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Use libsqlite3 directly from Python with ctypes: without using the built-in sqlite3 Python package, and without compiling anything
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| # From https://stackoverflow.com/a/68876046/1319998, which is itself inspired by https://stackoverflow.com/a/68814418/1319998 | |
| from contextlib import contextmanager | |
| from collections import namedtuple | |
| from ctypes import cdll, byref, string_at, c_char_p, c_int, c_double, c_int64, c_void_p | |
| from ctypes.util import find_library | |
| from sys import platform | |
| def query(db_file, sql, params=()): | |
| libsqlite3 = cdll.LoadLibrary(find_library('sqlite3')) | |
| libsqlite3.sqlite3_errstr.restype = c_char_p | |
| libsqlite3.sqlite3_errmsg.restype = c_char_p | |
| libsqlite3.sqlite3_column_name.restype = c_char_p | |
| libsqlite3.sqlite3_column_double.restype = c_double | |
| libsqlite3.sqlite3_column_int64.restype = c_int64 | |
| libsqlite3.sqlite3_column_blob.restype = c_void_p | |
| libsqlite3.sqlite3_column_bytes.restype = c_int64 | |
| SQLITE_ROW = 100 | |
| SQLITE_DONE = 101 | |
| SQLITE_TRANSIENT = -1 | |
| SQLITE_OPEN_READWRITE = 0x00000002 | |
| bind = { | |
| type(0): libsqlite3.sqlite3_bind_int64, | |
| type(0.0): libsqlite3.sqlite3_bind_double, | |
| type(''): lambda pp_stmt, i, value: libsqlite3.sqlite3_bind_text(pp_stmt, i, value.encode('utf-8'), len(value.encode('utf-8')), SQLITE_TRANSIENT), | |
| type(b''): lambda pp_stmt, i, value: libsqlite3.sqlite3_bind_blob(pp_stmt, i, value, len(value), SQLITE_TRANSIENT), | |
| type(None): lambda pp_stmt, i, _: libsqlite3.sqlite3_bind_null(pp_stmt, i), | |
| } | |
| extract = { | |
| 1: libsqlite3.sqlite3_column_int64, | |
| 2: libsqlite3.sqlite3_column_double, | |
| 3: lambda pp_stmt, i: string_at( | |
| libsqlite3.sqlite3_column_blob(pp_stmt, i), | |
| libsqlite3.sqlite3_column_bytes(pp_stmt, i), | |
| ).decode(), | |
| 4: lambda pp_stmt, i: string_at( | |
| libsqlite3.sqlite3_column_blob(pp_stmt, i), | |
| libsqlite3.sqlite3_column_bytes(pp_stmt, i), | |
| ), | |
| 5: lambda pp_stmt, i: None, | |
| } | |
| def run(func, *args): | |
| res = func(*args) | |
| if res != 0: | |
| raise Exception(libsqlite3.sqlite3_errstr(res).decode()) | |
| def run_with_db(db, func, *args): | |
| if func(*args) != 0: | |
| raise Exception(libsqlite3.sqlite3_errmsg(db).decode()) | |
| @contextmanager | |
| def get_db(db_file): | |
| db = c_void_p() | |
| run(libsqlite3.sqlite3_open_v2, db_file.encode(), byref(db), SQLITE_OPEN_READWRITE, None) | |
| try: | |
| yield db | |
| finally: | |
| run_with_db(db, libsqlite3.sqlite3_close, db) | |
| @contextmanager | |
| def get_pp_stmt(db, sql): | |
| pp_stmt = c_void_p() | |
| run_with_db(db, libsqlite3.sqlite3_prepare_v3, db, sql.encode(), -1, 0, byref(pp_stmt), None) | |
| try: | |
| yield pp_stmt | |
| finally: | |
| run_with_db(db, libsqlite3.sqlite3_finalize, pp_stmt) | |
| with \ | |
| get_db(db_file) as db, \ | |
| get_pp_stmt(db, sql) as pp_stmt: | |
| for i, param in enumerate(params): | |
| run_with_db(db, bind[type(param)], pp_stmt, i + 1, param) | |
| row_constructor = namedtuple('Row', ( | |
| libsqlite3.sqlite3_column_name(pp_stmt, i).decode() | |
| for i in range(0, libsqlite3.sqlite3_column_count(pp_stmt)) | |
| )) | |
| while True: | |
| res = libsqlite3.sqlite3_step(pp_stmt) | |
| if res == SQLITE_DONE: | |
| break | |
| if res != SQLITE_ROW: | |
| raise Exception(libsqlite3.sqlite3_errstr(res).decode()) | |
| yield row_constructor(*( | |
| extract[libsqlite3.sqlite3_column_type(pp_stmt, i)](pp_stmt, i) | |
| for i in range(0, len(row_constructor._fields)) | |
| )) |
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