Support for multipart/form-data?

[omani]

hi,

are there any plans to support multipart/form-data uploads? I need to upload raw binary. since json is encoding it to base64 I am not only suffering from 33% more space consumption but also more cpu usage for encoding/decoding.

it would be helpful to be able to upload raw binaries with eg. multipart/form-data.

[omani]

or is there a way to post raw binary to postgrest so I can insert bytea in postgresql? this is what I actually want to do here. open a file, read bytes, make a post request with that bytes in the body (no json here, because json encodes to base64) and store it into a field type bytea.

[steve-chavez]

Right now posting raw binary is not possible in postgREST, but I think you could encode base64 in the client, post the payload in an /rpc then decode it in the procedure to finally insert it in a table, if you don't want to encode/decode base64 you could do it directly in nginx with ngx_postgres, as suggested in this previous issue #894.

[omani]

ok that works. thanks.

[steve-chavez]

I'm interested in implementing multipart/form-data as it's really convenient, so I'll reopen.

My proposal for this would be to use PostgreSQL COPY BINARY, this would make the insertion off all the bytea fields in one go and it's also very efficient.

For this we would need to:

1. Add COPY support in hasql.
2. A library for pg binary formats for all the data types(required by COPY BINARY).

2 Would be a lot of work, I don' think a ready made haskell library exists.

For anyone interested in this feature, consider supporting PostgREST development.

[alf-mindshift]

This is outside of my understanding, but I was wondering if https://github.com/nikita-volkov/postgresql-binary might be a library for pg binary formats?

[steve-chavez]

@alf-mindshift True. That would only leave adding support for COPY on hasql.

[mxk]

An alternative to an /rpc call is to define an INSERT/UPDATE trigger and use a custom header to control base64 decoding. An example is below. It would be great to have a way of uploading binary content directly.

CREATE OR REPLACE FUNCTION b64decode() RETURNS trigger AS $$
BEGIN
	IF current_setting('request.header.postgrest-encoding', TRUE) = 'base64' THEN
		new.val = decode(convert_from(new.val, 'SQL_ASCII'), 'base64');
	END IF;
	RETURN new;
END
$$ LANGUAGE plpgsql;

CREATE TRIGGER decode
	BEFORE INSERT OR UPDATE OF val
	ON my_table
	FOR EACH ROW
EXECUTE FUNCTION b64decode();