DBHomework/addbookobject.cpp

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

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

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

        if(req.post["class_id"].empty() ||
           req.post["position"].empty() ||
           req.post["status"].empty() )
        {
            jsonfail(err_missing_parameter);
            break;
        }

        postval(class_id);
        postval(position);
        postval(status);
        postval(book_id);

        int class_id_real=ParseInt(class_id);
        if(class_id_real<0)
        {
            jsonfail(err_parameter,"Failed to parse class_id");
            break;
        }
        int status_real=ParseInt(status);
        if(status_real<0)
        {
            jsonfail(err_parameter,"Failed to parse status");
            break;
        }

        /// Connect to 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;
        }

        /// Verify class_id
        int count_val;
        if(conn.exec(make_str("select count(class_id) from bs_book where class_id=",
                              class_id_real),
                     [&](MySQLResult& res)
                     {
                         res.stepRow([&](char** val,unsigned long* len)
                                     {
                                         count_val=ParseInt(val[0]);
                                    });
                    })<0)
        {
            jsonfail(err_sql,"Step 2");
            break;
        }
        if(count_val!=1)
        {
            jsonfail(err_data,"Cannot verify class_id");
            break;
        }

        int book_id_real;
        if(!book_id.empty())
        {
            /// With book_id parameter.
            /// Parse It
            book_id_real=ParseInt(book_id);
            if(book_id_real<0)
            {
                jsonfail(err_parameter,"Failed to parse book_id");
                break;
            }

            /// Check if book_id exists.
            int count_val;
            if(conn.exec(make_str("select count(book_id) from bs_bookstatus where book_id=",
                                  book_id_real),
                         [&](MySQLResult& res)
                         {
                             res.stepRow([&](char** val,unsigned long* len)
                                         {
                                             count_val=ParseInt(val[0]);
                                        });
                        })<0)
            {
                jsonfail(err_sql,"Step 3");
                break;
            }

            if(count_val!=0)
            {
                jsonfail(err_data,"book_id conflict");
                break;
            }
        }
        else
        {
            /// Without book_id parameter
            int count_val,max_book_id;
            if(conn.exec(make_str("select count(book_id),max(book_id) from bs_bookstatus where book_id=",
                                  book_id_real),
                         [&](MySQLResult& res)
                         {
                             res.stepRow([&](char** val,unsigned long* len)
                                         {
                                             count_val=ParseInt(val[0]);
                                             max_book_id=ParseInt(val[1]);
                                        });
                        })<0)
            {
                jsonfail(err_sql,"Step 4");
                break;
            }
            if(count_val==0)
            {
                book_id_real=1;
            }
            else
            {
                book_id_real=max_book_id+1;
            }
        }

        /// Do Insert
        if(conn.exec(make_str("insert into bs_bookstatus values (",
                              book_id_real,
                              ",",
                              class_id_real,
                              ",'",
                              position,
                              "',",
                              status,
                              ")"),nullptr)<0)
        {
            jsonfail(err_sql,"Step 5");
            break;
        }

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

        j["success"]=1;

    }while(0);

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

    return 0;
}