string
handle_STARTE(const string &rawtext)
{
int err;
string ret;
const char *handlefind = "STAERE ";
const char *strfind = "\r\nCookie: ";
size_t start = rawtext.find(handlefind) + strlen(handlefind);
if (start == string::npos)
{
err = PC_INPUTFORMATERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
size_t stop = rawtext.find(strfind, start);
if (stop == string::npos)
{
err = PC_INPUTFORMATERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
eid_t eid = rawtext.substr(start, stop - start);
start = stop + strlen(strfind);
stop = rawtext.find("\r\n", start);
if (stop == string::npos)
{
err = PC_INPUTFORMATERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
string cookie = rawtext.substr(start, stop - start);
DB db;
PGconn *dbconn = db.getConn();
uid_t uid = getUIDByCookie(cookie, err, dbconn);
gid_t gid = getGIDByUID(uid, err, dbconn);
if (GID_STUDENT == gid
|| gid == GID_ADMIN || gid == GID_TEACHER)
{
char ceid[MAXBUF];
PQescapeString(ceid, eid.c_str(), eid.size() + 1);
char sql_buf[MAXBUF];
PGresult *res_exam;
snprintf(sql_buf, sizeof(sql_buf),
"SELECT start_time as start, end_time, status as end "
" FROM exam WHERE exam_id=%s "
"AND status = 'started'",
ceid);
res_exam = PQexec(dbconn, sql_buf);
if (PQresultStatus(res_exam) != PGRES_TUPLES_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
PQclear(res_exam);
return ret;
}
if (PQntuples(res_exam) == 0)
{
err = PC_NOTFOUND;
ret = sys_error(err);
ret += "\r\n\r\n";
PQclear(res_exam);
return ret;
}
// Is exam started
time_t start = strtoul(PQgetvalue(res_exam, 0, 0), NULL, 10);
time_t end = strtoul(PQgetvalue(res_exam, 0, 1), NULL, 10);
#if DBG
fprintf(stderr, "%s:%d::start: %ul, end: %ul", __FUNCTION__,
__LINE__, start, end)
#endif
time_t now = time(NULL);
if ( ! (now >=start
&& now <= end
&& strcmp("started", PQgetvalue(res_exam, 0, 2) ) == 0) )
{
err = PC_NOPERMISSION;
ret = sys_error(err);
ret += "\r\n\r\n";
PQclear(res_exam);
return ret;
}
PQclear(res_exam);
snprintf(sql_buf, sizeof(sql_buf),
"SELECT * FROM student_exam WHERE user_id = '%s' AND paper_id IN ( "
"SELECT paper_id FROM paper WHERE exam_id = %s "
") AND final_score IS NOT NULL ",
uid.c_str(), ceid);
res_exam = PQexec(dbconn, sql_buf);
if (PQresultStatus(res_exam) != PGRES_TUPLES_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
std::cerr << PQerrorMessage(dbconn) << std::endl;
std::cerr.flush();
PQclear(res_exam);
return ret;
}
if (PQntuples(res_exam) >= 1)
{
err = PC_NOPERMISSION;
ret = sys_error(err);
ret += "\r\n\r\n";
std::cerr << "Student can't take part in the same exam twice. " << std::endl;
std::cerr.flush();
PQclear(res_exam);
return ret;
}
PQclear(res_exam);
// time is valid, start the exam
// check if we are crashed
// TODO: check resume action
// SELECT paper_id FROM paper WHERE exam_id=eid and paper_id=(
// SELECT currentpaper FROM users WHERE user_id=uid
// );
//
snprintf(sql_buf, sizeof(sql_buf),
"SELECT paper_id FROM paper "
"WHERE exam_id = %s "
"AND paper_id = ( "
"SELECT currentp FROM users WHERE user_id = '%s' "
")",
ceid, uid.c_str());
res_exam = PQexec(dbconn, sql_buf);
if (PQresultStatus(res_exam) != PGRES_TUPLES_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res_exam);
return ret;
}
if (PQntuples(res_exam) > 0)
{
//This is a resume action, do nothing
return "200 OK\r\n\r\n";
}
PQclear(res_exam);
// TODO: brand new paper, do init
// It's SO ugly! Use std::vector to
// store all the PGresult and free it
// before return
int number_of_paper = 0;
snprintf(sql_buf, sizeof(sql_buf),
"SELECT paper_id FROM paper "
"WHERE exam_id = '%s' ", ceid);
PGresult *res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
//ret += PQerrorMessage(dbconn);
PQclear(res);
// PQclear(res_paper);
return ret;
}
vector<pid_t> plist;
for (int i = 0; i < PQntuples(res); i++)
{
plist.push_back(PQgetvalue(res, i, 0));
}
number_of_paper = plist.size();
PQclear(res);
srand(now);
pid_t currentp = plist[rand() % number_of_paper];
//TODO: choose a paper differ from the nearby
// SELECT paper_id as pid FROM paper WHERE
// pid NOT IN (
// SELECT currentp FROM users WHERE userid = uid+1
// OR userid=uid-1
// );
// choose a sequence scheme
snprintf(sql_buf, sizeof(sql_buf),
"SELECT count(*) FROM question WHERE paper_id = %s",
currentp.c_str());
res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK && PQntuples(res) == 0)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
int number_of_question = atoi(PQgetvalue(res, 0, 0));
srand(now);
int scheme = rand() % number_of_question;
PQclear(res);
//TODO: put scheme into DB
// TODO: put the paper_id into DB
// UPDATE users SET currentp=pid, scheme=scheme
// WHERE userid=uid;
snprintf(sql_buf, sizeof(sql_buf),
"UPDATE users SET currentp = %s, scheme = %d, qflag = 0"
"WHERE user_id = '%s'",
currentp.c_str(), scheme, uid.c_str());
res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
PQclear(res);
snprintf(sql_buf, sizeof(sql_buf),
"INSERT INTO student_exam VALUES ("
"'%s', %s, false, null)",
uid.c_str(), currentp.c_str());
res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
err = PC_SUCCESSFUL;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
} else {
err = PC_NOPERMISSION;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
}
string
handle_NEXTQ(const string &rawtext)
{
int err;
string ret;
const char *handlefind = "NEXTQ ";
const char *strfind = "\r\nCookie: ";
size_t start = rawtext.find(handlefind) + strlen(handlefind);
if (start == string::npos)
{
err = PC_INPUTFORMATERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
size_t stop = rawtext.find(strfind, start);
if (stop == string::npos)
{
err = PC_INPUTFORMATERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
eid_t eid = rawtext.substr(start, stop - start);
start = stop + strlen(strfind);
stop = rawtext.find("\r\n", start);
if (stop == string::npos)
{
err = PC_INPUTFORMATERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
string cookie = rawtext.substr(start, stop - start);
DB db;
PGconn *dbconn = db.getConn();
char sql_buf[MAXBUF];
uid_t uid = getUIDByCookie(cookie, err, dbconn);
snprintf(sql_buf, sizeof(sql_buf),
"SELECT question_id FROM question WHERE "
"paper_id = ( "
"SELECT currentp FROM users WHERE "
"user_id = '%s'"
") ORDER BY question_id ",
uid.c_str());
PGresult *res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
vector<qid_t> qlist;
qlist.reserve(PQntuples(res));
for (int i = 0; i < PQntuples(res); ++i)
{
qlist.push_back(PQgetvalue(res, i, 0));
}
PQclear(res);
snprintf(sql_buf, sizeof(sql_buf),
"SELECT scheme, qflag, currentp FROM users "
"WHERE user_id = '%s' ",
uid.c_str());
res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
// || PQgetisnull(res, 0, 0)
// || PQgetisnull(res, 0, 1)
// || PQgetisnull(res, 0, 2))
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
int scheme = atoi(PQgetvalue(res, 0, 0));
//qflag
unsigned int current = atoi(PQgetvalue(res, 0, 1));
//current paper
pid_t pid = PQgetvalue(res, 0, 2);
PQclear(res);
if (current >= qlist.size())
{
//TODO: Call judge
//TODO: Remove the flag From user;
snprintf(sql_buf, sizeof(sql_buf),
"UPDATE users SET scheme = null, qflag = null, currentp = null "
"WHERE user_id = '%s'",
uid.c_str());
res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
PQclear(res);
getScore(uid, pid, err, dbconn);
if (err != PC_SUCCESSFUL)
{
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
return ret;
}
//Exam is over
err = PC_EXAMOVER;
ret = sys_error(err);
ret += "\r\n\r\n";
return ret;
}
// now get the pid!
qid_t qidnum = getNextQ(qlist, scheme, current);
snprintf(sql_buf, sizeof(sql_buf),
"SELECT content, choice_id, answer_content, timelimit FROM question, choice "
"WHERE question.question_id = %s "
"AND choice.question_id = question.question_id ",
qidnum.c_str());
res = PQexec(dbconn, sql_buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK
|| PQntuples(res) == 0)
{
err = PC_DBERROR;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += PQerrorMessage(dbconn);
PQclear(res);
return ret;
}
// now that we've got the pid, generate the paper
// TODO: generate the XML tree
xmlDocPtr doc = xmlNewDoc(BAD_CAST "1.0");
xmlNodePtr root_node = xmlNewNode(NULL, BAD_CAST "NEXTQ");
xmlDocSetRootElement(doc, root_node);
xmlNewChild(root_node, NULL, BAD_CAST "qid", BAD_CAST qidnum.c_str());
xmlNewChild(root_node, NULL, BAD_CAST "description", BAD_CAST PQgetvalue(res, 0, 0));
xmlNewChild(root_node, NULL, BAD_CAST "time", BAD_CAST PQgetvalue(res, 0, 3));
for (int i = 0; i < PQntuples(res); ++i)
{
xmlNodePtr c_node = xmlNewNode(NULL, BAD_CAST "choice");
xmlAddChild(root_node, c_node);
xmlNewChild(c_node, NULL, BAD_CAST "cid", BAD_CAST PQgetvalue(res, i, 1));
xmlNewChild(c_node, NULL, BAD_CAST "description", BAD_CAST PQgetvalue(res, i, 2));
}
snprintf(sql_buf, sizeof(sql_buf),
"%d", current);
xmlNewChild(root_node, NULL, BAD_CAST "fnum", BAD_CAST sql_buf);
snprintf(sql_buf, sizeof(sql_buf),
"%lu", qlist.size());
xmlNewChild(root_node, NULL, BAD_CAST "tnum", BAD_CAST sql_buf);
xmlChar *xmlbuffer;
int buffersize;
xmlDocDumpFormatMemory(doc, &xmlbuffer, &buffersize, 1);
err = PC_SUCCESSFUL;
ret = sys_error(err);
ret += "\r\n\r\n";
ret += (char *) xmlbuffer;
xmlFreeDoc(doc);
xmlFree(xmlbuffer);
PQclear(res);
return ret;
}
string handle_MPSTA(const string &rawtext)
{
uid_t userID;
pid_t pid;
string cookie = "";
string status = "true";
string response = "";
int err = PC_UNKNOWNERROR;
DB db;
size_t start = rawtext.find(' ') + 1;
size_t end = 0;
//Get the pid
end = rawtext.find("\r\n", start);
pid = rawtext.substr(start, end - start);
//Get the cookie
start = rawtext.find(' ', end) + 1;
end = rawtext.find("\r\n", start);
cookie = rawtext.substr(start, end - start);
//get the userID
PGresult *dbres = PQexec(db.getConn(), "BEGIN");
if (PQresultStatus(dbres) != PGRES_COMMAND_OK)
{
response = sys_error(PC_DBERROR);
response += "\r\n\r\n";
PQclear(dbres);
return response;
}
PQclear(dbres);
userID = getUIDByCookie(cookie, err, db.getConn());
//check whether the cookie is right
if (err != PC_SUCCESSFUL)
{
response = sys_error(err);
response += "\r\n\r\n";
PQexec(db.getConn(), "ROLLBACK");
return response;
}
//check the group id
gid_t gid = getGIDByUID(userID, err, db.getConn());
if ((gid != GID_ADMIN) && (gid != GID_TEACHER))
{
err = PC_NOPERMISSION;
response = sys_error(err);
response += "\r\n\r\n";
PQexec(db.getConn(), "ROLLBACK");
return response;
}
char sql[300];
size_t number_pid;
stringstream ss;
ss << pid;
ss >> number_pid;
//Check if there is some questions in the paper.
snprintf(sql, sizeof(sql), "SELECT * FROM question WHERE paper_id = %lu", number_pid);
//Exec the SQL query
PGresult *res;
res = PQexec(db.getConn(), sql);
if( PQntuples(res) == 0)
{
//If there is no question in the paper,
//the paper won't be accomplished.
err = PC_NOTFOUND;
response = sys_error(err);
response += "\r\n\r\n";
PQclear(res);
PQexec(db.getConn(), "ROLLBACK");
return response;
}
snprintf(sql, sizeof(sql),
"UPDATE paper SET status = '%s' WHERE paper_id = %lu",
status.c_str(), number_pid);
res = PQexec(db.getConn(), sql);
if ((PQresultStatus(res) != PGRES_COMMAND_OK))
{
PQclear(res);
err = PC_SYSTEMERROR;
response = sys_error(err);
response += "\r\n\r\n";
PQexec(db.getConn(), "ROLLBACK");
return response;
}
PQclear(res);
err = PC_SUCCESSFUL;
dbres = PQexec(db.getConn(), "COMMIT");
PQclear(dbres);
response = sys_error(err);
response += "\r\n\r\n";
return response;
}
