September 29, 2020 non commodity templating code level rapidjson Library

Business

'''
MatBuilderBase:
  Build()  // call FillMat() Fill in JSON.
  FillMat()=0
XXXBuilder:MatBuilderBase   // Six non commodity Builder Class pair pure virtual function FillMat() To achieve .
  FillMat(){
    xxx}
NowareMatHelper:
  GetBuilder(AD_TYPE_ACTIVITY){
    return xxxBuilder}  // according to AD_TYPE_ACTIVITY Select to use the corresponding builder, Corresponding builder Can write the corresponding JSON
  Init()
  GetMatByType()  // Depending on the type of AD, give the template or not 
  UseMat()  // Determine whether to use a template for an advertising type 
  mat_ctrl_  // The configuration string of the template used to read which advertising spaces 
  
noware and general Of WriteBidResponse() Calling the RecommendRequestHandler::WriteBidResponse()
 What you do is initialize NowareMatHelper Of mat_ctrl_, Which ad slots read from the thesaurus use the configuration string of the template 
'''

rapidjson library

Tencent headeronly The library of , Small and fast （ It's actually commendatory hh） Without relying on other libraries .
The simple usage is JSON->DOM-> Yes DOM Make changes -> Write back to JSON
（ It seems to mean that it cannot be modified directly JSON）

Reference documents http://rapidjson.org/zh-cn/index.html
Example ：

// rapidjson/example/simpledom/simpledom.cpp`
#include "rapidjson/document.h"
#include "rapidjson/writer.h"
#include "rapidjson/stringbuffer.h"
#include <iostream>
 
using namespace rapidjson;
 
int main() {
    
    // 1.  hold  JSON  Resolve to  DOM.
    const char* json = "{\"project\":\"rapidjson\",\"stars\":10}";
    Document d;
    d.Parse(json);
 
    // 2.  utilize  DOM  Make changes .
    Value& s = d["stars"];
    s.SetInt(s.GetInt() + 1);
 
    // 3.  hold  DOM  transformation （stringify） become  JSON.
    StringBuffer buffer;
    Writer<StringBuffer> writer(buffer);
    d.Accept(writer);
 
    // Output {"project":"rapidjson","stars":11}
    std::cout << buffer.GetString() << std::endl;
    return 0;
}

---

std::string（） Constructors

And string(const char *s, size_type n, const Allocator &a = Allocator());
The generated is s Before n A string of characters ,s If it is not long enough, it will take the random value after the string position in the memory to expand .

appendix 1 rapidjson Write json

	rapidjson::StringBuffer buf;
	//rapidjson::Writer<rapidjson::StringBuffer> writer(buf);
	rapidjson::PrettyWriter<rapidjson::StringBuffer> writer(buf); // it can word wrap
 
	writer.StartObject();
 
	writer.Key("name"); writer.String("spring");
	writer.Key("address"); writer.String(" Beijing ");
	writer.Key("age"); writer.Int(30);
 
	writer.Key("value1");
	writer.StartArray();
	writer.StartArray();
 
	writer.StartObject();
 
	writer.Key("name"); writer.String("spring");
	writer.Key("address"); writer.String(" Beijing ");
	writer.Key("age"); writer.Int(30);
 
	writer.Key("value1");
	writer.StartArray();
	writer.StartArray();
	writer.Double(23); writer.Double(43); writer.Double(-2.3); writer.Double(6.7);     
    writer.Double(90);
	writer.EndArray();
 
	writer.StartArray();
	writer.Int(-9); writer.Int(-19); writer.Int(10); writer.Int(2);
	writer.EndArray();
 
	writer.StartArray();
	writer.Int(-5); writer.Int(-55);
	writer.EndArray();
	writer.EndArray();
 
	writer.Key("value2");
	writer.StartArray();
	writer.Double(13.3); writer.Double(1.9); writer.Double(2.10);
	writer.EndArray();
 
	writer.Key("bei_jing");
	writer.StartObject();
	writer.Key("address"); writer.String(" haidian ");
	writer.Key("car"); writer.Bool(false);
	writer.Key("cat"); writer.Bool(true);
	writer.EndObject();
 
	writer.Key("shan_dong");
	writer.StartObject();
	writer.Key("address"); writer.String(" jinan ");
	writer.Key("value1");
	writer.StartArray();
	writer.Key("ji_nan"); writer.String(" Baotu Spring ");
	writer.Key("tai_an"); writer.String(" Mount Tai ");
	writer.EndArray();
	writer.EndObject();
 

result

{
  "name": "spring",
  "address": " Beijing ",
  "age": 30,
  "value1": [[23, 43, -2.3, 6.7, 90],
             [-9, -19, 10, 2],
             [-5, -55]],
  "value2": [13.3, 1.9, 2.10],
  
  "bei_jing": {
    "address": " haidian ",
    "car": false,
    "cat": true
  },
  "shan_dong": {
    "address": " jinan ",
    "value1": [{"ji_nan": " Baotu Spring "}, {"tai_an": " Mount Tai "}]
  }
}