module pg import io #flag -lpq #flag linux -I/usr/include/postgresql #flag darwin -I/opt/local/include/postgresql11 #flag darwin -I/opt/homebrew/include #flag darwin -L/opt/homebrew/lib #flag windows -I @VEXEROOT/thirdparty/pg/include #flag windows -L @VEXEROOT/thirdparty/pg/win64 // PostgreSQL Source Code // https://doxygen.postgresql.org/libpq-fe_8h.html #include // for PG_VERSION_NUM, which is defined everywhere at least since PG 9.5 #include // for orm #include #include "@VMODROOT/vlib/pg/compatibility.h" pub struct DB { mut: conn &C.PGconn = unsafe { nil } } pub struct Row { pub mut: vals []string } pub struct Config { pub: host string = 'localhost' port int = 5432 user string password string dbname string } // struct C.pg_result {} struct C.pg_conn {} [typedef] pub struct C.PGresult {} [typedef] pub struct C.PGconn {} pub enum ConnStatusType { ok = C.CONNECTION_OK bad = C.CONNECTION_BAD // Non-blocking mode only below here // The existence of these should never be relied upon - they should only be used for user feedback or similar purposes. started = C.CONNECTION_STARTED // Waiting for connection to be made. made = C.CONNECTION_MADE // Connection OK; waiting to send. awaiting_response = C.CONNECTION_AWAITING_RESPONSE // Waiting for a response from the postmaster. auth_ok = C.CONNECTION_AUTH_OK // Received authentication; waiting for backend startup. setenv = C.CONNECTION_SETENV // Negotiating environment. ssl_startup = C.CONNECTION_SSL_STARTUP // Negotiating SSL. needed = C.CONNECTION_NEEDED // Internal state: connect() needed . Available in PG 8 check_writable = C.CONNECTION_CHECK_WRITABLE // Check if we could make a writable connection. Available since PG 10 consume = C.CONNECTION_CONSUME // Wait for any pending message and consume them. Available since PG 10 gss_startup = C.CONNECTION_GSS_STARTUP // Negotiating GSSAPI; available since PG 12 } [typedef] pub enum ExecStatusType { empty_query = C.PGRES_EMPTY_QUERY // empty query string was executed command_ok = C.PGRES_COMMAND_OK // a query command that doesn't return anything was executed properly by the backend tuples_ok = C.PGRES_TUPLES_OK // a query command that returns tuples was executed properly by the backend, PGresult contains the result tuples copy_out = C.PGRES_COPY_OUT // Copy Out data transfer in progress copy_in = C.PGRES_COPY_IN // Copy In data transfer in progress bad_response = C.PGRES_BAD_RESPONSE // an unexpected response was recv'd from the backend nonfatal_error = C.PGRES_NONFATAL_ERROR // notice or warning message fatal_error = C.PGRES_FATAL_ERROR // query failed copy_both = C.PGRES_COPY_BOTH // Copy In/Out data transfer in progress single_tuple = C.PGRES_SINGLE_TUPLE // single tuple from larger resultset } // fn C.PQconnectdb(const_conninfo &char) &C.PGconn fn C.PQstatus(const_conn &C.PGconn) int fn C.PQerrorMessage(const_conn &C.PGconn) &char fn C.PQexec(res &C.PGconn, const_query &char) &C.PGresult // fn C.PQgetvalue(const_res &C.PGresult, int, int) &char fn C.PQresultStatus(const_res &C.PGresult) int fn C.PQntuples(const_res &C.PGresult) int fn C.PQnfields(const_res &C.PGresult) int // Params: // const Oid *paramTypes // const char *const *paramValues // const int *paramLengths // const int *paramFormats fn C.PQexecParams(conn &C.PGconn, const_command &char, nParams int, const_paramTypes &int, const_paramValues &char, const_paramLengths &int, const_paramFormats &int, resultFormat int) &C.PGresult fn C.PQputCopyData(conn &C.PGconn, const_buffer &char, nbytes int) int fn C.PQputCopyEnd(conn &C.PGconn, const_errmsg &char) int fn C.PQgetCopyData(conn &C.PGconn, buffer &&char, async int) int // cleanup fn C.PQclear(res &C.PGresult) fn C.PQfreemem(ptr voidptr) fn C.PQfinish(conn &C.PGconn) // connect makes a new connection to the database server using // the parameters from the `Config` structure, returning // a connection error when something goes wrong pub fn connect(config Config) !DB { conninfo := 'host=${config.host} port=${config.port} user=${config.user} dbname=${config.dbname} password=${config.password}' conn := C.PQconnectdb(&char(conninfo.str)) if conn == 0 { return error('libpq memory allocation error') } status := unsafe { ConnStatusType(C.PQstatus(conn)) } if status != .ok { // We force the construction of a new string as the // error message will be freed by the next `PQfinish` // call c_error_msg := unsafe { C.PQerrorMessage(conn).vstring() } error_msg := '${c_error_msg}' C.PQfinish(conn) return error('Connection to a PG database failed: ${error_msg}') } return DB{ conn: conn } } fn res_to_rows(res voidptr) []Row { nr_rows := C.PQntuples(res) nr_cols := C.PQnfields(res) mut rows := []Row{} for i in 0 .. nr_rows { mut row := Row{} for j in 0 .. nr_cols { val := C.PQgetvalue(res, i, j) sval := unsafe { val.vstring() } row.vals << sval } rows << row } C.PQclear(res) return rows } // close frees the underlying resource allocated by the database connection pub fn (db DB) close() { C.PQfinish(db.conn) } // q_int submit a command to the database server and // returns an the first field in the first tuple // converted to an int. If no row is found or on // command failure, an error is returned pub fn (db DB) q_int(query string) !int { rows := db.exec(query)! if rows.len == 0 { return error('q_int "${query}" not found') } row := rows[0] if row.vals.len == 0 { return 0 } val := row.vals[0] return val.int() } // q_string submit a command to the database server and // returns an the first field in the first tuple // as a string. If no row is found or on // command failure, an error is returned pub fn (db DB) q_string(query string) !string { rows := db.exec(query)! if rows.len == 0 { return error('q_string "${query}" not found') } row := rows[0] if row.vals.len == 0 { return '' } val := row.vals[0] return val } // q_strings submit a command to the database server and // returns the resulting row set. Alias of `exec` pub fn (db DB) q_strings(query string) ![]Row { return db.exec(query) } // exec submit a command to the database server and wait // for the result, returning an error on failure and a // row set on success pub fn (db DB) exec(query string) ![]Row { res := C.PQexec(db.conn, &char(query.str)) return db.handle_error_or_result(res, 'exec') } fn rows_first_or_empty(rows []Row) !Row { if rows.len == 0 { return error('no row') } return rows[0] } pub fn (db DB) exec_one(query string) !Row { res := C.PQexec(db.conn, &char(query.str)) e := unsafe { C.PQerrorMessage(db.conn).vstring() } if e != '' { return error('pg exec error: "${e}"') } row := rows_first_or_empty(res_to_rows(res))! return row } // exec_param_many executes a query with the provided parameters pub fn (db DB) exec_param_many(query string, params []string) ![]Row { unsafe { mut param_vals := []&char{len: params.len} for i in 0 .. params.len { param_vals[i] = &char(params[i].str) } res := C.PQexecParams(db.conn, &char(query.str), params.len, 0, param_vals.data, 0, 0, 0) return db.handle_error_or_result(res, 'exec_param_many') } } pub fn (db DB) exec_param2(query string, param string, param2 string) ![]Row { return db.exec_param_many(query, [param, param2]) } pub fn (db DB) exec_param(query string, param string) ![]Row { return db.exec_param_many(query, [param]) } fn (db DB) handle_error_or_result(res voidptr, elabel string) ![]Row { e := unsafe { C.PQerrorMessage(db.conn).vstring() } if e != '' { C.PQclear(res) return error('pg ${elabel} error:\n${e}') } return res_to_rows(res) } // copy_expert execute COPY commands // https://www.postgresql.org/docs/9.5/libpq-copy.html pub fn (db DB) copy_expert(query string, mut file io.ReaderWriter) !int { mut res := C.PQexec(db.conn, &char(query.str)) status := unsafe { ExecStatusType(C.PQresultStatus(res)) } defer { C.PQclear(res) } e := unsafe { C.PQerrorMessage(db.conn).vstring() } if e != '' { return error('pg copy error:\n${e}') } if status == .copy_in { mut buf := []u8{len: 4 * 1024} for { n := file.read(mut buf) or { msg := 'pg copy error: Failed to read from input' C.PQputCopyEnd(db.conn, &char(msg.str)) return err } if n <= 0 { break } code := C.PQputCopyData(db.conn, buf.data, n) if code == -1 { return error('pg copy error: Failed to send data, code=${code}') } } code := C.PQputCopyEnd(db.conn, &char(0)) if code != 1 { return error('pg copy error: Failed to finish copy command, code: ${code}') } } else if status == .copy_out { for { address := &char(0) n_bytes := C.PQgetCopyData(db.conn, &address, 0) if n_bytes > 0 { mut local_buf := []u8{len: n_bytes} unsafe { C.memcpy(&u8(local_buf.data), address, n_bytes) } file.write(local_buf) or { C.PQfreemem(address) return err } } else if n_bytes == -1 { break } else if n_bytes == -2 { // consult PQerrorMessage for the reason return error('pg copy error: read error') } if address != 0 { C.PQfreemem(address) } } } return 0 }