data"  # py2neo 2.0.8写法
            host="127.0.0.1",  # py2neo 3写法
            user="neo4j",
            password="neo4j"
        )

    def buildNodes(self,nodeRecord):
        label = str(nodeRecord["n"].labels)[1:]

        data = {"id": str(nodeRecord["n"].identity), "label": label, "name": str(nodeRecord["n"]["name"])}
        # data = {"name": str(nodeRecord["n"]["name"]),"label": label}
        # data = {"id": str(nodeRecord["n"].identity), "label": str(nodeRecord["n"].labels),"name": str(nodeRecord["n"]["name"])}
        # data.update(nodeRecord["n"].properties)
        # data.update(nodeRecord["n"])
        return {"data": data}

    def buildEdges(self,relationRecord):
        data = {"source": str(relationRecord["r"].start_node.identity),
                "target": str(relationRecord["r"].end_node.identity),
                "relationship": relationRecord["r"]["name"]}

        return {"data": data}

    def get_graph(self,a):
        str = f'MATCH (n) where n.name="{a}"   RETURN n'

        nodes1 = list(map(self.buildNodes, self.graph.run(str).data()))
        str = f'MATCH (m)-[]->(n) where m.name="{a}" RETURN n'
        nodes2 = list(map(self.buildNodes, self.graph.run(str).data()))
        nodes = nodes1 + nodes2
        str = f'MATCH (n)-[r]->() where n.name="{a}" RETURN r '
        edges = list(map(self.buildEdges, self.graph.run(str).data()))
        # 保证中文不乱码

        datajson = {"nodes": nodes, "edges": edges}
        return datajson

在APP下创建一个模板文件templates，用于存放HTML页面模板，可以根据视图中传递的数据填充值

在Django中，视图对WEB请求进行回应
视图接收reqeust对象作为第一个参数，包含了请求的信息
视图就是一个Python函数，被定义在views.py中

Django提供了函数Render()简化视图调用模板

​
from django.shortcuts import render,HttpResponse
from .models import Neo4j
def index(request):
   neo = Neo4j()#
   neo.connectDB()#调用models.py文件里的connectDB()函数
   y=request.POST.get("disease")
   Dict = neo.get_graph(y)
   #print(Dict.keys())
   #print(type(Dict["nodes"]))
   #print(Dict["nodes"][0])
   return render(request, "index.html", {"Dict":json.dumps(Dict)})

​