DBHomework/old_src/addbook.cpp

#include "Session.h"
#include "Util.h"
#include "json.hpp"
using namespace std;
using json = nlohmann::json;

#define postval(NAME) string NAME=req.post[#NAME]

int main()
{
    Request req;
    Session se(req);
    Response res;
    json j;

    auto jsonfail=[&](int errcode,const std::string& errmsg)
    {
        j["success"]=0;
        j["errcode"]=errcode;
        j["errmsg"]=errmsg;
    };

    if(se.isNew()||se.getUser().empty())
    {
        jsonfail(1,"Please Login First");
    }

    if(req.requestMethod=="POST")
    {
        if(req.post["isbn"].empty() ||
           req.post["bookname"].empty() ||
           req.post["booktype"].empty() ||
           req.post["author"].empty() ||
           req.post["publisher"].empty() ||
           req.post["pubdate"].empty() ||
           req.post["status"].empty() )
        {
            jsonfail(3,"Missing parameter");
        }
        else
        {
            postval(isbn);
            postval(bookname);
            postval(booktype);
            postval(author);
            postval(publisher);
            postval(pubdate);
            postval(status);

            DBInfo db;
            if(db.readConfig()<0)
            {
                jsonfail(5,"Failed to read config");
            }
            else
            {
                MySQLConn conn;
                if(db.connectProxy(conn)<0)
                {
                    jsonfail(6,"Failed to connect DB");
                }
                else
                {
                    int counter;
                    if(conn.exec("select count(class_id) from bs_book",[&](MySQLResult& res)
                              {
                                  res.stepRow([&](char** val,unsigned long* len)
                                              {
                                                  counter=ParseInt(val[0]);
                                              });
                              })<0)
                    {
                        jsonfail(7,"Failed to execute SQL at Step 1");
                    }
                    else
                    {
                        if(counter==0)
                        {
                            /// First book, class_id = 1, goto step 3 directly.
                            if(conn.exec(make_str("insert into bs_book values (1,'",
                                                  isbn,
                                                  "','",
                                                  bookname,
                                                  "','",
                                                  booktype,
                                                  "','",
                                                  author,
                                                  "','",
                                                  publisher,
                                                  "','",
                                                  pubdate,
                                                  "',2)"),nullptr)<0)
                            {
                                jsonfail(9,"Failed to execute SQL at step 3");
                            }
                            else
                            {
                                if(conn.getAffectedRows()!=1)
                                {
                                    jsonfail(10,"Failed to execute SQL at step 4");
                                }
                                else
                                {
                                    j["success"]=1;
                                }
                            }
                        }
                        else
                        {
                            /// Try to find the max class id.
                            int maxId;
                            if(conn.exec("select max(class_id) from bs_book ",[&](MySQLResult& res)
                                         {
                                             res.stepRow([&](char** val,unsigned long* len)
                                                         {
                                                             maxId=ParseInt(val[0]);
                                                         });
                                         })<0)
                            {
                                jsonfail(8,"Failed to execute SQL at step 2");
                            }

                            /// Give new book.class_id as maxId+1
                            if(conn.exec(make_str("insert into bs_book values (",
                                                  maxId+1,
                                                  ",'",
                                                  isbn,
                                                  "','",
                                                  bookname,
                                                  "','",
                                                  booktype,
                                                  "','",
                                                  author,
                                                  "','",
                                                  publisher,
                                                  "','",
                                                  pubdate,
                                                  "',2)"),nullptr)<0)
                            {
                                jsonfail(9,"Failed to execute SQL at step 3");
                            }
                            else
                            {
                                if(conn.getAffectedRows()!=1)
                                {
                                    jsonfail(10,"Failed to execute SQL at step 4");
                                }
                                else
                                {
                                    j["success"]=1;
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    else
    {
        jsonfail(2,"Unsupported request method.");
    }

    res.content.append(j.dump());
    res.show();
    return 0;
}