Pony-pg

Pure pony PostgreSQL client. Implements a connection pool and an actor-friendly API.

Status

Large proof of concept. May be subject to heavy changes or a complete rewrite.

• Connect to the database (only clear text password)
• Connection pool stub
• Send simple raw queries (no query parameters) and fetchs raw results in text
• Pluggable password fetching
  • RawPasswordProvider: to retieve a hard coded password or a raw string
  • EnvPasswordProvider: fetch the password from the standard PGPASSWORD env var
  • The PasswordProviders can be chained

All these featurea are half-baked at the moment. Status is 'sort-of-works' with TODOs, Debug.out statements, poor logging and poor error handling. The purpose of this PoC is to experiment user-facing API and internal design alternatives.

Planned feature

Needed in the proof of concept

• Cursors (prevents from loading the entire dataset of a result)
• Prepared statements
• Codecs for values
  • binary values first
    • I prefer coding/decoding binary values than parsing text representation
  • The simple query protocol (used by raw queries) returns only text. We'll have to parse at some point.
• Binary result values
• Query parameters
  • Implemented using prepared statements, I don't want to implement escaping myself, too risky.
  • thus, raw queries are not likely to accept parameters any soon.

Later...

• More auth options (at least MD5)
• Get and set connection parameters (these are currently fetched from the server but not exposed on the API)
• Transaction Management
• Support logical decoding (I've already wrote a C/Python library for that, it's heavily asynchronous, it'll be a pleasure to do this in pony)

Roadmap

PoC

I'm currently working on prepared statements and a couple of codecs for a couple of types.

Design

Once it's done we'll have enough to start exploring designs and API. I plan to write small psql-like client and a CRUD JSON-REST web app to chalange API designs.

Release the best Postgres client library in the world.

TBD.

Usage

The API is a moving target at the moment. Please read example/main.pony. This program connects to a database (hard coded name) on localhost, using PGPASSWORD env var.

Make sure that in postgres' pg_hba.conf the authentication method is password, not md5

It can be compiled and run with:

make run

Questions

Testing: No test at the momeent. It's bad, but the code is evolving too fast. A good test suite is a must-have for the Design phase.

For any question, ask me, lisael on freenode.net. I'm never far from #ponylang