Ryan Malloy
52259f0152
Implements end-to-end round-trip for BYTE (type 11) and TEXT (type 12)
columns. Python bytes/bytearray map to BYTE; str is auto-encoded as
ISO-8859-1 for TEXT.
Wire protocol — write side:
* SQ_BIND payload carries a 56-byte blob descriptor with size at offset
[16..19] (per IfxBlob.toIfx). NULL is byte 39=1.
* After all per-param blocks, SQ_BBIND (41) declares blob count, then
chunked SQ_BLOB (39) messages stream the actual bytes (max 1024
bytes/chunk per JDBC), terminated by zero-length SQ_BLOB.
* Then SQ_EXECUTE proceeds normally.
Wire protocol — read side:
* SQ_TUPLE returns only the 56-byte descriptor; actual bytes live in
the blobspace.
* For each BYTE/TEXT column in each row, send SQ_FETCHBLOB with the
descriptor and read SQ_BLOB chunks until zero-length terminator.
* The locator is only valid while the cursor is open — must dereference
BEFORE sending CLOSE. Doing it after returns -602 (Cannot open blob).
Server-side prerequisites (one-time setup):
1. blobspace: onspaces -c -b blobspace1 -p /path -o 0 -s 50000
2. logged DB: CREATE DATABASE testdb WITH LOG
3. config + archive:
onmode -wm LTAPEDEV=/dev/null
onmode -wm TAPEDEV=/dev/null
onmode -l
ontape -s -L 0 -t /dev/null
Without #3, JDBC fails identically to our driver with "BLOB pages can't
be allocated from a chunk until chunk add is logged". This identical
failure was the diagnostic confirmation that our protocol bytes were
correct — same server response = byte-for-byte parity.
Tests: 9 integration tests in tests/test_blob.py — single-chunk,
multi-chunk (5120 bytes), NULL, multi-row, binary-safe, TEXT roundtrip,
ISO-8859-1, NULL TEXT, mixed columns. Plus the Phase 4
test_unsupported_param_type_raises was updated since bytes is no longer
the canonical unsupported type — switched to a custom class.
Total: 53 unit + 107 integration = 160 tests.
The smart-LOB family (BLOB/CLOB) is a separate state-machine extension
deferred to Phase 9 — it uses IfxLocator + LO_OPEN/LO_READ session
protocol against sbspace, not the BBIND/BLOB stream.
informix-db
Pure-Python driver for IBM Informix IDS, speaking the SQLI wire protocol over raw sockets. No IBM Client SDK. No JVM. No native libraries.
Status
🟢 Phase 1 complete. connect() / close() work end-to-end against a real Informix server. Cursor / execute / fetch land in Phase 2.
To our knowledge this is the first pure-socket Informix driver in any language — every other Informix driver (IfxPy, the legacy informixdb, ODBC bridges, Perl DBD::Informix) wraps either IBM's CSDK or the JDBC JAR.
Quick start
import informix_db
with informix_db.connect(
host="127.0.0.1", port=9088,
user="informix", password="in4mix",
database="sysmaster", server="informix",
) as conn:
# cursor() / execute() / fetchone() arrive in Phase 2
pass
Test against the official Informix dev container
docker compose -f tests/docker-compose.yml up -d # IBM Developer Edition, pinned by digest
uv sync --extra dev
uv run pytest # 34 unit tests (no Docker needed)
uv run pytest -m integration # 6 integration tests (needs the container)
Phase 0 artifacts (still useful — they ARE the public reference)
docs/PROTOCOL_NOTES.md— byte-level wire-format reference, derived from packet captures + JDBC decompilation, validated against a real serverdocs/JDBC_NOTES.md— index into the decompiled IBM JDBC driver's wire-protocol classesdocs/DECISION_LOG.md— running rationale for protocol / auth / type decisionsdocs/CAPTURES/— socat hex-dump captures of three reference scenarios (connect, SELECT, full DML cycle)tests/reference/RefClient.java— re-runnable JDBC ground-truth client for capturing fresh traces
License
MIT.