DBHomework/removebooktype.cpp

#include "Session.h"
#include "Util.h"
#include "json.hpp"
#include "jsonfail.h"
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 string& detail="")
    {
        j["success"]=0;
        j["errcode"]=errcode;
        j["errmsg"]=string(GetErrMsg(errcode))+" : "+detail;
    };

    do
    {
        if(!se.isReady()||se.isNew()||se.getUser().empty())
        {
            jsonfail(err_need_login);
            break;
        }

        if(req.requestMethod!="POST")
        {
            jsonfail(err_method_not_supported);
            break;
        }

        if(req.post["booktype"].empty())
        {
            jsonfail(err_missing_parameter);
            break;
        }

        postval(booktype);

        /// Connect DB
        DBInfo db;
        MySQLConn conn;
        if(db.readConfig()<0)
        {
            jsonfail(err_config);
            break;
        }

        if(db.connectProxy(conn)<0)
        {
            jsonfail(err_connect);
            break;
        }

        /// Check Permission
        int permission_level;
        if(conn.exec(make_str("select permission_level from bs_user where username='",
                              se.getUser(),
                              "'"),
                     [&](MySQLResult& res)
                     {
                         res.stepRow([&](char** val,unsigned long* len)
                                     {
                                         permission_level=ParseInt(val[0]);
                                    });
                    })<0)
        {
            jsonfail(err_sql,"Step 1");
            break;
        }

        if(permission_level>1)
        {
            /// Permission Denied.
            jsonfail(err_permission_denied);
            break;
        }

        /// Check if correct
        int countvalue;
        if(conn.exec(make_str("select count(book_type) from bs_booktype where book_type='",
                              booktype,
                              "'"),
                     [&](MySQLResult& res)
                     {
                         res.stepRow([&](char** val,unsigned long* len)
                                     {
                                         countvalue=ParseInt(val[0]);
                                     });
                     })<0)
        {
            jsonfail(err_sql,"Step 2");
            break;
        }

        if(countvalue!=1)
        {
            jsonfail(err_data,"value incorrect");
            break;
        }

        /// Check ref
        int count_ref;
        if(conn.exec(make_str("select count(book_type) from bs_book where book_type='",
                              booktype,
                              "'"),
                     [&](MySQLResult& res)
                     {
                         res.stepRow([&](char** val,unsigned long* len)
                                     {
                                         count_ref=ParseInt(val[0]);
                                     });
                     })<0)
        {
            jsonfail(err_sql,"Step 3");
            break;
        }

        if(count_ref!=0)
        {
            jsonfail(err_data,"value reference count not equals 0");
            break;
        }

        /// Do delete
        if(conn.exec(make_str("delete from bs_booktype where book_type='",
                              booktype,
                              "'"),nullptr)<0)
        {
            jsonfail(err_sql,"Step 4");
            break;
        }

        if(conn.getAffectedRows()!=1)
        {
            jsonfail(err_sql_logic,"Affected rows not equals 1");
            break;
        }

        /// Success
        j["success"]=1;

    }while(0);

    res.content.append(j.dump());
    res.show();

    return 0;
}